The most heavily-obscured, luminous quasars might represent a specific phase of the evolution of the actively accreting supermassive black holes and their host galaxies, possibly related to mergers. We investigated a sample of the most luminous quasars at z ≈ 1 − 3 in the GOODS fields, selected in the mid-infrared band through detailed spectral energy distribution (SED) decomposition. The vast majority of these quasars (~80%) are obscured in the X-ray band and ~30% of them to such an extent, that they are undetected in some of the deepest (2 and 4 Ms) Chandra X-ray data. Although no clear relation is found between the star-formation rate of the host galaxies and the X-ray obscuration, we find a higher incidence of heavily-obscured quasars in disturbed/merging galaxies compared to the unobscured ones, thus possibly representing an earlier stage of evolution, after which the system is relaxing and becoming unobscured.
Digital Object Identifier (DOI)
This research was supported by the UK Science and Technology Facilities Council (STFC, ST/L00075X/1); CONICYT-Chile (Basal-CATA PFB-06/2007, “EMBIGGEN” Anillo ACT1101, FONDECYT Regular 1141218); the Ministry of Economy, Development, and Tourism's Millennium Science Initiative through grant IC120009, awarded to The Millennium Institute of Astrophysics (MAS).
Del Moro, Agnese; Alexander, David M.; Bauer, Franz E.; Daddi, Emanuele; Kocevski, Dale D.; Stanley, Flora; and McIntosh, Daniel H., "Luminous and Obscured Quasars and Their Host Galaxies" (2018). Physics and Astronomy Faculty Publications. 600.