|
[Adapted from the ADC CD-ROM]
The Galaxies and Quasars catalog consists of two files in FITS table
format, one with IRAS point source information ordered by right
ascension and the other with identified associations with other
catalogs, keyed to the IRAS data records. FITS extension headers in
each file describe each column in the data tables. The information
in the extension headers is given in a more easily-readable format
below in Tables 1 and 5, which contain brief descriptions of each
variable in the files, including their logical types and lengths in bytes.
| Table 1. Format of IRAS Data for Extragalactic Catalog File |
| Start Byte |
Name |
Description |
Units |
Format |
| 1 |
NAME |
IRAS source name |
--- |
A11 |
| 12 |
RAHR |
Right Ascension 1950 |
Hours |
I2 |
| 15 |
RAMIN |
Right Ascension 1950 |
Minutes |
I2 |
| 18 |
RASEC |
Right Ascension 1950 |
Seconds |
F4.1 |
| 23 |
DECSGN |
Declination Sign |
+,- |
A1 |
| 24 |
DECDEG |
Declination 1950 |
Arc degrees |
I2 |
| 27 |
DECMIN |
Declination 1950 |
Arc minutes |
I2 |
| 30 |
DECSEC |
Declination 1950 |
Arc seconds |
I2 |
| 33 |
GLAT |
Galactic latitude 1950 |
Arc degrees |
I3 |
| 37 |
UNCMAJ |
Uncertainty ellipse semi-major axis |
Arc seconds |
I3 |
| 40 |
UNCMIN |
Uncertainty ellipse semi-minor axis |
Arc seconds |
I3 |
| 44 |
POSANG |
Uncertainty ellipse position angle |
Degrees (East of North) |
I3 |
| 47 |
NHCON |
Number of times observed |
--- |
I2 |
| 49 |
FNU_12 |
12 um flux density averaged, non color corrected |
Janskys (10E-26 W/m**2/Hz) |
F6.2 |
| 55 |
FQUAL_12 |
12 um flux quality where
(blank) = high quality
: = moderate quality
L = upper limit |
--- |
A1 |
| 56 |
FNU_25 |
25 um flux density averaged, non color corrected |
Janskys (10E-26 W/m**2/Hz) |
F6.2 |
| 62 |
FQUAL_25 |
25 um flux quality where
(blank) = high quality
: = moderate quality
L = upper limit |
--- |
A1 |
| 63 |
FNU_60 |
60 um flux density averaged, non color corrected |
Janskys (10E-26 W/m**2/Hz) |
7.2 |
| 70 |
FQUAL_60 |
60 um flux quality where
(blank) = high quality
: = moderate quality
L = upper limit |
--- |
A1 |
| 71 |
FNU_100 |
100 um flux density averaged, non color corrected |
Janskys (10E-26 W/m**2/Hz) |
F7.2 |
| 78 |
FQUAL_100 |
100 um flux quality where
(blank) = high quality
: = moderate quality
L = upper limit |
--- |
A1 |
| 79 |
FIR |
Log (FIR) far infrared flux combined 60 & 100 um flux |
W/m**2 |
F6.2 |
| 85 |
FQFIR |
FIR flux quality where
(blank) = high quality
: = moderate quality
L = upper limit |
--- |
A1 |
| 86 |
RELUNC [1] |
Percent relative flux density uncertainties, one value per band,
A - 0% < UNCS < 4%
B - 4 < UNCS < 8
C - 8 < UNCS < 12
D - 12 < UNCS < 16
E - 16 < UNCS < 20
F - UNCS > 20 |
--- |
4A1 |
| 91 |
CC [1] |
Point source correlation coefficient, one value per band
A = 100%
B = 99
C = 98
.
.
