J/A+A/649/A42 BCG up to z=1.80 physical properties (Chu+, 2021)
Physical properties of brightest cluster galaxies up to redshift 1.80 based on
HST data.
Chu A., Durret F., Marquez I.
<Astron. Astrophys. 649, A42 (2021)>
=2021A&A...649A..42C 2021A&A...649A..42C (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Galaxies, optical ; Galaxies, IR ;
Galaxies, photometry
Keywords: galaxies: clusters: general - galaxies: bulges
Abstract:
Brightest cluster galaxies (BCGs) have grown by accreting numerous
smaller galaxies and can be used as tracers of cluster formation and
evolution in the cosmic web. However, there is still a controversy on
the main epoch of formation of BCGs, since some authors believe they
have already formed before redshift z=2, while others still find them
to evolve at more recent epochs.
We aim to analyse the physical properties of a large sample of BCGs
covering a wide redshift range up to z=1.8 and analysed in a
homogeneous way, to see if their characteristics vary with redshift.
As a first step, we also present a new tool to define for each cluster
which galaxy is the BCG.
For a sample of 137 clusters with HST images in the optical and/or
infrared, we analyse the BCG properties by applying GALFIT with one or
two Sersic components. For each BCG, we compute the Sersic index,
effective radius, major axis position angle, surface brightness. We
then search for correlations of these quantities with redshift.
We find that BCGs follow the Kormendy relation (between the effective
radius and the mean surface brightness), with a slope that remains
constant with redshift, but with a variation with redshift of the
ordinate at the origin. Although the trends are faint, we find that
both the absolute magnitudes and effective radii tend to become
respectively brighter and bigger with decreasing redshift. On the
other hand, we find no significant correlation of the mean surface
brightnesses or Sersic indices with redshift. The major axes of the
cluster elongations and of the BCGs agree within 30 degrees for 73% of
our clusters at redshift z≤0.9.
Our results agree with the BCGs being mainly formed before redshift
z=2. The alignment of the major axes of BCGs with their clusters agree
with the general idea that BCGs form at the same time as clusters by
accreting matter along the filaments of the cosmic web.
Description:
The sample studied in this paper consists of 137 galaxy clusters with
HST imaging taken from Jee et al. (2011ApJ...737...59J 2011ApJ...737...59J), Postman et
al. (2012ApJS..199...25P 2012ApJS..199...25P, Cat. J/ApJS/199/25), Bai et al.
(2014ApJ...789..134B 2014ApJ...789..134B), Donahue et al. (2015ApJ...805..177D 2015ApJ...805..177D), West et
al. (2017NatAs...1..157W 2017NatAs...1..157W), DeMaio et al. (2020MNRAS.491.3751D 2020MNRAS.491.3751D), Durret
et al. (2019A&A...622A..78D 2019A&A...622A..78D), and Sazonova et al.
(2020ApJ...899...85S 2020ApJ...899...85S). We also add five more distant clusters at
z∼0.8, as well as the cluster Abell 2813 at z=0.29. Among them, we
identify 12 clusters that have in their center two BCGs similar in
magnitude and size. As a result, our final BCG sample contains 149
BCGs.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 86 149 Coordinates and redshifts of the BCGs detected
in our samples, as well as the filters
table2.dat 73 149 *Parameters obtained from fitting the luminosity
profiles of the BCGs with GALFIT with one
Sersic or two Sersic components.
table3.dat 62 85 Parameters obtained for the inner component for
BCGs fitted with two Sersic profiles
table4.dat 97 114 X-ray properties, M200 masses and position angle
of the cluster if available in the litterature
refs.dat 89 43 References
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Note on table2.dat: If fitted with two Sersic profiles, the parameters of the
outer component are given.
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 24 A24 --- Name Cluster name
26- 33 F8.4 deg RAdeg Right ascension (J2000) of the BCG
35- 42 F8.4 deg DEdeg Declination (J2000) of the BCG
44- 50 F7.5 --- z Spectroscopic redshift of the cluster
52 I1 --- Class [1/2] If two BCGs are defined for a cluster,
class 1 represents the brighter of the two
54- 60 A7 --- Inst Instrument
62- 67 A6 --- Filter Filter used to model the luminosity
profile of the BCG
69- 73 F5.3 kpc/arcsec Scale Scale in units of kpc per arcsec
75- 86 A12 --- Color Filters used to compute a color to
extract red sequence of the cluster
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 24 A24 --- Name Cluster name
26 I1 --- Class [1/2] If two BCGs are defined for a cluster,
class 1 represents the brighter of the two
28- 34 A7 --- Model Model chosen to fit the BCG with GALFIT
(Sersic* fixes n=4)
36- 42 F7.3 mag Mag ?=999.99 Absolute magnitude
44- 49 F6.3 mag/arcsec2 ?=99.999 Mean effective surface brightness
51- 56 F6.3 kpc Re ?=99.999 Effective radius
58- 61 F4.2 --- n ?=9.99 Sersic index
63- 66 F4.2 --- b/a ?=9.99 Elongation defined as the ratio of
the major to minor axis
68- 70 I3 deg PA ?=999 Position angle
(anticlockwise from North)
72- 73 I2 deg Align ?=99 Alignment of the BCG with its host
cluster
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 24 A24 --- Name Cluster name
26 I1 --- Class [1/2] If two BCGs are defined for a
cluster, class 1 represents the brighter
of the two
28- 34 F7.3 mag Mag-inn Absolute magnitude
36- 41 F6.3 mag/arcsec2 -inn Mean effective surface brightness
43- 48 F6.3 kpc Re-inn Effective radius
50- 53 F4.2 --- n-inn Sersic index
55- 58 F4.2 deg b/a-inn Elongation defined as the ratio of the
major to minor axis
60- 62 I3 deg PA-inn [] Position angle
(anticlockwise from North)
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 24 A24 --- Name Cluster name
26- 33 F8.4 deg RAdeg ?=999.999 Right ascension (J2000) of the
cluster X-ray center
36- 43 F8.4 deg DEdeg ?=999.999 Declination (J2000) of the
cluster X-ray center
45- 47 I3 --- r_pos ?=999 Reference for the X-ray center
coordinates
49- 53 F5.2 10+14Msun M200 ?=99.9 Mass contained in a radius r200 (1)
55- 59 F5.2 10+14Msun E_M200 ?=99.9 Mean positive error on
parameter M200
61- 65 F5.2 10+14Msun e_M200 ?=99.9 Mean negative error on
parameter M200
67- 85 A19 --- MethodM200 Method used to estimate M200
87- 88 I2 --- r_M200 ?=99 Reference for M200
90- 92 I3 deg PAcl ?=999 Position angle of the cluster
(anticlockwise from North)
94- 95 I2 deg e_PAcl ?=99 Mean error on parameter PAcl
97 I1 --- r_PAcl ?=9 Reference for PAcl
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Note (1): radius in which the density is 200 times the critical density of
the Universe.
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Byte-by-byte Description of file: refs.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Ref Reference number
4- 22 A19 --- BibCode Bibcode
24- 48 A25 --- Aut Author's name
50- 89 A40 --- Com Comments
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Acknowledgements:
Aline Chu, chu(at)iap.fr
(End) Patricia Vannier [CDS] 12-Mar-2021