The AGC databased is maintained separately by hemisphere (north and south) and epoch
(B1950 and J2000). The version available to ALFALFA is in J2000.
Variable name Format Data Content
AGCNUMBER I6 AGC entry number. See note 1.
1-12943: UGC galaxy (corresponds to UGC number)
20001-33656: ESO sequence number
100000 - 399999 northern hemisphere
400000 - 699999 southern hemisphere
700000 - 999999 northern hemisphere
WHICH A1 Identifier for multiple systems: a,b etc.
RAH I2 R.A. hours
RAM I2 R.A. minutes
RAS10 I3 R.A. seconds *10.
SIGN A1 Dec. sign
DECD I2 Dec. degrees
DECM I2 Dec. minutes
DECS I2 Dec. seconds
A100 I5 Blue major diameter *100. See note 15.
B100 I4 Blue minor diameter *100.
MAG10 I4 Zwicky magnitude *10. or RC3 ApparentBmag for decl<-3. See note 15
INCCODE I2 Nilson's inclination code
POSANG I3 Nilson's position angle (or other measure on same system)
DESCRIPTION A8 Morphological description
BSTEINTYPE I3 Burstein type code (see gallib/sgal/typeesgc.f)
VOPT I6 Radial velocity (helio)
VERR I3 Error in radial velocity
EXTRC3 I5 Galactic extinction *1000 either directly from RC3
or derived from nearest RC3 galaxy, following
Burstein&Heiles (1978) & RC3. See note 17.
EXTDIRBE I5 Galactic extinction ext*1000 from the DIRBE dust
maps following Schlegel et al. 1998
Value is: E(B-V) in mags (*1000). See note 17.
VSOURCE I3 Source for radial velocity measurement
(follows Huchra for < 50; > 50 = H-G, probably out of date;
-99 stands for NED; other negatives: see note (7).)
NGCIC A8 NGC or IC number from Dressel and Condon
or Fisher and Tully or other name from ZCAT
or MGC name abbreviated (SEZ strip) as
MsLNNMMM where M denotes MCG
s is sign of strip
L indicates 6 deg strip (as in MCG)
NN is which field along strip
MMM is galaxy entry number in field.
The MCG would have listed sLLNNMMM.
FLUX100 I5 Observed (uncorrected) 21 cm line
flux (in Jy-km/s) * 100.
RMS100 I4 Rms noise in mJy *100.
V21 I5 21 cm heliocentric velocity.
WIDTH I4 21 cm profile width.
WIDTHERR I2 Error in 21 cm width.
WIDTHCODE A4 Code for type of width measurement. See
note (2).
TELCODE A1 Telescope code. See note (3).
DETCODE I1 Detection code. See note (4).
HISOURCE I2 Code for source of 21 cm data. See note (5).
STATUSCODE I1 Code for status of data. See note (6).
SNRATIO I3 Signal-to-noise ratio*10 for 21 cm feature
IBANDQUAL I1 Quality of I-band data. See note (8)
IBANDSRC I2 Code for source of I-band data. See note (9).
IRASFLAG I1 FLAG for inclusion in internal IRAS database
See note (10).
ICLUSTER I2 Cluster membership. See note (11).
HIDATA I1 FLAG for inclusion in HI database (not yet
implemented). See note (12).
IPOSITION I1 A flag to indicate the source of the coordinates
used in the AGC. See note (13).
IPALOMAR I1 A flag to indicate that long slit spectroscopy has
been obtained at Palomar. See note (14).
RC3FLAG I1 A flag to indicate that the galaxy is included
in the RC3. See note (15).