M = 87 |
--- |
4A1 |
| 96 |
CIRR1 |
Cirrus indicator, number of 100 um only sources in window |
--- |
I1 |
| 97 |
CIRR2 |
Cirrus indicator, ratio of cirrus flux to source flux |
--- |
I1 |
| 99 |
CONFUSE |
Confusion flag, hex encoded see Table 3 and PSC Format |
--- |
I1 |
| 100 |
PNEARH |
Number hours-confirmed point sources in window
PNEARH > 9 = 9 |
--- |
I1 |
| 101 |
PNEARW |
Number of weeks-confirmed point sources in window
PNEARW > 9 = 9 |
--- |
I1 |
| 102 |
HSDFLG |
High source density flag, hex encoded, see Table 3 and PSC Format |
--- |
I1 |
| 104 |
SES1 [1] |
Number of seconds-confirmed small extended sources in window,
one value per band |
--- |
4I1 |
| 108 |
SES2 |
Number of weeks-confirmed small extended sources in window,
hex encoded, see Table 3 and
PSC Format |
--- |
I1 |
| 109 |
NSSS |
Number of associations from Small-Scale Structure Catalog |
--- |
I2 |
| 112 |
SSSNAM |
Name of closest SSS association |
--- |
A10 |
| 122 |
DISSSS |
Separation from the SSS source |
Arc minutes |
I3 |
| 125 |
NONGAL |
Number of associations from non-galaxy catalogs listed in PSC format |
--- |
I2 |
| 128 |
IDNGAL |
Code indicating non-galaxy catalog with closest association, see Table 4. |
--- |
A1 |
| 130 |
DSNGAL |
Separation of the non-galaxy source |
Arc minutes |
I3 |
| 133 |
NRECS |
Number of lines in association file which are keyed on this IRAS name |
--- |
I2 |
| 135 |
BLANKS |
Blank space for possible added data |
--- |
A26 |
[1] In the FITS header, these quantities are suffixed by the wavelength.
Example: CC(4) is given as CC_12, CC_25, CC_60, and CC_100.
- Name: NAME
- The IRAS source name is derived from its position by combining
the hours, minutes, and tenths of minutes of right ascension, and
the sign, degrees, and minutes of the declination. The right ascension
and declination have been truncated. A letter 'A', 'B', 'C', etc.
is appended to names of sources so close together that they would
otherwise have had identical names.
- Position: RAHR, RAMIN, RASEC, DECSGN, DECMIN, DECSEC
- IRAS positions are given for the equinox 1950.0.
- Galactic Latitude: GLAT
- Galactic latitude bII rounded to the nearest degree.
- Positional Uncertainties: UNCMAJ, UNCMIN, POSANG
- The uncertainty is expressed as a 95% confidence uncertainty
ellipse. The semi-major (UNCMAJ) and semi-minor (UNCMIN) axes
(arcsec) of the confidence ellipse are given. The orientation of
the ellipse on the sky, (POSANG), is expressed in terms of the
angle between the major axis of the ellipse and the local
equatorial meridian, expressed in degrees east of north. The
uncertainty is overestimated for large uncertainties; further
information is available in Explanatory Supplement V.D.9 and VII.C.
- Number of Sightings: NHCON
- The number of hours-confirmed sightings of a source (see
Explanatory Supplement V.D).
- Flux Densities and Their Qualities: FNU, FQUAL
- Flux densities in Janskys (10^-26 W m^-2 Hz^-1) are given in
the four bands, each followed by a flag indicating the quality of
the measurement. The flux densities assume an underlying energy
distribution f(nu) proportional to nu^-1, i.e., they have not
been color-corrected. The quoted flux
densities are averages of all the hours-confirmed sightings as
obtained by the prescription in Explanatory Supplement V.H.5.
If no flux quality flag is given, the flux density is a high
quality one. A colon (:) denotes a moderate quality flux density,
and an 'L' denotes an upper limit. An 'S' indicates a saturated flux
density. An upper limit is usually a 3-sigma value but may be much
more than this if the flux was deleted by the high-source-density
processor (Explanatory Supplement V.H.6 and High
Source Density Bins). The assignment of flux qualities is
described in Explanatory Supplement V.H.5.
- Combined 60 and 100 um Flux and Quality: FIR, FQFIR
- This quantity is a convenient representation of the far-infrared
flux of a galaxy, as measured by IRAS, at least for thermal infrared
sources; it is effectively the total flux between 42.5 and 122.5 um.
It is in units of W m^-2. A full description of this parameter is
given in Appendix B of the Cataloged Galaxies and Quasars reference;
numerically the quantity tabulated is given by:
Log(FIR) = Log(1.26 x [F(60) + F(100)]),
where F(60) and F(100) are the fluxes measured for the source, in
W m^-2, in the 60 and 100 um bands respectively. These fluxes can be
recovered from the nominal flux densities listed in the IRAS catalogs
using the formulae:
F(60) = 2.58 x 10^-14 x f(nu;60)
F(100) = 1.00 x 10^-14 x f(nu;100)
where f(nu;60) and f(nu;100) are the flux densities at the two
wavelengths, measured in Janskys.
