NEWSLETTER The completion of the Archive and Databases Project (Ray Stathakis et al.) et Stathakis (Ray Project Databases and Archive the of completion The news Local 2dF Highlights - the release of three 2dF databases 2dF three of release the - Highlights 2dF SPIRAL from Science Gibson) Brad & Bland-Hawthorn (Joss Group? Local the of blocks Building Clouds: Velocity High Orchiston) (Wayne mounting horseshoe the of origin design: telescope in innovation Australian al.) et Saunders (Will light! the sees 6dF 6dF has arrived! has 6dF 18 20 3 8 10 12 14 It is planned to collect 120,000 galaxy spectra for a major survey, and another 60,000 objects for objects 60,000 With another the and commissioning survey, major a for spectra galaxy 120,000 collect of to 6dF, theplanned is UKST It is poised top14. on enter article the See a newprogrammes. survey erasmaller of of range spectroscopica surveys.
contents
NUMBER 97 MAY 2001 MAY NUMBER 97 ANGLO-AUSTRALIAN OBSERVATORY DIRECTOR'S MESSAGE DIRECTOR'S DIRECTOR'S MESSAGE
A number of key decisions on the future of the AAO were reached at the March 2001 AATB meeting. I am delighted to report that the strategic alliance between the UK and Australia in the AATB will continue on for at least a further five years beyond 2005. The nature of the partnership will change over this time, recognizing the differing priorities of the UK and Australia. Australia will take on a larger role in operating the AAT, while the UK will increasingly look to the AAO to provide leading-edge instrumentation to meet its requirements over the coming decade. The UK will also maintain operational support for the AAT beyond 2005, albeit at a significantly reduced level. This will enable Australia to capitalise on operational funds released for the external instrumentation program.
The AAOís success in its external instrumentation initiative, started by Keith Taylor with the OzPoz project, has provided the AAO with the opportunity to embark on this new strategic direction. External projects now form a sustainable part of the AAOís business. As OzPoz is delivered to ESO by the end of the year, the AAO hopes to undertake new contracts to collaborate with the University of Cambridge on the DAZLE design and work with the Subaru team on the Echidna fibre positioner for the FMOS instrument.
Strategic planning also played a major part in the AATBís decision. I would like to take this opportunity to thank all members of the UK and Australian user communities for their input to the planning process which led to the production of the ëAAO of the Futureí ñ the document that forms the basis of the agreement reached between Australia and UK at the March meeting. I believe that we have achieved an excellent outcome for the communities, the AATB and AAO.
The AAO of the Future cannot be achieved, however, without significant operational savings. Although this will largely occur by moving existing Epping staff from telescope support to external instrumentation, it will still have a significant impact on the range of services we can provide at the telescope. The AAOís goal is still to provide the opportunity to carry out world-class science on the telescopes, but it will need to be done within the context of a reduced core instrument suite and longer observing runs. The challenge over the next five years is to invest sufficient resources in infrastructure and AAT instrumentation such as AAOmega, to allow us to sustain operations at a reduced level in the long term while maintaining as much functionality in the instrumentation suite as possible.
The success of the AAO has always been built on its innovative instrumentation and the strong science drivers behind such instrumentation. One only needs to look through the pages of this newsletter to see the scientific impact of the 2dF surveys (galaxy, QSO and Fornax cluster) and the promise of the 6dF survey. By building on this success, the AAO can look forward to the next ten years with renewed confidence.
Brian Boyle
Next Issue:
If you have some recent results based on AAT or UKST data, or other items of interest, please send articles to [email protected] by Monday, July 30, 2001. Article length can vary from 2 paragraphs to 2 pages, with preference for plain or latex text, postscript figures and postscript or tiff images.
Picture Credits: the Editors would like to thank Jonathan Pogson for his photographs used on the cover, in the 6dF article, and on page 21. Thanks to David Malin and Katie Powell for AAO photographs on pages 8, 20 and 21.
ANGLO-AUSTRALIAN OBSERVATORY page 2 NEWSLETTER MAY 2001 2QZ, but the main component is a searchable database, which allows the user to select objects from the THE 2DF QSO REDSHIFT SURVEY catalogue, and extract full FITS spectra and DSS 10K RELEASE postage stamps as well as information such as redshift, 2DF HIGHLIGHTS 2DF Scott Croom (AAO), Robert Smith magnitude etc. Also included on the CD are (LJMU), Brian Boyle (AAO), Tom Shanks completeness masks describing the current survey (Durham), Nicola Loaring and Lance coverage on the sky and much other information that Miller (Oxford) may be required in statistical analysis of the data set.
The 2dF QSO Redshift Survey (2QZ) will be completed A complete description of the 10k catalogue is given in at the end of this year, by which time it should contain Croom et al. (2001). The objects selected for this data approximately 25000 QSOs. At the time of writing, release were chosen to be in the fields with high almost 19000 QSOs have been discovered, almost a completeness (at least 85% of spectroscopic sources factor of two greater than the total number discovered identified in each field) observed prior to November 2000. prior to the 2dF survey. A number of key scientific papers The overall spectroscopic completeness of the dataset are already published and on the 4th April 2001 the ì10k is 93%. catalogueî was released. This first public release of data The 2QZ team welcome any comments regarding the was to contain 10000 QSOs from the first observations current data release, both in terms of the database of the 2QZ. In fact the ì10kî data set contains just over format and the data contained within it. We hope that 11000 QSOs, as well as almost 10000 other sources this first data release, along with the final data release (halo stars, white dwarfs, galaxies) to give a total of that should occur at the end of 2002, will provide a 20590 sources with 2dF spectra. valuable and lasting resource for the astronomical All the data from the 10k catalogue is available on line community. at http://www.2dfquasar.org and also on CD-ROM. A CD- References ROM version of the catalogue is included with each institutional copy of this quarterís AAO newsletter. The S.M. Croom, R.J. Smith, B.J. Boyle, T. Shanks, N.S. Loaring, CD contains some basic introductory material to the L. Miller, I.J. Lewis, 2001, MNRAS, 322, L29
PRESTIGIOUS AWARD FOR KEITH TAYLOR Brian Boyle
Keith Taylor has been awarded the Astronomical Society of the Pacificís prestigious Maria and Eric Muhlmann award for 2001. The award is given for recent significant observational results made possible by innovative astronomical instrumentation. Keithís instrumental innovations have resulted in the worldís first scanning imaging Fabry-Perot spectrograph, the low dispersion survey spectrograph and, of course, the 2-degree field. All have produced world-class scientific results that have made major contributions to their respective fields; amply demonstrated by the current scientific impact of 2dF redshift surveys. Previous award winners include Francois and Monique Spite, John Kormendy, Barry Lasker, Peter Stetson, Sam Barden and the DAO/NRC instrumentation group. Keith will receive his award at the summer meeting of the ASP in mid-July.
