Third Reference Catalogue of Bright Galaxies


This subdirectory contains the Third Reference Catalogue of Bright Galaxies. This file has details about the catalogue contents.

The two files with the extension .gz are gzipped UNIX versions of the data. The other files are ASCII files. "bintro.tex" is a LaTeX version of this brief introductory file.

The large file "rc39b.all.gz" has the entire catalogue gzipped into a single file. If you have a fast and reliable connection, download this file and the ASCII files.

If you have a slow connection, or if it is bothered by line noise, you may wish to download the individual base files "rc39b.nn" (listed below). These have exactly the same data as the single large file, but are split into 23 smaller files, each with data for about a thousand objects.

Finally, there is a comma-separated-variable version "rc39b.csv.gz" for those who wish to import RC3 into a spreadsheet or DBMS. The contents of the CSV file are the same as the other ASCII versions; the file is briefly described in "rc3colscsv.txt".

1. Introduction

This is a brief description of the data entries in the Third Reference Catalogue of Bright Galaxies (RC3) by G. and A. de Vaucouleurs, H.G. Corwin, R.J. Buta, G. Paturel, and P. Fouque. It accompanies an ASCII version of RC3.9b (dated 24 April 1994) distributed on the World Wide Web. Any problems relating to this particular distribution should be addressed directly to me at

hcorwin1153@sbcglobal.net

Files included in this distribution are:

Please note that there are only 23,010 entries in the current version of RC3. Several Galactic objects and duplicate entries have been removed. Details are in the bugs.rc3 file, and in 1994AJ....108.2128C.

Details of the reduction procedures, and Notes, References, and Appendices are in Volume 1 of the printed version of RC3, available from Springer-Verlag New York. References here to page numbers are to this first volume of RC3. Volumes 2 and 3 (included in the current distribution) are also be available from Springer-Verlag should you wish to have a printed and bound version of the complete catalogue.

2. Use and Distribution

You may use any of the data in RC3 in any way you wish. We do ask that you acknowledge RC3 and its authors in any publication that results from your use of the Catalogue. You may also freely distribute unaltered electromagnetic copies of RC3 to friends and colleagues as long as a copy of this documentation -- including this notice -- accompanies the Catalogue.

The printed version of RC3 is protected by copyright, and may not be reproduced in any manner without the written permission of the copyright holder, Springer-Verlag New York, Inc.

3. The Catalogue

The data for each galaxy are found on four successive lines. The entries are as follows:

  • Column 1 -- Positions
  • Line 1 -- RA and DEC = right ascension and declination for the equinox J2000.0, precessed from the 1950.0 position in Column 1, Line 4, given to 0.1 second of time and 1 arcsec when available, and to 0.1 minute of time and 1 arcmin otherwise (Section 3.1.a, page 11).
  • Line 2 -- l and b = galactic longitude and latitude in the IAU 1958 system (Blaauw et al. 1960); both to 0.01 degrees.
  • Line 3 -- SGL and SGB = supergalactic longitude and latitude in the RC2 system (Section 3.1.b), both to 0.01 degrees.
  • Line 4 -- RA and DEC = right ascension and declination for the equinox B1950.0 (Section 3.1.a, page 11).
  • Column 2 -- Names = commonly used designations for the galaxies (Section 3.2, page 12).
  • Line 1 -- Names (e.g. LMC, SMC) or NGC and IC designations.
  • Line 2 -- UGC (Nilson 1973), ESO (Lauberts 1982), MCG (Vorontsov-Velyaminov et al. 1962-1974), UGCA (Nilson 1974), and CGCG (Zwicky et al. 1961-1968) designations, given in that order of preference. MCG designations not listed here are given in UGC and ESO.
  • Line 3 -- Other common designations (see Table 1, page 14, for a complete list).
  • Line 4 -- PGC (Paturel et al. 1989a,b) designation. For cross identifications of various catalogues with PGC, see Appendix 10, page 561.
  • Column 3 -- Types and Luminosity Classes
  • Line 1 -- Type = mean revised morphological type in the RC2 system, coded as in RC2 (Section 3.3.a, page 13).
  • Line 2 -- S_T and n_L = sources of revised type estimates and number of luminosity class estimates.
  • Line 3 -- T = mean numerical index of stage along the Hubble sequence in the RC2 system (coded as explained in Section 3.3.c, page 16), and its mean error.
  • Line 4 -- L = mean numerical luminosity class in the RC2 system (coded as explained in Section 3.3.d, page 18), and its mean error.
  • Column 4 -- Optical Diameters and Axis Ratios
  • Line 1 -- logD_25 = mean decimal logarithm of the apparent major isophotal diameter measured at or reduced to surface brightness level mu_B = 25.0 B-mag/arcsec^2, and its mean error, as explained in Section 3.4.a, page 21. Unit of D is 0.1 arcmin to avoid negative entries. A few very uncertain diameters are flagged with question marks.
  • Line 2 -- logR_25 = mean decimal logarithm of the ratio of the major isophotal diameter, D_25, to the minor isophotal diameter, d_25, measured at or reduced to the surface brightness level mu_B = 25.0 B-mag/arcsec^2, and its mean error, as explained in Section 3.4.b, page 26. A few very uncertain axis ratios are flagged with question marks.
  • Line 3 -- logA_e = decimal logarithm of the apparent diameter (in 0.1 arcmin) of the "effective aperture," the circle centered on the nucleus within which one-half of the total B-band flux is emitted, and its mean error, both derived as explained in Section 3.4.c, page 28.
  • Line 4 -- logD_0 = decimal logarithm of the isophotal major diameter corrected to "face-on" (inclination = 0 degrees), and corrected for Galactic extinction to A_g = 0, but not for redshift, as explained in Section 3.4.d, page 29.
  • Column 5 -- Major Axis Position Angle, Galactic and Internal Extinctions
  • Line 1 -- p.a. = position angle, measured in degrees from north through east (all p.a. < 180 degrees), taken when available from UGC, ESO, and ESGC (and in a few cases from HI data) (Section 3.5.a, page 30).
  • Line 2 -- A_g = Galactic extinction in B-band magnitudes, calculated following Burstein and Heiles (1978a,b, 1982, 1984), as explained in Section 3.5.b, page 30.
  • Line 3 -- A_i = internal extinction in B-band magnitudes (for correction to face-on), calculated from logR and T, as explained in Section 3.5.c, page 31.
  • Line 4 -- A_21 = HI line self-absorption in magnitudes (for correction to face-on), calculated from logR and T >= 1, as explained in section 3.5.d, page 32.
  • Column 6 -- Optical and Infrared Magnitudes
  • Line 1 -- B_T = total (asymptotic) magnitude in the B system, and its mean error, derived by extrapolation from photoelectric aperture-magnitude data, B_T^A, and from surface photometry with photoelectric zero point, B_T^S, as explained in Section 3.6.a, page 32. The magnitude is followed by an "M" when it is the weighted mean of B_T^A and B_T^S, by a "V" when it is a V-band magnitude rather than a B-band magnitude, and by a "v" when the nucleus of the galaxy is variable. The magnitude is replaced by an asterisk (*) when deriving B_T^A would have required an extrapolation in excess of 0.75 mag.
  • Line 2 -- m_B = photographic magnitude and its mean error from Ames (1930), Shapley and Ames (1932), CGCG, Buta and Corwin (1986), and/or Lauberts and Valentijn (1989) reduced to the B_T system, as explained in Section 3.6.b, page 37.
