DOCSLIB.ORG

Distance Scale and Variable Stars in Local Group Galaxies: LMC and Fornax

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Distance Scale and Variable Stars in Local Group Galaxies: LMC and Fornax 1 Ò ÚÖÐ ×ØÖ× Ò ÄÓ ÖÓÙÔ ÐÜ× ÄÅ Ò ÓÖÒÜ M. Maio1, L. Baldacci1, G. Clementini1, C. Greco1, M. Gullieuszik2, E.V. Held2, E. Poretti3, L. Rizzi2, A. Bragaglia1, E. Carretta2, L. Di Fabrizio4, R. Gratton2, E. Taribello1 1 INAF - Osserv. Astron. di Bologna, via Ranzani 1, 40127 Bologna, Italy 2 INAF - Osserv. Astron. di Padova, Vicolo dell’Osservatorio 5, 35122 Padova, Italy 3 INAF - Osserv. Astron. di Brera, Via Bianchi 46, 23807 Merate, Italy 4 INAF - Centro Galileo Galilei & Telescopio Nazionale Galileo, PO Box 565, 38700 Santa Cruz de La Palma, Spain Abstract. We briefly review our photometric and spectroscopic study of RR Lyrae variable stars in the bar of the Large Magellanic Cloud (LMC), that allowed us to reconcile the so-called short and long distance moduli of the LMC on the value µLMC = 18.51 ± 0.085 mag. Then we present preliminary results from the photometric study of a 33’×34’ area in the Fornax dwarf spheroidal galaxy containing the stellar clusters Fornax 3 (NGC 1049) and 6. We identified about 1000 candidate variables in this field of Fornax, and report the first detection and measure of about 60 RR Lyrae variable stars in the globular cluster Fornax 3. Key words. Magellanic Clouds – Fornax – Variable stars – Distance scale 1. Introduction 2. The Large Magellanic Cloud Variable stars are important to set the as- tronomical distance scale, and to sample The distance to the LMC has for a long time remained uncertain notwithstanding arXiv:astro-ph/0303666v2 28 Apr 2003 different stellar populations in galaxies. RR Lyrae stars, in particular, trace the old- its vicinity to the Milky Way. In fact, the est stellar component and are the primary LMC distance modulus from different in- Population II distance indicators in the dicators ranges from about 18.3 mag (e.g. Local Group galaxies. Baade-Wesselink and statistical parallax methods: Fernley et al. 1998a,b) to about Send offprint requests to: M. Maio 18.7 mag (e.g. Cepheid trigonometric par- Correspondence to: allaxes: Feast & Catchpole 1997). In the fol- [email protected] lowing, we present the results of our study 2 M. Maio et al.: Distance scale and variable stars in LMC and Fornax Fig. 1. Left panel: V vs B − V color - magnitude diagram of our LMC Field A. Larger symbols mark the variables identified in this area. Right panel: examples of our light curves. of variable stars in the LMC and its im- the V light curves (Jurksic & Kov´acs 1996, pact on the short and long distance scale Kov´acs & Walker 2001) for 29 RRab’s. controversy. All these different estimates are in very We obtained time series photometric good agreement to each other, once differ- data (72 V , 41 B, and 15 I frames) of ences in the adopted metallicity scales are two 13’ × 13’ fields (Field A and B) close properly taken into account and give an av- to the bar of the LMC and derived light erage metal abundance of [Fe/H]=−1.5. curves accurate to 0.02-0.03 mag, for 125 We used the VLT spectroscopic metal- RR Lyrae stars (77 RRab’s, 38 RRc’s, 10 licity determinations and our estimates double-mode pulsators RRd’s), 4 anoma- of the average luminosities of the RR lous Cepheids, 11 classical Cepheids, 11 Lyrae stars and reddening, to derive the eclipsing binaries, and one δ Scuti star. luminosity-metallicity relation followed by Figure 1 shows, on the left, the loca- the LMC RR Lyrae stars: tion of the variable stars in the HR diagram of Field A; variables are plotted accord- < V0(RR) >= [0.214(±0.047)] × ([Fe/H]+ ing to their intensity-average magnitudes and colors. On the right, we show the light 1.5)+19.064(±0.017) curves for an RRab, an RRc, an RRd and an eclipsing binary in our sample. (Clementini et al. 2003, Gratton et al. 2003, We also derived metallicities for a to- in preparation). tal number of about 100 of the RR Lyrae Our estimate of the dereddened aver- stars using different methods. We applied age luminosity of the RR Lyrae stars in the ∆S method (Preston 1959) to 6 RRd’s the LMC bar is < V (RR) >0= 19.06 mag (Bragaglia et al. 2001), and a revised ver- (at [Fe/H] = −1.5 dex). This