ADC/CDS Standard Document for Catalog:/journal_tables/ApJ/496/39/
ADC/CDS Standard Document for Catalog:| 1. Use the ADC Data Viewer Suite to visualize the data. |
|
| 2. Get the data files via anonymous FTP. (See Note.) |
|
J/ApJ/496/39 Properties of poor groups of galaxies. I. (Zabludoff+ 1998)
================================================================================
The properties of poor groups of galaxies. I. Spectroscopic survey and results.
Zabludoff A.I., Mulchaey J.S.
<Astrophys. J. 496, 39 (1998)>
=1998ApJ...496...39Z (SIMBAD/NED BibCode)
================================================================================
ADC_Keywords: Clusters, galaxy ; Radial velocities
Keywords: galaxies: clusters: general - galaxies: distances and redshifts -
galaxies: elliptical and lenticular, cD - galaxies: evolution -
galaxies: interaction - large-scale structure of universe -
X-rays: galaxies
Abstract:
We use multifiber spectroscopy of 12 poor groups of galaxies to
address (1) whether the groups are bound systems or chance projections
of galaxies along the line of sight; (2) why the members of each group
have not already merged to form a single galaxy, despite the groups'
high galaxy densities, short crossing times, and likely environments
for galaxy-galaxy mergers; and (3) how galaxies might evolve in these
groups, where the collisional effects of the intragroup gas and the
tidal influences of the global potential are weaker than in rich
clusters. Each of the 12 groups has fewer than about five cataloged
members in the literature. Our sample consists of 1002 galaxy
velocities, 280 of which are group members. The groups have mean
recessional velocities between 1600 and 7600km/s. Nine groups,
including three Hickson compact groups, have the extended X-ray
emission characteristic of an intragroup medium (see Paper II,
1998ApJ...496...73M).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 50 1002 Galaxy data
table2.dat 81 12 Group kinematic properties
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Name Galaxy name
13- 14 I2 h RAh Right ascension (J2000.0)
16- 17 I2 min RAm Right ascension (J2000.0)
19- 22 F4.1 s RAs Right ascension (J2000.0)
24 A1 --- DE- Declination sign
25- 26 I2 deg DEd Declination (J2000.0)
28- 29 I2 arcmin DEm Declination (J2000.0)
31- 32 I2 arcsec DEs Declination (J2000.0)
34- 38 I5 km/s HRV Heliocentric radial velocity (1)
40- 42 I3 km/s e_HRV rms uncertainty on HRV
44 I1 --- Line [0/2] Type of measurement (2)
46 A1 --- MType [ES] Morphological type (3)
48 A1 --- Plate [pc] Plate/CCD (4)
50 A1 --- r_HRV [N0] Heliocentric radial velocity reference (5)
--------------------------------------------------------------------------------
Note (1): The velocities are either emission-line velocities, absorption-line
velocities, or a weighted average of the two
Note (2): 0: absorption lines
1: emission lines
2: combination of both
Note (3): E: early type
S: late type
Note (4): p: plate
c: CCD
Note (5): N: from NED
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Group Group name
10- 11 I2 h RAh Right ascension of the group optical
projected centroid in J2000
13- 14 I2 min RAm Right ascension of the group optical
projected centroid in J2000
16- 19 F4.1 s RAs Right ascension of the group optical
projected centroid in J2000
21 A1 --- DE- Declination sign
22- 23 I2 deg DEd Declination of the group optical
projected centroid in J2000
25- 26 I2 arcmin DEm Declination of the group optical
projected centroid in J2000
28- 29 I2 arcsec DEs Declination of the group optical
projected centroid in J2000
31- 33 I3 --- Ntot Total number of galaxies with measured
redshifts in the fiber field
35- 36 I2 --- Ngroup Number of group members
38- 41 I4 km/s HRV Biweight estimators of the mean
heliocentric velocity
43- 44 I2 km/s e_HRV rms uncertainty on HRV
46- 48 I3 km/s sigma Line-of-sight velocity dispersion
50- 52 I3 km/s E_sigma Error on sigma (upper limit)
54- 55 I2 km/s e_sigma Error on sigma (lower limit)
57- 60 F4.2 Mpc rsample Physical radius of the group sampled by the
fiber field (h^-1^Mpc)
62- 65 F4.2 Mpc rp ? Pair radius (h^-1^Mpc)
67- 70 F4.2 Mpc rh ? Mean harmonic (virial )radius (h^-1^Mpc)
72- 76 E5.1 solMass Mvir ? Virial mass (h^-1^Mpc)
78- 81 F4.2 --- tc/tH ? Ratio of the crossing time to Hubble time
--------------------------------------------------------------------------------
History: From ApJ electronic version
================================================================================
(End) James Marcout, Patricia Bauer [CDS] 15-Jun-1998