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## RC3 - Third Reference Catalog of Bright Galaxies |
HEASARC Archive |

Only brief parameter descriptions are given in this help file. Detailed information about, for example, how certain quantities were derived, or exactly what a given code means, can be found in the printed version of RC3.

<VII/155/rc3>

Third Reference Catalogue of Bright Galaxies (RC3) de Vaucouleurs G., de Vaucouleurs A., Corwin H.G., Buta R.J., Paturel G., Fouque P. <Springer-Verlag: New York, (1991)> Corrections and Additions to the Third Reference Catalogue of Bright Galaxies Corwin, H.G., Buta, R.J., de Vaucouleurs, G. <Astron. J., 108, 2128-2144 (1994)> =1994AJ....108.2128C

The First Reference Catalogue of Bright Galaxies (RC1) (G. and A. de Vaucouleurs 1964), prepared between 1949 and 1963, included 2,599 objects (six are not galaxies), over twice the number in the original Shapley-Ames catalogue. In addition to diameters, magnitudes, colors, and redshifts in relatively homogeneous systems, it gave revised classifications and detailed literature references from 1913 to 1963. (NGC 8 is a double star; NGC 4361 is a planetary nebula; NGC 5396 is nonexistent, probably = NGC 5375; IC 1308 is a H II region in NGC 6822; IC 3917 is nonexistent, probably a plate defect (M. Wolf 1905); and A2144 = Palomar 12 is a globular cluster.)

The Second Reference Catalogue (RC2) (G. and A. de Vaucouleurs, and H. G. Corwin 1976), prepared between 1971 and 1975, included 4,364 objects (two are not galaxies), for which it gave improved isophotal diameters and axis ratios in the D25 system, newly determined total magnitudes and colors in the UBV system, continuum and 21-cm radio magnitudes, HI index, and redshifts, as well as references to published photographs and a bibliography for the years 1964 to 1975. Both the First and Second Reference Catalogues are limited to galaxies with useful literature references and are incomplete beyond the Shapley-Ames limit. (A0733+02 = DDO 45 is a planetary nebula; A2143-21 = Palomar 12 is a globular cluster.)

The present, much enlarged Third Reference Catalogue of Bright Galaxies (RC3) attempts to be reasonably complete for galaxies having apparent diameters larger than 1 arcmin at the D25 isophotal level and total B-band magnitudes BT brighter than about 15.5, with a redshift not in excess of 15,000 km/s. Objects of special interest, such as compact galaxies smaller than 1 arcmin or fainter than magnitude 15.5, and those already in RC2, are also included. The number of RC3 objects meeting these conditions is 11,897. Additional objects meeting only the diameter or the magnitude condition, and objects of interest smaller than 1.00, fainter than 15.5, or with redshifts > 15,000 km/s, bring the total to 23,022. (PGC 41636 and P65386 have been deleted since the catalog was printed. The first is a globular cluster, Palomar 15, and the second is a duplicate entry for NGC 6967.) These were extracted from the database of 73,197 galaxies maintained by G. Paturel at Lyons Observatory (Paturel et al. 1989a,b). Data published prior to mid-1990 are included in the main RC3 table and appendices.

As might be expected in a compilation of this size, a number of errors have been detected since this catalog was archived. These have been corrected by H. G. Corwin who submitted the current, corrected version. Any problems relating to the catalog itself should be addressed to:

Dr. Harold G. Corwin, Jr. IPAC, M/S 100-22 California Institute of Technology Pasadena, CA 91125Details 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. The user is referred to this source volume for notes, references to data on individual galaxies, and the important information contained in the appendices as well as a discussion of how the entries were derived.

We ask that you acknowledge RC3 and its authors in any publication that results from your use of this catalog. 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 catalog. 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.

**Name**

The name of the galaxy, e.g., LMC, SMC, its NGC or IC designation, etc.

**RA**

The Right Ascension of the galaxy in the selected equinox. In the original
table, the RAs were given to 0.1 second of time when available, and to 0.1
minute of time otherwise (Section 3.1.a, page 11, of Volume I of the printed
version of the RC3).

**Dec**

The Declination of the galaxy in the selected equinox. In the original table,
the Declinations were given to 1 arcsecond of when available, and to 1
arcminute of otherwise (Section 3.1.a, page 11, of Volume I of the printed
version of the RC3).

