NEWSLETTER T Collier-Cameron (St.Andrews)andco-workers when inDecemberthediscovery byAndrew Last year1999endedwithmuch excitement smoothly asthatfirstnightof thenewyear. I hopetherestofyearwill goas no problemswereexperienced onJanuary1st. successfully wellbeforethedatechangeand The telescopespassedtheirY2Ktests hasjustcommenced. the newMillennium!) As IamwritingthistheYear2000(butnot Dear Reader, This grayscale phase plot illustrates the method of Cameron et al. for detecting reflected-light detecting for al. et Cameron of method the illustrates plot phase grayscale This Message fromtheDirector signatures from extra-solar planets, using data secured with the WHT + UES in 1998 and 1999. The 1999. and 1998 in UES + WHT the with secured data using planets, extra-solar from signatures left-hand panel shows 145 residual velocity profiles of the the of profiles velocity residual 145 shows panel left-hand model of the direct starlight from the data and averaging the profiles of the the of profiles the averaging and data the from starlight direct the of model HE in the residual spectrum. The velocity scale is in the reference frame of the star, and time increases time and star, the of frame reference the in is scale velocity The spectrum. residual the in ° upward. The dotted paths indicate the velocity curve of a planet orbiting with an orbital inclination of inclination orbital an with orbiting planet a of curve velocity the indicate paths dotted The upward. simulated spectrum of a planet with 1.4 Jupiter radii and Jupiter-like reflectivity to the original spectra. original the to reflectivity Jupiter-like and radii Jupiter 1.4 with planet a of spectrum simulated 29 The simulated planet signature appears as a dark linear feature with an amplitude about 10 about amplitude an with feature linear dark a as appears signature planet simulated The (left-hand panel) and 60 and panel) (left-hand WHT Achieves First Direct Detection of an Extra-solar Planet Extra-solar an of Detection Direct First Achieves WHT mean stellar continuum level, crossing from positive to negative velocity at phase 0.5 when the planet the when 0.5 phase at velocity negative to positive from crossing level, continuum stellar mean is on the far side of the star. The planetary signature detected in the data is much weaker, because of because weaker, much is data the in detected signature planetary The star. the of side far the on is the low inclination, but would follow the velocity curve shown in the left-hand panel. The “barber’s pole” “barber’s The panel. left-hand the in shown curve velocity the follow would but inclination, low the pattern of travelling ripples lies wholly within the residual stellar profile, is wavelength independent, and independent, wavelength is profile, stellar residual the within wholly lies ripples travelling of pattern probably originates in stellar surface features (see article by Andrew Collier-Cameron on page 3). page on Collier-Cameron Andrew by article (see features surface stellar in originates probably I OF SAAC ° (right-hand panel). The right-hand panel shows the effect of adding the adding of effect the shows panel right-hand The panel). (right-hand T ELESCOPES N EWTON τ a fewmonths we hopetohavethenewIR exciting projectsforING.Most importantly,in The newyearwillbringmany activitiesand Telescope. Spectrograph (UES)ontheWilliam Herschel were obtainedwiththeUtrecht Echelle observations leadingtothisbreak-through an extrasolarplanethadbeendetected.The the press.Forfirsttimeeverlightof of theMillenniumPlanetwasannouncedto Boo system, obtained by subtracting a subtracting by obtained system, Boo ∼ No. 2,March2000 2300 spectral lines buried lines spectral 2300 G ROUP –4 of the of 1 No. 2, March 2000 THE ING NEWSLETTER

(Continued from front cover) THE ISAAC NEWTON camera, INGRID, operational on the As you see ING and the various GROUP OF TELESCOPES WHT. Secondly, if all goes according to collaborating groups have a busy and plan, this summer the Adaptive Optics exciting year ahead! system, NAOMI, will become operational The Isaac Newton Group of on the WHT with the exciting prospect In the previous newsletter I reported Telescopes (ING) consists of the of delivering an image quality that on the negotiations that were taking 4.2m William Herschel Telescope will be measured in small fractions of place with Spain to seek collaboration (WHT), the 2.5m Isaac Newton an arcsecond. It will open a completely between the ING and the Spanish Telescope (INT) and the 1.0m new toolbox for ING users, with 10-m telescope project GranTeCan. Jacobus Kapteyn Telescope (JKT), hopefully many scientific discoveries to Regretfully, too many obstacles were and is located 2,350m above sea follow. Furthermore, ING’s new Data encountered and both the Netherlands level at the Roque de Los Muchachos Acquisition System, based upon the and the UK decided to withdraw from Observatory (ORM) on the island of latest version of the San Diego controllers, the negotiating table. A possible future La Palma, Canary Islands, Spain. will be rolled out to all foci of the WHT, collaboration is not wholly excluded, The WHT is the largest telescope of and a new unit with narrow and and hopefully scientific links and its kind in Western Europe. continuous fibres for AUTOFIB should technical interests common to the see first light in 2000. And last but not GranTeCan and ING will develop into The construction, operation, and least further laser guide star trials will strong ties between our two development of the ING telescopes is be carried out to complete the study of organisations. the result of a collaboration between suitability of the skies above La Palma the United Kingdom and the for sodium laser guide star deployment. Dr René Rutten. Director, ING. Netherlands. The site is provided by Spain, and in return Spanish astronomers receive 20 per cent of The ING Board The ING Newsletter the observing time on the telescopes. The ING Board oversees the operation, The operation of the site is overseen maintenance and development of the ISSN 1575-8958 (printed version) by an International Scientific Isaac Newton Group of Telescopes, and ISSN 1575-9849 (electronic version) Committee, or Comité Científico fosters collaboration between the Legal license: TF-1959/99 Internacional (CCI). international partners. It approves annual budgets and determines the Published in Spain by THE ISAAC A further 75 per cent of the arrangements for the allocation of observing time is shared by the observing time on the telescopes. ING NEWTON GROUP OF TELESCOPES (ING). Board members are: United Kingdom and the Netherlands. Apartado 321; 38700 Santa Cruz de La On the JKT the international Prof. T de Zeeuw, Chairman – Leiden Palma; Canary Islands; Spain. collaboration embraces astronomers Dr. W Boland – NWO Telephone: +34 922 425400 from Ireland and the University of Dr. A Collier-Cameron – St Andrews Fax: +34 922 425401 Porto (Portugal). The remaining 5 Dr. A Mampaso – IAC, Tenerife URL: http://www.ing.iac.es/ per cent is reserved for large scientific Prof. M Merrifield – Nottingham projects to promote international Dr. P Murdin – PPARC Editorial team: J Méndez, R Rutten, collaboration between institutions of Prof. J Drew – London D Lennon, S Sánchez. Dr. C Vincent, Secretary - PPARC the CCI member countries. Designer: J Méndez The Instrumentation Preprinting: Gráficas El Time. The ING operates the telescopes on Tel.: +34 922 416651 behalf of the Particle Physics and Working Group Printing: Gráficas Sabater. Astronomy Research Council (PPARC) Tel.: +34 922 623555 The Instrumentation Working Group of the United Kingdom and the for ING was recently re-constituted Nederlandse Organisatie voor primarily to provide scientifically The ING Newsletter is published twice Wetenschappelijk Onderzoek (NWO) informed advice on the instrumentation a year in March and September. of the Netherlands. The Roque de programme for the ING telescopes. The Available at http://www.ing.iac.es/PR/ Los Muchachos Observatory, which IWG fulfils an important function as newsletter/ in html, pdf and postscript is the principal European northern intermediate between ING and the user format. Please send an e-mail to Javier hemisphere observatory, is operated community. IWG members are: Méndez ([email protected]) if you wish to on behalf of Spain by the Instituto receive a printed copy. Notification of Dr. R G McMahon, Chairman – de Astrofísica de Canarias (IAC). every new issue is given by e-mail using Cambridge the [INGNEWS] mailing list. More Dr. S Arribas – IAC, Tenerife Dr. G B Dalton – Oxford information on [INGNEWS] can be Dr. V S Dhillon – Sheffield found on page 28. If you wish to submit Dr. S F Green – Kent a contribution, please contact Javier Dr. K Kuijken – Groningen Méndez ([email protected]). Submission Dr. N A Walton, Secretary – ING deadlines are 15 July, and 15 January.

2 THE ING NEWSLETTER No. 2, March 2000

each echellogram. The method yields SCIENCE composite profiles of Stokes V signatures hundreds or thousands of times fainter than the direct spectrum, with signal-to-noise ratios several WHT Achieves First Direct tens of times greater than the best- exposed parts of each echellogram. We expect the reflected-light signature of Detection of an Extra-solar a close-orbiting giant planet to contain the same set of lines as its parent star, but to be 10,000 to 30,000 times Planet fainter than the direct starlight and Doppler shifted by orbital motion. We found that it should be possible to 1 1 2 Andrew Collier-Cameron , Keith Horne , Alan Penny , isolate the moving planet signature, 1 provided we could first subtract an David James accurate model of the direct starlight from the data. 1: School of Physics and Astronomy, University of St Andrews; 2: Rutherford Appleton Laboratory We selected τ Boo (Butler et al., 1997) as our first target. Being closer to its he last few years have seen objects in highly eccentric orbits is star than any of the other known huge advances in the quest to surprising. Planetary-system T “Hot Jupiters”, the giant planet discover and characterise formation is increasingly looking like orbiting τ Boo should intercept more planetary systems orbiting stars other a violent business, with dynamical starlight, and hence appear brighter than the Sun. During the 1980s, interactions between discs and in relation to its star, than any of the infrared and mm-wave observations planets producing inward orbital other known planets of its class. We revealed a high incidence of solar migration, destabilisation of orbits secured our first 4 clear nights’ system-sized dusty discs around and possibly ejection of planets into observations in 1998 April. We initially T Tauri stars and young main- interstellar space. tried to model the direct starlight sequence stars. These both confirmed using spectra of the star taken near that our own planetary system Aside from the dynamical inferior conjunction, when the originated in a flattened, rotating disc considerations, these discoveries planet’s dark side is turned toward of dust and gas, and suggested that provide exciting new challenges for us. This proved unsatisfactory: small planetary systems should be models of the interior and atmospheric night-to-night shifts in the position of commonplace around other solar-type properties of giant planets at a variety the spectrum on the detector conspired stars. The expectation was that our of distances from their parent stars. with low-level fixed-pattern noise own system would turn out to be fairly Are they like the methane brown that could not be flat-fielded out, to typical. Small rocky planets should dwarfs, with extensive sodium and give non-Gaussian noise levels greatly condense from refractory dust grains methane absorption (Sudarsky et al., in excess of photon statistics. Within in the warm inner disc. Giant planets, 1999) at optical and IR wavelengths? any given night, however, the position with cores of a few Earth masses Do they possess cloud decks of silicates of the spectrum on the detector composed of dust grains with ice and iron condensates (Marley et al., remained essentially unchanged. By mantles, could sweep up the large 1999), and if so, what optical properties constructing the template spectrum amounts of gas available in the outer would be expected of such clouds? from the sum of all spectra taken on parts of the disc. a given night, the fixed-pattern noise The idea of attempting a direct level was reduced to 10 – 20% of the The discovery by Mayor & Queloz detection grew out of work one of us photon noise. The penalty for this is (1995) of a Jupiter-mass planet (ACC) has been conducting in that, on nights when the planet is (msini=0.45MJ) in a 4.2-day orbit collaboration with Jean-Francois near quadrature and the velocity is about the star 51 Peg thus came as a Donati (Toulouse) on Zeeman-Doppler almost constant, the planet signature surprise. In the four years since then, imaging of magnetic polarity patterns gets subtracted out along with the the tally has grown to some 30 on stellar surfaces. This entails starlight. Accordingly, the best times planetary candidates detected from precise registration and subtraction to observe the planet are just before the orbital “Doppler wobbles” of their of left-and right-circularly polarized and just after superior conjunction. parent stars. Even though this echelle spectra, and the use of least- The planet is then at its brightest, its method has a selection bias toward squares deconvolution (Donati et lines are Doppler shifted well clear of high-mass planets in short-period al., 1997) to combine Stokes V profile the star’s lines, and its velocity is orbits, the existence of close-orbiting information from the thousands of changing rapidly. These considerations giant planets and longer-period absorption-line profiles recorded in dictated our observing strategy in the