The flux quality assigned to FIR is carried over from the flux
qualities of the 60 and 100 um flux densities. FIR is of course
subject to the same uncertainties in the calibration as the individual
flux densities.
- Flux Uncertainties: RELUNC(4)
- Each high or moderate-quality flux density measurement has an
associated uncertainty expressed as a 1-sigma value in units of
delta[f(nu)]/f(nu). Uncertainties are discussed in Explanatory
Supplement V.H.5. These flux qualities have been encoded according
to the scheme in Table 2 (where the uncertainty was first rounded
to two significant figures).
| Table 2. Meaning of RELUNC Flag |
| Symbol |
Uncertainty Range |
| A |
0.00 <= delta[f(nu)]/f(nu) < 0.04 |
| B |
0.04 <= delta[f(nu)]/f(nu) < 0.08 |
| C |
0.08 <= delta[f(nu)]/f(nu) < 0.12 |
| D |
0.12 <= delta[f(nu)]/f(nu) < 0.16 |
| E |
0.16 <= delta[f(nu)]/f(nu) < 0.20 |
| F |
delta[f(nu)]/f(nu) >=0.20 |
- Correlation Coefficient: CC(4)
- The correlation coefficient, one per band, ranges from 87 to 100%.
It is derived from a least squares fit of the data for a source to
the point source template. The coefficient is described fully in
Explanatory Supplement V.C.4. In the Extragalactic Catalog the
coefficient is encoded as alphabetic characters with A=100%, B=99%,
etc., to M=87%, one for each band. The value quoted is the highest
correlation coefficient found for that source on any sighting.
- Cirrus Indicators: CIRR1, CIRR2
- Over a large range of Galactic latitudes the infrared sky at
100 um is characterized by emission from interstellar dust on a wide
range of angular scales. As described in Cataloged Galaxies and
Quasars II.F, this so-called "infrared cirrus" can seriously hamper
efforts to extract point source detections from the data. To aid the
user in interpreting the quoted 100 um measurements, three
cirrus-related quantities have been established (Explanatory Supplement
V.H.4 and VII.H). Two of these are given in the Extragalactic Catalog.
CIRR1 gives the number of 100 um-only hours-confirmed sources
located within a ±0.5° box in ecliptic coordinates centered
on the source. The sources included in this count are the
weeks-confirmed sources prior to high-source-density processing,
if applicable (see Cataloged Galaxies and Quasars II.E), plus those sources
hours-confirmed but not weeks-confirmed. Values of greater than 3
may indicate contamination by cirrus with structure on the
point-source size scale.
CIRR2 gives a cirrus indication on a larger scale than CIRR1 and
compares a "cirrus flux" with the source flux at 100 um (see
Explanatory Supplement V.H.4 for derivation of CIRR2). Values of
CIRR2 larger than 4 or 5 indicate the presence of considerable
structure in the 100 um emission on a 0.5° scale. A value of 0
indicates that no 100 um extended emission data were available for
the source in question.
- Confusion Status Flags: CONFUSE, PNEARH, PNEARW, HSDFLAG
- A great deal of care went into trying to untangle instances of
confusion between neighboring sources (Explanatory Supplement V.D.2,
D.3; see also Cataloged Galaxies and Quasars II.E).
In parts of the sky
where the source density is low, confusion processing was often
able to separate sources that are quite close together. The
CONFUSE flag is set if two or more sightings of the source in a
given band had confusion status bits set, indicating confusion in
the seconds-confirmation or band-merging processes. This flag is
hex encoded by band (see Table 3).
Other indicators of possible confusion are given by PNEARH and
PNEARW which are, respectively, the number of hours and weeks-confirmed
point sources located within a 4.5 arcmin cross-scan and 6 arcmin
in-scan window centered on the source. Values larger than 9 are given
as 9 (Explanatory Supplement VII.H.1.a, X.B).
