A "South-Equatorial Galaxy Catalogue" (SEGC) was originally intended to be an extension of the "Southern Galaxy Catalogue" (SGC; H. Corwin and A. and G. de Vaucouleurs, University of Texas Department of Astronomy Monograph No. 4, 1985), with data for RC2, NGC, and other generally large, bright, and nearby galaxies. SEGC, like SGC, is nominally "complete" for galaxies larger than 2.0 arcminutes at the 25.0 B-magnitude arcsec^-2 isophote. As we had for SGC, we intended to collect the data by eye from the IIIa-J plates taken with the UK Schmidt telescope. However, the extention of the southern Schmidt survey to the equator was not completed in time for the necessary prepatory work for "The Third Reference Catalogue of Bright Galaxies" (RC3; G. and A. de Vaucouleurs, H. Corwin, R. Buta, G. Paturel, and P. Fouque, 1991), so we used instead the glass copy plates of the first Palomar Sky Survey. These had the advantage over the POSS1 prints of lower photographic contrast (allowing us to see "further into" the centers of bright galaxies), but the disadvantage of frequent focus problems caused by the inability of the vacuum plate copier to pull the heavy copy plates into close contact with the positive "original". Originally, de Vaucouleurs had suggested the title "Extension" to the Southern Galaxy Catalogue (ESGC), but considering the different plate material, and the similarity of the acronyms SEGC and SGC (and the possible confusion of ESO with ESGC), we have decided to use SEGC for the final release of the catalogue. The name "South-Equatorial Galaxy Catalogue", acronym "SEGC", and name format "SEGC BHHMMSS.d-DDMMSS" are all registered with the IAU name registration service (http://cdsarc.u-strasbg.fr/viz-bin/DicForm). Thus, the name for any included galaxy may be simply constructed from its B1950.0 sexagesimal coordinates. An earlier version of SEGC found its main use in the construction of RC3 by providing a check between the northern and southern diameter/axis ratio systems, represented by UGC/MCG, and ESO-B/LV, respectively. This gave added assurance that this system, as presented in RC3, is systematically consistent over the entire sky. Unfortunately, that early version of SEGC has many incorrect position angles, a few incorrect positions and identifications, and other problems brought on by the speed with which it had to be produced. These defects are corrected in the present version of the catalogue. The current version of SEGC is 1.4.3, and is found in the file "segc143.dat". (The notes are in a separate file "segc143.notes", discussed below). There are 3333 entries, primarily for individual galaxies, but also for a few double or multiple systems where the objects are so closely interacting that data for indiviual objects could not easily be estimated. We have, however, attempted to give data for individual objects whenever possible. The data files use only 7-bit ASCII characters, and have UNIX line endings. ------ Catalogue The data are on one line per galaxy as follows: RA B1950.0 Dec np Position Sources Name NED-friendly Name Type and Lum. Class logD slD logR slR n_D PA sigPA n_PA <> <> <--> <-> <> <> <> <--------------------------><------------------------------><----------------------------><----------------------->|<--><> <-> <-><> <-> | | |<-><>| <> | Examples: 00 02 39.7 -11 46 53 2 SPC SPC IC 1529 IC 1529 (R':)SA(r:)0o: pec 1.40: .04: 1 --- 1 00 08 33.5 -12 23 07 1 SPC NGC 0034 = NGC 0017 NGC 0034 Pec [1.34 .23 ] 1 [ 30 ] 1 00 16 06.7 -15 35 59 1 SPC NGC 0073 NGC 0073 SAB(rs)bc II 1.43 .01 .09: .05 2 145 0 2 00 16 16.5 -19 17 07 1 GSC [RC2] A0016-19 = DDO 001 [RC2] A0016-19 SB:(s)m IV-V 1.35 .02 .08 .02 2 157: 10 2 00 16 17.3 -10 38 19 1 SPC MCG -02-01-052 MCG -02-01-052 SB(s)c? pec 1.24: .01 .22: .03 2 60: 7 2 00 16 17.7 -08 44 13 1 SPC MCG -02-01-050 MCG -02-01-050 (R':)SB(rs:)0/a 1.29: .01 .07: .00 2 172: 3 2 00 16 18.1 -10 39 17 1 SPC MCG -02-01-051 MCG -02-01-051 SB(s)b? pec 1.15: .05 .23? .02 2 71 2 2 00 17 27.0 -06 36 45 1 SPC MCG -01-02-001 MCG -01-02-001 SB:(s?)a? 1.36 .01 .27: .01 2 140 0 2 00 17 51.4 -14 18 45 3 SPC SPC HCo MCG -02-02-002 MCG -02-02-002 SB(s)m V 1.34: .02 .11 .01 3 33 1 00 24 21.3 -02 46 38 4 SPC SPC SPS SPS NGC 0113 NGC 0113 SA:0- 1.31:: .12:: 1 135 1 02 25 45.4 -00 49 55 1 HCo UGC 01949 UGC 01949 IAB(s:)m V 1.35:: .22:: 1 55: 1 08 54 38.7 -05 43 00 1 HCds SEGC B085438.7-054300 SEGC B085438.7-054300 cE0? 