Galaxy sizes as a function of environment at intermediate redshift from the ESO Distant Cluster Survey
Date Issued
2015
Author(s)
Kelkar, Kshitija
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Aragón-Salamanca, Alfonso
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Gray, Meghan E.
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Maltby, David
•
•
•
•
Zaritsky, Dennis
Description
KK would like to thank Boris Häußler for the useful discussions regarding galaxy fitting and galapagos . MEG was supported by an STFC Advanced Fellowship. KK would also like to thank the referee for the useful comments and suggestions that helped in making the content of this paper better. BV was supported by the World Premier International Research Center Initiative (WPI), MEXT, Japan and by the Kakenhi Grant-in-Aid for Young Scientists (B)(26870140) from the Japan Society for the Promotion of Science (JSPS). Based on observations made with the NAS/ESA HST , obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with proposal 9476. Support for this proposal was provided by NASA through grant from the Space Telescope Science Institute. Based on observations obtained at the ESO VLT as a part of the Large Programme 166.A-0162
Abstract
In order to assess whether the environment has a significant effect on galaxy sizes, we compare the mass--size relations of cluster and field galaxies in the $0.4 < z < 0.8$ redshift range from the ESO Distant Cluster Survey (EDisCS) using HST images. We analyse two mass-selected samples, one defined using photometric redshifts ($10.2 \le \log M_\ast/M_{\odot} \le 12.0$), and a smaller more robust subsample using spectroscopic redshifts ($10.6 \le \log M_\ast/M_{\odot} \le 11.8$). We find no significant difference in the size distributions of cluster and field galaxies of a given morphology. Similarly, we find no significant difference in the size distributions of cluster and field galaxies of similar rest-frame $B-V$ colours. We rule out average size differences larger than $10$--$20$\% in both cases. Consistent conclusions are found with the spectroscopic and photometric samples. These results have important consequences for the physical process(es) responsible for the size evolution of galaxies, and in particular the effect of the environment. The remarkable growth in galaxy size observed from $z\sim2.5$ has been reported to depend on the environment at higher redshifts ($z>1$), with early-type/passive galaxies in higher density environments growing earlier. Such dependence disappears at lower redshifts. Therefore, if the reported difference at higher-$z$ is real, the growth of field galaxies has caught up with that of cluster galaxies by $z\sim1$. Any putative mechanism responsible for galaxy growth has to account for the existence of environmental differences at high redshift and their absence (or weakening) at lower redshifts.
Volume
450
Issue
2
Start page
1246
Issn Identifier
0035-8711
Ads BibCode
2015MNRAS.450.1246K
Rights
open.access
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