value was sion of this technique to spectra obtained combined with a number of recent inde- with FORS at the VLT in 2001 for 101 pendent estimates for the absolute magni- RR Lyrae stars in our sample. Finally, pho- tude of the RR Lyrae stars (e.g. Gratton et tometric metallicities were estimated from al. 2002, Cacciari et al. 2000) to estimate parameters of the Fourier decomposition of the LMC distance. The distance moduli so M. Maio et al.: Distance scale and variable stars in LMC and Fornax 3 Fig. 2. On the left: Instrumental color-magnitude diagram of chip #7; candidate variables are marked as larger symbols. In the center: image 95” × 95” of the globular cluster NGC 1049, with candidate variables marked as filled squares. On the right: examples of light curves in Fornax 3, [panels (a) and (b)], and in the field, [panels (c) and (d)]. derived where compared with the most re- Fornax dSph have never been adequately cent and accurate LMC distance determi- surveyed for variability, in spite of clear nations from several other Population I and indications, from their HB morphologies, II distance indicators, reaching 1 σ conver- that they should indeed contain RR Lyrae gence on a distance modulus of µLMC = variables (Buonanno et al. 1998,1999). ± 18.51 0.085 mag, as fully described in Fornax 3, one of the two clusters that Clementini et al. (2003). lie in our Fornax field, is quite metal- poor ([Fe/H=−1.96 ±0.20, Buonanno et al. 3. The Fornax dwarf spheroidal galaxy 1998) and has a relatively well populated Located about 140 Kpc from the Milky Horizontal Branch (HB) characterized by Way, Fornax is a dwarf spheroidal galaxy a very extended HB blue tail. Buonanno et (dSph) dominated by an intermediate-age al. (1998) identified 66 candidate RR Lyrae stellar population (Stetson et al. 1998, stars in this cluster from their limited HST Saviane et al. 2000). There is also evidence data. for an old stellar component, since the We observed an area of 34’ × 33’ North galaxy contains 5 globular clusters and field to the Fornax dSph center with the Wild population as old and metal-poor as that Field Imager (WFI) of the 2.2 m ESO- in globular clusters (Saviane et al. 2000). MPI telescope, with the larger part of the The field of Fornax dSph has been inves- galaxy in chip #6 and #7 of the WFI tigated for variability by Bersier & Wood mosaic. We obtained time series B and (2002) who surveyed a half square de- V photometry (18 V and 62 B frames). gree covering the central region and found Photometric reductions using the packages about 600 variables (among which 515 RR DAOPHOT/ALLSTAR II (Stetson 1998) Lyrae). However, because of the small tele- and ALLFRAME (Stetson 1994) are in scope size and the mediocre seeing condi- progress. Candidate variables were iden- tions of their observations, RR Lyrae are tified using the package ISIS 2.1 (Alard close to the detection limit of their pho- 2000) that works with the image subtrac- tometry, and their observations did not re- tion method. We detected 335 candidate sult in high quality light curves. GCs of variable stars in chip #6 and 190 candidate 4 M. Maio et al.: Distance scale and variable stars in LMC and Fornax variables in chip #7. The globular cluster Bragaglia, A., Gratton, R.G., Carretta, Fornax 3 falls in chip #6. We selected a E., Clementini, G., Di Fabrizio, L. & box of 95” × 95” centered in the core of Marconi, M. 2001, AJ, 122, 207 Fornax 3 and in this area we find about Buonanno, R., Corsi, C.E., Zinn, R., Fusi 70 candidate variables. Even if decontam- Pecci, F., Hardy, E. & Suntzeff, N.B. 1998, ination from the field variables has not AJ, 501, L33 been made yet, these candidate variables Buonanno, R., Corsi, C.E., Castellani, M., are very likely to belong to the cluster, and Marconi, G., Fusi Pecci, F., Zinn, R. 1999, since most of them fall on the cluster HB, AJ, 118, 1671 they are RR Lyrae stars. This is the first Cacciari, C., Clementini, G., Castelli, F. detection and measure of the variable stars & Melandri, F. 2000, in ASP Conf. Ser. in one of Fornax dSph galaxy globular clus- 203, The Impact of Large Scale Surveys on ter system. Figure 2 shows in the left panel Pulsating Stars Research, ed. L. Szabados the (v, v-b) instrumental color-magnitude & D. Kurtz (San Francisco: