# Passive galaxies as tracers of cluster environments at $\it z$ ~ 2

9 Subaru Telescope
NAOJ - National Astronomical Observatory of Japan
Abstract : Even 10 billion years ago, the cores of the first galaxy clusters are often found to host a characteristic population of massive galaxies with already suppressed star formation. Here we search for distant cluster candidates at $\it z$~ 2 using massive passive galaxies as tracers. With a sample of ~40 spectroscopically confirmed passive galaxies at 1.3 < $\it z$ < 2.1, we tuned photometric redshifts of several thousand passive sources in the 2 sq. deg COSMOS field. This allowed us to map their density in redshift slices, probing the large-scale structure in the COSMOS field as traced by passive sources. We report here on the three strongest passive galaxy overdensities that we identify in the range 1.5 <$\it z$< 2.5. While the actual nature of these concentrations still needs to be confirmed, we discuss their identification procedure and the arguments supporting them as candidate galaxy clusters (probably in the mid-10$^{1{3}}$M⊙ range). Although this search approach is probably biased toward more evolved structures, it has the potential of selecting still rare, cluster-like environments close to their epoch of first appearance, enabling new investigations of the evolution of galaxies in the context of structure growth.
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https://hal-cea.archives-ouvertes.fr/cea-01300539
Contributor : Edp Sciences <>
Submitted on : Monday, April 11, 2016 - 11:12:34 AM
Last modification on : Friday, April 10, 2020 - 3:50:06 PM
Long-term archiving on: : Tuesday, November 15, 2016 - 12:05:17 AM

### File

aa25038-14.pdf
Publication funded by an institution

### Citation

V. Strazzullo, Emanuele Daddi, R. Gobat, B. Garilli, M. Mignoli, et al.. Passive galaxies as tracers of cluster environments at $\it z$ ~ 2. Astronomy and Astrophysics - A&A, EDP Sciences, 2015, 576, pp.L6. ⟨10.1051/0004-6361/201425038⟩. ⟨cea-01300539⟩

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