ANGLO-AUSTRALIAN OBSERVATORY NEWSLETTER page 3 MAY 2001 Our 2dF Fornax Cluster Spectroscopic Survey (FCSS; PUBLIC RELEASE OF 2DF DATA see Drinkwater et al. 2000a) was designed to make the FROM THE FORNAX CLUSTER most complete census possible of low-luminosity SPECTROSCOPIC SURVEY galaxies in the Fornax Cluster. As well as the 2DF HIGHLIGHTS 2DF M. Drinkwater (Melbourne), C. Engel conventional low-surface brightness dwarfs, we already (Melbourne), S. Phillipps (Bristol), had evidence (Drinkwater & Gregg 1998) that very J. Jones (Nottingham) & M. Meyer compact, high surface brightness dwarf cluster galaxies (Melbourne) had been missed in previous work, so we took the unusual step of observing all objects in each 2dF field, Spectroscopy of Everything both resolved (ìgalaxiesî) and unresolved (ìstarsî). In this way we avoided any morphological bias as to what Almost 20 years ago Morton, Krug & Tritton (1985) made a cluster galaxy should look like. Observing all the ìstarsî the first complete spectroscopic survey of a given region in each 2dF field leads to a large increase in the number 2 of sky. They surveyed stellar objects in a 0.3 deg region of targets observed: within our magnitude limits of sky to a limit of B=20, measuring 600 objective prism (16.5 Thanks to the arrival of the 2dF spectrograph on the Status of the Survey AAT, we have recently completed the first stage of a complete spectroscopic survey more than one order of As of 2001 January we have completed observations of magnitude larger than the Morton et al. study, measuring two of our four planned 2dF fields centred on the Fornax 7000 spectra in a 2p deg2 area as part of our study of Cluster. We have analysed the data from our first field the Fornax Cluster. In this article we describe the public and have released it for public access as described release of 3600 spectra from our first field. We hope below. The properties of the sample are summarised in that this public release will encourage colleagues making Figure 1, a plot of surface brightness against magnitude surveys for rare objects to choose these fields, as much for all the objects we successfully observed. The main of the follow-up spectroscopy that might be required is all-object sample was selected in the magnitude range available from our data. 16.5 limit of bJ ~ 20.2. There is some incompleteness for galaxies with surface brightness lower than about 23.5 -2 bJ mag arcsec as we were unable to measure their redshifts (see Drinkwater et al. 2000a). The diversity of objects in our sample is illustrated by Figure 2, a cone diagram of the sample in which the distance axis is scaled (as z1/4) so as to display both Galactic stars and the most distant QSOs. Note that although we avoid the use of conventional morphological classifications in our analysis (we use redshift, spectral signatures and luminosity instead), we do show the morphological classifications in both Figure 1 and Figure 2. The presence of unresolved objects (ìstarsî) in both the Fornax Cluster and among the background field galaxies demonstrates the importance of our all- object strategy. These objects would have been missed by conventional galaxy surveys only looking at objects Figure 1. Surface brightness-magnitude diagram for the that are resolved on UKST sky survey plates. objects we have successfully observed in our first 2dF field. Resolved objects (ìgalaxiesî) are plotted as (blue) filled The scientific highlight of our results to date has been triangles and unresolved objects (ìstarsî) as (red) open circles. The surface brightness measurements are based the discovery of a new population of Fornax Cluster dwarf on exponential fits to the photographic data and are only galaxies so compact they were previously mistaken for indicative for the stars (see Drinkwater et al. 2000a). ANGLO-AUSTRALIAN OBSERVATORY page 4 NEWSLETTER MAY 2001 galaxies previously assumed to be members of the Fornax Cluster are in fact background objects (Jones et al., in preparation). Public Web Access HIGHLIGHTS 2DF The 3600 2dF spectra from our first field are now available for public access at our web site http://astro.ph.unimelb.edu.au/data/ in Melbourne. The main function of the web site is to allow searches of our database by position on the sky and to return our 2dF spectra and redshift measurements of the selected objects. The complete database of measurements is available from the website as a plain text file as well as additional help material and references. The database consists of all the objects for which we have measured reliable redshifts (about 95% of the sample at present). Our 2dF spectra were all obtained with the same observing configuration as for the 2dF Galaxy Redshift Survey: a wavelength coverage of 3600 ñ- 8010 ≈ and a resolution of 9 ≈ (dispersion of 4.3 ≈ per pixel). The spectra have typical signal-to-noise ratios of 10 or more per pixel. The redshifts were measured by cross- correlation with star and galaxy templates; this gives Figure 2. Cone diagram of the objects we successfully -1 observed in our first 2dF field. The ìredshiftî axis measures velocities accurate to about 65 kms for galaxies (see z1/4 in order to display the four orders of magnitude in Drinkwater et al. 2000a for details). The database is distance spanned by our sample. Resolved objects (ìgalaxiesî) are plotted as (blue) filled triangles and searched by entering a co-ordinate and search radius, unresolved objects (ìstarsî) as (red) open circles. Note with a table listing the parameters of any objects that unresolved sources appear in the Fornax Cluster (z1/4 ~ 0.25) and among the background field galaxies observed within that radius being returned. The (z1/4 ~ 0.6). parameters listed include magnitudes and Galactic stars (Drinkwater et al. 2000b). They can be seen among the more normal, resolved Fornax Cluster dwarf galaxies in Figure 2. These ìultra-compact dwarfî (UCD) galaxies are unlike any known type of stellar system. They are smaller and more concentrated than any known dwarf galaxy, but are 2ñ3 magnitudes more luminous than the largest Galactic globular clusters. Numerical simulations have shown that the UCDs could have been formed by tidal stripping of nucleated dwarf galaxies in close orbits around the central galaxy of the cluster, NGC 1399 (Bekki, Couch & Drinkwater 2001). We are making detailed follow-up observations of the UCDs with Hubble Space Telescope imaging to measure their sizes along with high resolution spectroscopy on the VLT to measure their velocity dispersions and hence masses. Other results from the early stages of our survey include the first large QSO sample selected purely from Figure 3. Ub R colour-colour diagram of QSOs and stars spectroscopic identification without any pre-selection j from our first field. The multicolour selection cutoff used by bias (Figure 3; see Meyer et al. 2001) and the the 2dF QSO Redshift Survey is shown by the dotted line. identification of a population of L compact field galaxies We derive completeness values for this multicolour * selection of 90 ± 4 per cent for 0.3 ANGLO-AUSTRALIAN OBSERVATORY NEWSLETTER page 5 MAY 2001 THE 100K DATA RELEASE OF THE 2DF GALAXY REDSHIFT SURVEY 2DF HIGHLIGHTS 2DF The 2dFGRS Team1 The first one hundred thousand galaxy spectra and redshifts from the 2dF Galaxy Redshift Survey (2dFGRS) will be made publicly available on 30 June 2001. This will give the astronomical community and the general public access to the most comprehensive map of the local universe and the largest database of galaxy spectra ever assembled. The database that is released on 30 June will serve as a wonderful resource for many other astronomical projects. It can be used to find large samples of Figure 4. A z=2.43 QSO from our sample (see Meyer et al. 2001), as plotted by the web interface. rare objects for follow-up studies, such as galaxies with active black holes at their centres. It can be matched up with other astronomical surveys to identify radio galaxies or X-ray sources. The galaxy classifications from the APM Catalogues (Irwin, Maddox spectra themselves can be analysed to measure & McMahon, 1994) as well as our own redshift the rate at which stars are being formed and in some measurements. Following our philosophy of avoiding cases to measure the mass of the galaxies. morphological bias in classifications, we do not specifically classify objects in the database (although the APM The 2dFGRS will eventually contain 250,000 classifications are listed for reference). Instead we galaxies, but the data contained in this preliminary recommend the use of our spectroscopic redshifts (in release have already led to some remarkable conjunction with the magnitudes if necessary) to make results. As reported in AAO Newsletter 95, the classifications on a more physical basis, e.g. classifying 2dFGRS team found a distortion in the pattern of objects with redshifts less than 700 kms-1 as Galactic galaxy clustering that is due to the gravitational stars. attraction of all the matter in the universe. A measurement of this distortion implies that the mean To obtain the 2dF spectrum of any object returned in the mass density of the universe W ~ 0.3 (Peacock et output table, click on the ìplotî button for that object. When al. 2001). This means that the matter density is you click on the plot button, the spectrum will appear in a only about 30% of that necessary to stop the new window. The spectrum can then be replotted with expansion of the universe and cause it to re- different axis limits if necessary and downloaded in text, collapse. GIF, PostScript or FITS format. An example of the PostScript output is shown in Figure 4. The most recent result from the 2dFGRS is a measurement of the power spectrum of the galaxy References distribution, calculated using a direct FFT-based Bekki, K., Couch, W.J., Drinkwater M.J., 2001, ApJ, in press technique (Percival et al. 2001). The k-space region Drinkwater, M.J., Gregg, M.D., 1998, MNRAS, 296, L15 0.02 < k < 0.15 h Mpc-1 is sampled with an Drinkwater, M.J., et al., 1999, ApJ, 511, L97 uncertainty of 10ñ15% RMS. The power spectrum Drinkwater, M.J., et al., 2000a, A&A Drinkwater M.J., Jones, J.B., Gregg, M.D., Phillipps, S., 2000b, has been fitted with Cold Dark Matter (CDM) models PASA, 17, 227 to determine both the mean mass density and the Irwin M.J., Maddox S., McMahon R., 1994, Spectrum, 2, 14 ratio of baryonic to dark matter (Figures 1 and 2). Meyer M.J., Drinkwater M.J., Phillipps S., Couch