ASP), ASP, diagram of Fornax dSph field in chip #6, 176 and in the central panel an image of the Clementini, G., Gratton, R.G., Bragaglia, globular cluster Fornax 3. In both pan- A., Carretta, E., Di Fabrizio, L. & Maio, els the candidate variables are marked by M. 2003, AJ, 125, 1309 filled circles. Finally, the right panel shows Fernley, J., Barnes, T. G., Skillen, I., some preliminary light curves of RR Lyrae Hawley, S. L., Hanley, C. J., Evans, D. stars in Fornax GC3 (panels a and b) and W., Solano, E. & Garrido, R. 1998, A&A, Fornax dSph field (panels c and d). These 330, 515 are DAOPHOT instrumental differential b Fernley, J., Skillen, I., Carney, B.
Load more

Recommended publications
  • Arxiv:Astro-Ph/0507464V2 14 Jan 2009 Eso H Ai Fitgae A-Vpooer.The Photometry
    Astrophysics and Space Science DOI 10.1007/s•••••-•••-••••-• Horizontal Branch Stars: The Interplay between Observations and Theory, and Insights into the Formation of the Galaxy M. Catelan1,2 c Springer-Verlag •••• Abstract We review and discuss horizontal branch importance of bright type II Cepheids as tracers of (HB) stars in a broad astrophysical context, includ- faint blue HB stars in distant systems is also empha- ing both variable and non-variable stars. A reassess- sized. The relationship between the absolute V mag- ment of the Oosterhoff dichotomy is presented, which nitude of the HB at the RR Lyrae level and metallic- provides unprecedented detail regarding its origin and ity, as obtained on the basis of trigonometric parallax systematics. We show that the Oosterhoff dichotomy measurements for the star RR Lyr, is also revisited. and the distribution of globular clusters in the HB Taking into due account the evolutionary status of RR morphology-metallicity plane both exclude, with high Lyr, the derived relation implies a true distance mod- statistical significance, the possibility that the Galac- ulus to the LMC of (m−M)0 = 18.44 ± 0.11. Tech- tic halo may have formed from the accretion of dwarf niques providing discrepant slopes and zero points for galaxies resembling present-day Milky Way satellites the MV (RRL) − [Fe/H] relation are briefly discussed. such as Fornax, Sagittarius, and the LMC—an argu- We provide a convenient analytical fit to theoretical ment which, due to its strong reliance on the ancient model predictions for the period change rates of RR RR Lyrae stars, is essentially independent of the chem- Lyrae stars in globular clusters, and compare the model ical evolution of these systems after the very earli- results with the available data.
    [Show full text]
  • Globular Cluster Club
    Globular Cluster Observing Club Raleigh Astronomy Club Version 1.2 22 June 2007 Introduction Welcome to the Globular Cluster Observing Club! This list is intended to give you an appreciation for the deep-sky objects known as globular clusters. There are 153 known Milky Way Globular Clusters of which the entire list can be found on the seds.org site listed below. To receive your Gold level we will only have you do sixty of them along with one challenge object from a list of three. Challenge objects being the extra-galactic globular Mayall II (G1) located in the Andromeda Galaxy, Palomar 4 in Ursa Major, and Omega Centauri a magnificent southern globular. The first two challenge your scope and viewing ability while Omega Centauri challenges your ability to plan for a southern view. A Silver level is also available and will be within the range of a 4 inch to 8 inch scope depending upon seeing conditions. Many of the objects are found in the Messier, Caldwell, or Herschel catalogs and can springboard you into those clubs. The list is meant for your viewing enrichment and edification of these types of clusters. It is also meant to enhance your viewing skills. You are encouraged to view the clusters with a critical eye toward the cluster’s size, visual magnitude, resolvability, concentration and colors. The Astronomical League’s Globular Clusters Club book “Guide to the Globular Cluster Observing Club” is an excellent resource for this endeavor. You will be asked to either sketch the cluster or give a short description of your visual impression, citing seeing conditions, time, date, cluster’s size, magnitude, resolvability, concentration, and any star colors.
