Passive galaxies as tracers of cluster environments at $\it z$ ~ 2 - CEA - Commissariat à l’énergie atomique et aux énergies alternatives Access content directly
Journal Articles Astronomy and Astrophysics - A&A Year : 2015

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

Emanuele Daddi
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B. Garilli
A. Finoguenov
N. Arimoto
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D. Maccagni
  • Function : Author
G. Zamorani


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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Dates and versions

cea-01300539 , version 1 (11-04-2016)



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, 2015, 576, pp.L6. ⟨10.1051/0004-6361/201425038⟩. ⟨cea-01300539⟩
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