J/ApJ/549/172 X-ray-detected, poor groups galaxy populations (Tran+, 2001)
The galaxy populations of X-ray-detected, poor groups.
Tran K.-V.H., Simard L., Zabludoff A.I., Mulchaey J.S.
<Astrophys. J. 549, 172 (2001)>
=2001ApJ...549..172T 2001ApJ...549..172T
ADC_Keywords: Clusters, galaxy ; Morphology ; Magnitudes
Keywords: galaxies: clusters: general - galaxies: evolution -
galaxies: fundamental parameters - galaxies: structure
Abstract:
We determine the quantitative morphology and star formation properties
of galaxies in six nearby X-ray-detected, poor groups using multiobject
spectroscopy and wide-field R imaging. The mean recessional velocities
of the galaxy groups range from 2843 to 7558km/s. Each group has 1538
confirmed members ranging in luminosity from dwarfs to giants
(-13.7≥MR-5logh≥-21.9). We measure structural parameters for each
galaxy by fitting a PSF-convolved, two-component model to their
surface brightness profiles. To compare the samples directly, we fade,
smooth, and rebin each galaxy image so that we effectively observe
each galaxy at the same redshift (9000km/s) and physical resolution
(0.87h-1kpc). The structural parameters are combined with [O II]
measurements to test for correlations between morphological
characteristics and current star formation in these galaxies. We
compare results for the groups to a sample of field galaxies.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 80 18 Structural Parameters of Field Galaxies Measured
at cz0 and cz=9000km/s
table3.dat 80 171 Structural Parameters of Group Galaxies Measured
at cz0 and cz=9000km/s
--------------------------------------------------------------------------------
See also:
Table 1: Group Properties
--------------------------------------------------------------
Group RA (2000.0) DE N HRV sigma D
km/s km/s
--------------------------------------------------------------
NGC 2563 20 24 24. +21 05 46 36 4775±65 336±44 811
NGC 3557 11 09 58.5 -37 23 03 15 2843±64 282±50 488
NGC 4325 12 23 18.2 +10 37 19 23 7558±70 265±50 1272
NGC 5129 13 24 28.1 +13 55 32 34 6998±51 304±43 1173
HCG 42 10 00 13.1 -19 38 24 25 3830±47 266±37 654
HCG 62 12 53 12.4 -09 12 12 38 4356±50 376±52 741
--------------------------------------------------------------
Notes:
RA, DE, and sigma are from Zabludoff & Mulchaey,
1998. Cat. J/ApJ/496/39
N: Total number of group members in the 1°x1° field
(Zabludoff & Mulchaey, 1998, Cat. J/ApJ/496/39).
D: Physical diameter subtended by 1° at the group's
mean recessional velocity (H0=100hkm/s/Mpc; q0=0.5)
--------------------------------------------------------------
Byte-by-byte Description of file: table2.dat table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 A5 --- Field Field name (1)
7- 10 I4 --- Gal Galaxy number in the field (1)
12- 15 I4 km/s cz Redshift
17- 19 I3 km/s e_cz Uncertainty in cz
21- 25 F5.1 mag RMag Absolute R band magnitude (2)
27- 30 F4.1 0.1nm EW The [O II] (3727Å) equivalent width
32- 35 F4.1 0.1nm e_EW Uncertainty in EW
37- 40 F4.2 --- B/T Bulge fraction (3)
42- 45 F4.2 kpc Rad Half-light radius (in kpc/h) (4)
47- 51 F5.2 kpc RatA Asymmetry parameter (in kpc/h) (5)
53- 57 F5.2 --- RatT ? Fraction of residual light (6)
59- 62 F4.2 --- B/T9 Bulge fraction at cz=9000
64- 68 F5.2 kpc Rad9 Half-light radius at cz=9000 (in kpc/h)
70- 74 F5.2 kpc RatA9 ? Asymmetry parameter at cz=9000 (in kpc/h)
76- 80 F5.2 --- RatT9 ? Fraction of residual light at cz=9000
--------------------------------------------------------------------------------
Note (1): In Simbad, object are identified as
[TSZ2001] HCG NN NNN and [TSZ2001] NGC NNNN NNN
Note (2): RMag = MR - 5*log(h) where H0 = 100 km/s/Mpc, q0 = 0.5, and a
flat cosmology.
Note (3): Average error for B/T measurement is ∼0.1 (Simard et al. 2001, in
prep.), although B/T can change by as much as 0.59 when the original
(cz) and degraded (cz=9000km/s) values are compared for the individual
galaxies.
Note (4): Average error for Rad is ∼10% (Simard et al. 2001, in prep.).
Note (5): Average random error for RatA is ∼0.02 (Simard et al. 2001, in prep.;
Im et al. 2001, ApJ, submitted), although RatA can change by as much
as 0.16 when the original (cz) and degraded (cz=9000km/s) values are
compared.
Note (6): Average random error for RatT is ∼0.02 (Simard et al. 2001, in prep.;
Im et al. 2001, ApJ, submitted), although RatT can change by as much
as 0.30 when the original (cz) and degraded (cz=9000km/s) values are
compared.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 28-May-2001