    [Show full text]
  • Making a Sky Atlas
    Appendix A Making a Sky Atlas Although a number of very advanced sky atlases are now available in print, none is likely to be ideal for any given task. Published atlases will probably have too few or too many guide stars, too few or too many deep-sky objects plotted in them, wrong- size charts, etc. I found that with MegaStar I could design and make, specifically for my survey, a “just right” personalized atlas. My atlas consists of 108 charts, each about twenty square degrees in size, with guide stars down to magnitude 8.9. I used only the northernmost 78 charts, since I observed the sky only down to –35°. On the charts I plotted only the objects I wanted to observe. In addition I made enlargements of small, overcrowded areas (“quad charts”) as well as separate large-scale charts for the Virgo Galaxy Cluster, the latter with guide stars down to magnitude 11.4. I put the charts in plastic sheet protectors in a three-ring binder, taking them out and plac- ing them on my telescope mount’s clipboard as needed. To find an object I would use the 35 mm finder (except in the Virgo Cluster, where I used the 60 mm as the finder) to point the ensemble of telescopes at the indicated spot among the guide stars. If the object was not seen in the 35 mm, as it usually was not, I would then look in the larger telescopes. If the object was not immediately visible even in the primary telescope – a not uncommon occur- rence due to inexact initial pointing – I would then scan around for it.
    [Show full text]
  • Ngc Catalogue Ngc Catalogue
    NGC CATALOGUE NGC CATALOGUE 1 NGC CATALOGUE Object # Common Name Type Constellation Magnitude RA Dec NGC 1 - Galaxy Pegasus 12.9 00:07:16 27:42:32 NGC 2 - Galaxy Pegasus 14.2 00:07:17 27:40:43 NGC 3 - Galaxy Pisces 13.3 00:07:17 08:18:05 NGC 4 - Galaxy Pisces 15.8 00:07:24 08:22:26 NGC 5 - Galaxy Andromeda 13.3 00:07:49 35:21:46 NGC 6 NGC 20 Galaxy Andromeda 13.1 00:09:33 33:18:32 NGC 7 - Galaxy Sculptor 13.9 00:08:21 -29:54:59 NGC 8 - Double Star Pegasus - 00:08:45 23:50:19 NGC 9 - Galaxy Pegasus 13.5 00:08:54 23:49:04 NGC 10 - Galaxy Sculptor 12.5 00:08:34 -33:51:28 NGC 11 - Galaxy Andromeda 13.7 00:08:42 37:26:53 NGC 12 - Galaxy Pisces 13.1 00:08:45 04:36:44 NGC 13 - Galaxy Andromeda 13.2 00:08:48 33:25:59 NGC 14 - Galaxy Pegasus 12.1 00:08:46 15:48:57 NGC 15 - Galaxy Pegasus 13.8 00:09:02 21:37:30 NGC 16 - Galaxy Pegasus 12.0 00:09:04 27:43:48 NGC 17 NGC 34 Galaxy Cetus 14.4 00:11:07 -12:06:28 NGC 18 - Double Star Pegasus - 00:09:23 27:43:56 NGC 19 - Galaxy Andromeda 13.3 00:10:41 32:58:58 NGC 20 See NGC 6 Galaxy Andromeda 13.1 00:09:33 33:18:32 NGC 21 NGC 29 Galaxy Andromeda 12.7 00:10:47 33:21:07 NGC 22 - Galaxy Pegasus 13.6 00:09:48 27:49:58 NGC 23 - Galaxy Pegasus 12.0 00:09:53 25:55:26 NGC 24 - Galaxy Sculptor 11.6 00:09:56 -24:57:52 NGC 25 - Galaxy Phoenix 13.0 00:09:59 -57:01:13 NGC 26 - Galaxy Pegasus 12.9 00:10:26 25:49:56 NGC 27 - Galaxy Andromeda 13.5 00:10:33 28:59:49 NGC 28 - Galaxy Phoenix 13.8 00:10:25 -56:59:20 NGC 29 See NGC 21 Galaxy Andromeda 12.7 00:10:47 33:21:07 NGC 30 - Double Star Pegasus - 00:10:51 21:58:39