3 No. 2, March 2000 THE ING NEWSLETTER

At face value, our candidate detection appears to conflict with the upper limits from 3 nights of Keck data published by Charbonneau et al. (1999), who failed to see the planet at a signal level apparently half that of our claimed detection. Part of the discrepancy results from differences in the models used by the two teams to represent the angular dependence of the planet’s reflectivity. We also understand that they did not compensate fully for the fact that some of the planet signal goes missing when you subtract out the direct light from the star. This is Figure 1. The relative probability map testing for the presence of a planetary particularly important for a tilted reflected-light signature. For each possible value of the unknown planet-to-star orbit. Together these differences ε brightness ratio , and of the planet’s projected orbit velocity Kp, darker shades between the two analyses bring the denote progressively better fits to the data. The solid curves show the 68.3%, results into agreement within their 95.4%, and 99.7% upper limits above which a planet signature can be ruled out as uncertainties. a function of Kp. The plot shows significant evidence for a planet at projected orbital velocity K =74± 3 kms -1 and face-on planet-to-star flux ratio ε=7.5±3×10 -5. p We will seek confirmation of this Since the true orbital velocity amplitude is close to 152 kms -1, the implied orbital inclination is close to 29°. In the right-hand panel, the signature of a simulated detection using the WHT in the planet with Jupiter-like reflectivity, radius 1.4 times Jupiter, and orbital inclination spring of 2000, this time targeting a 60° is detected at a high level of significance. set of orbital phases optimized for an orbital inclination near 30°. The new 1999 season, when all observations and 6100 Å. This “spectrum” is phasing will allow us to gather up to were scheduled close to superior shown in Figure 2. Curiously, the 16 times as many “useful” photons conjunction. To maximize the photon signal is only significant at from the planet, as we’ve amassed so catch on each CCD exposure, we wavelengths between about 4600 and far. If the detection survives this nodded the telescope to widen the 5000 Å, suggesting that strong more intense scrutiny, we should be spatial profile of the spectrum on the absorption features may be present. able to quadruple the spectral detector. This also allowed us to The strength of the detection in the resolution and double the S:N expose for longer without saturating 4600 to 5000 Å region suggests a relative to the existing data, giving the CCD. radius nearly twice that of Jupiter us a better chance of identifying the for plausible albedo values, and the major optical absorbing species. By the end of the 1999 season we had inclination yields a mass 8 times that amassed a total of nearly 600 spectra of Jupiter. References: in 9 clear nights of observation. The Butler, R. P., Marcy, G. W., Williams, E., S:N ratios of the deconvolved profiles Hauser, H., Shirts, P., 1997, ApJ, 474, were typically around 20,000, easily L115 sufficient to detect a planet of Jovian Charbonneau, D., Noyes, R. W., dimensions and reflectivity if seen Korzennik, S., Nisenson, P., Jha, S., fully illuminated. This allowed us to Vogt, S. S., Kibrick, R. I., 1999, ApJ, 522, L145 place strong upper limits ruling out a Jupiter-like planet in near-edge-on Collier-Cameron, A., Horne, K. D., Penny, A. J., James, D. J., 1999, Nature, 402, orbits — and produced evidence for 751 detection of a planet at an orbital Donati, J. -F., Semel, M., Carter, B., Rees, inclination of 29° (Figure 1). A detailed D. E., Collier-Cameron, A., 1997, investigation suggests a false-alarm MNRAS, 291, 658 probability of about 5% (Collier- Marley, M. S., Gelino, C., Stephens, D., Cameron et al., 1999). Lunine, J. I., Freedman, R., Sharp, C., 1999, ApJ, 513, 879 We were able to construct a crude Figure 2. The wavelength dependence of the planet-to-star brightness ratio Mayor, M., Queloz, D., 1995, Nature, 378, albedo spectrum for the planet, by 355 ε(λ) at zero phase angle for τ Boo b, measuring the strength of the planet derived from six independent subsets of Sudarsky, D., Burrows, A., Pinto, P., signature in 6 independent subsets of the echelle data. Signals are present 1999, astro-ph/9910504 ¤ the data spanning different between 4600 and 5000Å but absent at wavelength ranges between 3850 other wavelengths. A. Collier-Cameron ([email protected])

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Gamma-Ray Burst Afterglows: GRB 970508

Surprises from the Sky The first OT for which the redshift was determined was GRB 970508: z= 0.835 (Metzger et al., 1997). It P. Vreeswijk1, N. Tanvir2, T. Galama3 was also the first burst for which a radio afterglow was discovered, by 1: Astronomical Institute “Anton Pannekoek”; 2: Astronomy Research Group, Dale Frail and colleagues (Frail et University of Hertfordshire; 3: California Institute of Technology al., 1997), and the ING observations of this burst showed evidence for a he GRB field of astronomy has burst detected by one of the WFCs spectral transition (Galama et al., T experienced a cascade of came along (GRB 970228) the team 1998a). Titus Galama and co-workers astonishing discoveries and of the late Jan van Paradijs, consisting also constructed a radio to X-ray new surprises over the past three of the two former PhD students Titus spectrum at day 12 after the burst years. In this paper we discuss some Galama and Paul Groot, were ready and showed that the observations for it. They pointed the WHT towards of the highlights of GRB afterglows, can be understood in terms of the the WFC X-ray source position 21 in which the ING telescopes have relativistic blastwave (or fireball) played an important role. With the hours after the burst, and on March 8, model (see Figure 2; the R-band light new generation of GRB satellites to the INT was used for a follow-up curve of this burst is also shown). In be launched, new exciting results are image. Using these images, they this model, a huge amount of energy on their way, giving important were able to identify the first optical is dumped into a compact region, which insights into the nature of the counterpart of a GRB (van Paradijs causes a relativistically expanding progenitors of GRBs, and also into et al., 1997), which marked the blast wave that sweeps up the the high redshift universe. beginning of a revolution in our surrounding matter. The electrons in understanding of GRBs (see Figure 1). the shock are accelerated to a power- This discovery, together with that of Afterglow highlights law distribution in energy and radiate the X-ray afterglows discovered by our Italian colleagues with the synchrotron emission. The bulk of the electrons have the Lorentz factor γ GRB 970228 Narrow Field Instruments (NFIs) of m and radiate near the peak frequency BeppoSAX is among the top 5 of νm major scientific breakthroughs of (corresponding to γ ). This produces Twenty five years after the discovery m 1997, according to Science. Later of Gamma-Ray Bursts (GRBs), there the typical synchrotron spectrum HST images showed a faint nebula was still a very strong debate about shown in sections II and III of Figure 2. around the optical transient (OT), for their distances. One camp put them Section I is modified by synchrotron which Keck has now been able to in the halo of the Galaxy, the other self absorption (frequency ν ), and determine the redshift: z= 0.695. a among the most distant objects These results confirmed that GRBs section IV is located above the electron known in the universe. It was expected occur at cosmological distances and cooling frequency (νc); cooling causes that the discovery of a counterpart at together with the fluxes received at a steepening of the spectrum. As the other wavelengths would resolve this Earth, indicated that GRBs are the blast wave slows down, the peak and issue. Searches for counterparts were most powerful photon emitters in cooling frequencies move to lower not successful because the error the Universe. frequencies as a power-law in time, boxes typically had the size of several degrees. Such positions could be refined by triangulation with the Inter-Planetary Network (IPN), but the few GRBs with such accurate positions were, with hindsight, not observed rapidly enough to give a chance of detecting afterglows. With the launch of the Italian-Dutch satellite BeppoSAX (near the end of 1996), which carries two X-ray Wide Field Cameras (WFCs) on board, burst positions became available with typical error circle radii of 3 arcminutes (a factor of ∼4000 improvement in Figure 1. Discovery V band images of the first optical counterpart (GRB 970228) localisation). These positions were (van Paradijs et al., 1997). The image on the left shows the transient on February 28, made available rapidly (several hours 1997. The image on the right shows the transient on March 8, 1997. The optical after the burst). When the second transient is denoted by ‘OT’. A late-type star (K-dwarf) is also indicated.

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Figure 2. Left: The X-ray to radio spectrum of GRB 970508 on May 21.0 UT (12.1 days after the event). Three break ν ν frequencies are indicated, corresponding to synchrotron self-absorption, a , the peak, m , and the transition to rapid electron ν cooling, c (from Galama et al., 1998b). Right: Rc band light curve of GRB 970508, based on ING data. A power law fit is represented by the solid line. Indicated by the dashed line is a fit of a power law plus a constant, F = F t α+ C. Left lower R R0 panel: the fit to the power law decay subtracted from the data. Deviations from a power-law decay are only moderate (r.m.s. = 0.15 magnitudes) (from Galama et al., 1998c). which, together with the fact that the Technology Telescope (NTT). They GRB 970228, to minimise differences spectral shape is also a power-law (in were frantically looking for a faint in analysis by different groups, has distinct regions), causes a power-law stellar-like object to disappear in also found evidence for a supernova decline of the afterglow. later frames, but couldn’t find any contributing to the light curve of good candidates. As Paul was on the GRB 970228 (see Figure 5). These GRB 971214 phone with his sister, who called him findings call for accurate determination up for his birthday, Titus shouted of afterglow magnitudes, not only at out: “Hey, what’s this??? Paul, look at early times, but especially at late Using the Keck 10-m telescope, Shri this!” It appeared Titus had discovered times (∼ 20–30 days after the burst), Kulkarni and his colleagues, were the supernova SN 1998bw (see Figure 3 for which the WHT is very suitable. able to determine the redshift of the and Figure 4), which marked the The link between GRBs and SNe was counterpart of GRB 971214 at beginning of a revolution in not only z= 3.42 (Kulkarni et al., 1998; the one of the ten major breakthroughs the GRB field, but also the SN most distant GRB detected so far). in 1999 according to Science. community. With our late supervisor The implied energy output, assuming Jan van Paradijs, we very a standard cosmological model and conservatively estimated the chance GRB 990123 isotropic energy release, was an of finding a supernova in the GRB 53 amazing 3×10 erg. error box, with the time of collapse After nearly two years of afterglow around the time of the burst, and studies, GRBs continued to surprise GRB 980425 found it to be 10–4. This being so the community with the discovery of small, the notion that some GRBs the afterglow of GRB 990123. The After GRB 970228, the redshift and SNe are physically related first report was of an afterglow of determination of GRB 970508, which became fairly hard to reject (Galama R ∼18th magnitude, which was not showed that GRBs come from et al., 1998d). very unusual at around 4 hours after cosmological distances, and the the burst. However, the ROTSE team outstanding energy output of GRB Since this discovery, more evidence had slewed their robotic telescope to 971214, the GRB community was for a relation between SNe and GRBs the burst position only 20 seconds waiting for the next surprise from has been found. Josh Bloom and after the BATSE alert and when they the sky. colleagues suggested that the late- analysed their images at the reported time afterglow of GRB 980326 could position of the afterglow, they found On Sunday April 29, 1998, two of us be explained by an underlying an incredible V∼ 9th magnitude (Titus Galama and Paul Vreeswijk) SN 1998bw type supernova at a flash, i.e. somebody with binoculars were analysing images taken the redshift of about unity (Bloom et al., looking at the right part of the sky days before with the Anglo-Australian 1999). Our team, after re-analysing would have been able to see it! The Telescope (AAT) and ESO’s New just about all the available data of total isotropic energy output of this

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Figure 3. Discovery R band NTT image showing SN 1998bw in the spiral galaxy ESO 184–G82 on May 1 1998 (left) and pre-discovery (1976) UK Schmidt Telescope image of ESO 184–G82 (right) (from Galama et al. 1998d).

Figure 4. Left: UBVRI light curves of the GRB supernova SN 1998bw (GRB 980425). Time is in days since April 25.91 UT. For comparison the V band light curve of the type Ic SN 1994I is shown. Right: Representative spectra near maximum light of SN 1998bw, SN 1994I, and SN 1984L (type Ib). The overall shape of the spectrum of SN 1998bw is similar to that of a Ic supernova, although the spectral features are less pronounced (from Galama et al. 1998d).

Figure 5. The V-, Rc-, and Ic-band lightcurves of GRB 970228 (log-log plot of fluxes versus time). The dotted curves indicate power-law decays, fixed at α = –1.46, and redshifted SN light curves. The thick line is the resulting sum of SN and afterglow. This, along with similar evidence for an SN component to GRB 980326 and the connection of GRB 980425 with SN1998bw, suggests that at least some classical GRBs are associated with a class of supernovae (from Galama, Tanvir, Vreeswijk et al., 1999).

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burst beat that of GRB 971214: over 1054 erg.

Combined with the BATSE data and images taken at other telescopes, including the ING, we were able to conclude that the BATSE γ-ray burst itself, the optical flash responsible for the 9th magnitude, and the late-time afterglow, came from three distinct emission regions. Figure 6 shows that the optical flash probably smoothly connects with the late-time afterglow, which means that if OTs are caught at an early time, they may be very bright. Observations of bright afterglows should become possible with the launch of HETE-II, which will provide accurate positions of the prompt X-ray burst accompanying the GRB within a minute. Figure 6. R-band light curve of the afterglow of GRB 990123, including our WHT and INT data. The filled circles indicate results of our observations. The open GRB 990510 circles are data taken from the literature. The dashed line indicates a power law fit to the light curve (for t>0.1days), which has exponent –1.12 ± 0.03. Also included are the ROTSE data. The power law fit is extrapolated backward (from In the past year many bursts went off Galama et al., 1999). at Southern declinations. With the first unit of the Very Large Telescope in use, our team was able to determine the redshifts for three afterglows (two are actually lower limits, since only absorption features are detected and these could in principle be caused by an intervening cloud in the line of sight): GRB 990510, GRB 990712 and GRB 991216.

For GRB 990510 we also studied the evolution of the metal absorption lines (see Figure 7). We found no evidence for a change in the equivalent width of the MgII feature, suggesting that the atoms responsible for the absorption are not in the immediate vicinity of the site of the explosion (Vreeswijk et al., 1999). Future prospects

The combination of their power and their large distances, makes GRBs extremely interesting as possible probes of the high redshift Universe. When we have a vast sample of Figure 7. VLT/FORS1 spectra of the afterglow of GRB 990510, from 0.8 to 5.9 redshifts available, and we find more days after the burst, plotted over the wavelength range 3700-9300Å. Several evidence that GRBs are directly absorption features are indicated with the broken lines, putting the absorber related to the formation of massive redshift at z = 1.619 ± 0.02, which is most likely the host galaxy of the burst stars, they can be used to trace the (From Vreeswijk et al., 1999).

