J/AJ/137/3942 Fossil galaxy groups (La Barbera+, 2009)
The nature of fossil galaxy groups: are they really fossils?
La Barbera F., De Carvalho R.R., De La Rosa I.G., Sorrentino G., Gal R.R.,
Kohl-moreira J.L.
<Astron. J., 137, 3942-3960 (2009)>
=2009AJ....137.3942L 2009AJ....137.3942L
ADC_Keywords: Clusters, galaxy ; X-ray sources
Keywords: galaxies: clusters: general - galaxies: evolution -
galaxies: formation - galaxies: fundamental parameters
Abstract:
We use SDSS-DR4 photometric and spectroscopic data out to redshift
z∼0.1 combined with ROSAT All Sky Survey X-ray data to produce a
sample of 25 fossil groups (FGs), defined as bound systems dominated
by a single, luminous elliptical galaxy with extended X-ray emission.
We examine possible biases introduced by varying the parameters used
to define the sample, and the main pitfalls are also discussed.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 124 46 Properties of fossil group (FG) and
field galaxies (FS) galaxies
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See also:
http://www.sdss.org : SDSS Home Page
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Seq Sequential number, [LDD2009] NN in Simbad
4- 12 F9.5 deg RAdeg Right ascension in decimal degrees (J2000)
14- 21 F8.4 deg DEdeg Declination in decimal degrees (J2000)
23- 27 F5.3 --- z SDSS-DR4 spectroscopic redshift
29- 35 F7.3 mag rMAG r band absolute magnitude of the first-rank
galaxy (z=0.1 k-corrected)
37- 40 F4.2 mag DM Magnitude gap of the fossil group, ΔM
42- 46 F5.3 mag g-r g-r colour index (z=0.1 k-corrected)) (1)
48- 51 F4.1 --- dN Density excess around each galaxy, δN
53- 58 F6.2 arcsec gReff Effective radii in g band
60- 65 F6.2 arcsec rReff Effective radii in r band
67- 70 F4.1 --- ng Sersic index in g band
72- 75 F4.1 --- nr Sersic index in r band
77- 82 F6.3 % a4 a4 parameter (describes boxy/disky departures
from elliptical shape)
83- 88 F6.3 mag n(g-r) Internal color gradient, ∇(g-r) (mag/dex)
90- 94 F5.2 [10+37W] logLX X-ray luminosity
96-101 F6.3 --- dCM Distance of the galaxy to the red sequence,
δCM (3)
103-107 F5.3 [km/s] log(sig) Velocity dispersion
109-111 F3.1 [yr] logAge Age
113-117 F5.2 [Sun] [Z/H] Metallicity
119-122 F4.2 --- [a/Fe] Abundance of α-elements [α/Fe]
124 A1 --- Flag [0/2] Pecularities, 1=fossil group (2)
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Note (1): For field galaxies, the values of DM have been randomly assigned.
Note (2): Flag as follows:
1 = fossil groups (FG) with extended X-ray contours
2 = field galaxies
0 = fossil group (FG) candidates that are not in the final FG sample
because they do not fulfill the X-ray extension criterion
Note (3): color distance normalized to the scatter of the red sequence;
(see section 6 of paper)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 19-Oct-2011