J/AJ/125/1660 Distant compact groups from DPOSS (Iovino+, 2003)
A new sample of distant compact groups from the
Digitized Second Palomar Observatory Sky Survey.
Iovino A., de Carvalho R.R., Gal R.R., Odewahn S.C., Lopes P.A.A.,
Mahabal A., Djorgovski S.G.
<Astron. J. 125, 1660 (2003)>
=2003AJ....125.1660I 2003AJ....125.1660I
ADC_Keywords: Surveys ; Clusters, galaxy ; Photometry
Keywords: galaxies: clusters: general - methods: statistical - surveys
Abstract:
We have identified 84 small, high-density groups of galaxies out to
z∼0.2 in a region of 2000deg2 around the north Galactic pole using
the digitized Second Palomar Observatory Sky Survey. The groups have
at least four galaxies satisfying more stringent criteria than those
used by Hickson in his pioneering work in 1982: the adopted limiting
surface brightness for each group is brighter (24mag/arcsec2 instead
of 26mag/arcsec2), and the spread in magnitude among the member
galaxies is narrower (2mag instead of 3). We also adopt a slightly
modified version of the isolation criterion used by Hickson, in order
to avoid rejecting groups with projected nearby faint background
galaxies. A 10% contamination rate due to projection effects is
expected for this sample based on extensive simulations.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 63 84 Characteristic parameters of the groups in
our sample
table2.dat 63 347 Catalog of group member galaxies
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- --- [PCG]
5- 14 A10 --- PCG Group name (JHHMM+DDMM)
16- 17 I2 h RAh Hour of right ascension (J2000) (1)
19- 20 I2 min RAm Minute of right ascension (J2000) (1)
22- 23 I2 s RAs Second of right ascension (J2000) (1)
25 A1 --- DE- Sign of the declination (J2000) (1)
26- 27 I2 deg DEd Degree of declination (J2000) (1)
29- 30 I2 arcmin DEm Arcminute of declination (J2000) (1)
32- 33 I2 arcsec DEs Arcsecond of declination (J2000) (1)
35- 38 F4.2 arcmin Rad Group radius (2)
40- 44 F5.2 mag rmag Brightest group galaxy r-band magnitude
46- 50 F5.2 mag/arcsec2 SB Mean r-band group surface brightness (3)
52- 55 F4.2 mag Dmag Magnitude interval between the brightest and
the faintest group member (4)
57- 60 F4.2 mag Dmag1 Magnitude interval between the brightest
group member and the brightest interloper
in the isolation ring (5)
62 I1 --- Nmemb Number of group members (6)
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Note (1): The coordinates of the center of the smallest circle containing all
member galaxies.
Note (2): The radius of the smallest circle containing the member galaxies.
Note (3): Measured as the total magnitude of the member galaxies averaged
over the smallest circle containing all member galaxies. The
compactness constraint imposes SB<24.0.
Note (4): The richness constraint imposes Comp≤2.0.
Note (5): The isolation constraint imposes Isol≥Comp+0.5. This quantity
is set to 99 when no interloper is found within the isolation ring.
Note (6): The richness constraint imposes Nmemb≥4 within an upper limit
of 2mag from the brightest group member.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- --- [PCG]
5- 14 A10 --- PCG Group name (JHHMM+DDMM)
16 A1 --- Mem Member galaxy (1)
18- 19 I2 h RAh Hour of right ascension (J2000)
21- 22 I2 min RAm Minute of right ascension (J2000)
24- 28 F5.2 s RAs Second of right ascension (J2000)
30 A1 --- DE- Sign of the declination (J2000)
31- 32 I2 deg DEd Degree of declination (J2000)
34- 35 I2 arcmin DEm Arcminute of declination (J2000)
37- 41 F5.2 arcsec DEs Arcsecond of declination (J2000)
43- 47 F5.2 mag rmag The SDSS r-band magnitude
49- 53 F5.2 mag g-r The SDSS (g-r) color
55- 57 I3 deg PosAng Position angle
59- 62 F4.2 --- Ellip Ellipticity
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Note (1): In alphabetical order starting from the brightest and going
to fainter members.
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History:
From electronic version of the journal
*14-Nov-2003: in table2.dat, a correction was made on PCG J1228+2725 members.
The second set of data, PCG J1228+2725 A to D was suppressed,
according to the finding chart.
(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 26-May-2003