W.J., 2001, The results show that models containing baryon MNRAS, in press Morton D.C., Krug P.A., Tritton K.P., 1985, MNRAS, 212, 325 oscillations are preferred at the 95% confidence level over featureless power spectra, and that the universe is made up of 15% baryonic matter and 85% dark matter. This result is consistent with a number of other constraints such as the current CMB data ANGLO-AUSTRALIAN OBSERVATORY page 6 NEWSLETTER MAY 2001 (Netterfield et al. 2001; Pryke et al. 2001), the latest Deuterium to Hydrogen ratio in QSO spectra (O'Meara et al. 2001) and X-ray cluster analysis (Evrard 1997). HIGHLIGHTS 2DF The observations for the 2dFGRS are due to be completed at the end of 2001, and even more accurate determinations of matter density and baryonic ratios will then be possible. Other results will follow, such as a crucial test of the inflation theory which predicts that, shortly after the Big Bang, the universe went through a† period of ëinflationí, when it increased enormously in size in a very brief instant of time. Such theories predict that on the very largest scales the distribution of galaxies will have a particular form (a Gaussian random field) ñ any deviation from this form would Figure 1. Likelihood surfaces for the best fit linear power be a strong argument against inflation. The galaxy spectrum over the region 0.02 ANGLO-AUSTRALIAN OBSERVATORY NEWSLETTER page 7 MAY 2001 Science from SPIRAL CEC HIGHLIGHTS SCIENCE Targets for a range of scientific projects were observed on SPIRAL in service mode during December and January. Here, preliminary results are shown for three of the projects. THE REFLECTION NEBULA NGC 2261 Jeremy Bailey (AAO) NGC 2261 (Hubbleís variable nebula) is the reflection nebula around the pre-main-sequence star R Mon (Figure 1). Figure 2 shows images derived from a mosaic of four SPIRAL observations which cover the region of the nebula close to R Mon (see Figure 1). The Ha image (on the left) shows the star and the surrounding reflection nebulosity. The star has very strong Ha emission which is scattered by dust in the nebula and is therefore seen throughout the nebula. Figure 2 (right) shows emission in the blue shifted region of the [SII] 6716 ≈ line. The [SII] emission shows a narrow jet extending to the north about 12 arcsec from the star. Figure 1. The reflection nebula NGC 2261 (from the three-colour photograph AAT 96). The 35 x 20 arcsec area covered by SPIRAL is shown as a box. The data are being used to study the variations of the Ha profile at different points in the nebula. In this way we can study what the star would look like if seen at different orientations and thus Figure 2. Images from a SPIRAL mosaic of constrain the properties of the Ha emitting region. NGC 2261 near R Mon. Left: The distribution of Ha emission. Right: Blue-shifted emission from [SII]. THE SN / CSM COLLISION BEGINS Ray Stathakis & Russell Cannon (AAO) Images of the circumstellar ring of SN 1987A taken with the HST show a growing number of hot spots (Figure 1), indicating that the long-awaited collision between the expanding envelope of the supernova and the ring has finally begun (Garnavich et al. 2000, IAUC 7360). Most recently, Figure 1. HST image of the collision Sugerman et al. (2001, IAUC 7623) report 9 interaction sites around the between the SN and the CSM ring. ring. SPIRAL is an ideal instrument to study the chemistry and energetics of the interaction by observing the evolution of emission lines from the ring. Even more importantly, SPIRAL enables us to more efficiently and accurately isolate the collision spectrum from the background nebulosity from 30 Dor and two very bright nearby stars which lie within a few arcsec of SN 1987A. In December a test observation was made, and the ring was detected in [OI] 6300≈ emission. The line profile is broader than the background LMC line (Figure 2), as expected for emission from shocked material in the ring. Following this successful test, we will be making more extensive Figure 2. SPIRAL observations of [OI] 6300≈ line profiles from the shocked ring observations next semester. and the unshocked LMC nebulosity. ANGLO-AUSTRALIAN OBSERVATORY page 8 NEWSLETTER MAY 2001 SPIRAL UNCOVERS LOW SURFACE BRIGHTNESS HIGHLIGHTS SCIENCE GALAXIES M. J. Drinkwater (Melbourne) & D. Lee (AAO) Background Dwarf and low surface brightness galaxies (LSBGs) play a key role in problems such as the ìfaint blue excessî in galaxy number counts (Phillipps & Driver 1995), the star formation history of the universe (Madau et al. 1998) and the irregular morphology of Figure 2. SPIRAL spectrum of sky (top) and LSBG F362-030 (bottom) both summed over 100 fibres (Note the logarithmic intensity scale). galaxies seen in deep HST images (Im et The emission line is Ha at a redshift of z=0.029 or cz=8680 km/s. al. 1995). Further progress in many areas of cosmology relies on a better knowledge of resolved spectroscopy. Most importantly, the ìnod-and-shuffleî the local population of dwarf/LSB galaxies. observing method virtually eliminates systematic errors in sky subtraction. We depend on photographic surveys for our current knowledge of local LSBG SPIRAL observations populations, which are limited by the lack of We performed a test observation of a LSBG with SPIRAL on the spectral confirmation of the dwarf night of 2001 January 5 in engineering time. The galaxy was F362-030, ìcandidatesî, so the true populations are with a total B mag of 18.6 and a surface brightness of 23.9 mag uncertain. There has been intense debate arcsec-2 (Morshidi-Esslinger et al. 1998). The 316R grating was in recent years on the number of faint/LSB used to cover the spectrum from 5800 ≈ to 7140 ≈ at ~4 ≈ resolution. galaxies in clusters, with some evidence for We made 3 cycles of observations, each consisting of 15 pairs of very large LSBG populations (e.g. Trentham 60 sec exposures on the target, and on a blank sky field 30" S ñ 1998; Kambas et al. 2000). effectively 3x15 min on target and sky. There was some cloud, Conventional slit and fibre spectrographs seeing was 1.5", and zenith distance was 45oñ60o. can measure redshift for moderately LSB Figure 1 shows an optical image of the galaxy and the spectra of dwarfs, but they cannot probe deeper into both the sky and the sky-subtracted object are given in Figure 2. the very interesting region at 23.5 Observations like these are a real technological challenge and have proved impossible with conventional spectroscopy, leaving many questions about the LSBG populations of galaxy clusters unanswered. This is therefore an excellent demonstration of the power of the AATís integral field unit SPIRAL combined with nod- and-shuffle observing. References Im et al. 1995, ApJ, 441, 494 Kambas et al. 2000, AJ, 120, 1316 Madau et al. 1998, ApJ, 498, 106 Morshidi-Esslinger, et al. 1998, MNRAS, 304, 297 Figure 1. A blue photographic image of the low Phillipps, Driver 1995, MNRAS, 274, 832 surface brightness galaxy F362-030 (at the Trentham 1998, MNRAS, 294, 193 centre of this 5 arcmin DSS image). ANGLO-AUSTRALIAN OBSERVATORY NEWSLETTER page 9 MAY 2001 Building blocks? HIGH VELOCITY CLOUDS: BUILDING CEC HIGHLIGHTS SCIENCE BLOCKS OF THE LOCAL GROUP? More than one third of the sky is peppered with clumps of neutral hydrogen whose Joss Bland-Hawthorn (AAO) & Brad Gibson (Swinburne) projected motions depart fairly radically from Galactic rotation. Discovered in 1963, these so-called ëhigh-velocity cloudsí Introduction (HVCs) have been the subject of When the early universe was cool enough to form atoms, much of wide-ranging speculation for almost the dark matter existed in small clumps. As time progressed, gravity four decades. inveigled these clumps to cluster together to form bigger systems, In 1999, Leo Blitz and David Spergel and onwards to galaxies. This, of course, is the Cold Dark Matter suggested that HVCs are associated with (CDM) paradigm of galaxy formation and evolution. dark-matter mini-haloes and are distributed While CDM seems to work on the largest scales, it has problems throughout the Local Group. More recently, on the scale of galaxies. The Local Group is predicted to have a Robert Braun and Butler Burton have thousand satellite objects when less than a hundred are seen. proposed a related model specifically for a The fraction of dark matter within the Solar Circle is predicted to subset of extremely compact high-velocity be higher than inferred from observations. Galaxy cores appear far clouds. Both groups argue that the cuspier in simulations than observed. These problems are projected motions of HVCs reflect the sufficiently serious to encourage many theorists to patch up CDM gravity field of the Local Group rather than or to construct alternative cosmologies. the Galaxy. This puts their average distance at hundreds of kiloparsecs, i.e. well beyond But, as CDM would have it, there are good reasons for believing the Galaxy. In consequence, these clouds that the outer reaches of galaxies are still in formation, at least in are typically 20 kiloparsecs in size, about backwaters like the Local Group. After all, we see direct evidence 30 million solar masses of hydrogen, with for infalling galaxies: moving star groups in the halo, the Sagittarius ten times more mass in the form of dark and Magellanic Streams, and so on. Rather than attempting to matter. modify CDM, some astronomers have wondered whether the missing ëbuilding blocksí have been staring us in the face all along. The ëLocal Group Infallí picture is very Itís just that we havenít recognized them. attractive as it unites ideas and observations which have been shelved for years. As early as 1966, Jan Oort noticed that, if HVCs are held up by their own gravity, the so- called ëvirial distanceí would put many of 40 them well beyond the Local Group. For each cloud, 21cm radio observations provide information on the total mass of 20 hydrogen independent of the gravitational mass; these have a different dependence on distance. Since the virial argument rests on a basic assumption, an independent 0 distance estimate is called for. Distance Methods -20 A key method is to look for stars with well- calibrated distances along the sight line to an HI cloud. If the cloud produces absorption in the optical spectrum of the -40 more distant source, but not in the spectrum of the nearer source, the distance -40 -20 0 20 40 to the HVC can be bracketted. This simple Figure 1. The shape of the ionizing radiation field above and below the technique