**LII**

The Galactic Longitude of the X-ray source.

**BII**

The Galactic Latitude of the X-ray source.

**Sg_Lon**

The supergalactic longitude of the galaxy given to 0.01 degrees, and in the
system where the North supergalactic pole is at (l_{II}, b_{II}) = (47.37,
+6.32) and the origin is at (l_{II}, b_{II}) = (137.37, 0.00).

**Sg_LAT**

The supergalactic latitude of the galaxy given to 0.01 degrees, and in the
system where the North supergalactic pole is at (l_{II}, b_{II}) = (47.37, +6.32)
and the origin is at (l_{II}, b_{II}) = (137.37, 0.00).

**Alt_Name_1**

An alternative designation for the galaxy. UGC (Nilson 1973),
ESO (Lauberts 1982), MCG (Vorontsov-Velyaminov et al. 1962-1974), UGCA (Nilson
1974), and CGCG (Zwicky et al. 1961-1968) designations, are given in that
order of preference.

**Alt_Name_2**

Another name for the galaxy.

**PGC_Name**

The PGC Designation of the galaxy (Paturel et al. 1989a,b).
For cross identifications of various catalogs with the PGC, see Appendix 10,
page 561, of Volume 1 of the printed RC3.

**Morph_Type**

The mean revised morphological type of the galaxy in the RC2 system, coded as
in RC2 (See Table 2 in Section 3.3.a, page 15, of the printed RC3, which is
reproduced in the file http://cdsarc.u-strasbg.fr/ftp/cats/VII/155/mtypes.tex.

**Ref_Morph_Type**

A reference code for the source of the revised morphological type, as listed
in Table 3 in Section 3.3.a, page 16, of Vol. I of the printed RC3, with the
additions of 'V' to indicate a classification by de Vaucouleurs and '4' to
indicate a ring galaxy classified by Buta on 4-meter plates.

**Hubble_Stage**

The mean numerical index T of the stage along the Hubble Sequence for the
galaxy, in the RC2 system, coded as explained in Section 3.3.c, page 16, of
Vol. I of the printed RC3 (see also the file
http://cdsarc.u-strasbg.fr/ftp/cats/VII/155/mtypes.tex.

**Hubble_Stage_Error**

The mean error in the value of T, the Hubble stage index.

**Lum_Class**

The mean numerical DDO (van den Bergh) luminosity class of the galaxy, as
explained in Section 3.3.c, page 18, of Vol. I of the printed RC3 (see also
the file http://cdsarc.u-strasbg.fr/ftp/cats/VII/155/mtypes.tex.

**Lum_Class_Error**

The mean error in the numerical DDO (van den Bergh) luminosity class of the
galaxy.

**Num_Lum_Class_Estimates**

The number of estimates used in the calculation of the mean numerical DDO
(van den Bergh) luminosity class of the galaxy.

**Log_D25**

The mean decimal logarithm of the apparent major isophotal diameter, log
D_25, measured at or reduced to the surface brightness level mu_B = 25.0
B-mag per square arcsecond, as explained in Section 3.4.a, page 21, of Volume
I of the printed RC3. The units of D_25 are 0.1 arcminutes.

**Log_D25_Flag**

This parameter is set to '?' to indicate galaxies for which log D_25 is very
uncertain.

**Log_D25_Error**

The mean error in log D_25, in units of 0.1 arcminutes.

**Log_R25**

The mean decimal logarithm of the ratio R_25 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 per square arcsecond, as explained
in Section 3.4.b, page 26, of Volume I of the printed RC3.

**Log_R25_Flag**

This parameter is set to '?' to indicate galaxies for which log R_25 is very
uncertain.

**Log_R25_Error**

The mean error in log R_25.

**Log_Do**

The decimal logarithm of the isophotal major diameter D_0, in units of 0.1
arcminutes, corrected to a "face-on" (i = 0 degrees) orientation, and for
galactic extinction to A_g = 0, but not for redshift, as explained in Section
3.4.d, page 29, of Volume I of the printed RC3.

**Log_Ae**

The decimal logarithm of the apparent diameter A_e, in units of 0.1
arcminutes, of the "effective aperture", i.e., of the circle centered on the
nucleus of the galxay within which one-half of the total B-band flux is
emitted, derived as explained in Section 3.4.c, page 28, of Volume I of the
printed RC3.