    [Show full text]
  • Galactic and Extragalactic Studies, I. Notes on Fornax
    VOL. 25, 1939 ASTRONOMY: H. SHAPLEY 565 GALACTIC AND EXTRAGALACTIC STUDIES, I. NOTES ON THE PECULIAR STELLAR SYSTEMS IN SCULPTOR AND FORNAX By HARLOW SHAPLEY HARVARD COLLEGE OBSERVATORY Communicated October 7, 1939 1. Results of a General Search.-The examination of one hundred and fifty-two small-scale plates, covering something more than fifteen thousand square degrees of the sky in galactic latitudes higher than 120°, has failed to show any other objects similar to the stellar systems in Sculptor and Fornax reported last year.' The plates were made at the Boyden Station, Bloemfontein, with the AX camera attached to the Bruce tele- scope; the exposures are each uniformly three hours in length; the scale is 1 mm = 11 5. Since the new objects in Sculptor and Fornax are readily shown on such plates, we must infer from the fruitless search that stellar systems of this sort are infrequent in the neighborhood of our Galaxy and probably not frequent within a million light years.2 In the course of the search, two new globular clusters and two new objects of the Magellanic Cloud type have been noted. The new globular clusters are in (or superposed upon) the Fornax system. One, of magnitude 14.2, is in the position 2h 35m 585, -34058' (1900), practically at the center of the system.3 The other, a loose globular cluster near the southern edge, is in the position 2h 34m 33S, _35°14', and of magnitude approximately 14.4. There is a third very faint cluster of unidentified character, magnitude 16.6:, at 2" 35m 56', -34°51', which is also prob- ably a part of the Fornax system.
    [Show full text]
  • DEEP-SKY CHALLENGE OBJECTS by Alan Dyer a Nd Alister Ling the Beauty of the Deep Sky Extends Well Past the Best and Brightest Objects
    322 Challenge Objects DEEP-SKY CHALLENGE OBJECTS BY ALAN DYER A ND ALISTER LING The beauty of the deep sky extends well past the best and brightest objects. The attraction of observing is not the sight of an object itself but our intellectual contact with what it is. A faint, stellar point in Virgo evokes wonder when you try to fathom the depths of this quasar billions of light-years away. The eclectic collection of objects below is designed to introduce some “fringe” catalogs while providing challenging targets for a wide range of apertures. Often more important than sheer aperture are factors such as the quality of sky, quality of the optics, use of an appropriate filter, and the observer’s experience. Don’t be afraid to tackle some of these with a smaller telescope. Objects are listed in order of right ascension. Abbreviations are the same as in THE MESSIER CATALOGUE and THE FINEST NGC OBJECTS, with the addition of DN = dark nebula and Q = quasar. Chart # indicates the chart in which the object can be found in Uranometria 2000.0 Deep Sky Atlas (2nd Ed., 2001). The last column suggests the minimum aperture, in millimetres, needed to see that object. Most data are taken from Sky Catalogue 2000.0, Vol. 2. Some visual magnitudes are from other sources. RA (2000) Dec Size Minimum Aperture # Object Con Type h m ° ′ mv ′ Chart # mm 1 NGC 7822 Cep E/RN 0 03.6 +68 37 — 60 × 30 8 300 large, faint emission nebula; rated “eeF”; also look for E/R nebula Ced 214 (associated w/ star cluster Berkeley 59) 1° S 2 IC 59 Cas E/RN 0 56.7 +61 04 — 10 × 5