is largely model independent Galactic Plane. The coordinates are with respect to a plane given the small uncertainties in stellar perpendicular to the Galactic disk. The dotted lines show the possible influence of the LMC. The greyscale shows the HI distribution in the Galaxy. ANGLO-AUSTRALIAN OBSERVATORY page 10 NEWSLETTER MAY 2001 distances derived from model atmospheres. At present, Nowhere to Hide this method has provided the most secure distances but it has only been applied to half a dozen clouds within We have now shown that when TAURUS is used in nod HIGHLIGHTS SCIENCE & shuffle mode, we should even be able to detect the 15 kpc. We are part of a 6dF team to obtain distances to thousands of stars along sightlines to HVCs. Some very faint H-alpha glow due to the cosmic UV field on a gas cloud. This experiment takes about two dark-grey fraction of these stars will be suitable for follow-up observations with high resolution spectrographs on nights per cloud. As a result, essentially any HI cloud which fills the TAURUS 10' beam should be detectable Gemini and the VLT in order to find the telltale absorption lines. in H-alpha. Our preliminary conclusion is that the elegant ëLocal An interesting possibility is to find red-giant branch stars within compact clouds. The tip of the RGB in the colour- Group Infallí model first proposed by Blitz and Spergel cannot be right for all HVCs. Most HVCs appear to be magnitude diagram would provide a direct distance to the cloud. Several teams are now using wide-field within 50 kpc of the Galaxy. Primordial gas clouds have yet to be uncovered, assuming such things still exist at imagers for this purpose and, indeed, the WFI camera at Siding Spring is well placed for this experiment. the present epoch. However, as Braun and Burton have suggested, compact H-alpha Distances HVCs ó which comprise a small subset of HVC In 1997, one of us (JBH) and P.R. Maloney proposed a catalogues ó could be much further out. Some appear new method which has the potential to reach to greater to have steep velocity gradients! If these clouds are not distances than stellar distance brackets. Any HI cloud associated with the Stream, we would predict that these that can be detected by a radio telescope will have a clouds are very weak in H-alpha emission. Future nod high enough column density to absorb UV ionizing & shuffle observations with TAURUS should provide the radiation that happens to fall upon it. In which case, the definitive result. observed Ha flux will be proportional to the strength of the external ionizing field. This method requires a model of the UV radiation field in the vicinity of the Local Group. One such model is shown in Figure 1. THE SUPERCOSMOS SKY Initially, we normalized the model to the H-alpha SURVEY: FULL SOUTHERN brightness of the Magellanic Stream which goes right HEMISPHERE COVERAGE over the South Galactic Pole. But Ben Weiner, using a IN Bj & R Fabry-Perot at Las Campanas, has now shown that the Stream is positively booming in places, and this cannot Nigel Hambly & Mike Read (Wide be explained by any reasonable Galactic model. This Field Astronomy Unit, Edinburgh) emission may arise from a rapid shock due to self- interaction along the Stream. We are pleased to announce the release of full southern hemisphere two-colour data from the H-alpha Detections SuperCOSMOS Sky Survey (SSS). All fields up to and including the equator now have coverage in at Three separate groups (Las Campanas, WHAM at Kitt least Bj and R; high latitude fields and some other Peak, TAURUS at AAT) have been collecting H-alpha areas additionally have data in I and a second epoch detections for a large set of HVCs. The TAURUS team in R. SSS data comprise pixels from digitised includes both authors, M. E. Putman, S. Veilleux and Schmidt plates along with object catalogues P. R. Maloney. Most of the HVCs appear to be detected containing astrometric (i.e. positions, proper at levels which put the clouds within 50 kpc of the motions), photometric (i.e. magnitudes/colours) and Galaxy. Individual cloud groups have a small H-alpha image morphology/classification data. For a cook- dispersion which is consistent with the H-alpha arising book style introduction to the database, please see from a distant source. Some HVCs which are known to the article by us in AAO Newsletter No. 92, page be close to the Galactic disk have enhanced [NII]/H- 16 (February 2000). The survey home page is at alpha emission as expected for the warmer temperatures at disk altitudes of a few kiloparsecs. This effect is http://www-wfau.roe.ac.uk/sss routinely seen in studies of high-altitude gas in edge-on spirals. The documentation section now provides links to three detailed papers recently submitted to MNRAS. These papers give a full description of the SSS. ANGLO-AUSTRALIAN OBSERVATORY NEWSLETTER page 11 MAY 2001 as the ordinary bearing, and it would work HISTORY OF ASTRONOMY AUSTRALIAN INNOVATION IN quite as freely. A small piece projecting from TELESCOPE DESIGN: the stand over the inner part of the semi-circle, ORIGIN OF THE HORSESHOE and two small stops, prevent the polar axis from MOUNTING being turned too far, or thrown off its bearing. Wayne Orchiston (AAO) Now the axis of the tube (declination axis) is made to bisect the polar axis, and the One of the most distinctive of all telescope mountings telescope may therefore be laid down in the is the modified yoke, or ìhorseshoeî design, of the 5.08m semi-circular bearing, until it points to the pole, Palomar Reflector. Although F.G. Pease is generally or it may be pointed at any degree of given credit for the mounting (King 1979: 408), a number declination between that and 20∫ north of other individuals independently came up with the declination, and in right ascension it may be design during the 1920s (Woodbury 1948: 208-211). moved at least six hours on either side of the What is not so widely known is that the first published meridian.... account of such a mounting dates much earlieróto the nineteenth centuryóand came from the pen of H.C. Now as to the weight of the polar axis. Russell, Director of the Sydney Observatory. Having much less to carry than the ordinary polar axis, and, from the method of support, While Henry Chamberlain Russell (1836-1907) is best all its own weight and that of the tube being known for his pioneering efforts in Australian brought within its bearings, it may be made meteorology, telescope-making and astronomical light without fear of vibration. Another photography and for the contribution that he made to advantage, or rather several, will be found in southern double star research, he also enjoyed designing the fact that there is less work in its construction, new scientific instruments (Orchiston 1988; Wood 1958). less metal to pay for, less trouble in putting it This is how he came to independently develop the together, less room required in the observatory, horseshoe style of telescope mounting (see Orchiston greater facility of transport, and greater ease 2000). of working. (Russell 1879a: 250; my italics). At the 1878 November meeting of the Astronomy Section Although no diagrams accompanied the paper, Russellís of the Royal Society of New South Wales Russell read original plans prepared to describe this mounting have a paper titled ìOn a new form of equatorial mountingî, survived in the archives of the Sydney Observatory and and this was subsequently published in the Journal and one of these is reproduced here in Figure 1 to illustrate Proceedings of the Society. In this paper, Russell the salient points of the design. describes his new form of mounting: As it happened, Russellís idea for this new style of The plan proposed then is, to make a polar mounting came at a most opportune time. When Asaph axis, the lower end of which is similar to that Hall reported the existence of two satellites of Mars in in an ordinary [English] equatorial stand, but 1877, Russell discovered to his profound disappointment from that point upwards it branches into two that they were not visible in the Observatoryís largest arms, wide enough apart to allow the telescope telescope, a 29.2cm Schroeder refractor. His solution room to move between them. On these arms was simple: he would save the Government money and the telescope is supported, like a transit construct a larger telescope himself. The instrument instrument, on its centre of gravity, so that no was a Newtonian reflector with an aperture of 38.1cm counterpoise is required; and the tube being (see Orchiston and Bhathal 1982), and Russell ground, supported at two points need not be made so polished and figured the optics himselfóno mean feat strong as in the ordinary mounting.... [We then in the days when silver-on-glass mirrors were beginning extend] the two sides of the polar axis beyond to gain supremacy over their speculum metal the point at which the telescope is supported, predecessors. Meanwhile, Russell had in mind to see about one-third of their length, and there unite whether his novel style of mounting would actually work them into a very rigid semi-circular piece, which by using it with the new telescope. is very carefully turned, and runs on two large friction wheels; this, in fact, constitutes the The completed telescope, with mounting, was proudly second bearing of the polar axis. With proper displayed at the Great Sydney Exhibition of 1880 care, such a bearing may be made sufficiently (Russell 1879c), and Russellís next challenge was to accurate for the purpose ñ I think as accurate adequately house the instrument within the grounds of ANGLO-AUSTRALIAN OBSERVATORY page 12 NEWSLETTER MAY 2001 run in an iron way level with the floor, and one foot above the HISTORY OF ASTRONOMY ground.