J/A+A/607/A131 Abell 520 galaxies redshifts (Deshev+, 2017)
Galaxy evolution in merging clusters:
The passive core of the "Train Wreck" cluster of galaxies, A520.
Deshev B., Finoguenov A., Verdugo M., Ziegler B., Park C., Seong Hwang H.,
Haines C., Kamphuis P., Tamm A., Einasto M., Hwang N., Park B.-G.
<Astron. Astrophys. 607, A131 (2017)>
=2017A&A...607A.131D 2017A&A...607A.131D (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Galaxies, optical ; Galaxies, photometry ;
Galaxies, spectra ; Galaxy catalogs ; Photometry, SDSS ;
Redshifts ; Spectroscopy
Keywords: galaxies: clusters: general -
galaxies: clusters: individual: Abell 520 - galaxies: evolution
Abstract:
The mergers of galaxy clusters are the most energetic events in the
universe after the Big Bang. An ever increasing fraction of local
clusters exhibit signs of recent or past mergers. Our goal is to probe
how these mergers affect the evolution and content of their member
galaxies. We specifically aim to answer the following questions: Is
the quenching of star formation in merging clusters enhanced when
compared with relaxed clusters? Is the quenching accompanied by a
(short lived) burst of star formation? We obtained optical
spectroscopy of $>400$ galaxies in the field of the merging cluster
Abell 520. We combine these observations with archival data to get a
comprehensive picture of the state of star formation in the members of
this merging cluster. Finally, we compare these observations with a
control sample of 10 non-merging clusters at the same redshift from
The Arizona Cluster Redshift Survey (ACReS). We split the member
galaxies in passive, star forming or recently quenched depending on
their spectra. The core of the merger shows a decreased fraction of
star-forming galaxies compared to clusters in the non-merging sample.
This region, dominated by passive galaxies, is extended along the axis
of the merger. We find evidence of rapid quenching of the galaxies
during the core passage with no signs of a star burst on the time
scales of the merger. Additionally, we report the tentative discovery
of an infalling group along the main filament feeding the merger,
currently at ∼2.5Mpc from the merger centre. This group contains a
high fraction of star forming galaxies as well as ∼2/3 of all the
recently quenched galaxies in our survey.
Description:
Multi-fibre spectroscopy carried out with Hectospec on MMT, USA on 19
and 22 of February 2014. Grism 270 was used. Photometry with
SExtractor on images from Megacam on CFHT in Hawaii, USA.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 56 407 Redshifts of 407 galaxies in the field of A520
spectra.fits 2880 4865 Spectra
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Num Sequential number
6- 13 F8.5 deg RAdeg Right ascension (J2000)
15- 22 F8.5 deg DEdeg Declination (J2000)
24- 30 F7.5 --- z Redshift
32- 38 F7.5 --- e_z Uncertainty on redshift
40- 46 F7.3 mag rMAG Absolute r' SDSS magnitude
48- 54 F7.3 mag gMAG Absolute g' SDSS magnitude
56 I1 --- Memb [1/3] Membership (1)
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Note (1): Membership code as follows:
1 = cluster member
2 = near field
3 = non member
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Acknowledgements:
Boris Deshev, boris(at)to.ee
(End) Patricia Vannier [CDS] 19-Jul-2017