    [Show full text]
  • THE LOCAL GROUP of GALAXIES* Sidney Van Den Bergh
    THE LOCAL GROUP OF GALAXIES* Sidney van den Bergh National Research Council of Canada Dominion Astrophysical Observatory Herzberg Institute of Astrophysics 5071 West Saanich Road Victoria, British Columbia, V8X 4M6 Canada e-mail: [email protected] Summary Hubble's (1936, p. 125) view that the Local Group (LG) is "a typical, small group of nebulae which is isolated in the general field" is confirmed by modern data. The total number of certain and probable Group members presently stands at 35. The half-mass radius of the Local Group is found to be Rh . 350 kpc. The zero-velocity surface, which separates the Local Group from the field that is expanding with the Hubble flow, has a radius Ro = 1.18 " 0.15 Mpc. The 12 total mass of the LG is MLG = (2.3 " 0.6) x 10 Mu . Most of this mass appears to be concentrated in the Andromeda and Milky Way subgroups of the LG. The total luminosity of the Local Group is found to be MV = -22.0:. This yields a mass-to-light ratio (in solar units) of M/LV = 44 " 12. The solar motion with respect to the LG is 306 " 18 km s-1 , directed towards an apex at R = 99E " 5E, - 1 and b = -4E " 4E. The velocity dispersion within the LG is Fr = 61 " 8 km s . The galaxies NGC 3109, Antlia, Sextans A and Sextans B appear to form a distinct grouping with Vr = +114 " 12 kpc relative to the LG, that is located * Based, in part, on a series of lectures given at the University of Victoria in the early spring of 1999.
    [Show full text]
  • ¼¼Çwªâðw¦¹Á¼ºëw£Àêëw ˆ†‰€ «ÆÊ¿Àäàww«¸ÂÀ ‰‡‡Œ†ˆ‰†‰Œ
    ¼¼ÇwªÂÐw¦¹Á¼ºËw£ÀÊËw II - C ll r l 400 e e l G C k i 200 r he Dec. P.A. w R.A. Size Size Chart N a he ss d l Object Type Con. Mag. Class t NGC Description l AS o o sc e s r ( h m ) max min No. C a ( ' ) ( ) sc R AAS e r e M C T e B H H x x NGC 3511 GALXY CRT 11 03.4 -23 05 11 6 m 2.1 m 76 SBc vF,vL,mE 98 x x NGC 3513 GALXY CRT 11 03.8 -23 15 11.5 2.9 m 2.4 m 75 SBb vF,vL,mE 98 IC 2627 GALXY CRT 11 09.9 -23 44 12 2.6 m 2.1 m SBbc eF,L,R,stell N 98 NGC 3573 GALXY CEN 11 11.3 -36 53 12.3 3.6 m 1 m 4 Sa eF,S,R,glbM,3 st 11 f 98 NGC 3571 GALXY CRT 11 11.5 -18 17 12.1 3 m 0.9 m 94 SBa pF,pL,iF,bM 98 B,pL,E,vsmbMN,2 B st x NGC 3585 GALXY HYA 11 13.3 -26 45 9.9 5.2 m 3.1 m 107 Elliptical 98 tri NGC 3606 GALXY HYA 11 16.3 -33 50 12.4 1.5 m 1.4 m Elliptical eF,S,R,gbM 98 x x x NGC 3621 GALXY HYA 11 18.3 -32 49 9.7 12.4 m 5.7 m 159 SBcd cB,vL,E 160,am 4 st 98 NGC 3673 GALXY HYA 11 25.2 -26 44 11.5 3.7 m 2.4 m 70 SBb F,vL,gvlbM,*7 s 6' 98 PK 283+25.1 PLNNB HYA 11 26.7 -34 22 12.1 188 s 174 s 98 x NGC 3693 GALXY CRT 11 28.2 -13 12 13 3.4 m 0.7 m 85 Sb cF,S,E,gbM 98 NGC 3706 GALXY CEN 11 29.7 -36 24 11.3 3.1 m 1.8 m 78 E-SO pB,cS,R,psmbM 98 NGC 3717 GALXY HYA 11 31.5 -30 19 11.2 6.2 m 1 m 33 Sb pB,S,mE,*13 att 98 «ÆÊ¿ÀÄÀww«¸ÂÀ ¼¼ÇwªÂÐw¦¹Á¼ºËw£ÀÊËw II - C ll r l 400 e e l G C k i 200 r he Dec.