  • Line 3 -- m_FIR = far-infrared magnitude calculated from m_FIR = - 20.0 - 2.5 logFIR, where FIR is the far infrared continuum flux measured at 60 and 100 microns as listed in the IRAS Point Source Catalog (1987). For galaxies larger than 8 arcmin in RC2 and for the Virgo cluster area, resolved by the IRAS beam, integrated fluxes are taken from Rice et al. (1988) or Helou et al. (1988). See Section 3.6.c, page 43, for details.
  • Line 4 -- B_T^0 = total "face-on" magnitude corrected for Galactic and internal extinction, and for redshift, as explained in Section 3.6.d, page 44.
  • Column 7 -- Total Color Indices
  • Line 1 -- (B-V)_T = total (asymptotic) color index in the Johnson B-V system, and its mean error, derived by extrapolation from photoelectric color-aperture data, and/or from surface photometry with photoelectric zero point, as explained in Section 3.7.a, page 45.
  • Line 2 -- (U-B)_T = total (asymptotic) color index in the Johnson U-B system, and its mean error, derived by extrapolation from photoelectric color-aperture data, and/or from surface photometry with photoelectric zero point, as explained in Section 3.7.a, page 45.
  • Line 3 -- (B-V)_T^0 = total B-V color index corrected for Galactic and internal extinction, and for redshift, as explained in Section 3.7.b, page 47.
  • Line 4 -- (U-B)_T^0 = total U-B color index corrected for Galactic and internal extinction, and for redshift, as explained in Section 3.7.b, page 47.
  • Column 8 -- Effective Color Indices and B-band Surface Brightness
  • Line 1 -- (B-V)_e = mean B-V color index, and its mean error, within the effective aperture A_e, derived by interpolation from photoelectric color-aperture data, as explained in Section 3.7.a, page 45.
  • Line 2 -- (U-B)_e = mean U-B color index, and its mean error, within the effective aperture A_e, derived by interpolation from photoelectric color-aperture data, as explained in Section 3.7.a, page 45.
  • Line 3 -- m'_e = mean B-band surface brightness in magnitudes per square arcmin (B-mag/arcmin^2) within the effective aperture A_e, and its mean error, as given by the relation m'_e = B_T + 0.75 + 5logA_e - 5.26. m'_e is statistically related to the effective mean surface brightness, mu'_e (RC2, p. 31; Olson and de Vaucouleurs 1981), with which it coincides when log R = 0 (i = 0 degrees) (Section 3.8.a, page 49).
  • Line 4 -- m'_25 = the mean surface brightness in magnitudes per square arcmin (B-mag/arcmin^2) within the mu_B = 25.0 B-mag/arcsec^2 elliptical isophote of major axis D_25 and axis ratio R_25, defined as in RC2 (Equation 21) by: m'_25 = B_T + Delta m_25 + 5 logD_25 - 2.5 logR_25 - - 5.26, where Delta m_25 = 2.5 log(L_T/L_D_25) = B_25 - B_T is the magnitude increment contributed by the outer regions of a galaxy fainter than mu_B = 25.0 B-mag/arcsec^2. For details, see Section 3.8.b, page 50.
  • Column 9 -- 21-cm Magnitude and Linewidths, Hydrogen Index
  • Line 1 -- m_21 = 21-cm emission line magnitude, and its mean error, defined by m_21 = 21.6 - 2.5 log(S_H), where S_H is the measured neutral hydrogen flux density in units of 10^-24 W/m^2. For details, see Section 3.9.a, page 51.
  • Line 2 -- W_20 = neutral hydrogen line full width (in km/s) measured at the 20% level (I_20/I_max), and its mean error, as explained in Section 3.9.b, page 51.
  • Line 3 -- W_50 = neutral hydrogen line full width (in km/s) measured at the 50% level (I_50/I_max), and its mean error, as explained in Section 3.9.b, page 51.
  • Line 4 -- HI = corrected neutral hydrogen index, which is the difference m_21^0 - B_T^0 between the corrected (face-on) 21-cm emission line magnitude and the similarly corrected magnitude in the B_T system. Details are given in Section 3.9.c, page 52. Footnote: Since m_21 and B_T are listed separately in columns 6 and 9, line 1, there is no need to list the uncorrected index.
  • Column 10 -- Radial Velocities
  • Line 1 -- V_21 = cz is the mean heliocentric radial velocity, and its mean error, in km/s derived from neutral hydrogen observations, as explained in Section 3.10.a, page 52.
  • Line 2 -- V_opt = cz is the mean heliocentric radial velocity, and its mean error, in km/s derived from optical observations, as explained in Section 3.10.b, page 53.
  • Line 3 -- V_GSR = the weighted mean of the neutral hydrogen and optical velocities, corrected to the "Galactic standard of rest," as explained in Section 3.10.c, page 54.
  • Line 4 -- V_3K = the weighted mean velocity corrected to the reference frame defined by the 3 K microwave background radiation, as explained in Section 3.10.d, page 55.

  • Latest update: 25 October 2016