**Log_Ae_Error**

The mean error in log A_e, in units of 0.1 arcminutes.

**Position_Angle**

The position angle of the major axis of the galaxy, measured in degrees from
north through east (all < 180 degrees) for the 1950.0 equinox, taken when
available from UGC, ESO, and ESGC (and in a few cases from H I data): see
Section 3.5.a, page 30, of Volume I of the printed RC3.

**BT_Mag**

The total (asymptotic) magnitude in the B system, B_T, derived by
extrapolation from photoelectric aperture- magnitude data, B_AT, and from
surface photometry with photoelectric zero point, B_ST, as explained in
Section 3.6.a, page 32, of Volume I of the printed RC3.

**BT_Mag_Flag**

This parameter contains the following possible coded flags for the B_T of the
galaxy:

"M" = B_T is the weighted mean of B_A^T and B_S^T, "S" = only surface photometry used "V" = B_T is a V-band magnitude rather than a B-band magnitude "v" = the nucleus of the galaxy is variable. "E" indicates that deriving B_A^T would have required an extrapolation in excess of 0.75 mag.

**BT_Mag_Error**

The mean error in the total (asymptotic) B magnitude B_T.

**Phot_Mag**

The photographic magnitude m_B from Ames (1930), Shapley and Ames (1932),
CGCG, Buta and Corwin (1986), and/or Lauberts and Valentijn (1989) reduced to
the BT system as explained in Section 3.6.b, page 37, of Volume I of the
printed RC3.

**Phot_Mag_Error**

The mean error in the photographic magnitude, m_B.

**BT_Mag_Corr**

The total "face-on" magnitude B_T^{0} corrected for galactic and internal
extinction, and for redshift, as explained in Section 3.6.d, page 44, of Vol.
I of the printed RC3.

**Surf_Brtness_D25**

The mean surface brightness in magnitudes per square arcmin (B-magnitudes per
square arcminute) within the mu_B = 25.0 B-mag per square arcsec elliptical
isophote of the major axis log D_25 and the axis ratio log R_25, defined as
in RC2 (Equation 21) by:

m'_25= B_T + delta(m25) + 5 log D_25 - 2.5 log R_25 - 5.26,where delta(m25) = 2.5 log L_T/L_25 = B_25 - B_T and is the magnitude increment contributed by the outer regions of a galaxy fainter than mu_B = 25.0 B-mag per eq arcsec. For details, see Section 3.8.b, page 50, of Vol I of the printed RC3.

**Surf_Brtness_D25_Error**

The mean error in the mean surface brightness within the D_25 isophote, in
B-magnitudes per square arcminute.

**Surf_Brtness_Ae**

The mean B-band surface brightness in magnitudes per square arcminute within
the effective aperture A_e, calculated by the relation

m'_e= B_T + 0.75 + 5 log A_e - 5.26.This 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) (Section 3.8.a, page 49, of Vol I of the printed RC3).

**Surf_Brtness_Ae_Error**

The mean error in the mean B-band surface brightness within the effective
aperture, in B-magnitudes per square arcminute.

**Far_IR_Mag**

The far-infrared magnitude calculated from the relation m_FIR = -20.0 - 2.5
log F_IR, where F_IR is the weighted average far-infrared continuum flux
measured at 60 and 100 microns as listed in the IRAS Point Source Catalog
(1987; CDS Cat. <II/125>). For galaxies larger than 8 arcmin in RC2 and for
the Virgo cluster area, which are well-resolved by the IRAS beam, integrated
fluxes were taken from Rice et al.(1988) or Helou et al.(1988). See Section
3.6.c, page 43, of Vol. I of the printed RC3 for more details.

**H_21cm_Mag**

The 21-cm emission-line magnitude defined by m_21 = 21.6 - 2.5 log S_H ,
where SH is the measured neutral hydrogen flux in units of 10^{-24} W/m^{2}. For
details, see Section 3.9.a, page 51, of Vol. I of the printed RC3.

**H_21cm_Mag_Error**

The mean error in the 21-cm emission-line magnitude m_21.

**BV_Color_Tot**

The total (asymptotic) color index in the Johnson B-V system, (B-V)_T,
derived by extrapolation from photoelectric color-aperture data, and/or from
surface photometry with a photoelectric zero point, as explained in Section
3.7.a, page 45, of Vol. I of the printed RC3.