    [Show full text]
  • Appendix Appendix
    Appendix Appendix Abbreviations Here general abbreviations, as used in the text, are explained. Excluded: galaxy classifica- tion (Table 1.2), catalog designations and names (Chapter 3), publications (see next Appendices), or directions (e.g., NW). AGN Active galactic nucleus BCD Blue compact dwarf (galaxy) BSO Blue stellar object CCD Charge coupled device CDM Cold dark matter DSS Digital Sky Survey fst Faintest star GA Great attractor GC Globular cluster GRB Gamma ray burst HII HII region HDF Hubble Deep Field HST Hubble Space Telescope LBV Luminous blue variable LF Luminosity function LG Local Group LPR Light pollution reduction (filter) LSB Low surface brightness (galaxy) OC Open cluster PN Planetary nebula POSS Palomar Observatory Sky Survey QSO Quasi stellar object (quasar) SC Star cloud SCT Schmidt-Cassegrain telescope SDSS Sloan Digital Sky Survey SSC Super star cluster UHC Ultra high contrast (filter) ULIRG Ultra luminous infrared galaxy WR Wolf-Rayet (galaxy) ZOA Zone of avoidance 230 General Literature Books on Galaxies and Related Subjects Appendix Binney, J., Merrifield, M., Galactic Astronomy, Princeton University Press, Princeton, NJ, 1998 Bok, B. J., Bok, P. F., The Milky Way, Harvard University Press, Cambridge, MA, 1981 Combes, F., Boisse, P., Mazure, A., Blanchard, A., Galaxies and Cosmology, Springer- Verlag, Heidelberg, 2002 Elmegreen, D. M., Galaxies and Galactic Structure, Prentice-Hall Inc., Upper Saddle River, NJ, 1998 Ferris, T., Galaxies, Stewart, Tabori & Chang Publ., New York, NY, 1982 Hodge, P. W., Galaxies, Harvard University Press, Cambridge, MA, 1986 Hubble, E. P., Realm of the Nebulae, Dover Publ., Mineola, NY, 1958 Jones, M., Lambourne, R. (eds), An Introduction to Galaxies and Cosmology, Cambridge University Press, Cambridge, 2004 Keel, C.
    [Show full text]
  • The COLOUR of CREATION Observing and Astrophotography Targets “At a Glance” Guide
    The COLOUR of CREATION observing and astrophotography targets “at a glance” guide. (Naked eye, binoculars, small and “monster” scopes) Dear fellow amateur astronomer. Please note - this is a work in progress – compiled from several sources - and undoubtedly WILL contain inaccuracies. It would therefor be HIGHLY appreciated if readers would be so kind as to forward ANY corrections and/ or additions (as the document is still obviously incomplete) to: [email protected]. The document will be updated/ revised/ expanded* on a regular basis, replacing the existing document on the ASSA Pretoria website, as well as on the website: coloursofcreation.co.za . This is by no means intended to be a complete nor an exhaustive listing, but rather an “at a glance guide” (2nd column), that will hopefully assist in choosing or eliminating certain objects in a specific constellation for further research, to determine suitability for observation or astrophotography. There is NO copy right - download at will. Warm regards. JohanM. *Edition 1: June 2016 (“Pre-Karoo Star Party version”). “To me, one of the wonders and lures of astronomy is observing a galaxy… realizing you are detecting ancient photons, emitted by billions of stars, reduced to a magnitude below naked eye detection…lying at a distance beyond comprehension...” ASSA 100. (Auke Slotegraaf). Messier objects. Apparent size: degrees, arc minutes, arc seconds. Interesting info. AKA’s. Emphasis, correction. Coordinates, location. Stars, star groups, etc. Variable stars. Double stars. (Only a small number included. “Colourful Ds. descriptions” taken from the book by Sissy Haas). Carbon star. C Asterisma. (Including many “Streicher” objects, taken from Asterism.
