Submillimeter array identification of the millimeter-selected Galaxy SSA22-AzTEC1 : a protoquasar in a protocluster?
| Autor: | Yoichi Tamura, Soh Ikarashi, David J. Wilner, Tomoki Hayashino, Toru Yamada, Takashi Ichikawa, Aeree Chung, Bret D. Lehmer, David H. Hughes, Yuichi Matsuda, Ryohei Kawabe, Bunyo Hatsukade, Hajime Ezawa, Yuka Katsuno Uchimoto, M. S. Yun, David M. Alexander, Kouichiro Nakanishi, Kotaro Kohno, Masaru Kajisawa, Daisuke Iono, Tadafumi Takata, Grant W. Wilson |
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| Rok vydání: | 2010 |
| Předmět: |
Physics
Cosmology and Nongalactic Astrophysics (astro-ph.CO) Extinction (astronomy) FOS: Physical sciences Formation Astronomy and Astrophysics Starburst Astrophysics Galaxies Astrophysics - Astrophysics of Galaxies Submillimeter Array Galaxy Redshift Luminosity Gravitational potential X-rays Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) Spectral energy distribution Submillimeter Infrared Quasars Astrophysics - Cosmology and Nongalactic Astrophysics Photometric redshift |
| Zdroj: | Astrophysical journal, 2010, Vol.724(2), pp.1270-1282 [Peer Reviewed Journal] |
| Popis: | We present results from Submillimeter Array (SMA) 860-micron sub-arcsec astrometry and multiwavelength observations of the brightest millimeter (S_1.1mm = 8.4 mJy) source, SSA22-AzTEC1, found near the core of the SSA22 protocluster that is traced by Ly\alpha emitting galaxies at z = 3.09. We identify a 860-micron counterpart with a flux density of S_860um = 12.2 +/- 2.3 mJy and absolute positional accuracy that is better than 0.3". At the SMA position, we find radio to mid-infrared counterparts, whilst no object is found in Subaru optical and near-infrared deep images at wavelengths \le 1 micron (J > 25.4 in AB, 2\sigma). The photometric redshift estimate, using flux densities at \ge 24 microns, indicates z_phot = 3.19^{+0.26}_{-0.35}, consistent with the protocluster redshift. We then model the near-to-mid-infrared spectral energy distribution (SED) of SSA22-AzTEC1, and find that the SED modeling requires a large extinction (A_V \approx 3.4 mag) of starlight from a stellar component with M_star ~ 10^{10.9} M_sun, assuming z = 3.1. Additionally, we find a significant X-ray counterpart with a very hard spectrum (Gamma_eff = -0.34 ^{+0.57}_{-0.61}), strongly suggesting that SSA22-AzTEC1 harbors a luminous AGN (L_X ~ 3*10^{44} ergs s^{-1}) behind a large hydrogen column (N_H ~ 10^{24} cm^{-2}). The AGN, however, is responsible for only ~10% of the bolometric luminosity of the host galaxy, and therefore the star-formation activity likely dominates the submillimeter emission. It is possible that SSA22-AzTEC1 is the first example of a protoquasar growing at the bottom of the gravitational potential underlying the SSA22 protocluster. Comment: 16 pages, 2 tables, 6 figures, accepted for publication in the Astrophysical Journal |
| Databáze: | OpenAIRE |
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