0.18: .00: 1 --- 1 08 54 39.6 -05 42 19 1 HCds SEGC B085439.6-054219 2MASX J08570843-0553532 S0? pec 0.81? .41 1 55: 1 Positions: Mean positions for equinox B1950.0 are generally an informally- weighted mean position from the sources listed. These are presented in a single sexagesimal format: hh mm ss.d -dd mm ss Equinox B1950.0 positions have been retained here as most of the source catalogues consulted during SEGC's initial construction during the 1980s carry positions with that equinox. In addition, almost all of the positions measured for the included objects were referred to stars with positions on a frame defined by FK4 for which B1950.0 was the native equinox. A few large galaxies (e.g. NGC 6822, WLM) have over-precise positions for ease of reading the electronic data file. Their estimated positions would be better represented by an "hh mm ss -dd mm.d" format. The positions given for all galaxies are always accurate enough to unambiguously identify the object to which they point. np: Number of positions used to determine the listed mean; this varies between 1 and 12. Position sources: Most galaxies carry positions measured by Brian Skiff on Lowell Observatory 13-inch "Pluto Camera" archive plates; he used the PDS then available (mid-1980s) at Lowell. The measurements were reduced against AGK3 and SAO stars, so the reference frame is formally FK4. These "Pluto Camera" positions are coded "SPC"; standard deviations are about 3 arcseconds. Other positions measured by Skiff are from 18-inch Palomar Schmidt films taken by Gene and Carolyn Shoemaker for their asteroid survey, coded "SPF"; standard deviations are about 1-2 arcsec. PPM provided reference stars for some of these positions, so they can be on the FK5 system. Skiff has also measured some positions on the Palomar Sky Survey (POSS1) prints at Lowell; these, too, are referred to SAO/AGK3 stars. They are coded "SPS" and have standard deviations similar to those measured on the 18-inch films. We note that systematic errors introduced by the use of different reference frames are much smaller than the accidental errors in the measurements themselves. The "Guide Star Catalog" (Lasker et al, AJ 99, 2019, 1990; Russell et al, AJ 99, 2059, 1990) has very good positions, too, but we checked all of them against DSS images or POSS1 prints for superposed stars, interacting companions, and so forth. Corwin also measured many galaxy positions with respect to the GSC stars; these have standard deviations of around 3-4 arcsec. Even better are positions measured on DSS images using IPAC's "Skyview" software; these have standard deviations of about 1-1.5 arcsec (see Corwin et al, PASP 110, 779, 1998). Adequate positions also come from the pointer read-outs of the several DSS image display programs (though can be subject to a 2-arcsec declination offset from an incorrect interpretation of the pixel centers on the DSS scans); Corwin regularly used HESARC's "SkyView" on UNIX, Linux, and Macintosh computers, and "CCDSoft" on MS Windows machines. All of these sources are, of course, utterly dependent on the accuracy of the astrometric calibration of the first-generation DSS scans. As with most of Skiff's positions, this calibration is based on AGK3 and SAO, so the reference frame is again FK4. Finally, we have incorporated positions from several published and unpublished sources cited below. We thank Basilio Santiago for sending positions for objects observed in the Southern Redshift Survey, and Brian Cuthbertson for using his program "HyperSky" to provide many secure identifications for SEGC galaxies to which we referred our position measurements. Position Sources: BSa Basilio Santiago (overlays on PSS), s.d. ~10 arcsec DC Dressel and Condon (ApJSup 31, 187, 1976), s.d. ~5 arcsec ESO Lauberts, ESO survey (1982), s.d. ~5 arcsec FT Fisher and Tully (AA 44, 151, 1975), s.d. ~10 arcsec GHD Gallouet, Heidmann, and Dampierre (AASup 19, 1, 1975), s.d. ~5 arcsec GSC Guide Star Catalog, Version 2.2 or W. Gray's version tied to ACT, s.d. 1-2 arcsec in either case. HCcd H. Corwin, pointer in CCDSoft's DSS image window, s.d. ~2-3 arcsec HCds H. Corwin, Skyview "ex" command on DSS images, s.d. 1-1.5 arcsec HCe H. Corwin, estimate of central position in a DSS image window, s.d. 8-10 arcsec HCo H. Corwin, offset from nearby SAO or GSC stars, s.d. ~3-4 arcsec HCsv H. Corwin, pointer in HESARC's SkyView DSS image window, s.d. ~2-3 arcsec HC2m H. Corwin, Skyview "ex" command on 2MASS J-band images, s.d. 0.3-0.5 arcsec. HC3 H. Corwin, three-star astrometric reduction, s.d. ~4-5 arcsec HC H. Corwin, n-star astrometric reduction, s.d. ~4-5 arcsec HKA Hickson, Kindl, Auman (ApJSup 70, 687, 1989), s.d. ~2 arcsec MDB Bicay (AJ 91, 732, 1986), s.d. 6-8 arcsec SMH Spellman, Madore, Helou (PASP 101, 360, 1989), s.d. 8-10 arcsec SPC B. Skiff, Lowell Observatory 13-inch "Pluto Camera" plates, s.d. ~3 arcsec. SPF B. Skiff, Palomar Observatory 18-inch films taken for the Shoemaker asteroid survey, s.d. ~1-2 arcsec. SPS B. Skiff, POSS1 prints, s.d. ~1-2 arcsec. TM4 Takase and Miyauchi-Isobe (Ann. Tokyo. Astron Obs 21, 127, 1986), s.d. 2-3 arcsec The following were occasionally consulted for objects with questionable positions in the above lists, or where the initially-measured positions disagreed with those found in NED: UB1 Monet et al (AJ 125, 984, 2003), USNO-B1.0, s.d. ~0.3 arcsec for compact galaxies, probably ~2-3 arcsec for diffuse objects. UC3 Zacharias et al. (AJ 139, 2184, 2010), UCAC3, s.d. ~0.1 arcsec for compact galaxies, probably ~1 arcsec for more diffuse objects. 2MP Cutri et al (IPAC, 2000), 2MASS Point Source Catalog, s.d. ~0.2 for compact galaxies, probably ~1 arcsec for more diffuse objects. 2MX Jarrett et al (IPAC, 2003), 2MASS Extended Source Catalog, s.d. ~0.2 for compact galaxies, probably 1-2 arcsec for more diffuse objects. CMC Carlsberg Meridian Catalog Number 14 (Carlsberg 2006; see Evans et al. A&A 395, 347, 2002), s.d. ~0.3-0.5 arcsec for galaxies. SDSS Sloan Digital Sky Survey (Data Release 7, 2009), s.d. ~0.3-0.5 arcsec. The appropriate codes were entered as used. Names: We have generally adopted these from the literature in, roughly, the following order of preference: NGC, IC, MCG, RC2, ESO, UGC, all others. We have constructed names for galaxies without previous designations following standard IAU practice, adopting the numerical portion directly from the given B1950.0 position in the form: SEGC BHHMMSS.d-DDMMSS. We often give additional names in the first name column to aid in the object's identification. Several galaxies, "discovered" during the preparation of SEGC, have entries in subsequent catalogues (e.g. 2MASS, NPM1G); we have not hesitated to adopt these later names when they were available during final preparation of SEGC in 2008-2010. We have almost always adopted NGC and IC names from Corwin's list in his NGC/IC position files (see CDS catalogue number VII/239A, http://ngcicproject.org/corwin/default.htm, and the latest available files at http://web.ipac.caltech.edu/staff/hgcjr/misc/ . If you find differences between SEGC and Corwin's files, use his identification in the NGC/IC files). Some NGC objects nominally in the SEGC zone are missing. These have such poor discovery positions that they are now unrecoverable (e.g. NGC 7666), they have confused identifications (e.g. NGC 1538), or they are asterisms (e.g. NGC 7453 is a triple star). NED-friendly Name: We also give a second 30-byte name column with a name that appears (or will appear soon) in the NASA/IPAC Extragalactic Database (NED). We have made extensive use of NED to correct the various problems present in previous versions of SEGC (see above). Type and Lum. Class: Morphological types are on the de Vaucouleurs revised Hubble-Sandage system as presented in "The Reference Catalogue(s) of Bright Galaxies" (RC1/2/3, G. and A. de Vaucouleurs, H. Corwin, R. Buta, G. Paturel, and P. Fouque, 