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star formation rate up to the very and hopefully other observatories not have been possible. Clearly, in early Universe. And just like quasars, will follow. the longer term, a move towards they can be used to study the queue /reactive scheduling will benefit chemical composition of the inter- Coming from cosmological distances, both GRB astronomers and the rest galactic medium. In several GRB GRBs have the possibility of being of the community. afterglow spectra, multiple absorption gravitationally lensed. Although this systems have been detected through possibility is estimated to be less References: the identification of redshifted UV than 0.1% (Blaes & Webster, 1992), metal lines. When these GRBs were with 3 bursts per day going off over Akerlof, C. et al., 1999, Nature, 398, 400 caught, they were typically fainter the whole sky, detecting a lensed Blaes, O. M. & Webster, R. L., 1992, ApJ, GRB is just a matter of time. With than R= 20. With the launch of 391, L63 HETE–II (expected date of launch: the clear variability that GRBs Bloom, J. S. et al., 1999, Nature, 401, 453 23 Jan. 2000), however, it will display, the time lag should be easy become possible to catch GRB to determine, and assuming a mass Frail, D. A. et al., 1997, Nature, 389, 261 afterglows when they are still very model for the lensing galaxy or Galama, T. J. et al., 1998a, ApJL, 500, L101 bright, at R ∼15–16. This is due to cluster, one will be able to estimate Galama, T. J. et al., 1998b, ApJL, 500, L97 the fact that HETE will be able to the value for H0 (as has been done Galama, T. J. et al., 1998c, ApJL, 497, L13 make an accurate position available for several lensed variable quasars). Galama, T. J. et al., 1998d, Nature, 395, 670 immediately (less than one minute), Galama, T. J., Vreeswijk, P. M., Tanvir, whereas the WFC positions of Following up GRB afterglows has N. et al., 1999, ApJ, in press BeppoSAX typically are available pushed traditional ground-based after 4 hours. At that brightness, observing into a new mode of operation Galama, T. J. et al., 1999, Nature, 398, 394 high signal-to-noise, high resolution — of frequent and substantial Kulkarni, S. R. et al., 1998, Nature, 393, 35 spectroscopy will become feasible. overrides. Thanks to the support of Kulkarni, S. R. et al., 1999, Nature, 398, 389 For some bursts it may even become the time-allocation committees and Metzger, M., et al., 1997, Nature, 387, 878 possible to catch them when they are observatory staff, and goodwill of the van Paradijs, J. et al., 1997, Nature, 386, 686 brighter than R= 10, but this large majority of observers, this has Vreeswijk, P. M. et al., 1999, ApJ, requires an automated activation actually worked very successfully. procedure of the telescopes. ESO is Without the target-of-opportunity submitted ¤ already investigating the possibilities possibility, many of the above of automated activation of the VLT, mentioned exciting discoveries would Paul Vreeswijk ([email protected]) The Sakurai Object: A Case Study in Advanced Stellar Evolution

Don Pollacco (Dept. of Physics, QUB)*

*Don worked as a Support Astronomer at ING from 1995 to 1999

n 1996 Y. Sakurai, a Japanese of the most intriguing objects in has led to new physics being I amateur astronomer, discovered stellar astrophysics and promises to developed —mass loading into a what was originally described as be a rosetta stone to our understanding stellar wind (e.g. Hartquist et al., a nova in Sagittarius. Spectroscopy of the evolution of ancient stars. 1986), with application in many other soon after discovery indicated the branches of research. Theories Sakurai Object to have a cool To understand why stellar astronomers developed to account for the odd hydrogen-deficient photosphere were excited by Sakurai’s discovery physical properties of these systems —quite unlike that of a normal nova we must review some history. Hazard explosion— and the only similar and other hydrogen deficient stars, object being Nova Aql 1919 (Lundmark, et al. (1980) discovered that the inner involved either merging binary white 1921). With the detection of a faint regions of the planetary nebula dwarfs (Webbink, 1984) or else a and ancient planetary nebula around Abell 78 had material that strongly delayed helium shell flash (Iben et the star, it was clear that this was emitted [OIII] and [NII] but emission al., 1983). This later phenomena not like a typical nova but was probably from hydrogen was absent —the results from the small possibility a highly evolved single star undergoing conclusion being that this object was that a shell flash (as experienced by some form of rather exotic evolution. hydrogen-deficient. Since then a stars ascending the AGB) may be In fact the Sakurai Object (now known number of other similar objects have delayed until the post-AGB star has as V4334 Sagittarii) has become one been identified, the study of which, almost become fully degenerate,

9 No. 2, March 2000 THE ING NEWSLETTER

Figure 1. The position of the Sakurai Object prior to its shell flash derived from a model of the nebula ionisation (Pollacco, 1999). The solid lines are evolutionary tracks for post-AGB stars, while the broken lines represents the expected evolutionary track for a star suffering a helium shell flash. The Sakurai Object is currently positioned towards the top right of this diagram (high luminosity, and low temperature), but is heavily obscured by circumstellar dust.

albeit with a relatively massive pre-white dwarf to red supergiant but with the benefit of modern envelope. Although exotic physics and back to hot central star! detectors we will gain real insight to was necessary, it did seem that the the rate and nature of evolution of strange abundance patterns produced So this is where the Sakurai Object the central star as it becomes hotter by mixing during the shell flash fits in: it is the first observational as well as the development of its could be related to the observed test of this theory. In the 5 months wind and its interaction with its values (although the evolutionary following its discovery its surface environment. timescales seemed far too short to abundance of hydrogen diminished explain some classes of hydrogen- by more than 0.7 dex and its The Sakurai Object is the subject of deficient stars). temperature by several hundred an ongoing long-term monitoring degree’s Kelvin per month. campaign using the ING telescopes. One of the hydrogen-deficient objects Furthermore, mixing of the envelope The next few years promise much as discovered is the central knot in brought s process enhanced material it continues its evolution casting Abell 58. Ford (1971) noted the to the surface (Asplund et al., 1999). ‘light’ on many hitherto unobserved apparent coincidence in position During the first few months of 1997 areas of evolution. between this object and Nova Aql the stellar temperature had diminished 1919 —a highly unusual, very slow to the point where molecular (swan) References: nova. Although the nova has long bands had appeared and as dust Asplund et al., 1999, A&A, 343, 507 since faded from view it had been formation started the whole Ford, 1971, ApJ, 170, 547 given the designation V605 Aquila. photospheric spectrum became Hartquist et al., 1986, MNRAS, 221, 715 However, Seitter (1987) obtained reddened and washed out. Evolution Hazard et al., 1980, Nature, 285, 463 deep spectra of the central knot in of the light curve resembled that of Iben et al., 1983, ApJ, 264, 605 Abell 58 and also found superimposed V605 Aql (as far as we can tell an extremely reddened continuum anyway) and eventually as massive Lundmark, K., 1921, PASP, 33, 314 with V∼22. The only features visible amounts of dust were generated the Pollacco, 1999, MNRAS, 304, 127 in her spectra were [C IV] 5801/11Å object became heavily obscured in the Seitter, 1987, ESO Messenger, 50, 14 emission, indicative of a strong wind optical (V~22), while it remains Webbink, 1984, ApJ, 277, 355 ¤ and usually seen in Wolf-Rayet carbon bright in the IR. All measurements stars. If the 1919 event was a shell taken over the last year suggest the flash then this object gives us the photosphere/dust shell is still Don Pollacco ([email protected]) first indication of evolutionary cooling. As for the future, we expect timescales —less than 70 years from the similarity to V605 Aql to continue

10 THE ING NEWSLETTER No. 2, March 2000

TELESCOPES AND INSTRUMENTATION The One Eye that Sees All: Integral Field Spectroscopy with SAURON on the WHT

P. T. de Zeeuw1, J. R. Allington-Smith2, R. Bacon3, M. Bureau1, C. M. Carollo4, Y. Copin3, R. L. Davies2, E. Emsellem3, H. Kuntschner2, B. W. Miller5, G. Monnet6, R. F. Peletier7, E. K. Verolme1

1: Leiden Observatory; 2: Durham University; 3: Observatoire de Lyon; 4: Columbia University; 5: Gemini International Project; 6: University of Nottingham; 7: European Southern Observatory

n 1999, a new and unique and OASIS on the CFHT), to study and a camera then images the I integral-field spectrograph, galactic nuclei. By contrast, studies resulting spectra onto a CCD. The SAURON, made its debut at the of the large-scale kinematics of CCD is rotated slightly to avoid WHT. SAURON has a large field of galaxies still make do with long-slit overlap of adjacent spectra. This view and high throughput, and was spectroscopy along at most a few design is similar to that of the developed as a private instrument in position angles. Therefore, the galaxy prototype IFU TIGER, which a collaborative effort between groups dynamics groups at the Observatoire operated on the CFHT between 1987 at Observatoire de Lyon, Leiden de Lyon, Leiden Observatory, and and 1996 (Bacon et al., 1995), and of Observatory, and the University of the University of Durham joined OASIS, a common-user IFU for use Durham for the systematic study of forces to build SAURON (Spectroscopic with natural guide star adaptive the stellar and gaseous kinematics Areal Unit for Research on Optical optics at the CFHT. Table 1 and the line-strength distributions of Nebulae), an IFU optimized for summarizes the basic specifications nearby early-type galaxies. studies of the kinematics of gas and of SAURON. stars in galaxies, with high Galaxy dynamics and throughput, and most importantly, The SAURON optics are optimized with a large field of view. for the wavelength range 4500 –7000Å. integral-field spectroscopy Currently only one filter and one SAURON grism are available, for the range Many elliptical galaxies and spiral 4810– 5400Å. This allows bulges are triaxial and/or display The optical layout of SAURON is simultaneous observation of the OIII multiple kinematic components. illustrated in Figure 1. A filter and Hβ emission lines to probe the Triaxiality leads to velocity structures selects a fixed wavelength range, gas kinematics, and a number of that are difficult to map with after which an enlarger images the absorption features (the Mg b band, traditional long-slit spectroscopy. sky on the heart of the instrument, various Fe lines and again Hβ) for Furthermore, the central few the lenslet array (Figure 2). Each measurements of the stellar arcseconds are often ‘kinematically lenslet produces a micropupil. After kinematics (mean velocity, velocity decoupled’: the inner and outer the collimator, the light of each dispersion, and the full line-of-sight regions appear to rotate around micropupil is dispersed by a grism, velocity distribution), and the line different axes. This makes two- dimensional (integral-field) Spatial sampling 0.26″ 0.94″ spectroscopy of stars and gas Field of view 9″ × 11″ 33″× 41″ essential for determining the internal Spectral resolution (FWHM) 2.8 Å 3.6 Å structure of these systems, and for Instrumental dispersion (σ) 70 km/s 90 km/s understanding their formation and Grism 514 lines/mm evolution. Spectral sampling 0.9 Å/pix 1.1 Å/pix Wavelength coverage 4810– 5400 Å Substantial instrumental effort has Calibration lamps Ne, Ar, W × gone into high-spatial resolution Detector EEV12 2148 4200 Pixel size 13.5 µm spectroscopy with slits (e.g., STIS on Efficiency (optics/total) ~35% / 14% HST), or in small areas (e.g., the integral-field units (IFUs) TIGER Table 1. SAURON specifications.

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rebalance the WHT when SAURON is mounted, four counterweights totalling 580 kg are bolted on with the instrument: these are visible as a steel ring surrounding the top of SAURON. The dewar, made available by the ING, can be seen at the very bottom of the photograph.

The plan to develop SAURON was hatched in the summer of 1995, and the first work started in late spring 1996. The instrument was completed in January 1999. This fast schedule was possible because SAURON is a special-purpose instrument with few Figure 1 (top). Optical layout of modes, and because much use could SAURON. be made of the expertise developed at Figure 2 (bottom). The SAURON lenslet Observatoire de Lyon through the array is made of fused silica, and building of TIGER and OASIS. While consists of over 1600 square lenslets, SAURON was constructed as a private each 1.35 mm on the side. instrument, plans are being developed to make it accessible to a wider Figure 3 (right). SAURON mounted on community. the Cassegrain port of the WHT. Commissioning the Eye

SAURON was commissioned on the WHT in early February of 1999, during time shared with the ESA STJ team (see ING Newsletter, 1, 13). In the preceding days, the instrument was checked, together with the software to run it, and the interface to the WHT environment. We paid particular attention to the optical strengths (age, metallicity, and SAURON contains a mechanism for alignment of SAURON and the abundance ratios). switching to another enlarger, detector, to be sure that the spectra resulting in a 9 × 11 arcsec field of were aligned accurately with the A new feature of SAURON compared view, sampled at 0.26 × 0.26 arcsec. columns of the CCD. to existing IFUs is the ability to do This mode can be used in excellent simultaneous sky subtraction. This is seeing to study galactic nuclei with The instrument performed very well achieved by means of an extra the highest spatial resolution from the moment of first light, on enlarger which observes a patch of achievable at La Palma without February 1. We modified an internal sky 1.7 arcmin away from the main adaptive optics. baffle slightly, to avoid some residual field, using about 100 lenslets. light leak between the main field and The total throughput of SAURON, the sky part. A small tilt of the filter Each of the lenslets normally images including atmosphere, WHT and removed an unwanted ghost image. 0.94 × 0.94 arcsec on the sky. This detector, is 14%. The slow read-out of the CCD led to undersamples the typical seeing at some inefficiencies, but this is being La Palma, but provides essentially The mechanical design of SAURON fixed by the ING. all one can extract from the integrated is similar to that of OASIS; it is light light of a galaxy over a remarkably and strong, and minimizes flexure. Figure 4 presents some calibration large field of view, 33 × 41 arcsec, Figure 3 shows the instrument data taken during commissioning. observed with a filling factor of 100% mounted on the Cassegrain port of Panel a) shows a small part of an (1500 lenslets). SAURON therefore the WHT. SAURON weighs less than exposure with the grism taken out, does justice to its name, as its 300 kg, as compared to about 1500 kg which produces an image of the mythical predecessor was also known for ISIS, which normally occupies micropupils. Panels b) and c) show as ‘The one eye that sees all’. this port. In order not to have to spectra obtained with the internal