IROTCAT I1 Included in rotcurve.cat rotation curve database
See note (16)
NEWSTUFF I2 UNUSED
AGC records are now 125 characters in length:
CHARACTER DESCRIPTION*8,NGCIC*8,WHICH*1,TELCODE*1,WIDTHCODE*4,
* SIGN*1
INTEGER AGCNUMBER,RAH,RAM,RAS10,DECD,DECM,DECS,
* A100,B100,MAG10,INCCODE,POSANG,BSTEINTYPE,
* VOPT,VERR,EXTRC3,EXTDIRBE,VSOURCE,
* FLUX100,RMS100,V21,WIDTH,WIDTHERR,
* DETCODE,HISOURCE,STATUSCODE,SNRATIO,
* IBANDQUAL,IBANDSRC,IRASFLAG,ICLUSTER,HIDATA,
* IPOSITION,IPALOMAR,RC3FLAG,IROTCAT,NEWSTUFF
READ(10,125) AGCNUMBER,WHICH,RAH,RAM,RAS10,SIGN,DECD,DECM,DECS,
* A100,B100,MAG10,INCCODE,POSANG,DESCRIPTION,BSTEINTYPE,
* VOPT,VERR,EXTRC3,EXTDIRBE,VSOURCE,NGCIC,
* FLUX100,RMS100,V21,WIDTH,WIDTHERR,WIDTHCODE,TELCODE,
* DETCODE,HISOURCE,STATUSCODE,SNRATIO,
* IBANDQUAL,IBANDSRC,IRASFLAG,ICLUSTER,HIDATA,
* IPOSITION,IPALOMAR,RC3FLAG,IROTCAT,NEWSTUFF
125 FORMAT(I6,A1,2I2.2,I3.3,A1,3I2.2,I5,2I4,I2,I3,A8,I3,I6,I3,
* 2I5,I3,A8,I5,I4,I5,I4,I2,A4,A1,i1,I2,I1,I3,I1,I2,I1,
* I2,5I1,I2)
Note 1 The UGC is the Uppsala General Catalog (Nilson, 1973); a copy
is available in the reading room. Further information on the entries
can be obtained from reading Nilson's introduction to his catalog.
The ESO catalog is a version based on Vince Ford's catalog and
the entry number is simply a sequence number within that catalog
(note it is meant to be used only as a pointer privately).. The
ESGC catalog has been privately communicated by Harold Corwin.
A permanent AGC is assigned when an object is added to the catalog.
Sequencing is not retained if a position is updated, but assignment
of numbers is made per hour of right ascension:
100001-109999 0-1h north 400001-409999 0-1h south
110001-119999 1-2h north 410001-419999 1-2h south
etc. until
330001-339999 23-24h north 630001-639999 23-24h south
**** NOTE
Effective 2007 Jan 04
Numbers above 700000 are used for objects in the north where there are
>10000 galaxies per hour of RA. These are added sequentially without
consideration of RA. ****
The last number assigned per hour per catalog is listed in
AGC.NUMBERS and AGC700000.NUMBERS
Assignment of new numbers is done regularly using the program
assign.f. Additional entries to the AGC should be entered
first with sequence number "0". Assignment of new numbers should
only be performed by MH.
Note 2 Widths measured as follows:
Code Measurement
' M50' 50% of the mean flux density
' P20' 20% of the peak flux density
' P50' 50% of peak flux density
'5M2P' average of (50% of mean) and (20% of peak) widths
'2P50' 50% of each of the two peaks (if double-horned)
' F50' 50% level of fit to slope on either side
(using 1991 msr algorithm .825 .5 .5 .2 .5)
' A50' Similar to above, but using IDL_ALFALFA code
Note 3 Telescope code:
0 - Arecibo circular feed - no corrections applied
1 - NRAO 91 m. - no corrections
2 - Bonn 100 m. - no corrections
3 - NRAO 42 m. - no corrections
4 - Arecibo flat feed. - no corrections
5 - Nancay. - corrected flux
6 - Parkes. - observed flux
7 - Hybrid - corrected flux
8 - Optical, or else unspecified radio dish (see Note 5,
HI Source = 69)
9 - No observations made
A - Arecibo non-detection WITHOUT known optical redshift
B - Arecibo flat feed, corrected flux (normally mapping)
C - Nancay, uncorrected flux (we should change this)
D - VLA
E - WSRT
F - Australia Compact Array
G - Arecibo Gregorian, 3.5arcmin beam, uncorrected.