**BV_Color_Tot_Error**

The mean error in (B-V)_T.

**BV_Color_Ae**

The mean B-V color index within the effective aperture A_e,
(B-V)_e, derived by interpolation from photoelectric color-aperture data, as
explained in Section 3.7.a, page 45 of Vol. I of the printed RC3.

**BV_Color_Ae_Error**

The mean error in (B-V)_e.

**BV_Color_Tot_Corr**

The total B-V color index, (B-V)_T^{0}, corrected for galactic and internal
extinction, and for redshift, as explained in Section 3.7.b, page 47, of Vol.
I of the printed RC3.

**UB_Color_Tot**

The total (asymptotic) color index in the Johnson U-B system, (U-B)_T,
derived by extrapolation from photoelectric color-aperture data, and/or from
surface photometry with a photoelectric zero point, as explained in Section
3.7.a, page 45, of Vol. I of the printed RC3.

**UB_Color_Tot_Error**

The mean error in (U-B)_T.

**UB_Color_Ae**

The mean U-B color index within the effective aperture A_e, (U-B)_e, derived
by interpolation from photoelectric color-aperture data, as explained in
Section 3.7.a, page 45 of Vol. I of the printed RC3.

**UB_Color_Ae_Error**

The mean error in (U-B)_e.

**UB_Color_Tot_Corr**

The total U-B color index, (U-B)_T^{0}, corrected for galactic and internal
extinction, and for redshift, as explained in Section 3.7.b, page 47, of Vol.
I of the printed RC3.

**H_Index_Corr**

The corrected neutral hydrogen index, HI, 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, of Vol. I of the printed RC3.

**A_Bmag_Internal**

The internal extinction A_i in B-band magnitudes (for the correction to
face-on), calculated from log R_25 and Hubble stage index T as explained in
Section 3.5.c, page 31, of Vol. I of the printed RC3.

**A_H_21cm**

The A_21 or H I line self-absorption in magnitudes (for correction to
face-on), calculated from log R_25 and T values greater or equal to 1, as
explained in Section 3.5.d, page 32, of Vol. I of the printed RC3.

**A_Bmag_Galactic**

The Galactic extinction A_g in B-band magnitudes, calculated following
Burstein and Heiles (1978a,b, 1982, 1984,) as explained in Section 3.5.b,
page 30, of Vol. I of the printed RC3.

**H_21cm_W20**

The weighted mean neutral hydrogen line full width W_20 (in km/s) measured at
(or reduced to) the 20% level compared to the maximum intensity, as explained
in Section 3.9.b, page 51, of Vol. I of the printed RC3.

**H_21cm_W20_Error**

The mean error in the H I line full width at the 20% level, in km/s.

**H_21cm_W50**

The weighted mean neutral hydrogen line full width W_50 (in km/s) measured at
(or reduced to) the 50% level compared to the maximum intensity, as explained
in Section 3.9.b, page 51, of Vol. I of the printed RC3.

**H_21cm_W50_Error**

The mean error in the H I line full width at the 50% level, in km/s.

**H_21cm_Radial_Vel**

The mean heliocentric radial velocity V_21 derived from neutral hydrogen
observations, in km/s, as explained in Section 3.10.a, page 52 of Vol. I of
the printed RC3.

**H_21cm_Radial_Vel_Error**

The mean error in the mean heliocentric radial velocity V_21, in km/s.

**Radial_Velocity**

The mean heliocentric radial velocity, V_opt = c * z, derived from optical
observations, in km/s, as explained in Section 3.10.b, page 53 of Vol. I of
the printed RC3.

**Radial_Velocity_Error**

The mean error in the mean heliocentric radial velocity V_opt, in km/s.

**Radial_Velocity_GSR**

The weighted mean of the neutral hydrogen and optical velocities, in km/s,
and corrected to the "Galactic standard of rest", as explained in Section
3.10.c, page 54, of Vol. I of the printed RC3.

**Radial_Velocity_3K**

The weighted mean velocity corrected to the reference frame defined by the 3
K microwave background radiation, in km/s, as explained in Section 3.10.d,
page 55, of Vol. I of the printed RC3.

**Class**

The HEASARC Browse object classification, derived from the galaxy class part
(the second character) of the galaxy's morphological type, i.e., whether it
is an elliptical, lenticular, spiral or irregular galaxy.