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tungsten and neon lamps, respectively. The former shows the nicely aligned continuum spectra, while the latter shows the emission lines used for wavelength calibration. Data Analysis

Each SAURON exposure produces a Figure 4. Examples of various SAURON calibration measurements, taken during CCD frame containing about 1600 commissioning. Each panel shows only a small part of the entire CCD frame so individual spectra. These are extracted that details can be seen. a) Micropupil image taken with the grism out. Each dot by means of an optimal algorithm is the diffraction pattern from one square lenslet. b) Continuum image using the based on a full optical model of the tungsten lamp. c) Neon arc. instrument. The resulting data cube is reduced in the standard manner, angular extent of the maps should be type galaxies, and to gain insight archived, and analysed by means of noted. into the relation between the stellar a set of programs modelled on the and gaseous kinematics and the XOASIS package. During our run in October 1999, we stellar populations in spheroids. Our observed the E3 galaxy M32 to test strategy is to study a representative We have developed a special pipeline, the high-resolution mode. Figure 6 sample of nearby ellipticals, lenticulars, fittingly called Palantir, to analyse shows the integrated intensity and and early-type spiral bulges. The the SAURON data cubes in a very the mean velocity field of the central SAURON data are combined with systematic manner. The first module region of M32, derived from a single high spatial resolution spectra of the of Palantir removes the instrumental 45 min exposure with good seeing. nuclei, and interpreted through signature, the cosmic rays, and also The velocity field is very regular, is state-of-the-art dynamical and stellar does the wavelength and flux consistent with axisymmetry, and calibration and the sky subtraction. population modelling. has a peak amplitude of about 50km/s. The second module allows merging of Individual velocity measurements are individual exposures and mosaicing Our sample was constructed as follows. accurate to a few km/s. The velocity of different pointings for the same We first compiled a complete list of dispersion in M32 is significantly object. Measurement of the kinematic accessible E/S0 galaxies and Sa bulges smaller than the SAURON quantities and the line strengths is for which SAURON can measure the instrumental dispersion, except in then done with dedicated algorithms. stellar kinematics: –6º ≤ δ ≤ 64º (zenith the inner few arcseconds (e.g., van The reduced data is archived at distance), cz < 3000 kms-1 (spectral der Marel et al., 1998), and we do not Leiden Observatory, and will be coverage), σ > 90 kms-1 (spectral show this here. made public in due course. resolution). The objects span a factor 50 in luminosity (M < –18) and Figures 5 and 6 also illustrate a key B First Results advantage of integral-field spectroscopy cover the full range of environment, over traditional aperture and long- nuclear cusp slope, rotational support, Figure 5 shows results from the first slit spectroscopy: by integrating the and apparent flattening. The galaxies SAURON observing run (February flux in each spectrum, the surface were then divided into six categories 14–20, 1999). Reconstructed total brightness distribution of the galaxy (E/S0/Sa; field/cluster) and a intensity, stellar Mg b line strength, is recovered. As this is derived from representative sample of 72 objects mean velocity and velocity dispersion, the same spectra that are used to was selected to populate the ellipticity and emission-line gas intensity and obtain the kinematics and line versus absolute magnitude planes velocity maps are presented for the strengths, there is never any doubt homogeneously (Figure 7). Based on E6 galaxy NGC 3377. The stars show about the relative location of these our two observing runs in 1999, we a striking rotating disk pattern with measurements and the galaxy hope to complete the observations of a spin axis misaligned ∼10º from the morphology. the entire sample by early 2002. photometric minor axis. The Mg b isophotes seem to follow the continuum The SAURON project: The detailed measurements will be light. A comparison with the Hβ compared with fully general galaxy isophotes will reveal whether this structure of E/S0/Sa models constructed by means of galaxy contains a younger stellar Schwarzschild’s numerical orbit disk. The gas also reveals non- Galaxies superposition technique (e.g., Cretton axisymmetric structures and motions. et al., 1999). The dynamical These results are based on a total of We built SAURON to measure the modelling uses all appropriate only four 30 min exposures (no spatial intrinsic shapes and internal velocity imaging and spectral data that are binning was applied). The large and metallicity distributions of early- available, including HST and OASIS

13 No. 2, March 2000 THE ING NEWSLETTER

a b c

e f d

Figure 5. SAURON measurements of the E6 galaxy NGC 3377. Each pixel is 0.94″× 0.94″ and the FOV shown is 30″× 39″. a) Reconstructed total intensity. b) Stellar Mg b index. c) Stellar mean velocity. d) Stellar velocity dispersion. e) Gas total intensity ([OIII] λ5007). f) Gas mean velocity. spectra to constrain the mass of a central black hole. When combined with the constraints on the stellar populations derived from the line- strength distributions (Kuntschner & Davies, 1998), this will shed new light on the fundamental connections between the large and small scale dynamics, the formation (and existence) of supermassive black holes and galactic nuclei, and the history of metal enrichment in early- type galaxies.

It is a pleasure to thank René Rutten, the ING staff, in particular a b Tom Gregory, and Didier Boudon and Rene Godon for enthusiastic and competent support on La Palma. The SAURON project is made possible Figure 6. SAURON measurements of M32. a) Reconstructed total intensity. through financial contributions from b) Stellar mean velocity. The FOV is 9″×11″, and the spatial sampling is NWO, the Institut National des 0.26″× 0.26″. Sciences de l’Univers, the Université Claude Bernard Lyon I, the universities of Durham and Leiden, and PPARC.

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References:

Bacon, R., et al., 1995, A&AS, 113, 347 Cretton, N., de Zeeuw, P. T., van der Marel, R. P., Rix, H-W., 1999, ApJS, 124, 383 Kuntschner, H., Davies, R. L., 1998, MNRAS, 295, 29 van der Marel, R. P., Cretton, N., de Zeeuw, P. T., Rix, H-W., 1998, ApJ, 493, 613 ¤ Figure 7. Distribution of E, S0, and Sa galaxies in the SAURON sample in the ε plane of ellipticity versus absolute blue magnitude MB. Open circles: field Tim de Zeeuw ([email protected]) galaxies. Solid circles: cluster galaxies. First Sodium Laser Beacon at La Palma

L. Michaille, J. C. Quartel, J. C. Dainty, N. J. Wooder (Imperial College London), R. W. Wilson (ATC), T. Gregory (ING)

n the ING Newsletter No. 1, an would like to be able to simply dial- A Laser Guide Star (LGS) system is I ongoing project to implement an up a guide star exactly where it is being planned for the WHT to adaptive optics system on the needed, and this is possible with the compliment the NAOMI system. In WHT was described. Called NAOMI use of a “sodium laser beacon”. preparation, the Applied Optics group (Nasmyth Adaptive Optics for Multiple at Imperial College London has been Instrumentation), this system will be At an altitude of 90km, well above investigating some practical aspects capable of eliminating, to a large the troublesome turbulence (which of creating and using sodium beacons for adaptive optics. Amongst these is degree, the image degrading effects rarely reaches beyond 25km altitude), a study of the sodium layer dynamics of atmospheric turbulence. is a 15km thick layer of sodium at La Palma using observations of atoms which, just as in a sodium an experimental sodium laser beacon. lamp, can be excited to spontaneously As with any adaptive optics system, We have built a laser system which emit light. To achieve this from the NAOMI will rely on measuring light launches a 25cm diameter, diffraction from a relatively bright reference ground we can use a laser tuned to limited beam from the liquid nitrogen object, or “guide star”, close to the an absorption wavelength (589.0nm) building located roughly midway desired target in order to make the of the sodium atoms. The excited between the JKT and the WHT necessary correction. At visible region of atoms creates a bright spot (Figure 2). Part of the laser beam is wavelengths, however, it is often not in the sky, the sodium laser beacon, directed through a small sodium oven possible to find a sufficiently bright which can be used as the guide star and by measuring the absorption we star in the neighbourhood of the for an adaptive optics system can lock the (tuneable) laser output astronomical region of interest. One (Figure 1). to precisely the correct wavelength

Figures 1 and 2. Left: A laser, tuned exactly to the D2 transition of sodium, can be used to excite the sodium layer at 90km altitude. The beacon thus created can be used as the guide star for an adaptive optics system. Right: The Liquid Nitrogen (LN) building which houses the laser. The beam is launched through a hole in the roof.

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for resonant excitation of the sodium drives the dynamics of the sodium layer. The light scattered from our layer, these variations must be taken laser beam is shown in Figure 3, an into account when designing a laser image taken in September 1999 from guide star adaptive optics system. a 20cm Meade telescope 3m away from the launch. Above the long The results shown here represent streak of Rayleigh backscatter the only part of our sodium monitoring sodium beacon is clearly visible. campaign, which will also encompass With only the slightest detuning of observations in January, April, and the laser wavelength the sodium spot June 2000 in order to measure disappears. seasonal variations in the layer. Along with our other related studies, Observing the sodium beacon from the this work paves the way for the Figure 3. A pseudocolour image of the JKT, some 160m away, gives a construction of a laser guide star laser scattering taken with a small different perspective. Figure 4 shows system for the WHT. Our present telescope 3m away from the laser the long streak through the sodium laser (an argon ion pumped ring dye launch. The small spot at the top is the layer created by the laser, with laser) will not be used for this purpose sodium laser beacon. brighter emissions from those parts as its 400mW output power cannot of the layer more abundant with produce a bright enough beacon for sodium. Analysing the profile of an adaptive optics system. With a these images allows us to measure more powerful laser system working fluctuations in the sodium density in conjunction with the NAOMI profile above La Palma, on both adaptive optics system, the WHT will minute-to-minute and season-to- be placed in a highly competitive season time scales. In September position against the larger 8m class 1999 we recorded some very interesting telescopes whose larger diameter profiles. Figure 5 depicts one night’s makes the use of laser guide stars data (22 September) and shows large, less effective. slow variations in the shape and total area of the sodium profile, as Further information about this and well as a sporadic event of high other related research can be found Figure 4. A pseudocolour image of the at http://op.ph.ic.ac.uk/. ¤ resonant backscatter from the sodium sodium concentration, lasting about layer as viewed from the JKT at 15 minutes, in the upper part of the midnight 22 September 1999. layer. While it is not certain what Laurent Michaille ([email protected])

a b

Figure 5. Relative sodium density measured on 22 September 1999. (a) and (b) are early and late parts of the night, respectively. Time is indicated in hours from midnight.

16

M33 Galaxy

his image of Messier 33 was obtained with the mosaic CCDs of the Wide Field Camera at the INT T telescope. The authors are L. Magrini and M. Perinotto (University of Florence, Italy), R. Corradi (ING), and A. Mampaso (IAC). The image is a composition of frames taken in three narrow bands: the green colour represents the galaxian emission in a filter centred on the [OIII] nebular line at 500.7nm, red is the Hα hydrogen emission at 656.3nm, while blue is mainly stellar light taken through a continuum filter centred at 555.0nm (Stromgren Y). In only one observing night, and with two positionings of the telescope, it was possible to cover the whole galaxy which has a size of approximately one degree in the sky.

The main scientific goal of these observations was to search for planetary nebulae in this nearby galaxy. They are recognised as emission-line objects with generally intense [OIII] and Hα lines, negligible continuum emission, and a point-like appearance (1 arcsec corresponds to about 4 pc at the distance of M33). 134 newly discovered planetary nebulae were selected, but these observations also contain a large amount of information about other ionised nebulae, such as HII regions, supernova remnants, Be stars, symbiotic binaries, Wolf-Rayet stars, LBVs, etc. Their excitation status can be estimated by using the ratio between the [OIII] and Hα emission. Results concerning the search for planetary nebulae are in press on the Astronomy and Astrophysics Journal (Magrini et al., 2000).