Regions of high source density received special processing to improve
the reliability of the quoted sources (see
Cataloged Galaxies and Quasars II.E and Explanatory
Supplement V.H.6). The regions are band dependent. If a particular band
of a given source went through high source density processing, then
the appropriate bit in HSDFLAG. HSDFLAG is hex encoded by band (see
Table 3).
| Table 3. Meaning of Hex Encoded Flags |
| Flag Set in A Particular Band (microns) |
Resultant Value |
100
(Bit 3) |
60
(Bit 2)> |
25
(Bit 1> |
12
(Bit 0) |
of Encoded Flag
xxxx = HEX = Decimal |
| 0 |
0 |
0 |
0 |
0000 = 0 = 0 |
| 0 |
0 |
0 |
1 |
0001 = 1 = 1 |
| 0 |
0 |
1 |
0 |
0010 = 2 = 2 |
| 0 |
0 |
1 |
1 |
0011 = 3 = 3 |
| 0 |
1 |
0 |
0 |
0100 = 4 = 4 |
| 0 |
1 |
0 |
1 |
0101 = 5 = 5 |
| 0 |
1 |
1 |
0 |
0110 = 6 = 6 |
| 0 |
1 |
1 |
1 |
0111 = 7 = 7 |
| 1 |
0 |
0 |
0 |
1000 = 8 = 8 |
| 1 |
0 |
0 |
1 |
1001 = 9 = 9 |
| 1 |
0 |
1 |
0 |
1010 = A = 10 |
| 1 |
0 |
1 |
1 |
1011 = B = 11 |
| 1 |
1 |
0 |
0 |
1100 = C = 12 |
| 1 |
1 |
0 |
1 |
1101 = D = 13 |
| 1 |
1 |
1 |
0 |
1110 = E = 14 |
| 1 |
1 |
1 |
1 |
1111 = F = 15 |
- Small Extended Source Flags: SES1(4), SES2(1)
- SES1 is the number of seconds-confirmed small-scale structure
detections in a given band found within a window centered on the
source. The size of the window is 6 arcsec in-scan x 4.5 arcsec
cross-scan. As described in Explanatory Supplement VII.H.1, values
of SES1 greater than 1 indicate that significant extended structure
may exist in the region and that the source in question may be a
point-source-like piece of a complex field.
SES2 is the number of weeks-confirmed small-scale structure sources
in a given band located within a 6 arcsec in-scan x 4.5 arcsec
cross-scan window centered on the source. Values greater than zero
mean that the point source flux measurement should be treated with
caution as the source in question may, in fact, be extended, and the
flux density quoted in the Small-Scale Structure
Catalog may provide a better representation of the source. SES2 is
hex encoded by band (see Table 3).
Small-Scale Structure Associations: NSSS, SSSNAM, DISSSS
The Small-Scale Structure associations were established by
searching the Small-Scale Structure Catalog near
the positions of IRAS point sources rather than near galaxies. The
associations were made in much the same way as was used for
associations in other astronomical catalogs with entries in the
Point Source Catalog. NSSS is the
number of small-scale structure sources that associate with the
point source. In the Extragalactic Catalog N is never larger than one.
SSSNAM is the name of the associated source as in the
Small-Scale Structure Catalog, and DISSSS is
the separation in arcseconds between the point source and
the small-scale structure source.
For many galaxies, the SES2 flag is set but no extended-source
associations are given. This situation arises primarily because the
SES2 flag is based on weeks-confirmed small-scale structure sources
(which numbered about 40,000), whereas associations were established
with the Small-Scale Structure Catalog which
contains only 16,740 entries. The presence of a SES2 flag is sufficient
cause for suspecting that the galaxy may have been resolved by IRAS,
though the extended detection did not make it through the stringent
final catalog selection process. (See the Explanatory Supplement for
more details.)
Another reason that may have led to the situation described
above is that SES2 flags were based on a slightly larger search
window than associations with the Small Scale Structure Catalog.
- Other Associations: NONGAL, IDNGAL, DSNGAL
- If an IRAS point source associates with an object from any of
the various non-galaxy catalogs listed in
the Format of the Point
Source Catalog, that fact is indicated here. NONGAL is the
number of associations made for the source among these non-galaxy
catalogs and IDNGAL is a code which indicates which catalog the
nearest of these associations is from (see Table 4). DSNGAL
is the separation of this object from the point source (arcsec).
