CaltechAUTHORS
Published May 2010 | Version Published
Journal Article Open

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

Creators

  • 1. ROR icon University of Hawaii at Manoa
  • 2. ROR icon National Astronomical Observatory of Japan
  • 3. ROR icon University of Tokyo
  • 4. ROR icon Institute of Space and Astronautical Science
  • 5. ROR icon Rutherford Appleton Laboratory
  • 6. ROR icon University of Lethbridge
  • 7. ROR icon The Open University
  • 8. ROR icon Seoul National University
  • 9. ROR icon California Institute of Technology
  • 10. ROR icon University of California, Los Angeles
  • 11. ROR icon Nagoya University
  • 12. ROR icon Institute of Astronomy and Astrophysics, Academia Sinica
  • 13. ROR icon Iwate University
  • 14. ROR icon National Institute of Technology, Asahikawa College

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.

Additional Information

© ESO 2010. Received 14 October 2009. Accepted 22 December 2009. Published online 03 May 2010. We thank the anonymous referee for many insightful comments, which significantly improved the paper. We are grateful to Masayuki Tanaka for useful discussions. We thank L. Bai for providing data for comparison. T.G., Y.K., and H.I. acknowledge financial support from the Japan Society for the Promotion of Science (JSPS) through JSPS Research Fellowships for Young Scientists. M.I. was supported by the Korea Science and Engineering Foundation (KOSEF) grant No. 2009-0063616, funded by the Korea government (MEST). H.M.L. acknowledges the support from KASI through its cooperative fund in 2008. This research is based on the observations with AKARI, a JAXA project with the participation of ESA. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this sacred mountain.

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Additional details

Identifiers

Eprint ID
18556
Resolver ID
CaltechAUTHORS:20100604-073622745

Funding

Japan Society for the Promotion of Science (JSPS)
Korea Science and Engineering Foundation
2009-0063616
Ministry of Education, Science and Technology (Korea)
Korea Astronomy and Space Science Institute (KASI)

Dates

Created
2010-06-04
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Updated
2021-11-08
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Caltech groups
Infrared Processing and Analysis Center (IPAC)