Romano Corradi ([email protected])

THE ING NEWSLETTER No. 2, March 2000

Figure 1. The Half Arcsecond Programme (I) The ING DIMM tower 1 2 1 1 near the C. Packham , R. W. Wilson , M. Azzaro , N. O’Mahony , WHT. S. Fine1, D. Gray1, V. Reyes1, C. Martín1

1: Isaac Newton Group 2: ATC, Astrophysics Group, Cavendish Laboratory (soon to join the astronomical instrumentation group at Durham) ver the last three years, the the primary mirror, heated by oil where l is the wavelength of Half Arcsecond Program warmed during its lubricating passage observation. Hence the accuracy of O the DIMM seeing estimates depends (HAP) has found some around the WHT structure. It was important and surprising results. clear that the WHT image quality on the validity of the standard seeing These results, recently published in suffered from this turbulence and model at the site. the MNRAS (Wilson et al., 1999, 309, that an engineering solution was 379), are summarised on the HAP required to reduce the temperature The DIMM has been used by ING to WWW site (http://www.ing.iac.es/ differential between the fork structure provide an extensive set of seeing hap/haphomepage.htm) and a short and dome air. Hence in September data for the WHT site. The results of summary of the key conclusions 1996 an oil cooling plant was installed the monitoring campaign between follows. to reduce and track the temperature October 1994 to August 1998 are of the telescope bearing oil to within displayed in Figure 2, which shows The HAP was started by the ING in a fraction of a degree of the dome air median site seeing at the WHT to be 1993 in order to optimise the image temperature. Subsequent pupil images 0.69 arcseconds, in good agreement with other surveys carried out at quality of the WHT, especially in showed the turbulent air plumes were other sites on the Roque by preparation for NAOMI, the natural eliminated, and also that heating of collaborators at the IAC. guide star adaptive optics system due the air in the dome was significantly to be commissioned in mid-2000 (see reduced during both night and day. Initial attempts to measure the seeing ING Newsletter No. 1). The goal of obtained inside the WHT made use of the HAP is to eliminate non- A Targeted but Sensitive the Cassegrain autoguider, but several atmospheric degradations of the subtle effects blunted the effectiveness WHT’s image quality, so that the Approach of this approach. However, a set of measured image width for the WHT observations based around the JOSE will be as close as possible to the Having removed the obvious (Joint Observatories Seeing Evaluation) intrinsic (site) seeing value. contribution to dome seeing, more wavefront sensor, installed in preparation sophisticated and quantitative seeing for NAOMI, was in progress at the WHT Two main sources of image degradation measurement techniques were required between 1995–1998. JOSE is a can be distinguished in addition to the to search for more subtle effects. In Shack-Hartmann sensor equipped atmospheric seeing: (1) imperfections of order to reduce the seeing of the WHT with a fast readout CCD. The pupil the telescope itself, including tracking to that of the site, it was first necessary of the WHT is re-imaged onto a and focus errors and other optical to accurately determine the site seeing. lenslet array, so that sections of the aberrations, and (2) turbulence effects In October 1994 a Differential Image aperture ∼50cm in diameter are such as convection at the primary Motion Monitor (DIMM) was installed imaged separately onto the detector. mirror and mixing of air at different on a tower near the WHT (see Figure 1). The CCD camera records images of the spot pattern continuously at temperatures in the light path, A DIMM measures the seeing via the frame rates of typically 100Hz for a collectively referred to as dome seeing differential motion of stellar images or artificial seeing. and hence is unaffected by wind shake, poor tracking, focus, etc. and therefore An Early Result gives an unbiased estimate of the atmospheric seeing. In fact the DIMM One of the first problems identified measures the Fried parameter (r0) or by the HAP was the presence of two spatial coherence length of starlight. plumes of turbulent warm air flowing For the standard (Kolmogorov) theory into the optical light path above the of atmospheric turbulence this is primary mirror. These were clearly related to the seeing FWHM for a visible in defocused (pupil) images large telescope (in the absence of from the WHT. The plumes emanated other aberrations) by: from the supporting fork structure of FWHM = 0.98 l / r0 (1) Figure 2. DIMM seeing measurements.

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few tens of seconds, so that the temporal development of the wavefront distortion can be analysed. Centroids are measured relative to the mean spot location for each data sequence, so that static perturbations are ignored. The measurements are therefore unaffected by fixed (or very slowly varying) optical aberrations such as telescope defocus, but are sensitive to changing distortions due to atmospheric and dome turbulence. As for the DIMM, JOSE gives a measure of r0, Figure 3 (left). Normalised probability distributions for contemporaneous JOSE which can be translated to the seeing (solid line) and DIMM (broken line) r0 measurements determined from FWHM via equation 1. Correlating measurements on 18 nights between 1995 May and 1998 August. the JOSE (internal) and DIMM Figure 4 (right). Example of contemporaneous JOSE (filled squares) and DIMM (external) seeing measurements (open circles) r0 measurements. provides a powerful diagnostic of WHT dome seeing. somewhat over-estimate the WHT to artificial seeing. Figures 6 and 7 seeing at long wavelengths (R-band show the summation of several years JOSE/DIMM Correlation and longer), since equation 1 data obtained during observing assumes an infinite outer scale. nights for the dome minus external air temperature and mirror minus By collating JOSE and DIMM Seeing arising from excess mirror or dome temperature respectively. observations to form an integrated data dome temperature is likely to be Figure 6 shows that large dome set, it is possible to compare statistics of described poorly by the Kolmogorov temperature excesses are very rare. the seeing inside the WHT to the site model (Bridgeland, M. T., Jenkins, Calibration of the temperature sensors seeing. In Figure 3 measured values of C. R., 1997, MNRAS, 287, 87), with has shown a drift in the external r from DIMM observations (4500 0 excess power in aberrations on small thermometer by ∼1.5K over the a measurements on 18 nights) and spatial scales (high order Zernike several years of operation and hence contemporaneous JOSE observations modes). Hence this analysis also in reality the 1K offset suggested by (2998 measurements) are plotted. suggests that there is no strong dome Figure 6 is even smaller. Large Clearly there is no significant offset seeing contribution at the WHT. A primary mirror temperature offsets in the distribution of r0 between similar analysis of JOSE data before are more frequent, but the differential JOSE and DIMM. oil cooling was implemented showed is >2K for only ∼25% of observing excess power on small scales, consistent time. We speculate that such a large The JOSE wavefront sensor data with artificial seeing from the offset occurs only during rapid allows the validity of the standard turbulent air plumes. weather changes where the large turbulence model for the WHT site to thermal inertia of the (thick) primary be examined. Figure 5 shows the Conclusions mirror retains excess thermal energy mean (relative) distribution of rms for one or two nights, but that the Zernike mode strengths for the It is important to consider why the atmospheric seeing will in that case seeing-induced wavefront aberrations WHT does not appear to suffer from be sub-optimal due to rapidly changing at the WHT focus. The data are artificial seeing. It is generally weather conditions. It also seems that plotted against their theoretical accepted that excess temperature of under normal circumstances, the values for the Kolmogorov turbulence the mirror, dome or support gives rise considerable thermal inertia and model (Noll, R. J., 1976, J Opt Soc good insulation of both the primary Am, 66, 207). Clearly the measured mirror and dome air mass prevent distribution is close to theoretical the mirror from absorbing significant expectation, so that the DIMM and heat from the air during the daytime, JOSE seeing FWHM predictions are leaving it close to the air temperature valid. In fact the data show evidence of the previous night. for an outer scale of turbulence (i.e. upper limit to the scale of the seeing The fact that no significant artificial aberrations) with a mean value of seeing in the WHT has been detected approximately 15m. As a result the after cooling the WHT’s oil is certainly DIMM and JOSE predictions may against common perception of the WHT seeing. In part this is due to (a) We wish to thank the IAC seeing group for providing some DIMM measurements useful reliance on the WHT’s autoguider for for our analysis. Figure 5: Zernike Modelling of JOSE Data. seeing information. The autoguider

22 THE ING NEWSLETTER No. 2, March 2000

has an independent focus, optical aberrations and several other ‘features’, and so gives only an approximate (and certainly pessimistic) estimate of the true WHT seeing.

In the absence of dome seeing, the remaining tasks for the HAP at the WHT are to optimise the tracking and focus of the telescope. The power spectrum of image motion measured Figure 6. Dome-External Air Figure 7. Mirror-External Air by the JOSE sensor reveals a spike Temperature Difference. Temperature. due to the known oscillation of the WHT support structure at 2.7Hz. Whilst this resonance contributes WHT Millenium Upgrade little power on average, the oscillation can have a significant effect on image width if it is strongly excited, for Gordon Talbot (Head of Engineering, ING) example by wind buffeting of the telescope structure. In future it may be possible to monitor the telescope he Isaac Newton Group have mimic displays until all focal stations drive encoders automatically, and to T embarked on a comprehensive and instruments are converted. alert the observer to excess tracking upgrade of the William This project will build on basic errors at high frequencies. A significant Herschel Telescope (WHT), involving control to provide more complex contribution to the image FWHM at replacing and enhancing many modes of observing —such as the WHT (as for all telescopes) may systems. The programme embraces a automatic guide star acquisition. result from imperfect focus. Current number of projects, and all ING Finally it will provide an efficient methods for estimation of the optimum engineering groups are contributing. queue-observing tool to automate focus are limited by the inherent The upgrade directly supports the service observing. variability of the site seeing. Improved NAOMI adaptive optics system and methods to focus and to track the INGRID IR imager but also brings – New autoguider. This will be a focus of the WHT are under performance and reliability DRAMA based system similar to investigation. improvements to the WHT in support the INT system, replacing the of other instruments. Previous, existing FORTH based system that In the next issue of the ING newsletter recent improvements include an runs on unreliable, obsolete and we will discuss the HAP at the INT Alpha computer based Telescope irreplaceable hardware. and the future of the HAP. Control System (TCS), the introduction of 4k×2k EEV– 42 detectors and – New acquisition TV system will HAP Publications: improved dome seeing through oil replace the existing, obsolete system cooling. with a modern supportable system 1. Wilson, R. W., O’Mahony, N., Packham, that offers improved performance. C., Azzaro, M., 1999, “The seeing at the The programme includes: Initially implemented as a stand- William Herschel Telescope”, MNRAS, alone system the ultimate aim is to 309, 379. – New Observatory Control System integrate with other telescope to replace the existing Instrument systems. 2. Packham, C., O’Mahony, N., Wilson, R. W., 1998, “Recent developments in the Control System for improved Half Arcsecond Programme”, New AR, performance, ease of maintenance – Faster CCD readout through the 42, 431. and development, further increased ULTRADAS system. This embraces commonality between subsystems the production of a new data 3. Azzaro, M., Breare, M., 1998, “Some and reduced maintenance costs. acquisition system (DAS), and its meteorological parameters affecting the Initially the system will support implementation for all science image quality of the WHT on La ING’s new data acquisition system, detectors at ING using the San Palma”, New AR, 42, 471. ULTRADAS, for faster CCD readout, Diego State University SDSU-2 and the implementation of the CCD controller. Principle gains 4. O’Mahony, N., Packham, C., Wilson, R. W., Rutten, R., 1997, “Characterisation 4k×4k two chip EEV–42 mosaic for from the project are faster readout and Optimisation of Seeing at ING use at prime focus and on UES. speed, and improved reliability Telescopes”, 23rd IAU General Instrument control will then be —from both the DAS system and Assembly, Kyoto. ¤ implemented sub-system by sub- CCD controller— together with system using DRAMA and EPICS reduced maintenance requirements. Chris Packham ([email protected]) (channel access) with appropriate The system will ultimately use a

23 No. 2, March 2000 THE ING NEWSLETTER

PCI interface between the CCD the causes of much lost time while – Improvements to GHRIL seeing controller and DAS computer, requiring a large support effort. by re-coating and adding CaF2 however due to delivery delays it is windows to the infrared de-rotator. initially being implemented using – Improvements to GHRIL (Ground The windows will prevent airflow an S-BUS card. With the S-BUS based High Resolution Imaging through the unit, eliminating interface the system produces Laboratory) for NAOMI which turbulence in the light path and typically a threefold decrease in un- include: stopping the deposition of dust on windowed readout cycle time over the reflecting surfaces. Additionally, previous ING systems, with the – Reducing telescope vibration by once the sealed unit is fitted, PCI interface this will improve to tuning and modifying the oil airflow within the optical bench sixfold, potentially offering an overall damping system with extra room will be studied in an effort 5% increase in telescope observing dampers near to the bearing to understand and improve local time. The project is currently being surfaces. seeing. expanded to include infra-red detectors, first in support of INGRID, – A new cooling system with glycol – Improvement in telescope and eventually the LIRIS lines routed through the telescope tracking/positioning ready for spectrograph being developed by to an external heat exchanger. NAOMI, by the elimination of the IAC. ULTRADAS has been This system was installed and glitches seen by ELECTRA commissioned on the INT Wide operated for the last ELECTRA Field Camera and WHT Prime adaptive optics run. Extension is After only 11 years of operation the Focus 4k×4k 2 chip mosaic. planned to the UES cooler — thus WHT is still a young telescope. These removing a further source of measures ready it for common user – A new UNIX based Guide Star vibration in the telescope structure adaptive optics, will offer better Server will be implemented. This and heat within the dome. performance for observers together with improved reliability/reduced work has been placed at the UKATC maintenance operation. In short they (to begin in FY 2000/2001) and it is – A new optical bench for NAOMI. take it into the new millennium, and expected it will be based on the The previous two ELECTRA runs as they are being implemented over porting of an existing system. identified that the original, the next two years, fit in with either although adequate for other 2000 or 2001 as defining the start of – The above improvements will remove instruments was insufficiently the next millennium. ¤ several obsolete, failing and damped for NAOMI and so will unsupportable systems, including be replaced. the Network Interface Units (NIUs) Gordon Talbot ([email protected]) and Data Management System – Improved access for instruments, (DMS) both dependent on bespoke including NAOMI through a roof hardware and software and both hatch. New Instrumentation for the WHT

René Rutten (Director ING)

n order for the William Herschel I Telescope to keep offering the best possible instrumentation in the future, it is important that new ideas and instruments are developed. For that reason, in June 1999 an announcement was sent out inviting novel ideas for new instrumentation for the WHT to be brought forward. The following four proposals for new instruments were received:

Figure 1. Simulated H-band coronagraphic PSFs with a secondary star – Bacon (Lyon): OASIS — an 1.0 arcsec away from the central object (∆m= 7m) without (left) and with Adaptive Optics (AO) optimised adaptive optics correction (right). The diameter of the focal plane stop was integral field spectrograph. 1.0 arcsec and the uncorrected seeing was ~0.7 arcsec.