î By mid-October of 1880 the new observatory was finished and the reflector was operational (Russell 1880c), but despite its increased light grasp there is no evidence that this instrument was ever used for serious observational astronomy and in 1891 it was removed to make way for the 33cm Grubb astrograph acquired for the International Astrographic Project. The telescope was later donated to the University of Sydney, while the horseshoe mounting remained in storage at Figure 1: Russellís horseshoe equatorial mounting. the Observatory, gathering dust, until the 1950s when it was given to a local amateur the Sydney Observatory. In a letter to John Tebbutt astronomer. dated 1880 September 20 he wrote: It was only following the closure of the Observatory as a research facility and its conversion to a museum of I am putting up a cheap observatory for the astronomy that the historic significance of the old Russell large reflector which I hope to show you in mounting was finally recognized, and in 1999 staff position next time you come [to the Sydney succeeded in retrieving it. As a result, an important Observatory]. The Observatory will be round, Australian contribution to international telescope design 26 feet in diameter and 18 feet in height, and is now preserved for posterity in the scientific collections with the one exception of the great reflector at of the Museum of Applied Arts and Sciencesóthe Melbourne it is I believe the largest telescope institution that currently operates the Sydney in the Southern Hemisphere. (Russell 1880b). Observatory. Russellís reference to the aperture of the telescope vis- References ‡-vis the ìGreat Melbourne Telescopeî (38.1cm versus 1.22m) is interesting, as is his mention of a ìcheapî King, H.C., 1979. The History of the Telescope. New York, observatory. In fact, Government assigned £200 for its Dover Orchiston, W., 1988. Vistas in Astron., 32, 49 construction (Russell 1880a), a non-trivial sum at the Orchiston, W., 2000. J.Antique Telescope Society, 19, 13 time considering that Russellís annual salary in 1876 Orchiston, W., and Bhathal, R., 1982. B.A.A. N.S.W. Branch was just £600 and by 1884 had crept up to £700. Bull., 612 (Supplement), S1 Russell, H.C., 1879a. J.P.Roy.Soc.N.S.W., 12, 249 Just like the telescope it protected, the design of the óó, 1879b. Letter to the Under Secretary, Department of observatory was itself of considerable interest. Instead Justice and Public Instruction, dated September 6 (copy in Sydney Observatory Letter Book 1875-1888) of the more typical hemispherical design, the dome was óó, 1880a. . Letter to the Under Secretary, Department of conical in form. Moreover, in this instance the entire Justice and Public Instruction, dated July 21 (copy in building rotatedónot just the domeóthereby serving Sydney Observatory Letter Book 1875-1888) as a worthy Australian predecessor to the novel óó, 1880b. Letter to John Tebbutt, dated September 20 (in Letters to J. Tebbutt 1880, Mitchell Library) observatory built nearly a century later at Siding Spring óó, 1880c. Letter to John Tebbutt, dated October 7 (in to house the New Technology Telescope. Russell (1892) Letters to J. Tebbutt 1880, Mitchell Library) provides a brief but useful description of the 1880 óó, 1892. Description of the Star Camera at the Sydney observatory building: ìÖ The walls and roof are made Observatory. Sydney, Sydney Observatory Wood, H.W., 1958. Sydney Observatory 1858 to 1958. of thin iron on a light wooden frame, which is 26 feet in Sydney, Government Printer (Sydney Observatory diameter. This construction secures the same Papers No. 31) temperature inside and outside. The walls and roof are Woodbury, D.O., 1948. The Glass Giant of Palomar. New attached and revolve together on five cannon balls, which York, Dodd, Mead & Company ANGLO-AUSTRALIAN OBSERVATORY NEWSLETTER page 13 MAY 2001 6DF SEES THE LIGHT! OBSERVATORYNEWS Will Saunders, Quentin Parker, Fred Watson, Gabriella Frost, Tony Farrell, Peter Gillingham, Brian Hingley, Rolf Muller, Urs Klauser, Dale Douglas, John Dawson, Roger Haynes, Niki Frampton, Stan Miziarski, Dwight Horiuchi, Neal Schirmer, Jeremy Bailey, Kristin Fiegert, Ken Russell, Malcolm Hartley, Paul Cass, Alan Lankshear, Bob Dean, Ed Penny, Robert Patterson, Darren Stafford, Brendan Jones, Neville Hopkins, John Stevenson, Chris McCowage & Matthew Colless 6dF (Six Degree Field) is the new robotic multifibre A proposal by MMC, QAP, WS, Gary Mamon (Paris) spectroscopy system for the UKST. It allows 150 targets and others to carry out an all-southern-sky galaxy redshift to be simultaneously observed over a field 5.7 deg survey ó with the unique additional component of a diameter at resolutions of R = 600 - 5000. It offers a subset peculiar-velocity survey ó was a key element unique facility for spectroscopic follow-up of bright (V<17) of an options paper for the UKST, presented to the AATB targets with source densities in the range 1 ñ 50 deg-2 ñ in August 1997. As a result of this, a Phase-A study for i.e. almost anything too sparse for effective use with an automated fibre positioner was carried out, and 2dF but with too many objects for efficient single-slit construction was approved by the Board in March 1998. spectroscopy. In particular, the first large surveys in new Its preliminary anticipated cost was ~$A0.6M and the wavebands (IRAS, ROSAT, 2MASS, HIPASS) are almost survey was expected to start in April 2001. The scope invariably wide-angle but shallow, ideally matched to of the project was then increased in September 1999 6dF follow-up. Many other projects demand all-sky after a submission to ATAC by QAP and FGW to include coverage, and for these a Schmidt is the only realistic the implementation of a new CCD detector system for wide-field multiplexing option. the original FLAIR II spectrograph. This was approved at an extra cost of $A150k. The Road to 6dF 6dF shares many features with OzPoz (the fibre The amount of information received by a telescope, or positioner being built by the AAO for the VLT): e.g. an the number of galaxies observable in a given integration R-theta robot allowing a curved focal surface to be time, depends on the product of aperture and field of configured (even if it is in the opposite sense) and a view. In this respect, the UK Schmidt is almost identical zero-friction pneumatically-controlled fibre-button gripper. to the AAT+2dF or Sloan, and easily beats all other These features alone reduce the number of motor-driven telescopes. It was the imposing W (Aperture x field of A degrees of freedom from the 5 of 2dF to just 2 for 6dF. view) product of the UKST that led Dawe and Watson to The robotic software is based on the 2dF software, suggest in 1984 that multi-fibre spectroscopy could be modified for an R-theta robot and the 6dF computer carried out with the telescope. The original proposal interfaces, and has provided valuable feedback for the included the idea of an automated fibre positioner. OzPoz software development. Detailed technical However, when multi-fibre spectrography was offered at descriptions of 6dF may be found in Parker, Watson, & the UKST using the FLAIR prototype (1985), the Miziarski (1998 ASP 152) and Watson et al. (2000 SPIE PANACHE upgrade (1988) and the FLAIR II system 4008 ). A broad outline of the instrument follows. (1992), only manual positioning of the fibres was possible due to budgetary constraints. Despite this, useful science was obtained from all versions of the system, particularly FLAIR II during its heyday in the 1990s. Upgrades to the FLAIR II spectrograph during that period resulted in improved sensitivity, which highlighted the principal deficiency of the system. This was that the manual fibre-reconfiguration time could easily exceed the necessary exposure time on a given field by a factor of more than four. Even with new magnetic buttons introduced in 1998 (partly to test the feasibility of 6dF), no more than two fields per night could be observed. This severely limited the usefulness of the system for the large-scale spectroscopic surveys to which the telescope is intrinsically well-suited. Figure 1. Kristin Fiegert and the 6dF positioner ANGLO-AUSTRALIAN OBSERVATORY page 14 NEWSLETTER MAY 2001 Description The main components are: OBSERVATORYNEWS 1) two interchangeable 6 deg diameter field-plate units (each with a permanently attached fibre feed and slit output block). These can be loaded either into the robot for reconfiguration or into the telescope for observing. The only time-on-target lost with this ìdouble-bufferedî arrangement is in the exchange between one field-plate and the other in the telescope, and the associated calibration exposures which together add overheads of around 30 minutes; 2) optical cables containing 150 x 6.7" science fibres and four field acquisition and guide-star bundles for each field- plate; 3) a robotic pick-place fibre positioner housed in an enclosure within the Figure 2. A raw data frame taken with 6dF of obscured galaxies in Vela with dome. It incorporates a back- ~2 mag. blue extinction. The spectra from each fibre run vertically, with blue illumination facility for the fibres to at the top and red at the bottom. The aligned bright spots are night sky enable accurate positioning/location lines, and other bright spots are emission lines from the target galaxies. of fibre buttons. Hence when a field- plate unit is unloaded from the telescope, the attached slit-unit must Commissioning and current status also be unloaded from the The camera with new chip and controller was delivered in November spectrograph and transferred to the 2000. Camera commissioning was completed by Christmas, except positioner; for quite bad comatic aberrations evident at the edges of the imaged 4) the refurbished FLAIR II area. Such aberrations were always present in the camera at some spectrograph, which is also mounted level but are now more obvious and severe. This is due partly to the on a rigid optical bench on the dome bigger physical imaged area and larger slit length/fibre numbers, but floor. This has been shown to result also to the difficulty of re-aligning all the optical components in such a in extremely high spatial and fast camera, including the new CCD and field-flattening lens. Preliminary wavelength stability; adjustment and corrections have already significantly improved the imaging. 