Hot Dust-Obscured Galaxies (Hot DOGs) are among the most luminous galaxies in the Universe. Powered by highly obscured, possibly Compton-thick, active galactic nuclei (AGNs), Hot DOGs are characterized by SEDs that are very red in the mid-IR yet dominated by the host galaxy stellar emission in the UV and optical. An earlier study identified a sub-sample of Hot DOGs with significantly enhanced UV emission. One target, W0204-0506, was studied in detail and, based on Chandra observations, it was concluded that the enhanced emission was most likely due to either extreme unobscured star-formation (SFR>1000M⊙yr−1) or to light from the highly obscured AGN scattered by gas or dust into our line of sight. Here, we present a follow-up study of W0204-0506 as well as two more Hot DOGs with excess UV emission. For the two new objects we obtained Chandra/ACIS-S observations, and for all three targets we obtained HST/WFC3 F555W and F160W imaging. We conclude that the excess UV emission is primarily dominated by light from the central highly obscured, hyper-luminous AGN that has been scattered into our line of sight. We cannot rule out, however, that star-formation may significantly contribute to the UV excess of W0204-0506.
@article{arxiv.1905.04320,
title = {Hot Dust-Obscured Galaxies with Excess Blue Light},
author = {R. J. Assef and M. Brightman and D. J. Walton and D. Stern and F. E. Bauer and A. W. Blain and T. Diaz-Santos and P. R. M. Eisenhardt and R. C. Hickox and H. D. Jun and A. Psychogyios and C. -W. Tsai and J. W. Wu},
journal= {arXiv preprint arXiv:1905.04320},
year = {2020}
}
Comments
17 pages, 12 figures, 3 tables. Accepted for publication in The Astrophysical Journal