24 THE ING NEWSLETTER No. 2, March 2000

– Doel (UCL, London): Coronagraph for the NAOMI AO system.

– Sharples (Durham): MOSAIC – Multi-Object Spectrograph with Adaptive Optics Image Correction.

– Vick (ATC, Edinburgh): High- resolution spectral imaging facility for the NAOMI AO system.

Each of these proposals was of high quality, which made it difficult to set priorities. It is noteworthy that all four proposals focus on adaptive optics, which is conceived as a key development area for the WHT.

Following a review by the Figure 2. OASIS on the CFHT. Figure 3. MOSAIC layout. Instrumentation Working Group (IWG) the ING Board discussed the instrument is fully developed and Clearly this instrument would have various submissions and operational, but would have to be great potential and potentially keep recommendations in December adapted to work with NAOMI. An the WHT competitive next to the 8-m 1999, and I will present here what assessment is being undertaken to class telescopes. MOSAIC, with its the outcome was. see whether both systems can be laser system and own AO hardware made compatible. is a comparatively complex instrument The ING Board considered that the that would require a major investment. proposal by Doel et al. to build a OASIS is a versatile spectrograph Technical and performance aspects, as coronagraphic unit to work with allowing a wide range of science well as its impact on telescopes NAOMI should be supported on the projects to be carried out, and operation will need to be studied shortest possible time scale. Examples therefore it is anticipated that the further. of science areas where the coronagraph interest in its exploitation will would be particularly useful are the be large. study of brown dwarfs and substellar LDSS and TAURUS on companions, proto-planetary disks The MOSAIC proposal by Sharples is the WHT around young stellar objects, QSO for an AO-corrected multi-object host galaxies, and mass outflow from spectrograph and imager for the objects such as symbiotic stars and WHT Nasmyth focus. This system is A second announcement-of-opportunity luminous blue variables. distinct from the NAOMI AO system was issued also in June 1999 asking and would have its own (restricted interested parties to adopt the existing This development has a clear set of conjugate) AO system, which aims to common-user instruments: the Low science applications and can be achieve not so much the best Dispersion Survey Spectrograph, delivered at a modest cost. This possible image quality over a small LDSS, and the Fabry-Perot imaging instrument would be able to exploit field, but instead aims for significant spectrograph, TAURUS, as private the capability of NAOMI with natural improvements in image quality over instruments. guide stars, as it will be used in the a wide field. The AO feature in investigation of faint sources around combination with a multi-object The reason to retire these less-used bright objects. It would help increase spectrograph would present important instruments as common-user facilities the early scientific impact of NAOMI. gains over existing facilities, and be was driven by a combination of unique. financial and operational pressures. The proposal by Bacon et al. to deploy Rather than just decommissioning an existing instrument, OASIS MOSAIC would have an important the instruments they were offered to (currently available on the CFHT) on impact on the WHT. It would be interested groups in the user the WHT with NAOMI was considered mounted at the Nasmyth focus where community to take on as private extremely attractive. OASIS is a currently UES is mounted. (UES instruments. In this way the state-of-the-art and unique integral would have to be positioning elsewhere instruments could be retained for the field spectrograph using a lenslet and fed by a fibre from MOSAIC). continued use by the astronomical array. Its design allows very fine The AO correction would also involve community, but no longer be a burden spatial sampling to take full advantage installing a Rayleigh laser system to on the observatory, which is faced to of an Adaptive Optics system. The generate the artificial guide star. have to take care of a growing

25 No. 2, March 2000 THE ING NEWSLETTER

number of instruments under ever tighter financial constraints. The New WHT Mosaic Camera

Four proposals were received as a Simon Tulloch (ING) result of this announcement. The proposal by Richard Bower (Durham) to adopt LDSS and by Richard ork on this camera started PF Performance Summary McMahon (Cambridge) to adopt W at the RGO in Cambridge TAURUS were considered the shortly before its closure strongest on the basis of their science and was continued at the ATC in Pixel scale: 0.24 ″/pixel case and ideas for developing the Edinburgh and subsequently ING. Field of view: 16.4′ × 16.4′ instruments further. The ING Board The design incorporates two EEV42- Pixel size: 13.5µm square 80 CCDs mounted in a standard 2.5l decided that these instruments Image size: 4096 × 4100 pixels would transfer to Durham and Oxford Instruments cryostat normally Cambridge respectively as private used for single chip cameras. This Readout time: 54 s – instruments. Both PIs indicated the camera therefore has the same Readout noise: 6 e rms possibility that the instrument may mechanical interface to the telescope Gain: 2.2 e–/adu for chip #1 be used on other telescopes in the and could in principle be used at any 2.0 e–/adu for chip #2 future. Both proposers also indicated port where a single chip camera is Quantum efficiency: interest in collaborating with other normally used. In practice it will be 380nm 400nm 650nm 950nm groups on future use of the dedicated for use at Prime Focus (PF) instruments. Therefore from now on and at UES on the WHT. CCD1 62% 78% 75% 14% anyone interested in using either CCD2 67% 81% 76% 13% LDSS or TAURUS should contact At prime focus this camera will double ± 5µm accuracy. Subsequent Richard Bower or Richard McMahon, the field of view of the telescope with measurement of the CCD surfaces, respectively. ¤ no vignetting from either the existing filter wheel or corrector. At UES the using an instrument developed at the RGO, showed that all pixels lay within René Rutten ([email protected]) benefits will be from the EEVs smaller pixels (0.20″/pixel) and better blue 20µm of an optimal plane. The slight response compared to the existing defocus that this will introduce into SITe detector. The EEV mosaic is the small regions of the image furthest marginally bigger than the SITe but from the optimal plane, does not since the UES output is already exceed 0.1 pixels. The physical gap heavily vignetted in the outlying between the CCDs was minimised by areas of the image, this will offer no the use of PTFE shims. These allowed advantage. the devices to be close butted without actually touching. Once the chips were The camera performed well during firmly screwed down to the base plate its first science run at PF at the end the shims were removed. The gap of September 1999 and obtained the between adjacent image areas is only images that accompany this article. 39 pixels: approximately 1% of the Some problems due to stray light total image width. were highlighted during this run and are currently being solved by the The camera was designed and built addition of extra baffling around the by Simon Tulloch. Dave Gellatly at PF filter wheel. Some images obtained the RGO was responsible for some close to the celestial equator seemed to suffer some degradation due to a initial mechanical design work and number of horizontal streaks extending the ATC Mechanical Workshop was across the full width of the images. responsible for the machining. These were later identified as geostationary satellites! Final The camera is now available as a commissioning at UES will start in common user instrument at Prime late January 2000. Focus and at UES on the WHT. ¤ The CCDs were mounted on an invar baseplate that was ground flat to Simon Tulloch ([email protected])

26 1

2 (All the images on this page are credit to Simon Tulloch and Nik Szymanek)

Figure 1. BVR image of M33 Galaxy using the new 2-detector WHT prime focus camera. Exposure time was 10s.

Figure 2. 10s exposure of the Horse Head nebula with the new prime focus camera on the WHT.

Figure 3. Again as before but now combining B, V, and R images. Only one detector is shown.

Figure 4. The star-formation region M42, also known as the Orion nebula. Shown here is a 10s exposure true- colour image on the new WHT prime focus camera. 3 The gas and dust in the nebula emits light because it is irradiated by nearby emerging stars.

4 Figure 5. The new WHT prime focus camera contains two EEV-42-80 thinned CCDs butted along their long axes to provide a 4K x 4K pixel mosaic. Each pixel is 13.5µm square. A single detector comprises 2148 x 4128 pixels in total including 50 x-underscan, 50 x- overscan and 28 y-overscan pixels. The active area of the mosaic measures 55.8 x 55.35 mm, with a 0.53mm gap between the chips. Both chips have two working amplifiers giving 3–4 electrons noise. 5 No. 2, March 2000 THE ING NEWSLETTER

OTHER NEWS FROM ING

Y2K at the ING

Gordon Talbot (Head of Engineering, ING)

he year 2000 (if not the true Prior to 2000 all three telescopes were Overall, so many of ING’s staff were T millennium) is now with us, successfully tested for compliance and involved that I can’t name them here and like the rest of the world, showed that they were able to operate, for lack of space. Additionally support the ING has not been brought to its point and track with dates in the new and advice was received from within knees by the ‘Millennium Bug’. century. Much preparatory work was PPARC. However, this cannot just be ascribed needed in updating operating systems, to good fortune — or that the Y2K applying our own and manufacturers’ Finally a last thought, perhaps now problem was mere hype— it was patches and replacing non-compliant we should send a time capsule because of the efforts of many of systems. A great deal of time was forward to 9999 AD warning of the ING’s staff. also spent isolating systems for testing. imminent ‘Y10K problem’. ¤

A plan was drawn up and followed During 1998 and 1999 the ING Gordon Talbot ([email protected]) followed a planned programme of for operating over the year-end and investigation, assessment, correction arrangements made to have the and testing of systems to ensure necessary staff available. Uniquely at [INGNEWS] Mailing List readiness for the year 2000. ING a complete night’s closure for observing was scheduled for 31 [INGNEWS] is an important source All systems at ING were assessed December, followed by observing on of breaking news concerning current developments at the ING, including not only the telescopes but all three telescopes in service mode especially with regard to also the infrastructure and on the nights of 1 and 2 January. instruments. administration. Once the priorities of This was mainly on the grounds of safety of people then protection of safety, in case of failure to external You can subscribe to this mailing equipment were satisfied the major services —principally communications— list by sending an email to effort was in ensuring that our three but also to minimise travelling [email protected] with the telescopes would operate and return problems for observers. However message subscribe ingnews in the scientific data in the year 2000, bearing during the day of 1 January a full body. Please leave the subject field in mind that they are scheduled for and the rest of the body of the engineering team was on the mountain operation 365 nights of the year. message empty. top re-testing system operation, beginning with safety related systems. Once subscribed, you can subscribe To operate, the telescopes rely on a Apart from our weather web-site, computer network of over 200 devices a colleague by sending to which was back on line the same day, [email protected] the with thousands of lines of bespoke no Y2K faults were found. code using many operating systems command subscribe ingnews your_colleague’s_ address. To and languages. Key systems are real- Since then no other date related unsubscribe from [INGNEWS] time telescope /instrument controls problems have emerged. However, send to [email protected] the and astronomical data acquisition. some systems, particularly instruments command unsubscribe ingnews. More Additionally astronomical data that have not yet been used, will be information on [INGNEWS] can be processing and archiving are essential checked prior to scheduled use, found on this web page: to maintain operations. There is although most have already passed http://www.ing.iac.es/INGinfo/ continuous development and Y2K tests last year. We will continue to bulletin/ replacement of systems, which vary be vigilant throughout the year as in age from those being installed now problems could still emerge. These are the subjects of the last to some over ten years old. ING are messages sent to the list: self reliant in engineering and have a I would like to thank all ING staff six strong Computer Facilities Group who have contributed to our smooth 24 August and eight strong Control Software rollover into 2000 AD, especially – ‘First issue of the ING Newsletter’ Group who are familiar with our those working on the network and systems and used to providing all telescope software on tight schedules 8 September maintenance and upgrades. for the overnight telescope tests. – ‘Submitting Large Proposals’

28 THE ING NEWSLETTER No. 2, March 2000

News from the Personnel Movements Computing Don Pollacco has left ING after several years of service. Don has been a Facilities Group key person in the development of fibre-based instruments at ING. In particular his efforts on improving the AUTOFIB and WYFFOS systems has been highly appreciated. He is leaving behind an important gap which Nick Johnson (Head of CFG, ING) will be difficult to fill. We thank him for his efforts and wish him well in his new job at Queen’s University Belfast. he Computing Facilities Group T starts 2000A eagerly Also Daniel Folha left at the end of his tour on La Palma to return to the anticipating the arrival of its University of Porto. Many thanks to Daniel for his excellent support, and Digital Video Disc (DVD-R) libraries. welcome to Paolo Garcia who is taking up the vacant position left by During 2000A, these 400 disc towers Daniel. will be integrated into the ING archiving system and increase our on- Begoña García and Thomas Augusteijn have taken up vacant positions line storage capacity ten fold. The as Support Astronomers. Both are highly experienced in observational DVD library will operate in parallel astronomy and we are very pleased that they decided to join ING. Prior to with our CD library and pick up the coming to La Palma Begoña worked at the Instituto de Astrofísica de increased number of images generated Canarias, whilst Thomas was working at the European Southern by our UltraDAS computers and Observatory in Chile. SDSU controllers. Capacity will be doubled again in 2000B with the Romano Corradi and Johan Knapen also joined the Astronomy Group as addition of a device to flip the DVDs research fellows. Their key task will be to strengthen the research over and allow writing to both sides of environment at ING. Romano was working at the Instituto de Astrofísica de the disc giving 9.4GB of data storage Canarias before taking up his position at ING, and Johan is on leave of per disc. absence from the University of Hertfordshire. Computer systems performed without Kenny Britton and Ermano Villani filled temporary posts in the Site errors through the famous Y2K event. Services and Mechanical Engineering groups, respectively. Both have left Our detailed planning and testing was ING at the end of their term after helping the groups through a very busy apparently thorough, and we are period. We wish both of them well in their future career. delighted at the results of the hours spent in designing and building new Vicente Reyes temporarily filled the post of Telescope Operator during network services. At the same time, we have almost completed the last absence of Neil O’Mahony. Vicente returned to his previous business, telescope’s conversion to new managed while we welcome Neil back on La Palma. data network cabling. Finally, the ING network has ceased to be a bottleneck to system performance. Other Recent ING Publications Annual Reports During the last days of 1999B we completed migration of all users and Available at http://www.ing.iac.es/PR/annualreports_index.html applications to a unified Solaris environment. This has altered Technical Notes procedures for visiting astronomers to use our computers with guest accounts. – No 124. ING Bibliography and Publication Rates (1999), S F Sánchez, January 2000. Tighter security management and faster user administration mean we Available at http://www.ing.iac.es/~manuals/man_tn.html can respond to requests with better efficiency. But we always welcome as Manuals much advance notice from visitors as possible. Please complete the form on – Observers Guide to the JKT and JAG-CCD Camera. Version 4.06, J Telting, January 2000. http://www.ing.iac.es/~cfg/pub_notes/ – INT and JKT TCS Users’ Manuals. Version 2.0, R Laing and M Fisher, October 1999. visiting_astronomer_request.htm – WHT TCS Users’ Manual. Version 2.0, R Laing, M Fisher and R Clark, December 1999. to ensure CFG knows all about your IT needs before you arrive here. Available at http://www.ing.iac.es/~manuals/manmain.html Thanks for your continued help with this. ¤ In-house Research Papers