5) the upgraded CCD system, incorporating a 1k x 1k 13m pixel The robot was delivered to Siding Spring in late February. There then Marconi CCD47-10 device and SDSU- ensued a significant ëshake-downí period. There were many problems 2 detector controller. The new detector with getting the astrometry right, the inherent R-theta coordinate system system, together with the CICADA turned out to be a real minefield; also the absolute calibration of the operating system and operational plate scale proved to be quite tricky given button virtual focus offsets interface, have been supplied under and the like. Other problems were the reliability of the retractors (now contract by the RSAA at ANU; greatly improved by the retrofitting of internal teflon glide sheets in each retractor by Kristin Fiegert), and the fragility of the guide bundles 6) new robotic control software, and which may necessitate a re-design down the track. The throughput is a new version of CONFIGURE allowing somewhat down on original expectations due to the unforeseen efficient allocation of fibres to targets; introduction of excessive Focal Ratio Degradation (FRD) in the fibres, 7) new 6dF specific data reduction mostly caused by the spare fibre loops in the retractors. In general, software called 6dFDR based on the most of these problems are related to the difficulty of shoehorning the equivalent 2dFDR package allowing fibre retractors into the existing physical envelope of the Schmidt rapid spectral reduction. photographic plateholders. ANGLO-AUSTRALIAN OBSERVATORY NEWSLETTER page 15 MAY 2001 The robot itself has worked very well, with only a handful a 3-faceted slit unit to more adequately match the of hardware errors. Configuring speed is still a little slow, curved ideal slit shape required by Schmidt optics; the OBSERVATORYNEWS currently at about 30 seconds per fibre for a combined collimator mirror is to be rotated to reduce light losses park and placement operation with an 18 sec / 12 sec in the spectrograph by accepting the full beam emitted split). However this is adequate for most programs and by the fibres. Furthermore, we have ordered new ultra- there is plenty of scope in the robot operation for efficient VPH gratings from Ralcon which can replace significant improvement. the current reflection gratings for many projects. These and other smaller modifications should lead to an Basic commissioning is now complete ó fields can be estimated 30-50% efficiency gain! We are basically set accurately and rapidly acquired with the light going to start the main 6dF Galaxy Redshift Survey (6dFGRS) down the fibres. Science-grade observations have in June, a mere two months later than originally already commenced. Figure 2 shows 1 hour combined proposed more than two years ago. data for a field of galaxies (optically and 2MASS selected) behind the Milky Way in Vela at latitude The 6 Degree Field Galaxy Redshift Survey o b=7.5 , and Figure 3 shows the reduced spectra from The primary motivation for 6dF is the all southern-sky a series of 12 target fibres. Currently, the efficiency is spectroscopic galaxy redshift survey. The principal data around 10% (top of atmosphere to detected photons) source for this will be the wonderful 2MASS data, at 5500≈. the first all-sky digital imaging survey (http:// www.ipac.caltech.edu/2mass). This gives the first clean Various improvements are still underway: a new ring of picture of the Local Universe, unaffected by current star calibration lamps is being fitted to the telescope top formation or dust in our own or external galaxies ñ it is end with full remote operation; the camera misalignment the natural place to study Large-Scale Structure, but responsible for the coma in the corners of the CCD this has not been possible until now because of the images is still under investigation but improvements lack of source material. have already been obtained; some of the guide fibres are set to be replaced with a new design to tighten up The primary 6dFGRS sample will be 120,000 galaxies the acquisition and reduce the effect of field rotation brighter than Ks=13. The median redshift depth is 0.05 errors; both field plates have now been retrofitted with and the sky coverage will be d<0, |b|>10, outside the Figure 3. Reduced spectra from 12 successive target fibres, taken from the field in Figure 2. The feature near the centre of the spectrum is due to imperfect subtraction of the strong OI 5577≈ sky line. ANGLO-AUSTRALIAN OBSERVATORY page 16 NEWSLETTER MAY 2001 area of the 2dF strips. In addition, 6dFGRS will include a large number (17!) of smaller target samples as follows: OBSERVATORYNEWS ∑ we will observe 15,000 nearby (<15,000km/s) early type galaxies to a higher signal to noise (25/A) to give accurate (10%) linewidths and hence, when combined with the 2MASS photometry, direct distance and peculiar velocity measurements. This is an order of magnitude larger than previous peculiar velocity surveys; ∑ we will observe additional sources as necessary to give complete samples of ~100,000 galaxies flux- limited at each of H and J (from 2MASS), also at J Figure 4. The two proud commissioning scientists, Will and I from the now completed DENIS survey Saunders and Quentin Parker (cdsweb.u-strasbg.fr/denis.html), and at rF and bJ from the newly available SuperCOSMOS data (www- wfau.roe.ac.uk/sss); 75% of UK Schmidt time is to be devoted to the survey. The data will be distributed via the Wide Field Astronomy ∑ Additional targets solicited last year and selected Unit in Edinburgh (www.roe.ac.uk/ifa/wide_field.html) and by peer review have been defined: these include will be non-proprietary. 10,000 2MASS-selected red AGN, 5000 optically bright ROSAT quasars and 3000 from the HES survey, Non-survey Spectroscopy with 6dF and 10,000 IRAS FSS sources. By December 2001, the UKSTís remaining photographic In total we expect to take 180,000 spectra. All sources surveys (the Ha- and I-surveys) will be essentially will be observed, whether a redshift is known or not, to complete. It is expected that photography will then give a complete homogeneous library of high quality become a minor (<10%) part of the telescopeís spectra. The first strip to be surveyed will be defined by programme, being carried out only in the very best 10h < RA < 20h, -42o < d < -23o, and |b|>10. seeing. Except for small amounts of time that may be allocated to a yet to be implemented 1-degree-field CCD 6dFGRS will utilise a new 580/mm VPH grating for the mosaic (an Australian National University/University of blue, and a 425/mm grating for the red, both working at Tokyo collaboration), the main activity on the telescope the same collimator-grating-camera angles and hence will be 6dF spectroscopy. giving the same dl/l resolution. We aim to get S/N=10/A and R=1000 at 5500≈, with coverage from The 75% of time devoted to the Galaxy Survey will leave 3900 ñ 8300≈. Both S/N and R are significant some 15 - 20% available for non-survey spectroscopy, improvements over 2dF, giving accurate (<50km/s) and this time will be allocated bi-annually through redshifts and allowing detailed studies of how clustering the normal Schmidt Telescope Time Assignment interacts with spectral morphology, linewidth, Committees. All AAO reflection gratings are available, linestrength, metallicity etc. Over the next four years, as will be the new VPH gratings. (<0.5e-/1800s once the device has stabilised). The THE NEW EEV CCD device has VERY nice cosmetics with low-level flat field Chris Tinney & Ray Stathakis structure in the blue, and just one hot spot and associated warm column. We measure an increase in EEV2, a 2k x 4k blue-sensitive CCD, saw its first action efficiency of up to 40% over the Tek in the 4000ñ6000≈ in April with the RGO Spectrograph. We found that range. The cosmic ray hit rate is lower than for the MITLL EEV2 performs much as advertised by EEV/Marconi. It devices. The only down side is extreme fringing, as is a thinned, back-illuminated device with 15 mm square expected with thinned devices. The fringes appear at pixels, and offers unprecedented efficiency in the blue. the 0.5% level at 6500≈, but are ~60% peak-to-peak by 9000ñ10000≈. Read noises and gains as measured on the telescope are consistent with those measured by John Barton in Commissioning of the EEV with other AAT instruments the Epping labs. Linearity is similar to that measured will be undertaken shortly. More details on the by John and (unusually) is well corrected with a ëlinearí commissioning tests can be found at http:// alpha correction term. Dark current rates are low www.aao.gov.au/local/www/cgt/ccdimguide/eev.html. ANGLO-AUSTRALIAN OBSERVATORY NEWSLETTER page 17 MAY 2001 THE COMPLETION OF THE the user and the database. ARCHIVE & DATABASES PROJECT OBSERVATORYNEWS Information is stored in a number of tables. The main Ray Stathakis, Steve Lee, Dionne James, table contains telescope-based information such as Garry Kitley, Danuta Kisiel & Fred Watson position, time and observer; and basic instrumental details and exposure times. Secondary tables hold Early this year, with a minimum of fan-fare, the Archive information specific to each type of observation, such & Databases (A&D) Project was completed at the AAT. as the grating used. These tables form the electronic The RGO + FORS data from January 1, 1990 was log, and a subset of the information in the main table is spooled to CDROM, completing the database from 1990 searchable as an archive database. The fault log and to the present, and the new observing diary was diary are in separate tables and can be searched for released, completing the package of observing extra information on each night. This combination of databases. observing database and archive database was first The A&D Project, which was started in mid-1997, had a implemented at the AAT. number of aims: to streamline and partially automate The Log Interfaces the archival procedure for current observations; to update the storage media of older data; to streamline and Hand-written observing logs were replaced in 1999 by upgrade access to data from the AAT archive; to provide the electronic log (with much acclaim by long-suffering an on-line observing log; and to update the PC-based night assistants with writerís cramp). After an observation fault log and observing diary. The first version of the archive is complete, the night assistant copies the file to the database was released in April 1998, and since then 5 archive machine where the data is translated into FITS more years of older data have been spooled and entered, and the relevant information is stripped from the data 3 more years of current data have been archived, over headers into a TCL front end for the log. The night 100 archive requests have been handled, and the three assistant can check this information, correct errors and observational databases have been added, as well as a add missing parameters and comments, which will number of improvements to the original archive. update not only the database index, but also the headers of the archived data (but not the original data). Observers The AAT Archive can add comments via the OBSERVER system (before Early in the operation of the AAT, it was decided to the completion of the run), or via the night assistant. At maintain an archive of all raw data, excepting only the end