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: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- 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 -------------------------------------------------------------------------------- Byte-by-byte Description of file: table1.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 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) -------------------------------------------------------------------------------- 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. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table2.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 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 -------------------------------------------------------------------------------- Note (1): In alphabetical order starting from the brightest and going to fainter members. -------------------------------------------------------------------------------- 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
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