H - HIPASS/Parkes multibeam
I - HIJASS/Jodrell multibeam
J - AO/ALFA
K - GBT
L - ATCA
M - GMRT
Note 4 HI detection code:
0 - not detected/not observed
1 - detected.
This is equivalent to CODE=1 in the ALFALFA scheme.
2 - marginally detected; everything uncertain.
This is equivalent to CODE=3 in the ALFALFA scheme
3 - detection, but inadequate for FT purposes. This
may mean width cannot be measured because of baseline
or noise on edge, or the profile is very asymmetric or
weird, or confusion is suspected. In this case, the flux
and velocity are usually measured ok, but one is not
certain what they all refer to.
4 - HI profile shows absorption. Flux certainly affected.
5 - Confused with obvious optical companion (i.e. confusion
is certain).
6 - This means the width has been BOXCAR+HANNING not just simple
Hanning. NOTE THIS IS AN UPDATE TO PREVIOUS DOCUMENTATION!
7 - Used for ALFALFA detections to indicate an object which is
detected at low SN but with apriori redshift. This is
equivalent to CODE=2 in the ALFALFA scheme.
THIS DISTINCTION IS NOT YET IMPLEMENTED!
8 - Profile obtained by some of us, but parameters not final
9 - preliminary measurement
Note 5 Source for 21 cm data:
-3 - Misc from NED
-2 - Entry from RC3
-1 - Entry from Richter catalog of March 1989. You must go
look this reference up in the catalog and then in the
original publication to be sure the number is right.
For other codes, check NED or ask Martha;
Codes > 50 are ours. ALFALFA detections are coded "75".
Note 6 21 cm data status:
0 - No data.
1 - Published.
2 - Unpublished but available.
4 - Observed by source in reference but not available
to public.
5 - Obtained from on-line compilation, such as GOLDMINE etc,
may not be original source.
Note 7 Extra codes used for velocity where not in ZCAT
-98 is SDSS
-99 is NED
Check NED anyway....
Watch out that code "6" is from ZCAT, misc AO fluxes (21cm!) -- not
optical!
Note 8 IBANDQUAL - I1 - quality/status flag:
Ask Martha
Note 9 Source for I-band ccd data
Ask Martha, or look at the Cornell digital archive for the SFI++ dataset
http://arecibo.tc.cornell.edu/hiarchive/sfiplusplus.php
Note 10: Out of date; ignore.
Note 11: Cluster membership.
Out of date: ignore.
Note 12: Flag set to "1" indicates that there is a spectrum of
this galaxy in the "final" HI digital archive and derived parameters
are included in the HI results archive. IN PROGRESS!
Note 13: It is beneficial to know where the coordinates listed in the
AGC came from. This 1-digit code will allow us to identify the
source and hence the expected accuracy of the position entered into the
AGC. We should make use of this code in the future.
1 -- From measurements made using digital pad
2 -- From POSS prints with OVERLAY only (either
OSU overlays or our own).
3 -- From DSS by DD
5 -- Found using SKYVIEW
6 -- Published positions
UGC objects: Cotton et al. 1999 ApJS 125, 409.
8 -- From SDSS SQL
9 -- NED positions with accuracy quoted to be <2"
Note 14: Identifier for existence of data in Palomar long-slit DBS
database.
Ask Martha.
Note 15: Flag for objects that are listed in the RC3. A cross reference
file is maintained in /galaxy/rc3/rc3agc.cross. It should be accurate
except in some cases of confusion in multiple systems. In July 00, we
updated magnitudes and diameters in the agc.south using RC3 scaling so
that
(a) for galaxies in the MCG strip with RC3FLAG=1 (-18 ext_I = 0.45*extrc3
DIRBE E(B-V) ==> ext_I = 1.962*extdirbe
NOTE: THIS HAS NOT BEEN UPDATED LATELY!!! MANY OBJECTS MISSING THESE VALUES!