Oral Presentation

The Population of Luminous Obscured Quasars at Cosmic Noon Unveiled with Deep and Wide Multiwavelength Survey

Author(s): Bovornpratch Vijarnwannaluk (Tohoku U.), Masayuki Akiyama (Tohoku U.), Malte Schramm (Saitama U.), Yoshihiro Ueda (Kyoto U.), Yoshiki Toba (NAOJ), Yoshiki Matsuoka (Ehime U.), Naoki Matsumoto (Tohoku U)

Presenter: Bovornpratch Vijarnwannaluk (Tohoku University)

Statistical studies of X-ray selected AGN indicate that the fraction of obscured AGN increases towards high redshifts which suggest that a large fraction of accretion activity is buried under large amounts of gas and dust, hidden away from large optical surveys which are heavily biased against obscuration but can be detected with X-ray emission. Using the deep and wide multiwavelength datasets in the HSC-Deep XMM-LSS field, we have investigated the fraction of luminous obscured AGN using a unique sample of 306 X-ray AGN detected in the 2-10 keV band at redshift 2-5 assuming a parametric X-ray luminosity and absorption functions. We estimate that $76^{+4}_{-3}\%$ of luminous quasars ($\log L_X (\rm erg s^{-1}) > 44.5$) above $z>2$ are obscured by Hydrogen column density ($\log N_H$) larger than $\log N_H (\rm cm^{-2}) > 22$ indicating an increased contribution of obscured accretion at high redshift. The SED of obscured and unobscured AGN follow a red-obscured, blue-unobscured trend but with a broad SED distribution which may reflect the broad variety of host galaxy properties and physical processes associated with the obscuration. Preliminary SED fitting analysis suggests that obscured AGN reside in more massive galaxies than unobscured AGN but have similar SMBH mass assuming a M_{stellar}to M_{BH}relations for obscured sources.