There is a priority scheme in selecting the nearest association:
if an association exists from one of the first nine catalogs in
Table 4 it takes priority over the remainder. Similarly,
associations from catalogs A-E take precedence over F-J, and
catalogs F-I are preferred over J. Although this field is
included primarily to warn of possible confusion of the galaxy
with a star or nebula, the catalog of extragalactic radio sources,
J, is included on the lowest priority, since it provides a
useful piece of additional information.
| Table 4. Key to Identifications from Non-Galaxy Catalogs [1] |
| Code |
Catalog |
| 1 |
Smithsonian Astrophysical Observatory Star Catalog, 1966 |
| 2 |
Bright Star Catalogue - 4th Edition, Hoffleit and Jascheck 1982 |
| 3 |
Dearborn Observatory Catalogue of faint Red Stars, Lee et al. 1943, 1944, 1947 |
| 4 |
General Catalogue of Variable Stars, Kukarkin et al. 1970, 1971 |
| 5 |
Early Type Stars with Emission Lines, Wackerling 1970 |
| 6 |
New Catalog of Suspected Variable Stars, Kukarkin et al. 1981 |
| 7 |
General Catalogue of Cool Carbon Stars |
| 8 |
Catalog of Nearby Stars, Gliese 1969 |
| 9 |
General Catalog of S Stars, Stephenson 1973, 1976 |
| A |
Strasbourg Planetary Nebulae |
| B |
Parkes HII Region Survey, Haynes et al. 1979 |
| C |
Bonn HII Region Survey, Altenhoff et al. 1979 |
| D |
Catalog of CO Radial Velocities Toward Galactic HII Regions, Blitz et al. 1982 |
| E |
Catalogue of Dark Nebulae, Lynds 1962
Comparison Catalog of HII Regions, Marsalkova 1974
Catalog of Star Clusters and Associations, Alter et al. 1970
Catalog of Bright Diffuse Nebulae, Cederblad 1946
Untersuchungen Uber Reflexionsnebel am Palomar Sky Survey, Dorschner and Gurtler 1964
A Study of Reflection Nebulae, van den Bergh 1966b
Catalog of Southern Stars Embedded in Nebulosity, van den Bergh and Herbst 1975 |
| F |
Revised Air Force Geophysical Laboratory Four-Color Survey, Price and Murdock 1983 |
| G |
Two Micron Sky Survey, Neugebauer and Leighton 1969 |
| H |
Equatorial Infrared Catalogue, Sweeney et al. 1978 |
| I |
Two Micron Sky Survey with Improved Positions, Kleinmann and Joyce 1984 |
| J |
Catalog of Extragalactic Radio Sources Having Flux Densities Greater than 1 Jy at 5 Ghz, Kuhr et al. 1981 |
| Table 5. Format of Association Data for Extragalactic Catalog File |
| Start Byte |
Name |
Description |
Units |
Format |
| 1 |
NAME |
Repeat of IRAS source name |
--- |
A11 |
| 12 |
PGCNAM |
Galaxy name from Primary Galaxy Catalog (UGC, UGCA, ESO, OR CGCG) |
--- |
A12 |
| 25 |
NPGC |
Number of appearances |
--- |
I1 |
| 27 |
DIAMP |
Major axis diameter |
Arc seconds |
I4 |
| 33 |
DISPGC |
Distance from IRAS source |
Arc seconds |
I3 |
| 37 |
PAPGC |
Position angle of separation vector |
Degrees East of North |
I3 |
| 41 |
POSFLG |
Position flag, see Sec.IX of Cat. Galaxies and Quasars ref. |
--- |
A1 |
| 42 |
MAGFLG |
Magnitude flag, see Sec.IX |
--- |
A1 |
| 44 |
MAGPGC |
Magnitude from Primary Galaxy Catalog |
Magnitude |
F4.1 |
| 49 |
CLASSN |
Classification field |
--- |
A7 |
| 57 |
MCGNAM |
Galaxy name from MCG |
--- |
A11 |
| 69 |
NMCG |
Number of appearances |
--- |
I1 |
| 71 |
DIAMM |
Major axis diameter |
Arc seconds |
I4 |
| 76 |
DISMCG |
Distance from IRAS source |
Arc seconds |
I3 |
| 80 |
PAMCG |
Position angle of separation vector |
Degrees East of North |
I3 |
| 84 |
NGCIC |
NGC or IC identification of Primary Catalog or MCG galaxy |
--- |
A7 |
| 91 |
AMDNAM |
ARP, MKN, DDO associations |
--- |
A7 |
| 99 |
NAMD |
Number of appearances |
--- |
I1 |
| 101 |
DISAMD |
Distance from IRAS source |
Arc seconds |
I3 |
| 105 |
PAAMD |
Position angle of separation vector |
Degrees East of North |
I3 |
| 109 |
VVZNAM |
VCV, VV, Zwicky list associations |
--- |
A11 |
| 121 |
NVVZ |
Number of appearances |
--- |
I1 |
| 123 |
DISVVZ |
Distance from IRAS source |
Arc seconds |
I3 |
| 127 |
PAVVZ |
Position angle of separation vector |
Degrees East of North |
I3 |
| 131 |
VCVFLG |
VCV identifier or VV flag,see Sec. IX |
--- |
A2 |
| 133 |
RECNO |
Main Data Table record number for IRAS source |
--- |
I5 |
| 138 |
BLANKS |
Blank space for possible added data |
--- |
A23 |
- Name: NAME
- Repeat of the IRAS name.
