Environmental dependence of 8 μ m luminosity functions of galaxies at z ∼ 0.8: Comparison between RXJ1716.4+6708 and the AKARI NEP-deep field

T. Goto, Y. Koyama, T. Wada, C. Pearson, H. Matsuhara, T. Takagi, H. Shim, M. Im, M. G. Lee, H. Inami, M. Malkan, S. Okamura, T. T. Takeuchi, S. Serjeant, T. Kodama, T. Nakagawa, S. Oyabu, Y. Ohyama, H. M. Lee, N. HwangH. Hanami, K. Imai, T. Ishigaki

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

Aims. We aim to reveal environmental dependence of infrared luminosity functions (IR LFs) of galaxies at z ∼ 0.8 using the AKARI satellite. AKARI's wide field of view and unique mid-IR filters help us to construct restframe 8 μm LFs directly without relying on SED models. Methods. We construct restframe 8 μm IR LFs in the cluster region RXJ1716.4+6708 at z = 0.81, and compare them with a blank field using the AKARI north ecliptic pole deep field data at the same redshift. AKARI's wide field of view (10' × 10') is suitable to investigate wide range of galaxy environments. AKARI's 15 μm filter is advantageous here since it directly probes restframe 8 μm at z ∼ 0.8, without relying on a large extrapolation based on a SED fit, which was the largest uncertainty in previous work. Results. We have found that cluster IR LFs at restframe 8 μm have a factor of 2.4 smaller L* and a steeper faint-end slope than that of the field. Confirming this trend, we also found that faint-end slopes of the cluster LFs becomes flatter and flatter with decreasing local galaxy density. These changes in LFs cannot be explained by a simple infall of field galaxy population into a cluster. Physics that can preferentially suppress IR luminous galaxies in high density regions is required to explain the observed results.

Original languageEnglish
Article numberA7
JournalAstronomy and Astrophysics
Volume514
Issue number1
DOIs
Publication statusPublished - 2010 May 3
Externally publishedYes

Keywords

  • Galaxies: evolution
  • Galaxies: formation
  • Galaxies: interactions
  • Galaxies: peculiar
  • Galaxies: starburst
  • Infrared: galaxies

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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