    [Show full text]
  • For – Objektauswahl NGC
    For – Objektauswahl NGC NGC 686 NGC 857 NGC 1210 NGC 1326 NGC 1366 NGC 1385 NGC 1428 NGC 689 NGC 897 NGC 1217 NGC 1327 NGC 1387 NGC 1459 NGC 696 NGC 922 NGC 1255 NGC 1336 NGC 1371 NGC 1396 NGC 698 NGC 964 NGC 1288 NGC 1339 NGC 1373 NGC 1398 NGC 727 NGC 986 NGC 1292 NGC 1341 NGC 1374 NGC 1399 NGC 749 NGC 1049 NGC 1302 NGC 1344 NGC 1375 NGC 1404 NGC 775 NGC 1079 NGC 1306 NGC 1350 NGC 1379 NGC 1406 NGC 823 NGC 1097 NGC 1310 NGC 1351 NGC 1380 NGC 1412 NGC 824 NGC 1165 NGC 1316 NGC 1360 NGC 1381 NGC 1425 NGC 854 NGC 1201 NGC 1317 NGC 1365 NGC 1382 NGC 1427 Zur Objektauswahl: Nummer anklicken Sternbild- Übersicht Zur Übersichtskarte: Objekt in Aufsuchkarte anklicken Zum Detailfoto: Objekt in Übersichtskarte anklicken For Sternbildübersichtskarte Auswahl NGC 686_689_775 Aufsuchkarte Auswahl NGC 696_698_727_749 Aufsuchkarte Auswahl NGC 823 Aufsuchkarte Auswahl NGC 824_854_857_897 Aufsuchkarte Auswahl NGC 922 Aufsuchkarte Auswahl NGC 964_986 Aufsuchkarte Auswahl NGC 1049 Aufsuchkarte Auswahl NGC 1079_1097 Aufsuchkarte Auswahl NGC 1165 Aufsuchkarte Auswahl NGC 1201_1210_1255 Aufsuchkarte Auswahl NGC 1217_1310_1316_1317_1326 Aufsuchkarte Auswahl NGC 1288_1339_1344_1350_1366_1406_1425 Aufsuchkarte Auswahl NGC 1292_1302_06_27_60_71_85_98_1412_59 Aufsuchkarte Auswahl NGC 1336_1341_1365 Aufsuchkarte Auswahl NGC 1351_73_74_75_79_80_81_82_87_96_99_1404_27_28Aufsuchkarte Auswahl NGC 686 Übersichtskarte Aufsuch- Auswahl karte NGC 689 Übersichtskarte Aufsuch- Auswahl karte NGC 696_698 Übersichtskarte Aufsuch- Auswahl karte NGC 727 Übersichtskarte Aufsuch-
    [Show full text]
  • Observing Faint Nearby Galaxies Jay Reynolds Freeman Nearby
    Observing Faint Nearby Galaxies Jay Reynolds Freeman Nearby galaxies include the Magellanic Clouds, M31, and other Messier galaxies, but there are many fainter ones. Some are easy, others require skill and excellent conditions to detect. Several of the ones I have seen are well placed for northern hemisphere viewing in autumn. Finding them helped develop my observing skills, so I will describe them in approximately the order I logged them. NGC 147 and 185: NGC 147 and NGC 185 are near the Andromeda border of Cassiopeia. NGC 185 is a degree west of omicron Cassiopeiae, NGC147 is a degree farther and a little north. The proximity of M31 fosters neglect of these lesser luminaries, but I find them easy in dark sky, even with apertures of 70 mm or less. NGC 185 is on the Astronomical League's Herschel-400 observing list, and NGC 147 is not, but nothing in my notes suggests the latter galaxy is more difficult than the former. IC 1613: IC 1613 is a low surface-brightness irregular galaxy in Cetus, about 15 arc minutes across. I first observed it in 1979, using a 15 cm hand-held Newtonian reflector at 36x, which showed no detail. It was featureless again the next year, in a 36 cm Schmidt-Cassegrain telescope (SCT) at 71x, and also featureless twenty years later, with the same instrument at 98x. At least I could see it! IC 1613 is a stepping-stone in difficulty toward the other galaxies described below. Maffei 1: In 1981, I needed targets for my shiny new 36 cm SCT, and stumbled across Maffei 1 in an old _Sky_&_Telescope_.
    [Show full text]