- Primary Galaxy Catalog Names: PGCNAM
- This column lists the name of the galaxy from four of the five
main galaxy catalogs; the UGC (U), the UGC Appendix (UA), the
CGCG (Z), and the ESO (E), with which the IRAS source is associated.
A UGC galaxy with the suffix 'A' is from the addendum to the UGC.
MCG associations appear elsewhere. As described in Cataloged Galaxies
and Quasars III.A, these four catalogs were fully combined prior
to making the associations (see III.C and D), so there is at most
one entry for each IRAS source in this column unless the IRAS source
is associated with more than one galaxy. Details of the catalogs and
nomenclature used in various regions of the sky are given in
Cataloged Galaxies and Quasars III.C and in Table III.C.1. Positions for
the galaxies have been taken from the same catalog as the name,
except in the case of the Dressel and Condon (1976) positions for
UGC galaxies, and except for a few errors discovered in the UGC
coordinates (see Sec. III.F).
If more than one Primary Catalog Galaxy associates with a
particular IRAS source, the one matching the IRAS source more
closely in position is listed first. The next galaxy appears on
the following line.
- Number of Appearances of the Galaxy: NPGC
- An entry in this column indicates that the galaxy named in
the preceding column appears more than once in the Extragalactic
Catalog. The value of NPGC is the number of times that the galaxy
name appears, i.e., the number of IRAS sources with which the galaxy
was associated. Galaxies appearing more than twice in the
Extragalactic Catalog are listed in Table III.A.2 in the Cataloged
Galaxies and Quasars reference.
- Major Axis Diameter: DIAMP
- The major axis diameter of the galaxy listed in the Primary
Galaxy Catalog column (arcsec). For catalogs that list both blue
and red sizes, the blue one has been adopted. The size quoted here
is that used to decide whether the galaxy should be treated as a
large or small galaxy for the association procedure (see Cataloged
Galaxies and Quasars III.B). For a large galaxy (> 90 arcsec in semi-major
axis), the association search radius used was one-half of the major
axis given here. If no size was available in the catalog the
number zero appears in this column.
- Separation: DISPGC
- Distance of the galaxy from the IRAS Source (arcsec).
- Position Angle: PAPGC
- Position angle of the separation vector from the IRAS source
to the optical galaxy, in degrees east of north.
- Position and Magnitude Flags: POSFLG, MAGFLG
- POSFLG is a flag indicating any special circumstances concerning
the optical position used for the galaxy. MAGFLG is a flag that
refers to the magnitude quoted. Explanations of both flags are given
in Cataloged Galaxies and Quasars IX. These flags only indicate discrepancies
that came to light during the merger process; they are not intended
to indicate all discrepancies that may be present in the galaxy
catalogs.
- Magnitude: MAGPGC
- The magnitude is carried over from the galaxy catalog in question.
Most often it is a photographic blue magnitude derived ultimately
from the CGCG.
- Classification Field: CLASSN
- In this column the first seven characters of the classification
field of the catalog in question have been reproduced. There is no
guarantee that these types are in any way homogeneous, and they are
often truncated.
- MCG Galaxies: MCGNAM
- This column contains MCG identifications for the Primary Catalog
Galaxy, and also MCG galaxies that have not been identified with
the Primary Catalog galaxy for which an independent association has
been made with the IRAS source (see Cataloged Galaxies and Quasars III.D).
MCG identifications for Primary Catalog galaxies may be identified
by the absence of any diameter or separation information for the
MCG galaxy.