Available at http://andromeda.roque.ing.iac.es/~sanchez/ingpub/index.html Nick Johnson ([email protected])

29 No. 2, March 2000 THE ING NEWSLETTER

systems and instruments was achieved, CAUP at ING leading to a better service to the observatory and visiting astronomers. Daniel Folha (CAUP)* and Teresa Lago (Director CAUP) As a final result, I believe I am now a proficient optical, as well as infrared astronomer. Although I should leave *Ex-CAUP Support Astronomer at ING those at ING under whose supervision I worked, as well as those whom I entro de Astrofísica da brings an added value component for supported, and the future, to be the C Universidade do Porto (CAUP), CAUP, namely the training of the judges. Portugal, is a scientific private astronomers in the management and association of the University recognised operation of telescopes and their Another important point of my by the government as an institution scientific instrumentation. Therefore presence at ING was having had the of public utility. It started its this is an important complement to opportunity to meet many people activities in October 1990. Its other facilities available to the from different backgrounds. From objectives include the promotion and astronomers associated with CAUP. astronomers working in various support of Astronomy through Namely, the access to ESO facilities areas of astronomy, to engineers research, education at undergraduate under the agreement of cooperation taking care of observatory equipment and graduate levels, as well as the between Portugal and ESO, signed or bringing new instrumentation to popularisation of Astronomy. in 1990. commission. It was a pleasure to meet them all and be able to discuss many aspects of their work. In 1997 the University of Porto, La Palma – A Personal PPARC and NWO signed a Cooperative For our institution, having wider Agreement concerning the participation Experience access to telescope time is, obviously, in the ING. Within the terms of this one of the goals of the PPARC-CAUP agreement signed in Porto, the During most of 1999 I was based in agreement. Since the start of semester researchers of CAUP have the right La Palma, serving as CAUP’s support 98A, when the agreement became to use the JKT during 28 nights per astronomer at ING. My task consisted effective, observations with ING year. In addition, they have access to of providing support on all three instrumentation were done for a the other telescopes, within the ING, telescopes and various instruments, number of projects lead by CAUP under the same conditions of scientific namely the JAG-CCD camera on the astronomers. As examples, using competition as the astronomers of the JKT, the WFC and IDS on the INT JKT’s JAG-CCD, a study of oscillations United Kingdom and the Netherlands. and UES, ISIS and Auxiliary Port in roAp and δ Scuti stars; with UES As a reciprocal part of the agreement, imaging on the WHT. I replaced my and IDS, high resolution spectra of CAUP maintains one resident colleague Antonio Pedrosa upon his T Tauri stars were obtained in order astronomer at La Palma, integrated return to Porto and I have recently to learn more about the properties of within the ING team. The possibility been replaced by Paulo Garcia, the their strong emission lines; with IDS, of CAUP’s participation in the current CAUP astronomer in La low spectral resolution data was programmes of instrumental Palma. To smooth the handover of taken, again of a sample of T Tauri development associated with the ING CAUP astronomers an overlap of stars, this time to investigate their telescopes is also provided for. approximately two weeks is granted excess continuum emission. These for two consecutive astronomers. observing programmes have been The agreement was implemented in developed within CAUP’s Stellar February 1998. Since then, three Having only used infrared Astrophysics group, which goal is a astronomers associated with CAUP instrumentation prior to my arrival better understanding of the formation, have worked at La Palma. The regular at ING, becoming a support astronomer structure and evolution of low-mass replacement of CAUP’s astronomer in an optical observatory meant that stars. a very steep learning curve had to be followed. Fiddling with filters, gratings, Beyond having access to telescope dichroics and so on and so forth for time, cooperation proposals have every run, is certainly something one already been advanced regarding does not do with cooled instrumentation CAUP’s participation in programmes used for infrared observations. The of instrumental development associated help of other ING astronomers, and with ING telescopes. Yet, the path is engineers, to whom I take this open to many other possibilities in opportunity to publicly thank, made the sharing of new cooperative those initial times a lot easier although adventures in this field. ¤ A view of the Centro de Astrofísica da not less stressful. With practice, more Universidade do Porto (CAUP). in depth knowledge of the various Daniel Folha ([email protected])

30 THE ING NEWSLETTER No. 2, March 2000

Seminars and Talks A Big Effort (and a Big given at ING Crane) Solves a Big isiting observers are politely V invited to give a seminar at ING. Problem Talks usually take place in the sea level office in the afternoon and last for about 30 minutes plus time for Kevin Dee (Head of Mechanical questions afterwards. Astronomers from ING and other institutions on Engineering, ING) and Gordon Talbot site are invited to assist. Please (Head of Engineering, ING) contact Johan Knapen ([email protected]) for more details. These were the seminars and talks given in the last six months: uring the night of 20 February D 1999 there was a major failure 13 September of the top dome shutter Quasar Host Galaxies, S Sánchez (ING) mechanism on the Isaac Newton Telescope, which potentially could 16 September have either left the telescope exposed Gemini Introductory Talk, I Hook to the elements (in winter! ) or rendered (UK Gemini Support Group) the telescope unusable (shutter stuck 22 September closed) for a considerable period. The Present and Future Laser Guide Star first priority was to make sure the Developments for the WHT, C Dainty telescope would be left in a safe (Imperial College London) condition, but this did not prevent that night’s observing taking place. 27 October Forever Blowing Bubbles... White The following day, a Sunday, a full Dwarfs, Supernovae and Local Interstellar Space, M Barstow team went to the telescope and (University of Leicester) effected a temporary repair, using spares already held. Again no observing 4 November time was lost. ground. After a risk analysis a safe Triffid Optical Observations of system of working was introduced, Isolated Neutron Stars, Andy It was decided after inspection that a involving first of all physically securing Shearer (University College Galway) longer term solution was needed. What the several tonne dome shutter, to prevent it descending, while the 22 November was found was that the mechanism The Background and Status of the over the last 15 years ‘hard labour’ mechanisms and cables were removed. SALT Project, David A H Buckley had bored through the casing, so at a Staff working outside the handrailed (South African Astronomical cost of 25,000 pounds it was decided areas were secured by ‘bosuns chairs’ Observatory) to replace all units and include a set safety harnesses. of strategic spares for the future. After 10 February research the units were sourced from After long hours the team from the The Formation of Multiple Shells in Mechanical and Site Services groups Planetary Nebulae, R Corradi (ING) the original supplier. completed the work within the 15 February While they were being delivered two allocated period and handed the Mid and FIR Spectral Energy nights/three days (24–26 August) telescope back for observing on the Distribution of Two Active Galaxies: were allocated in semester 2000B to third night. NGC 6090 and NGC 7582, J Acosta carry out the work, with as much (Instituto de Astrof ísica de Canarias) preparation as possible done off the It is to everyone involved’s credit telescope. that from the problem occurring in 21 February The Stellar Content of Elliptical and February until its permanent repair Spiral Galaxies from Near-Infrared To carry out the work the largest six months later, no observing time Spectroscopy, P James (Liverpool crane on La Palma was hired (see was lost — what could have been a John Moores University) photographs) to lift the half-tonne long outage was averted. units. 28 February So the INT dome shutter is now ready WHT-Integral Field Spectroscopy A major concern was naturally the for the next fifteen or more years combined with HST-imaging of Central Regions of Galaxies, S Arribas safety of those carrying out the work, service. ¤ (Instituto de Astrof ísica de Canarias) due to the exposed location on top of a concave dome 30 metres above the Kevin Dee ([email protected])

31 No. 2, March 2000 THE ING NEWSLETTER

TELESCOPE TIME

Applying for Time

Danny Lennon (Head of Astronomy, ING)

t is important that applicants for INGRID commissioning slipped from from Hertfordshire University, on a I telescope time familiarise January 2000 (99B) into March 2000. one year placement scheme, and themselves with the latest news The 99B commissioning slots were besides providing JKT support are on instrumentation and detector re-allocated to three PATT 2000A working on science projects supervised combinations on offer, as well as with proposals (P/2000A/4, 6 and 8), many by ING astronomy staff. (Dan is our scheduling restrictions. PPARC thanks to Tom Marsh and Sean Ryan working a project concerning issue the PATT newsletter for coming out at very short notice supernovae environments supervised electronically, about one month for these observing runs. NAOMI by Nic Walton, while Rachel’s project before application deadlines, which commissioning, using INGRID, is is on the use of radio galaxies to contains up-to-date information on now scheduled for June and July in probe the dust in spiral galaxy disks instrument availability. However for semester 2000A. Prospective users of and is supervised by Chris Benn.) the very latest news always refer to INGRID should keep a check on its the ING web pages, homepage homepage at: Service http://www.ing.iac.es, where http://www.ing.iac.es/IR/INGRID/ application forms and style files may ingrid1_home.htm, also be obtained. The ING’s or contact Chris Packham for the The service program is now managed scheduling constraints were latest information. For the latest on by Ian Skillen, the ING Scheduler summarised in the first issue of the NAOMI, please contact Chris Benn. and Technical Secretary to PATT. ING Newsletter and will not be Note that the slippage in INGRID Service users with time-critical repeated here, please refer to that has also had a knock-on effect for programs in particular are reminded issue, which is also available on our small fibres on AF2, and they will that there is no guarantee of a program Public Information web pages. now not be commissioned in 2000A. being carried out on a particular Applications should be submitted by service night. Time-critical observations email only, by the appropriate As discussed by René Rutten in this are carried out on a best efforts basis deadline and no earlier than one issue, both LDSS and TAURUS only. This is due to a number of month before that deadline, to were withdrawn as common-user factors, among them instrument [email protected]. instruments, and offered to the availability, grade and nationality community for adoption. Both (we aim for a balance between all What’s new instruments received bids and indeed three allocation panels). For time- LDSS is back on the WHT as a visitor critical observations, especially for those where it is possible to predict The 2-chip CCD mosaic, consisting of instrument in 2000A. Anyone interested the frequency of events, it might be two 4k×2k EEV detectors, was in using LDSS in future semesters better applying for an over-ride successfully commissioned on the should contact Richard Bower at proposal through the normal PATT/NL prime focus of the WHT, see the article Durham ([email protected]). channels. At present, time-critical by Simon Tulloch in this issue for It seems likely that TAURUS will service proposals do not have over- further details. Commissioning on also be adopted, subject to the ride status on service nights, or UES is due to be completed in early successful completion of some indeed any other night, while 2000, no problems are foreseen. One ongoing discussions. of the important advantages which approved over-ride programs can this will offer over the 2k×2k SITe In the last issue we proposed two over-ride service nights, as well as detector is an increased maximum possible ways of reducing operational UK and NL scheduled nights. resolving power of 80,000. However, costs of the JKT, either by providing due to fringing problems with the a day-time introduction only or Service users are also reminded that EEVs in the red, the SITe will remain providing night-time support using the time limit of INT and JKT the detector of choice with UES if one students. We settled on the latter programs has now been increased is working beyond about 6000Å. Some solution and night-time support on from three to five hours. ¤ testing will be done to quantify the the JKT is now provided mainly by fringing problem with the EEVs on Rachel Curran and Dan Batcheldor. UES during commissioning. Rachel and Dan are undergraduates Danny Lennon ([email protected])

