ALMA 26 arcmin² Survey of GOODS-S at One-millimeter (ASAGAO): X-Ray AGN Properties of Millimeter-selected Galaxies

<jats:title>Abstract</jats:title> <jats:p>We investigate the X-ray active galactic nucleus (AGN) properties of millimeter galaxies in the Great Observatories Origins Deep Survey South (GOODS-S) field detected with the Atacama Large Millimeter/submillimeter Array (ALMA), by utilizing the <jats:italic>Chandra</jats:italic> 7-Ms data, the deepest X-ray survey to date. Our millimeter galaxy sample comes from the ASAGAO survey covering 26 arcmin<jats:sup>2</jats:sup> (12 sources at a 1.2 mm flux-density limit of <jats:inline-formula> <jats:tex-math> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjaa9f10ieqn1.gif" xlink:type="simple"/> </jats:inline-formula> mJy), supplemented by the deeper but narrower 1.3 mm survey of a part of the ASAGAO field by Dunlop et al. Ofthe 25 total millimeter galaxies, 14 have <jats:italic>Chandra</jats:italic> counterparts. The observed AGN fractions at <jats:inline-formula> <jats:tex-math> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjaa9f10ieqn2.gif" xlink:type="simple"/> </jats:inline-formula> are found to be <jats:inline-formula> <jats:tex-math> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjaa9f10ieqn3.gif" xlink:type="simple"/> </jats:inline-formula>% and <jats:inline-formula> <jats:tex-math> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjaa9f10ieqn4.gif" xlink:type="simple"/> </jats:inline-formula>% for the ultra-luminous and luminous infrared galaxies with log <jats:inline-formula> <jats:tex-math> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjaa9f10ieqn5.gif" xlink:type="simple"/> </jats:inline-formula>/<jats:inline-formula> <jats:tex-math> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjaa9f10ieqn6.gif" xlink:type="simple"/> </jats:inline-formula> = 12–12.8 and log <jats:inline-formula> <jats:tex-math> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjaa9f10ieqn7.gif" xlink:type="simple"/> </jats:inline-formula>/<jats:inline-formula> <jats:tex-math> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjaa9f10ieqn8.gif" xlink:type="simple"/> </jats:inline-formula> = 11.5–12, respectively. The majority (∼2/3) of the ALMA and/or Herschel detected X-ray AGNs at <jats:italic>z</jats:italic> = 1.5−3 appear to be star-formation-dominant populations, having <jats:inline-formula> <jats:tex-math> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjaa9f10ieqn9.gif" xlink:type="simple"/> </jats:inline-formula>/ <jats:inline-formula> <jats:tex-math> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjaa9f10ieqn10.gif" xlink:type="simple"/> </jats:inline-formula> ratios smaller than the “simultaneous evolution” value expected from the local black-hole-mass-to-stellar-mass (<jats:inline-formula> <jats:tex-math> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjaa9f10ieqn11.gif" xlink:type="simple"/> </jats:inline-formula>–<jats:italic>M</jats:italic> <jats:sub>*</jats:sub>) relation. On the basis of the <jats:inline-formula> <jats:tex-math> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjaa9f10ieqn12.gif" xlink:type="simple"/> </jats:inline-formula> and stellar mass relation, we infer that a large fraction of star-forming galaxies at <jats:inline-formula> <jats:tex-math> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjaa9f10ieqn13.gif" xlink:type="simple"/> </jats:inline-formula> have black hole masses that are smaller than those expected from the local <jats:inline-formula> <jats:tex-math> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjaa9f10ieqn14.gif" xlink:type="simple"/> ...