If a single UGC, UGCA or ESO galaxy is identified with two or
more MCG galaxies, this is usually indicated with a '+' symbol.
The second and subsequent MCG galaxies will not appear by name in
the Extragalactic Catalog. If there is both an identification with
a Primary Catalog galaxy and an independent association with another
MCG galaxy for a particular source, the identification will appear
first, and the independent association will be on the following line.
Additional MCG independent associations will appear on subsequent
lines, in order of proximity to the IRAS source.
- Number of Appearances of the MCG name: NMCG
- This column lists the number of times that a given MCG name
appears in the Extragalactic Catalog. Unlike the situation for the
Primary Galaxy Catalog entries, NMCG does not necessarily indicate
the number of IRAS sources that the MCG galaxy is associated with,
because there exist cases in which two or more components of a galaxy
or galaxy pair have the same MCG name.
- Major Axis Diameter: DIAMM
- Outer major axis diameter of the MCG galaxy, if the MCG name is
not just an identification for a Primary Catalog galaxy (arcsec).
If no size was available for the galaxy, the number zero is entered
in this column. For large galaxies (> 180 arcsec in semi-major axis)
the association search radius used was one-half of the major axis
given here.
- Separation: DISMCG
- Separation of the MCG galaxy from the IRAS source (arcsec), if
that MGC galaxy has been associated independently with the IRAS source.
- Position Angle: PAMGC
- Position angle of the radius vector from the IRAS source to
the MCG galaxy, in degrees east from north, if that MCG galaxy has
been associated independently with the IRAS source.
- NGC/IC Name: NGCIC
- NGC or IC identification for the Primary Catalog galaxy, if
available, or for the MCG galaxy. If size and separation
information exists for the MCG galaxy, then the NGC/IC
identification belongs to it; otherwise, the NGC/IC identification
belongs to the Primary Catalog galaxy. No identifications are
available for CGCG galaxies. Only six characters of the
identification field have been copied into the Extragalactic
Catalog. The symbols '+', '/' or '=' indicate additional NGC/IC
names, which will not appear by name in the Extragalactic Catalog.
A '?' or ':' denotes an uncertain identification. These symbols
have the same meaning as they do in the optical catalog in question.
Note that NGC or IC galaxies that are IRAS sources but that do
not appear in the optical catalogs (Table II.A.1 of Cataloged
Galaxies and Quasars), if any exist, will not appear here.
- Secondary Catalogs: AMDNAM
- This column contains the names of galaxies from the Markarian
lists (MKN), the Atlas of Peculiar Galaxies (ARP) and the
Catalogue of Dwarf Galaxies (DDO). No attempt has been made to
identify objects appearing in this column with each other or with
Primary Catalog and MCG galaxies.
- Number of Appearances of the Name: NAMD
- NAMD indicates the number of appearances of the ARP, MKN or DDO
name in the Extragalactic Catalog.
- Separation: DISAMD
- Separation of the ARP, MKN or DDO galaxy from the IRAS source (arcsec).
- Position Angle: PAAMD
- The position angle of the radius vector from the IRAS source
to the galaxy, in degrees east from north.
- Secondary Catalogs: VVZNAM
- This column contains the names of galaxies and quasars from the
compilation of Veron-Cetty and Veron (nomenclature from the original
listings combined by Veron-Cetty and Veron), the Atlas of Interacting
Galaxies (V) and the eight lists of F. Zwicky (1ZW through 8ZW).
As for the previous secondary column, no attempt has been made to
internally identify objects in this column amongst themselves, or
with objects in any of the other galaxy-name columns.
- Number of Appearances of the Name: NVVZ
- NVVZ indicates the number of times that the galaxy name appears
in the Extragalactic Catalog.
- Separation: DISVVZ
- Separation of the galaxy from the IRAS source (arcsec).
- Position Angle: PAVVZ
- Position angle of the radius vector of the IRAS source from
the galaxy, in degrees east of north.
- VCV Type or VV Flag: VCVFLG
- This column is used to identify VCV entries because many entries
from this catalog are duplicated in one of the other secondary
catalogs - most notably the Markarian lists. The type of the galaxy
from VCV has been used as this identification flag. For VCV galaxies
with no type, the letters "AN", for "Active Nucleus", have been
inserted to mark the entry.
This column also contains a number of flags for VV galaxies;
the meaning of these flags is explained in Cataloged Galaxies and
Quasars IX.
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