J/A+A/670/A58 CARLA cluster sample study (Mei+, 2023)
Morphology-density relation, quenching, and mergers in CARLA clusters and
proto-Clusters at 1.4 < z < 2.8.
Mei S., Hatch N.A., Amodeo S., Afanasiev A.V., De Breuck C., Stern D.,
Cooke E.A., Gonzalez A.H., Noirot G., Rettura A., Seymour N.,
Stanford S.A., Vernet J., Wylezalek D.
<Astron. Astrophys. 670, A58 (2023)>
=2023A&A...670A..58M 2023A&A...670A..58M (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Morphology ; Photometry, infrared ; Optical ;
Redshifts
Keywords: galaxies: clusters: general - galaxies: clusters: individual: CARLA -
galaxies: evolution - quasars: general - galaxies: high-redshift
Abstract:
At redshifts of z≲1.3, early-type galaxies (ETGs) and passive
galaxies are mainly found in dense environments, such as galaxy
clusters. However, it remains unclear whether these well-known
morphology-density and passive-density relations have already been
established at higher redshifts. To address this question, we
performed an in-depth study of galaxies in 16 spectroscopically
confirmed clusters at 1.3<z<2.8 from the Clusters Around Radio-Loud
AGN (CARLA) survey. Our clusters span a total stellar mass in the
range of 11.3<log(Mc*/M☉)<12.6 (approximate halo mass in the
range of 13.5≲log(Mch/M☉)≲14.5). Our main finding is that
the morphology-density and passive-density relations are already in
place at z∼2. The cluster at z=2.8 shows a similar fraction of ETG as
in the other clusters in its densest region, however, only one cluster
does not provide enough statistics to confirm that the
morphology-density relation is already in place at z∼3. The cluster
ETG and passive fractions depend mainly on local environment and only
slightly on galaxy mass; also, they do not depend on the global
environment. At lower local densities, where ΣN<700gal/Mpc2,
the CARLA clusters exhibit a similar ETG fraction as the field, in
contradiction to clusters at z=1, which already exhibit higher ETG
fractions. This implies that the densest regions influence the
morphology of galaxies first, with lower density local environments
either taking longer or only influencing galaxy morphology at later
cosmological times. Interestingly, we find evidence of high merger
fractions in our clusters with respect to the CANDELS fields, but the
merger fractions do not significantly depend on local environment.
This suggests that merger remnants in the lowest density regions can
reform disks fueled by cold gas flows, but those in the highest
density regions are cut off from the gas supply and will become
passive ETGs. The percentages of active ETGs, with respect to the
total ETG population, are 21±m6% and 59±14% at 1.35<z<1.65 and
1.65<z<2.05, respectively, and about half of them are mergers or
asymmetric in both redshift bins. All the spectroscopically confirmed
CARLA clusters have properties that are consistent with clusters and
proto-clusters, confirming that radio-loud active galactic nuclei are
lighthouses for dense environments. The differences between our
results and other findings that point to enhanced star formation and
starbursts in cluster cores at similar redshifts are probably due to
differences in the sample selection criteria; for example, selection
of different environments hosting galaxies with different accretion
and pre-processing histories.
Description:
We performed an in-depth study of galaxy population,
morphology and quenching in the CARLA cluster sample (Noirot et al.,
2018ApJ...859...38N 2018ApJ...859...38N, Cat. J/ApJ/859/38). The CARLA survey is a unique
sample of spectroscopically confirmed clusters and protoclusters at
1.3<z<2.8, with HST, Spitzer, and groundbased imaging and HST grism
spectroscopy.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
photocat.dat 271 271 Photometric catalog, mass, morphology
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See also:
J/ApJ/859/38 : HST grism obs. of CARLA galaxy cluster candidates
(Noirot+, 2018)
Byte-by-byte Description of file: photocat.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Cluster Cluster CARLA name, JHHMM+DDMM,
CARLA JHHMM+DDMM in Simbad
12- 16 F5.3 --- z Cluster redshift
18- 30 F13.9 deg RAdeg Right ascension (J2000)
32- 53 F22.18 deg DEdeg Declination (J2000)
55 I1 --- Morph Morphology (1)
57- 65 F9.6 mag IRAC1 IRAC channel 1 magnitude
66- 86 F21.18 mag e_IRAC1 ?=- Error IRAC channel 1 magnitude
88- 96 F9.6 mag IRAC2 IRAC channel 2 magnitude
98-117 F20.18 mag e_IRAC2 Error IRAC channel 2 magnitude
119-125 F7.4 Msun Mass Galaxy stellar mass
127-132 F6.4 Msun e_Mass Error galaxy stellar mass
134-142 A9 --- Type Source type (2)
144-161 F18.15 mag F140Wmag F140W magnitude
163-182 F20.18 mag e_F140Wmag Error F140W magnitude
184-201 F18.15 mag imag ?=- i-band magnitude
203-224 F22.19 mag e_imag ?=- Error i-band magnitude
226-243 F18.15 mag zmag ?=- z-band magnitude
245-264 F20.18 mag e_zmag ?=- Error z-band magnitude
266-271 A6 --- Inst Ground-based observation instrument
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Note (1): Morphology as follows:
0 = LTG
1 = ETG
8 = QSO
9 = excluded radio galaxy (see paper text)
Note (2): Source type as follows:
Dont_know = sources identified as galaxies
QSO = quasars
HzRG = High redshift Radio Galaxy
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Acknowledgements:
Simona Mei, mei(at)apc.in2p3.fr
(End) Patricia Vannier [CDS] 01-Feb-2023