1964, 1976, and 1991; and in de Vaucouleurs, ApJS 8, 31, 1963). Also see "The de Vaucouleurs Atlas of Galaxies"; R. Buta, H. Corwin, and S. Odewahn, Cambridge University Press, 2007, for an updated, extended, and illustrated introduction to the VRHS types. We have used the RC2/3 version of the VRHS system -- EXCEPT that the "cD" galaxies, inserted by de Vaucouleurs at numerical type stage T = -4 in RC2/3, have been replaced with the transitional E/S0 types as in RC1 (the "cD" galaxies have been placed in their appropriate morphological type bins, generally one of the S0 stages). We have retained the RC2/3 compact elliptical galaxies at T = -6 and the compact irregulars at T = +11. A few dwarf ellipticals and spheroidals have a "d" prepended to their classifications. An ASCII underline symbol appears BEFORE the symbol that would, in normal text, be underlined. MCG -02-33-100 is an example: S_AB(s)bc pec II-III; this is closer to being an non-barred galaxy than a barred one. Luminosity classes in van den Bergh's system have, where possible, been assigned for spirals and irregulars later than Hubble stage "ab" (T = +2). As in SGC, we have extended the system to luminosity classes V-VI and VI (based on surface brightness estimates). We believe it is unlikely that these additional luminosity classes are correlated with fainter absolute magnitudes, but this has yet to be tested. Where there is more than one type estimate, we've simply averaged them. In general, then, the classifications we present here are compatible with those in SGC and in the Reference Catalogues. Note again, however, that we give appropriate morphological classifications to the "cD" galaxies that appear in RC2/3 at T = -4. We use the numerical stage T = -4 for true transitional types, E/S0, as de Vaucouleurs did in RC1. logD: log of the major diameter in 0.1 arcmin units. If the diameter was measured on more than one plate, the number presented is an unweighted mean. Occasionally, diameter measurements by Corwin made on DSS images are presented for galaxies in close pairs or multiplets. These assume symmetry of the galaxy's image, and are always followed by the uncertainty symbol "?". Standard uncertainty symbols ":", "::", and "?" also often appear when warranted by irregularities in the image. Common problems leading to uncertain diameters are not only nearby stars and galaxies, but uneven sky background on the plates (whether real, due to faint, diffuse nebulosity; or due to large-scale plate defects), and -- particularly for the early type galaxies -- uncertainty as to the maximum extent of the galaxy. If the measurement applies to more than one galaxy, or if it includes unusual extended features (e.g. "plumes", "jets", or "bridges"), it is enclosed in square brackets "[]". slD: standard deviation in logD when two or more values were averaged. logR: log of the axis ratio: logR = log(D/d). The minor axis logd = logD - logR can, of course, be calculated easily. Uncertainty symbols (see above) following the axis ratio actually apply to the minor axis itself rather than to the axis ratio. slR: Standard deviation in logR when two or more values were averaged. n_D is the number of diameters and axis ratios used in determining the mean values. PA is the position angle of the major axis of the galaxy's image, measured from north through east. Sometimes the major axis is not readily apparent, but a "principal axis" (for e.g. an inner isophote, or a bar) is; these are flagged in the notes for the object. All of the position angles in SEGC 1.4 have been checked against the DSS images; position angles from earlier versions of SEGC should be discarded. Position angles are generally given to the nearest five degrees, though many for flat galaxies are given to the nearest degree. If no position angle can be measured (e.g. for a round galaxy image), this column carries an em-dash (three hyphens) "---". As with the diameters and axis ratios, unweighted means and standard deviations are calculated when more than one position angle is available for an object. Similarly, if the position angle applies