32 THE ING NEWSLETTER No. 2, March 2000

Telescope Time Awards Semester 2000A

ITP Programmes on the ING Telescopes – Rawlings (Oxford), The cosmic evolution of radiosources using the TEXOX 1000-radiosource redshift survey (99B, long-term) – Barcons (Santander), An XMM international survey — – Rawlings (Oxford), Evolution of z∼1 6C galaxies: AXIS: the origin of the hard X-ray background discerning the role of the radio source – Pérez-Fournon (IAC), Optical and near-infrared follow- – Refregier (IoA), Measuring the cosmic shear arising up of the European large area (ELAIS) and ISOCAM from large-scale structure Lockman Hole (ILHS) ISO surveys – Ryan (OU), The primordial lithium abundance – Sarre (Nottingham), Search for diffuse band carriers in William Herschel Telescope the circumstellar shell of IRC+10°216 – Serjeant (ICSTM), Optical wide field imaging of CHANDRA/ISO/UK sub-millimetre survey area UK PATT – Skillen (ING), Rapid observation of gamma–ray burst optical afterglows – Smail (Durham), A joint WHT/HST survey of the – Bower (Durham), Galaxy evolution in poor clusters galaxy populations within lensing clusters – Burleigh (Leicester), The mass distribution, magnetic – Storey (UCL), H-deficient knots as the cause of spatial field function and origin of magnetic white dwarfs abundance variations in planetary nebulae – Cameron (St Andrews), The albedo spectrum of the – Tadhunter (Sheffield), The physics of the narrow line giant exoplanet orbiting τ Boo region in powerful radio galaxies – Clements (Cardiff), Arp 220 integral field spectroscopy: – Tanvir (Herts), Rapid imaging of GRB error boxes and supporting CHANDRA observations spectroscopy of GRB-related optical/IR transients – Davies (Durham), Mapping early type galaxies along – Terlevich (Birmingham), The triggering mechanism for the Hubble sequence the Butcher-Oemler effect – Haswell (OU), Outbursts in black hole X-ray transients: – Walton (ING), Lambda – Omega: The low redshift coordinated WHT/RXTE/HST observations (99A, Type Ia SN connection long-term) – Jeffery (Armagh), Asteroseismology of pulsating NL NFRA PC subdwarf B stars and a DB white dwarf – Jeffries (Keele), The true lithium abundance in halo stars – Kleyna (IoA), Dark matter in the UMi and Draco dwarf – van den Berg (Utrecht), High-resolution spectroscopy of spheroidal galaxies two blue straggler binaries in M67 – Knapen (Herts/ING), Star formation in arm and – Best (Leiden), Emission line gas inside and outside CSS radio sources: determining the origin of the gas interarm environments in spiral galaxies – Best (Leiden), Evolution of z∼1 6C galaxies: discerning – Knapen (Herts/ING), Hα survey of nuclear star-forming the role of the radio source rings in spirals – Bézecourt (Kapteyn), R and Z band imagery of cluster – Mathieu (Nottingham), Dynamics of superthin galaxies A2219 for the determination of photometric redshifts – Maxted (Southampton), Testing theories of common – Douglas (Kapteyn), Planetary nebulae in Virgo cluster envelope evolution with double degenerates galaxies – Merrifield (Nottingham), Mapping elliptical galaxy – Kregel (Kapteyn), The stellar velocity distribution in mass distributions using gravitational redshift the thin disk of NGC 5529 – McHardy (Southampton), Deep R-band imaging of very – Luu (Leiden), Rotational properties of Kuiper Belt objects deep XMM survey fields – Pickering (Kapteyn), Near-IR imaging of low surface – McMahon (IoA), Probing the ionization state of the brightness galaxies universe at z>5 – Vreeswijk (Amsterdam), Rapid imaging of GRB error – Morales-Rueda (Southampton), What distorts the boxes and spectroscopy of GRB-related optical/IR radial velocity curves of accretion disks? transients – Pettini (IoA), The large-scale structure of galaxies at – van der Werf (Leiden), Distant submillimeter galaxies – redshift z≈3 their nature and their redshift distribution – Pollacco (QUB), Restarting the fast wind in the Sakurai – de Zeeuw (Leiden), Mapping galaxies along the Hubble object (V4334 Sagittarii) sequence

33 No. 2, March 2000 THE ING NEWSLETTER

SP CAT – Ellis (IoA), Comparisons of star formation diagnostics in the local and intermediate redshift universe – Howarth (UCL), Colliding winds in massive close binaries – Aretxaga (INAOE), The QSO – host galaxy luminosity – Keenan (QUB), Identification of hot stars in globular relationship at z=2 clusters – Cairós (IAC), Infrared photometry of blue dwarf – Maxted (Southampton), Are sub-dwarf B stars the galaxies: the low surface brightness component result of common-envelope evolution? – Colina (IFCA), Integral field spectroscopy of – McMahon (IoA), A public near IR imaging survey on ultraluminous infrared galaxies the INT – Colina (IFCA), A study of galaxies under star formation – Morales-Rueda (Southampton), Spectroscopy of dwarf at high redshift novae in outburst (99B, long-term) – Díaz (UAM), Determination of the velocity dispersion in – Naylor (Keele), Does magnetic activity drive mass starforming circumnuclear regions transfer in cataclysmic variables? – González (IAC), Star formation history in galaxies from – Stetson (DAO), Helium burning variables in Ursa mid-infrared measurements Minor and Draco dwarf spheroidals – Israelian (IAC), Searching for the evidence of supernova – Tanvir (Herts), Rapid imaging of GRB error boxes and spectroscopy of GRB-related optical/IR transients events in the low mass X-ray binary systems Her X-1 – Terlevich (Birmingham), The photometric properties of and Cyg X-2 galaxy groups – López (IAC), Kinematics of the nuclear bar of NGC 5850 – Watson (Leicester), Wide field imaging for the XMM – Pérez (IAA), Stellar dynamics and circumnuclear serendipitous sky survey structure in isolated galaxies – Pérez-Fournon (IAC), Mach disks and bow shocks in NGC 4258: testing the role of mechanical energy in NL NFRA PC AGN NLR’s – Rodríguez (IAC), Fe abundance in blue compact galaxies – Jimenez (Kapteyn), A much-improved stellar library for stellar population synthesis – Orosz (Utrecht), Atmospheric parameters of subdwarf Isaac Newton Telescope binary stars – Tschager (Leiden), The optical hosts of young radio UK PATT sources – redshifts (3) – Vreeswijk (Amsterdam), Rapid imaging of GRB error boxes and spectroscopy of GRB-related optical/IR – Benn (ING), Extinction of background radio galaxies by transients foreground spirals – Croom (ICSTM), A photometric redshift survey in deep UK/NL WFS Programmes X-ray fields – Dalton (Oxford), The Oxford deep WFC imaging survey Important Dates – Davies (Cardiff), Multi-coloured large area survey of the Virgo cluster – Driver (St Andrews), The Millenium galaxy catalogue Deadlines for submitting applications – McMahon (IoA), The INT wide angle survey – Groot (Amsterdam), The faint sky variability survey UK and NL PATT: 31 March, 30 September SP CAT SP CAT: 1 April, 1 October – Aparicio (IAC), The north-west tidal current in Sagitarius ITP: – Caon (IAC), The environment’s influence on the ionised 30 June gas in elliptical galaxies – González-Serrano (IFCA), Redshifts of bright galaxies from the Westerbork radio survey Semesters – Hammersley (IAC), A deep multi-wavelength survey of Semester A: the galactic plane – Marín (IAC), Globular cluster systems in Coma 1 February – 31 July – Martínez-Delgado (IAC), Structure of tidal residuals in Semester B: the Ursa Minor galaxy – Nebot (Barcelona), Physical parameters of the open 1 August – 31 January clusters NGC 1817, NGC 1807 and NGC 2548

34 THE ING NEWSLETTER No. 2, March 2000

– Pérez-Fournon (IAC), Near-infrared imaging of a deep Abbreviations CHANDRA X-ray survey – Rosenberg (IAC), Galactic globular cluster relative ages AAO Anglo-Australian Observatory and the Milky Way formation (II) CAT Comité para la Asignación de Tiempo CfA Harvard-Smithsonian Centre for Astrophysics – Vazdekis (Durham), Horizontal branch effects in the DAO Dominion Astrophysical Observatory (Canada) spectra of globular clusters DIAS Dublin Institute for Advanced Studies – Vega (IAC), Search for galaxies with orthogonal ESTEC European Space Technology Centre rotating bulge and disk HST Hubble Space Telescope – Vílchez (IAA), An Hα survey of the Coma and A1367 IAA Instituto de Astrofísica de Andalucía Clusters IAC Instituto de Astrofísica de Canarias IAUNAM Instituto de Astronomía de la Universidad Nacional Autónoma de México Jacobus Kapteyn Telescope IC Imperial College London ICSTM Imperial College of Science, Technology and Medicine IFCA Instituto de Física de Cantabria UK PATT INAOE Instituto Nacional de Astrofísica, Optica y Electrónica (Mexico) IoA Institute of Astronomy – James (LJMU), A survey of star formation in the local ITP International Time Programme universe LJMU Liverpool John Moores University – Knapen (Herts/ING), Star formation in arm and MSSL Mullard Space Science Laboratory interarm environments in spiral galaxies MSSSO Mount Stromlo and Siding Spring Observatories – Norton (OU), Photometric study of the newly discovered NBST National Board of Science and Technology of Ireland intermediate polar 1WGA J1958.2+3232 NFRA Netherlands Foundation for Research in Astronomy NL The Netherlands – Seigar (Gent), Optical properties of the disks of spiral OAN Observatorio Astronómico Nacional (Spain) galaxies OU Open University (UK) – Shahbaz (Oxford), Probing the accretion disc in SW Sex PATT Panel for the Allocation of Telescope Time type stars PC Programme Committee – Sorensen (ING), The binary frequency in planetary QUB Queen’s University of Belfast nebula central stars: short period objects RAL Rutherford Appleton Laboratory – Tanvir (Herts), Rapid imaging of GRB error boxes and SP Spain STScI Space Telescope Science Institute spectroscopy of GRB–related optical/IR transients UAM Universidad Autónoma de Madrid – Tsapras (St Andrews), A search for planetary UCL University College London anomalies on high amplification microlensing events UCLAN University of Central Lancashire – Walton (ING), Lambda – Omega: the low redshift UK The United Kingdom Type Ia SN connection WFS Wide Field Survey – Warren (ICSTM), Remote halo blue horizontal branch stars and the mass of the Milky Way (99B, long-term) – Woolf (Armagh), Photometry of pulsating helium stars NL NFRA PC

– van den Berg (Utrecht), Photometric monitoring of an X-ray blue straggler in M67 – van der Hulst (Kapteyn), R-band imaging of galaxies in the WHISP sample – Pickering (Kapteyn), B-band imaging of LBS galaxies – Vreeswijk (Amsterdam), Rapid imaging of GRB error boxes and spectroscopy of GRB-related optical/IR transients SP CAT

– Delfosse (IAC), Accurate optical and infrared photometry of field very low mass stars and brown dwarfs – de Diego Onsurbe (IAUNAM), Spectral characterisation of quasar microvariavility – Nebot (Barcelona), Physical parameters of the open clusters NGC 1817, NGC 1807 and NGC 2548

35 Contents

Message from the Director ...... 1 The Isaac Newton Group of Telescopes ...... 2 The ING Board and the Instrumentation Working Group ...... 2 The ING Newsletter ...... 2 SCIENCE

A Collier-Cameron, K Horne, A Penny, D James, WHT Achieves First Direct Detection of an Extra-solar Planet ...... 3 P Vreeswijk, N Tanvir, T Galama, Gamma-Ray Burst Afterglows: Surprises from the Sky ...... 5 D Pollacco, The Sakurai Object: A Case Study in Advanced Stellar Evolution ...... 9 R Corradi, M33 Galaxy miniposter (central pages) TELESCOPES AND INSTRUMENTATION

P T de Zeeuw, J R Allington-Smith, R Bacon, M Bureau, C M Carollo, Y Copin, R L Davies, E Emsellem, H Kuntschner, B W Miller, G Monnet, R F Peletier, E K Verolme, The One Eye that Sees All: Integral Field Spectroscopy with SAURON on the WHT ...... 11 L Michaille, J C Quartel, J C Dainty, N J Wooder, R W Wilson, T Gregory, First Sodium Laser Beacon at La Palma ...... 15 C Packham, R W Wilson, M Azzaro, N O’Mahony, S Fine, D Gray, V Reyes, C Martín, The Half Arcsecond Programme (I) ...... 21 G Talbot, WHT Millenium Upgrade ...... 23 R Rutten, New Instrumentation for the WHT ...... 24 S Tulloch, The New WHT Mosaic Camera ...... 26 OTHER NEWS FROM ING

G Talbot, Y2K at the ING ...... 28 [INGNEWS] Mailing List ...... 28 N Johnson, News from the Computing Facilities Group ...... 29 Personnel Movements ...... 29 Other Recent ING Publications ...... 29 D Folha and T Lago, CAUP at ING ...... 30 Seminars and Talks given at ING ...... 31 K Dee and G Talbot, A Big Effort (and a Big Crane) Solves a Big Problem ...... 31 TELESCOPE TIME

D Lennon, Applying for Time ...... 32 Telescope Time Awards Semester 2000A ...... 33 Important Dates ...... 34

Contacts at ING Tel. (+34 922) E-mail (@ing.iac.es)

Site Receptionist Mavi Hernández 405655 mavi Sea-level Office 425400 Director René Rutten 425420 rgmr Personal Secretary to Director Rachael Miles 425420 miles Head of Astronomy Danny Lennon 425441 djl Head of Engineering Gordon Talbot 425419 rgt Public Relations Javier Méndez 425464 jma Telescope Scheduling Ian Skillen 425463 wji Service Programme Ian Skillen 425463 wji WHT Manager Chris Benn 425432 crb INT Manager Thomas Augusteijn 425433 tau JKT Manager Thomas Augusteijn 425433 tau Instrumentation Scientist Nic Walton 425440 naw Engineering Operations Manager Clive Jackman 425446 cwmj Freight Juan Martínez 425414 juan

ISAAC NEWTON GROUP OF TELESCOPES Roque de Los Muchachos Observatory, La Palma WHT INT JKT