RC3 (G0): Third Reference Catalog of Bright Galaxies (19940507)
FILES:
File Dec (2000) Range #Galaxies
rc3n.g0 northern sky: 20<= Dec <+90 8661
rc3e.g0 equatorial sky: -20< Dec <+20 8126
rc3s.g0 southern sky: -90< Dec <=-20 6225
CONTENTS: Third Reference Catalog of Bright Galaxies (RC3.9b)
DATASET: These files come in HyperSky dataset G-7, version 19940507. Availability on HyperSky CD-ROM: RC3.9a: Vol. 1 (1993); RC3.9b: Vol. 2 (1995)
DESCRIPTION: These datafiles contain a total of 23012 galaxies from the THIRD REFERENCE CATALOG OF BRIGHT GALAXIES (RC3), by G. and A. de Vaucouleurs, H. G. Corwin, R. Buta, G. Paturel and P. Fouque. The specific revision from which this HyperSky set is built is RC3.9b, the machine-readable version of 24 April 1994.
The RC3 is the latest in a series of increasingly more comprehensive catalogs, and was made necessary by the explosive growth in extragalactic astronomy since the 1976 publication of its immediate successor, the SECOND REFERENCE CATALOG OF BRIGHT GALAXIES (RC2). The RC2, by G. and A. de Vaucouleurs and H. G. Corwin, contained 4362 galaxies. Likewise, the RC2 succeeded the first REFERENCE CATALOG OF BRIGHT GALAXIES (RC1) by G. and A. de Vaucouleurs, which was published in 1964 and contained 2594 galaxies.
All of the above catalogs build upon the the original Harvard SURVEY OF THE EXTERNAL GALAXIES BRIGHTER THAN 13TH MAGNITUDE, by H. Shapley and and A. Ames, which contained 1244 galaxies and was published in 1932.
The RC3 attempts to be reasonably complete for galaxies having apparent diameters larger than one arc minute at the D25 isophotal level and total B-band magnitudes brighter than about 15.5, with a redshift less than or equal to 15000 km/sec. Roughly half of the RC3 galaxies meet all these conditons. The remaining RC3 galaxies are objects of interest which meet at least some of the conditions.
Support for RC3 development was provided by The National Science Foundation. The printed version of the catalog was published in 1991 by Springer Verlag.
DATA: The HyperSky datafiles contain the following data from the catalog:
MAG: the galaxy magnitude, if available. Normally this will be the value BT, the total (asymtotic) magnitude in the B-system. If BT is not available, then the photographic magnitude reduced to the BT system will be used and will be indicated by the flag "mp" in the comments following the galaxy identification line.
IDENTIFICATION: The galaxy identification as provided by RC3. The NGC or IC designation is used if available. Otherwise, the designation is taken from one of several recognized galaxy catalogs including PGC, MCG, CGCG, ESO, UGC, UGCA and others. Up to 4 possible identifications are provided in RC3 for each galaxy.
COMMENTS: The comment lines contain the following information, provided if available for each galaxy:
* The mean revised morphological type in the RC2 system, using a 7-character code. The code is completely described in RC3. A dot is equivalent to a blank for any given letter position. The most relevant codes are described here:
1st letter: VARIETIES or PECULIARITIES: C=compact; R=outer ring;
P=pseudo outer ring.
Example: "CE....." is a compact elliptical.
2nd letter: CLASS: E=elliptical; L=lenticular; S=spiral; I=irregular
P=peculiar.
Example: ".S....." is a spiral.
3rd letter: FAMILIES: A=ordinary; B=barred; X=mixed.
Example: ".SB...." is a barred spiral.
4th letter: VARIETIES: R=inner ring; S=S-shaped; T=mixed;
Example: ".L.R..." is a lenticular with an inner ring.
STAGES(for ellipticals): can be any of 0-6.
Example: ".E.4..." is an E4 elliptical.
5th letter: STAGES(for lenticulars): -=early; 0=intermediate; +=late.
Example: ".L..+.." is a late-type lenticular.
STAGES(for spirals): 0=0/a; 1=a; 2=ab; 3=b; 4=bc; 5=c;
6=cd; 7=d; 8=dm; 9=m.
Example: ".S..5.." is a type Sc spiral.
6th,7th letters: P=peculiarity; *=uncertain; $=doubtful;
/=spindle (edge-on).
Example: ".L..../" is a spindle-shaped lenticular.
* The Hubble type based on the RC3 mean numerical galaxy type. This type is a simplified equivalent of the RC3 morphological type described above, and will be one of cE, E, E/S0, S0^-, S0^0, S0^+, S0/a, Sa, Sab, Sb, Sbc, Sc, Scd, Sd, Sdm, Sm, Im, cI. The Hubble type is more familiar to most amateurs than the morphological type.
* The length of the major and minor galactic axes, in the form Dxd' (minutes of arc). These dimensions are converted from the values logD25 and logR25, which are supplied and explained in RC3.
* The position angle, measured in degrees from north through east (range 0 to 180 degrees). This value is flagged by "PA=".
* The weighted mean radial velocity corrected to the reference frame defined by the 3-degree Kelvin background radiation, in units of km/sec. This value is flagged by "RV=".
* The flag "mp" if the galaxy magnitude is photographic. See the discussion about magnitudes above.