of the night, the night assistant sends the log observations made with visitor instruments in non- to the database from where it is accessible via the web standard formats. As a result, the AAO is unique in its (http://site.aao.gov.au/AATdatabase/aat). The archive of 4-m observations (the bulk being digital standardisation and completeness of header information spectra) spanning 28 years. By 1997, there were several has been an important issue, as it is the main source of reasons to upgrade the archive: the bulk of the data information for the log, and we are most grateful for help were stored on ~1500 9-track tapes which were nearing from AAO programmers in correcting and expanding the or past their use-by-date; the ~1000 Exabytes storing instrumentation header keywords. data from 1993 would require respooling by 2003; there The fault log records problems experienced at the AAT was no way of searching for data on-line; and the AAT and UKST, together with comments and fixes. Previously was about to enter a new era of survey work, with the held on a PC, the new database has web access which commissioning of 2dF. It was evident that the data output allows input from Epping staff, observers and support rate, and the increased interest in archival data, could astronomers as well as AAT staff. Non-AAO users can not be handled with the current system. search the fault log by date to check problems relating The Database to their data, or to archival data of interest (http:// site.aao.gov.au/AATdatabase/faults). The archive database is compatible with other CADC astronomical archive databases for observatories The observing diary records instrumental setups, including HST, La Palma and UKIRT, and the initial telescope settings, weather details, time usage and version was set up by Daniel Durand of the CADC. The other pertinent information. The night assistant writes underlying software is a commercial SQL database to the diary via a TCL interface. Diary pages dating from engine by Sybase. The database resides on an NT PC 1993 are kept on the archive CDROMs, and can also which is accessed via a SUN-based web server. Sybase be searched via the web by date (http://site.aao.gov.au/ client software, and CADC Perl-based packages WDB AATdatabase/diary). Users of archival data are and Sybperl are used to provide communication between recommended to check the diary in order to assess the ANGLO-AUSTRALIAN OBSERVATORY page 18 NEWSLETTER MAY 2001 Figure 1. database. Old databases have been included to cover Some of the 900 most optical spectra taken with the IPCS and all 9-track tapes and 1000 exabytes photographic plates. Note, however, that the pre-1990 OBSERVATORYNEWS which have been IPCS data remain on 9-track tape and the photographic spooled to CDROM, and plates are not available in digital form. indexed on-line. Users of the AAT Archive The AAT archive plays a number of roles, as reflected by the archival requests. Most importantly, it is a safe house for observersí data to ensure that observations arenít lost due to tape problems or disk crashes. The archive is also a valuable source of comparison data expected quality of the data. essential for monitoring instruments and analysing The Archival Process problems. Archival data have been extensively used in investigating the throughput of UCLES, UHRF, the RGO The archival process at the AAT has been streamlined. spectrograph and, most recently, the new EEV CCD. The copying, translating and indexing of data is carried out during the night as part of the logging of observations. Finally, the archive contains observations of countless All that remains is to save two copies of the data to objects observed over 28 years. These are available for CDROM, and typically between 1 and 10 CDROMs are request once they reach 2 years old. Examples of filled each week, depending on the observing mode. Data scientific projects which have used AAT archival data from instruments creating very large amounts of data, are: ìThree Quasars from a Survey of Strong 25mm like WFI, are archived to DLT. As well as substantially Emittersî, Wolstencroft et al. 2000, MNRAS, 311, 541; reducing the effort involved in archiving, archival mistakes ìThe Parkes Half-Jansky Flat-Spectrum Sampleî, and data loss have virtually disappeared under the new Drinkwater et al. 1997, MNRAS, 284, 85 and 4 related system. One copy of the CDROMs is stored at the papers; ìExtremely Metal-Poor Stars. VII. The Most telescope, and another is sent to the Laboratory at Metal-Poor Dwarf, CS 22876-032î, Norris, Beers & Ryan Epping. 2000, ApJ, 540, 456; ìModelling the Spectral Energy Distribution and SED Variability of the Carbon Mira R Spooling Seven Years of Data Fornacisî, Lobel, Doyle & Bagnulo 1999, A&A, 343, 466; ìHigh Resolution Optical and Infrared Spectroscopic In addition to the observations made after the start of Observations of CIR X-1î, Johnston, Fender & Wu 1999, the A&D project, it was decided to transfer to CDROM MNRAS, 308, 415 and related papers; ìA Comparative all data archived from the beginning of 1990. Data dating Direct Analysis of Spectra of Type Ib Supernovaeî, from 1993 were downloaded from Exabytes, and headers Branch et al. 2001, in press. were checked and edited to add information not present in these earlier files. Headers were then stripped and So whatís next? entered into the archive database. The archive and database project provided the impetus Spooling was more difficult for the ~900 9-track tapes and resources for the AAO to set up a database, index written in 1990 ó 1992. The twenty-year-old tape drives and spool a decade of data, provide a sophisticated were unreliable, requiring frequent maintenance from suite of observing database tools, and streamline archive Bob Dean (thanks Bob!) and a direct copy to CDROM creation and request support. In particular, it has was unacceptably slow due to the VAX / SUN link. Data provided the framework for future archive and database download was also slow and headers required more applications. A number of smaller operational databases conversion to standard forms. In order to speed this are being produced at the telescope, the earliest AAT process, a casual archivist was employed to spool the spectra taken with the IDS will shortly be added to the 9-track tapes directly to Exabyte on the VAX. The archive, and non-survey 2dF data are being reduced for Exabytes were then transferred as before, minimising direct access to the data via ftp. In this issue we see loss of time to tape drive problems and load on the local the first release of 2dF survey data. Over the next few network. Observers were contacted to ask for copies of years we expect Virtual Observatories (such as the missing or unreadable data ( ~2% of the Exabytes STARGRID in the UK) to be established, which will and ~15% of the 9-track tapes). The final archive for provide access to astronomical archives around the 1990 to 1996 is ~96% complete. world, and we are confident that AAT archival data will continue to be used as an important resource. Some pre-1990 data are also indexed in the archive ANGLO-AUSTRALIAN OBSERVATORY NEWSLETTER page 19 MAY 2001 LETTER FROM MELOCCO LOCAL NEWS LOCAL David Malin In July I will be leaving the AAO after 26 stimulating and hut with his secretary, two large drawing boards and a enjoyable years. However, I will retain strong links with draftsman (John Rock). In the adjoining hut were Don the Observatory, and with the encouragement of the AAT Mayfield and John Barton plus the mechanical, accounts board and Director I will continue to manage the AAOís and personnel departments, their members hidden astronomical photographs much as I do now but through among piles of paper and hardware, then as now. There my business ìDavid Malin Imagesî (DMI). I will also was nowhere to stand, never mind sit, and not a continue to maintain and improve the AAOís images computer to be seen. There was also clearly no room web pages, and even hope to make some new pictures for me and I was alarmed to find that the ladies toilet from archival material that for one reason or another had been converted into a photographic darkroom. It was never exploited. I have some scientific projects I turned out that this was for Don Mayfield, who is still want to work on and have another book in mind, so I will the AAO's Equal Opportunity Officer. not be idle. Although my years with the AAO have been Joe pointed to the shrubbery beyond the rear door. ìYouíre exhilarating they have also been very full, so above all I over thereî he said as my heart sank further. I had arrived want to have some free time to spend with Phillipa and in Australia with a wife and three young children to find our first grandchild, Mia. myself in a couple of Portacabins on what was evidently I suppose all long-serving retirees are reflective as the an abandoned chicken farm. Through the trees I made day approaches and Iím no exception. In July 1975 I out a series of weird, ribbed concrete structures, had left a successful 18-year career as a chemical obviously still being assembled. Joe told me they were microscopist in the north of England to try something pre-fabricated modules made by a company called new. I had heard of this fancy 3.9-m telescope in Melocco, and they would soon be the new ëofficesí. I Australia, and Phillipa, my wife, was Australian so there tried to look enthusiastic. At the far end of this should be no language or cultural difficulties. How little conglomeration and still open to the air was a completely I knew. I did not know much about the Observatory empty, windowless, rectangular 7 x 7m concrete except that they were keen to hire someone who section. ìYour darkroomî he said. ìAnything else you understood something about scientific photography. I need, just let me knowî. was very pleased when I landed the job but more than a So that is how it began. The assistant I was to have at little anxious, mainly because my knowledge of Siding Spring resigned before I arrived and was never astronomy was ñ er ñ microscopic. replaced. The position became that of night assistant The sense of excitement and (especially) apprehension and was eventually filled by a clean-shaven young man increased when I first turned up at the Epping ëofficesí, called Steve Lee. I found myself the proud manager of which turned out to be a couple of portable buildings about 12 furnished but otherwise empty darkrooms at much like those dotted about the CSIRO site now. They