J/ApJ/543/178 Nearby Optical Galaxy (NOG) sample (Giuricin+, 2000)
Nearby optical galaxies: selection of the sample and identification of groups. Giuricin G., Marinoni C., Ceriani L., Pisani A. <Astrophys. J. 543, 178 (2000)> =2000ApJ...543..178G
ADC_Keywords: Clusters, galaxy ; Galaxies, nearby ; Redshifts ; Magnitudes Keywords: galaxies: clusters: general - galaxies: distances and redshifts - large-scale structure of universe Abstract: In this paper we describe the Nearby Optical Galaxy (NOG) sample, which is a complete, distance-limited (cz≤6000km/s) and magnitude-limited (B≤14) sample of ∼7000 optical galaxies. The sample covers 2/3 (8.27sr) of the sky (|b|>20°) and appears to have a good completeness in redshift (97%). We select the sample on the basis of homogenized corrected total blue magnitudes in order to minimize systematic effects in galaxy sampling. We identify the groups in this sample by means of both the hierarchical and the percolation "friends-of-friends" methods. The resulting catalogs of loose groups appear to be similar and are among the largest catalogs of groups currently available. Most of the NOG galaxies (∼60%) are found to be members of galaxy pairs (∼580 pairs for a total of ∼15% of objects) or groups with at least three members (∼500 groups for a total of ∼45% of objects). About 40% of galaxies are left ungrouped (field galaxies). We illustrate the main features of the NOG galaxy distribution. Compared to previous optical and IRAS galaxy samples, the NOG provides a denser sampling of the galaxy distribution in the nearby universe. Given its large sky coverage, the identification of groups, and its high-density sampling, the NOG is suited to the analysis of the galaxy density field of the nearby universe, especially on small scales. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 79 4404 Galaxy Members of the Hierarchical (H) Catalog of Groups table3.dat 79 4496 Galaxy Members of the Percolation (P1) Catalog of Groups table4.dat 79 4575 Galaxy Members of the Percolation (P2) Catalog of Groups table5.dat 168 1093 Catalog of the Hierarchical (H) Groups table6.dat 176 1112 Catalog of the Percolation (P1) Groups table7.dat 165 1128 Catalog of the Percolation (P2) Groups
See also: VII/221 : PSCz catalog (Saunders+, 2000) J/PASP/111/438 : Updated Zwicky catalog (UZC) (Falco+, 1999) J/A+AS/100/47 : Study of group membership. II. (Garcia, 1993) http://leda.univ-lyon1.fr/ : LEDA homepage Byte-by-byte Description of file: table2.dat table3.dat table4.dat
Bytes Format Units Label Explanations
1- 4 I4 --- NOGG Nearby Optical Galaxy (NOG) group number (1) 7- 16 A10 --- PGCGal Name of galaxy member of the group, from Gourgoulhon et al. (1992A&A...255...69G) & Fouque et al. (1992A&AS...93..211F) (2) 19- 33 A15 --- NameGal Other name of "PGCGal" galaxy member 36- 37 I2 h RAh Galaxy member right Ascension (B1950) 39- 40 I2 min RAm Galaxy member right Ascension (B1950) 42- 45 F4.1 s RAs Galaxy member right Ascension (B1950) 48 A1 --- DE- Galaxy member declination sign (B1950) 49- 50 I2 deg DEd Galaxy member declination (B1950) 52- 53 I2 arcmin DEm Galaxy member declination (B1950) 55- 56 I2 arcsec DEs Galaxy member declination (B1950) 60- 63 I4 km/s cz Velocity (in Local Group Frame) 66 A1 --- r_cz Velocity reference (3) 69- 73 F5.2 mag Bmag Corrected B band magnitude 76 A1 --- r_Bmag B magnitude reference (4)
Note (1): Notation in Simbad: Table 2: <NOGG H NNNN> Table 3: <NOGG P1 NNNN> Table 4: <NOGG P2 NNNN> Note (2): There is an entry for each galaxy member of a group Note (3): L: Lyon-Meudon Extragalactic Database (LEDA, http://leda.univ-lyon1.fr/ ) O: Other source. e.g. NASA Extragalactic Database (NED, http://nedwww.ipac.caltech.edu/ , Updated Zwicky Catalog (UZC; Falco et al., 1999, Cat. J/PASP/111/438), ORS (Santiago et al., 1995ApJ...446..457S), PSCz, Saunders et al., 2000, Cat. VII/221 Note (4): L: Denotes the galaxies which have B magnitudes taken from LEDA and strictly constitute the NOG sample. E: Additional galaxy members which are part of a small extension of the NOG containing 156 additional galaxies. These objects have rough estimates of B magnitudes (with B≤14mag) derived from diameters. O: Additional galaxy members which are part of a small extension of the NOG containing 156 additional galaxies. These objects have rough estimates of B magnitudes (with B≤14mag) derived from other recent sources.
Byte-by-byte Description of file: table5.dat table6.dat table7.dat
Bytes Format Units Label Explanations
1- 4 I4 --- NOGG Nearby Optical Galaxy (NOG) group number (1) 6 A1 --- f_NOGG [*+=] See note (2) 8- 22 A15 --- Name Name of the brightest galaxy of the group 23- 25 I3 --- NGal Number of galaxy members of the group 28- 29 I2 h RAh Median group Right Ascension (B1950) 31- 32 I2 min RAm Median group Right Ascension (B1950) 34- 37 F4.1 s RAs Median group Right Ascension (B1950) 40 A1 --- DE- Median group Declination (B1950) 41- 42 I2 deg DEd Median group Declination (B1950) 44- 45 I2 arcmin DEm Median group Declination (B1950) 47- 48 I2 arcsec DEs Median group Declination (B1950) 52- 55 I4 km/s cz Median group recession velocity 57- 71 A15 --- Common Common name of the group 73- 91 A19 --- P1 Percolation algorithm method 1 cross-id (3) 93-111 A19 --- P2 Percolation algorithm method 2 cross-id (4) 113-139 A27 --- LGG Cross-identification with Garcia (1983, Cat. J/A+AS/100/47) 141-165 A25 --- NBGG Cross-identification with Tully (1987ApJ...321..280T)
Note (1): Notation in Simbad: Table 5: <NOGG H NNNN> (Nos 1-1093) Table 6: <NOGG P1 NNNN> (Nos 1-1112) Table 7: <NOGG P2 NNNN> (Nos 1-1128) Note (2): *: Systems which are split by the Hierarchical algorithm along the line of sight and then are reconstructed by us with the aid of the results of the P1 method. +: Systems which are constructed with the aid of membership assignments provided directly in the literature for the Virgo region and for four very nearby groups. =: The P1 and P2 systems are by definition taken to be equal to those identified with the H method in the Virgo region and in the very nearby region (cz < 500 km/s). See section 4.2. Note (3): P1 calculated with czL kept constant. Note (4): P2 calculated with czL scaled with z.
History: From ApJ electronic version
(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 24-Jan-2001
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