J/MNRAS/448/2530 Morphology and structure of BCG (Zhao+, 2015)
The link between morphology and structure of brightest cluster galaxies:
automatic identification of cDs.
Zhao D., Aragon-Salamanca A., Conselice C.J.
<Mon. Not. R. Astron. Soc., 448, 2530-2545 (2015)>
=2015MNRAS.448.2530Z 2015MNRAS.448.2530Z (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Morphology
Keywords: galaxies: clusters: general -
galaxies: elliptical and lenticular, cD - galaxies: structure
Abstract:
We study a large sample of 625 low-redshift brightest cluster galaxies
(BCGs) and link their morphologies to their structural properties. We
derive visual morphologies and find that ∼57% of the BCGs are cD
galaxies, ∼13% are ellipticals, and ∼21% belong to the intermediate
classes mostly between E and cD. There is a continuous distribution in
the properties of the BCG's envelopes, ranging from undetected (E
class) to clearly detected (cD class), with intermediate classes (E/cD
and cD/E) showing the increasing degrees of the envelope presence. A
minority (∼7%) of BCGs have disc morphologies, with spirals and S0s in
similar proportions, and the rest (∼2%) are mergers. After carefully
fitting the galaxies light distributions by using one-component
(Sersic) and two-component (Sersic+Exponential) models, we find a
clear link between the BCGs morphologies and their structures and
conclude that a combination of the best-fitting parameters derived
from the fits can be used to separate cD galaxies from non-cD BCGs. In
particular, cDs and non-cDs show very different distributions in the
Re-RFF plane, where Re is the effective radius and RFF (the
residual flux fraction) measures the proportion of the galaxy flux
present in the residual images after subtracting the models. In
general, cDs have larger Re and RFF values than ellipticals.
Therefore we find, in a statistically robust way, a boundary
separating cD and non-cD BCGs in this parameter space. BCGs with cD
morphology can be selected with reasonably high completeness (∼75%)
and low contamination (∼20%). This automatic and objective technique
can be applied to any current or future BCG sample with good-quality
images.
Description:
To study the structural properties of BCGs in galaxy groups and
clusters, we use the BCG catalogue published by von den Linden
(2007MNRAS.379..867V 2007MNRAS.379..867V, Cat. J/MNRAS/379/867, hereafter L07).
The 625 BCGs in L07 sample were visually classified by careful
inspection of the SDSS images.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 135 625 Properties of the BCG sample
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See also:
J/MNRAS/379/867 : BCG C4 cluster catalog (Von Der Linden+, 2007)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- ID2 ?=- SDSS-C4 number <SDSS-C4 NNNN> (1)
6- 9 I4 --- ID3 SDSS C4_2003 number, <SDSS-C4-DR3 NNNN> (1)
11- 20 F10.6 deg RAdeg Right ascension (J2000)
22- 31 F10.6 deg DEdeg Declination (J2000)
33- 37 F5.3 --- z Redshift of the cluster
39- 42 I4 km/s sigma Velocity dispersion of the cluster
44- 48 F5.3 [kpc] logRe1c Effective radius (2)
50- 54 F5.2 --- n1c Sersic number (2)
56- 62 F7.5 --- RFF1c Residual flux fraction (2)
64- 69 F6.3 --- chi21c Reduced chi2 (2)
71- 75 A5 --- MType Visual morphological classification of the BCGs
77-133 A57 --- Com Some comments from the classifier
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Note (1): as given in Simbad (von der Linden et al., 2007MNRAS.379..867V 2007MNRAS.379..867V,
Cat. J/MNRAS/379/867).
Note (2): derived from the single-Sersic fits (see the text for details).
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History:
* 18-Dec-2015: From electronic version of the journal
table was unfortunately troncated (only 271 lines)
* 18-Apr-2016: Complete table replaced
(End) Patricia Vannier [CDS] 15-Sep-2015