the AAT ó I never did find them all ó and an unpromising were situated beneath the trees where we now have concrete shell in Epping. The mixture of excitement and morning tea and the concrete paths and steps are still apprehension I felt that day has never completely gone, to be seen. I had not been to the AAT at this time, so it indeed, with the benefit of hindsight I believe it is part of was easy to think that Epping was all there was to the the energy that sustains the AAO. Although being given AAO (this is still a problem). the opportunity to take on new challenges (or being thrown in at the deep end, depending on oneís point of I was so excited because I was entering the new AAO view) is not unique to the Observatory, it is a recurrent Headquarters and astronomy, astronomical theme in its history. For me it was an opportunity to photography, and Australia were all new to me in 1975. move in a new direction and I was lucky to be in the You can therefore imagine my dismay when I discovered right place at the right time, surrounded by the most the Director (then Joe Wampler) sharing one cramped stimulating and supportive people imaginable. ANGLO-AUSTRALIAN OBSERVATORY page 20 NEWSLETTER MAY 2001 I have mentioned a few names of early staff members above, but there were some itinerant astronomers too. Eventually, in the part of the Melocco building with a roof, I found Bruce Peterson, John Danziger, Mike Penston and Louise Turtle, soon to be joined by Paul Murdin, NEWS LOCAL Bob Fosbury and David Allen. These people and their successors were also an essential ingredient in my education and development, as were the staff at the UK Schmidt. Without their help and encouragement I could not have had the career I have enjoyed so much, and without others like them the AAO would not be the success it is. Long may the excitement and apprehension continue. It certainly will for me as I find myself unsalaried for the first time since 1957 and at the beginning of a new venture. I sincerely hope that my third career lasts at least as long as my first and that the David Malin in the AAT Prime Focus a couple of years ago. AAO outlives us all. FOUR LEGENDS BECOME FIVE Fred Watson If you are a music-lover, you might be familiar with the ìFour Legendsî of Jean Sibelius. And if you are an astronomer, you might also be familiar with the four legends of the AAO. These legends are not particularly melodic, but are very effective at their jobs. They are the four AAT Night Assistants, and their legendary status comes from the feedback we get from visiting observers. It seems they still provide the world-standard for telescope operators. Of course, they are supported in that by a lot of other dedicated people in the organisation, but the fact remains that the NAs are the main point of contact between the AAO and its telescope users. Recently, one of the legends ñ Gordon Schafer ñ retired. (Strangely enough, he now seems to have turned up in Epping, but thatís another epic saga.) The internal recruitment that took place to find a new proto-legend has yielded not one, but two: John Stevenson (left) and Garry Kitley (above). No doubt it will gratify Gordon immensely that the AAO has had to find two people to replace him, but in fact it has more to do with a rearrangement of duties. We are introducing a system of working that allows some NAs to fulfill some of the functions of the afternoon shift technician ñ for some of the time. This has been possible because Steve Lee and Frank Freeman have agreed to reduce the number of shifts they work, enabling us to develop a roster that incorporates five NAs instead of four. While the transition to the new scheme should be invisible to observers, it will benefit the AAO in both the short and the long term. The Night Assistants will continue to play a key role in the AAOís interaction with its telescope users. The new line-up is Frank Freeman, Garry Kitley, Steve Lee, Jonathan Pogson and John Stevenson. It goes without saying that someone will now have to write an appropriate piece of music called ìFive Legendsî. ANGLO-AUSTRALIAN OBSERVATORY NEWSLETTER page 21 MAY 2001 Sauvignon or Chardonnay. It is always a battle for LETTER FROM COONABARABRAN Wayne as to just who gets his grapes, the winemaker Rhonda Martin or the currawongs. Currawongs, as expounded previously, are big, black and white birds with yellow Come back Gordon ñ all is forgiven! We at the AAT eyes and beaks made for scoffing grapes. Many are LOCAL NEWS miss the old devil ñ even the telescope misses him, the mornings that Wayne has sat, with a long, explosive after all, it has known him longer than it has known the device across his lap, waiting ...... waiting for that black rest of us. We miss the acerbic wit, the dry humour and and† white cloud that sneakily comes with the dawn from his intimate knowledge of the telescope and all its works. all directions with evil intent, laughing ...... We envy Peter G in Epping his access to all this, as The mountain raven, now called Griffin ñ a noble name Gordon shares his knowledge in between good surfing for a noble bird ñ has, if anything, grown even bigger. runs and emptying the ocean of fish. This is probably down to the Ginger Nut biscuits, We saw Gordon and Rae off in style at a local restaurant blueberries, pieces of apple and bread that he delicately and it was a great night as anecdotes were rolled out takes from our fingers. But sad to say, there are those by the dozen. Even the weather gave its approval with a of sadistic bent who want to break the spirit, or at least series of extremely noisy and very wet thunderstorms the beak, of this noble creature, this ex-velociraptor. that sometimes made thinking almost impossible ñ but They fed him numerous pieces of bread initially, but thinking was not why we were there anyway ñ we just Griffin sneered. They graduated to bigger pieces, and wished to extend our very best wishes to a valued then to whole slices but Griffin rose to the challenge member of staff. and folded the bread with ease before flying off ñ so they froze the bread ...... Wayne Clarke, as well as being our indispensable Trades Assistant, is also a vigneron. Wayne has just harvested The iron emu on the road to the observatory is now his latest crop of grapes and we look forward to the wearing a veil. A wedding perhaps? or a First results of all his hard work in the form of Cabernet- Communion? OBSERVATORY NEWS Helen Woods Over the last few months the AAO has enjoyed some excellent visits. Fraser Clarke (U Cambridge) has been visiting Chris Tinney to work on brown dwarfs, Heath Jones (ESO/VLT) has been working with Peter Gillingham and Joss Hawthorn on a new instrument concept for the VLT and Jim Stilburn from DAO has been working on solgel coatings with Roger Haynes and Steve Lee. In March, the AAT Board met in Sydney and staff enjoyed a pleasant lunch with the members. Ian Corbett, who has been on the Board since 1991 was presented with a framed David Malin galaxy photograph. The AAO hopes this gift goes some way towards recognising Dr Corbettís huge contribution to the AAO over his 10 year association with us. We enjoyed welcoming back, if only for a short time, ex-AAO astronomer Jason Spyromilio, who visited Epping from ESO with his colleagues Luca Pasquini and Paolo Santin to inspect the OzPoz project. Shanthi Iyer, the AAOís temporary receptionist said farewell to us on Friday 27th April. Not before time as it turned out, because her son was born on 1 May! The Iyer family is happy and well. The AAO also recently said farewell to David Lee, who has returned to the UK to work for Crown Corning. Davidís expertise with SPIRAL as well as his understated humour will be missed. Mark Hilliard, who has been with us, on and off, for a long time as an agency contractor, has now become an AAO staff member. Mark does general and detailed design work associated with IRIS2 and OzPoz. We also welcome Scott Smedley and Peter Innes, who have joined the software group. ANGLO-AUSTRALIAN OBSERVATORY page 22 NEWSLETTER MAY 2001 LIBRARY NEWS CROSSWORD COMPETITION Sandra Ricketts We are pleased to announce that the winner of the crossword competition in the February issue was Denis NEWS LOCAL Another page has been added to the library's web site. Coates of Monash University (again!). Denis wins a David There is now a list of items borrowed from the library, in Malin photograph of his choice. alphabetical order of borrower. If you cannot locate a The solution is printed below. book in the library, and the librarian is absent, then this list can be readily searched to see if in fact the item is already on loan (and to find out who has it if desperate!) It is hoped that this list will save users time and reduce frustration. The page can be found at http:// www.aao.gov.au/library/loans.html and is the next link on the web page after the search engine for the catalogue. The rearrangement of journals in the telescope library has now been completed. All the Astrophysical Journal issues are now in the corridor just outside the library, while those in the studies are mostly unchanged. Within the library itself journals are still in the same order, just spread out differently. Seen at the AAT Russell Cannon took this picture of Swiss Alpine Horn players who were some of the more colourful visitors to the AAO. If you have a good picture or short story of unusual visitors to the AAT or Epping Labs, send them in, and the most interesting will receive a prize. Entries close July 30, email to [email protected]. As always, the judges' decision is final! ANGLO-AUSTRALIAN OBSERVATORY NEWSLETTER page 23 MAY 2001 announce the release of release the announce the first 100k galaxies from the 2dF Galaxy the and Survey, Redshift first field of the Fornax Cluster Spectroscopic See articles Survey. on 7. to 3 pages In In this issue we also .au .au > @aaoepp.aao.gov @aaocbn.aao.gov.au > @aaocbn.aao.gov.au < user < user RICKETTS Australia Fax +61 2 9372 4880 email 1710 1710 .au .au > editorial assistant SANDRA 4800 4800 .aao.gov HAKIS HAKIS ANGLO-AUSTRALIAN OBSERVATORY The The 2dF Redshift QSO Survey (2QZ) released their first 10,000 QSOs to the public in April. Institutional issues of newsletter include a copy of this the databaseCDROM. on 10k QSOs 10k AAT/Schmidt Telephone +61 2 6842 6291 Fax +61 2 6884 2298 email < http://wwwURL editor RAY STAT RAY editor ISSN 0728-5833 Published by PO Box 296 Epping, NSW Epping Lab Telephone +61 2 9372 THE BACK PAGE