to more than one galaxy, or applies to extended features ("plumes", "bridges", etc.), it is given in square brackets. Occasionally, a position angle is noted to have two or more measurements, but a standard deviation is not given. In these cases, the position angle was not measured on one or more of the plates, so the given position angle is from a single plate. ------ Notes The Notes are in a separate file "segc.notes". The format is as follows: Name RA (1950) Dec Plt l Note <----------------------------><> <--> <-> <> <--> | <------------------------------------------------------> MCG -01-01-024 00 00.0 -04 00 1198 1 Short OX bar(?), vB pat inner arms, F outer arms. MCG -01-01-024 00 00.0 -04 00 1198 2 1st in grp. NGC 7808 00 01.0 -11 01 1193 0XN, pB lens, incomp R in F corona. S0 sp 2.9 sw. MCG -02-01-014 00 01.4 -11 27 1193 1 0XN, F arms. Optical(?) P(a) at 0.3 w MCG -02-01-015. MCG -02-01-014 00 01.4 -11 27 1193 2 -14 behind(?) -15. MCG -02-01-015 00 01.5 -11 27 1193 1 pS pB N, r': 0.3 x 0.18, pat arms, vF env. MCG -02-01-015 00 01.5 -11 27 1193 2 Optical(?) P(a) at 0.3 w MCG -02-01-014. NGC 7813 00 01.6 -12 15 1193 0XN, p smooth arms. Stage unsure. MCG -01-01-030 00 02.1 -08 22 1198 OXN, trace of r' in lens, F corona. 1st in grp. MCG -03-01-018 00 02.2 -16 19 365 S B N, pB bar, r: 0.45 x 0.4, pF pat arms. Name: One of the names of the galaxy given in the "segc143.dat" file. Position: An abbreviated B1950.0 position usually taken from the original SEGC work book. These are usually also the position in "segc143.dat" rounded off to 0.1 minutes of time and one arcminute, though final digit differences of 1 or 2 are possible. A tie-breaking letter, usually a compass direction ("n", "s", "e", or "w", or some combination thereof) is added when necessary. Plate: The POSS1 plate number on which the galaxy was seen. Line number: If the note extends beyond one line in length, the lines are numbered (these are a computer sorting aid). Lines with no numbers indicate notes on a single line. Note: Finally, the note itself. Not all galaxies in SEGC have notes, but most do. Sometimes, these are a relatively elaborate description of the galaxy and its surrounding field, sometimes they simply note a feature of the object. All measurements in the notes -- including rings and other features in the galaxy, distances on the sky between objects, etc. -- are in arcminutes unless noted. Abbreviations are more or less standard, adopted from those in SGC, RC1, NGC, and other well-known (though now ancient) galaxy catalogues. ------ A simple analysis of the catalogue data will be presented later, but here is an "abstract". logD-logN plots show that SEGC is 50% complete at about logD = 1.2, but has a long "tail" to smaller diameters. Diameters and axis ratios may be reduced to the 25.0 B-magnitude isophote (RC3's standard diameter system) as follows (see the RC3 Introduction, Volume 1, Section 3.4, Tables 6 and 9) log D_25 = logD - 0.187, s.d. = 0.085, for T >= 1 log D_25 = logD - 0.157, s.d. = 0.093, for T < 1 and log R_25 = 1.26 * logR, s.d. = 0.08, for T >= 1 log R_25 = 1.11 * logR, s.d. = 0.07, for T < 1 ------ Acknowledgments: We are indebted in particular to the late Gerard and Antoinette de Vaucouleurs for initiating the project, and for general guidance and inspiration throughout its duration. The University of Texas, Austin, Department of Astronomy; The University of Texas, McDonald Observatory; Lowell Observatory; and the California Institude of Technology, Infrared Processing and Analysis Center; all provided computing and other physical facilities, including the plates we scanned (POSS1, UT Austin; Pluto Camera, Lowell). NED, CDS, LEDA, ADS, HESARC, and STScI all provided invaluable access to on-line catalogues, the DSS, and the astronomical literature. We also benefitted from conversations with (in no particular order) Basilio Santiago, Michael Strauss, Will Sutherland, Barry Madore, George Helou, Marion Schmitz, Joe Mazzarella, Marianne Brouty, Georges Paturel, Brian Cuthbertson, and Ronald Buta. Harold Corwin and Brian Skiff Latest revision 27 August 2010