Moircs deep survey. III. Active galactic nuclei in massive galaxies at z = 2-4

T. Yamada, M. Kajisawa, M. Akiyama, T. Ichikawa, M. Konishi, T. Nishimura, K. Omata, R. Suzuki, I. Tanaka, C. Tokoku, Y. K. Uchimoto, T. Yoshikawa

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)


We investigate the X-ray properties of the K-band-selected galaxies at redshift 2 < z < 4 by using our deep near-infrared images obtained in the Multi-Object Infrared Camera and Spectrograph Deep Survey project and the published Chandra X-ray source catalog. Sixty-one X-ray sources with the 2-10 keV luminosity LX = 1042-1044 erg s -1 are identified with the K-selected galaxies and we found that they are exclusively (90%) associated with the massive objects with a stellar mass larger than 1010.5 M 1. Our results are consistent with the idea that the M BH/M str ratio of the galaxies at z = 2-4 is similar to the present-day value. On the other hand, the active galactic nucleus (AGN) detection rate among the very massive galaxies with a stellar mass larger than 1011 M 1 is high, 33% (26/78). They are active objects in the sense that the black hole mass accretion rate is 1%-50% of the Eddington limit if they indeed have similar M BH/M str ratio with those observed in the local universe. The active duration in the AGN duty cycle of the high-redshift massive galaxies seems large.

Original languageEnglish
Pages (from-to)1354-1364
Number of pages11
JournalAstrophysical Journal
Issue number2
Publication statusPublished - 2009


  • Galaxies: active
  • Galaxies: evolution
  • Galaxies: formation

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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