ALMA Lensing Cluster Survey: Properties of Millimeter Galaxies Hosting X-Ray-detected Active Galactic Nuclei

Abstract

We report the multiwavelength properties of millimeter galaxies hosting X-ray detected active galactic nuclei (AGNs) from the ALMA Lensing Cluster Survey (ALCS). ALCS is an extensive survey of well-studied lensing clusters with ALMA, covering an area of 133 arcmin ^2 over 33 clusters with a 1.2 mm flux-density limit of ∼60 μ Jy (1 σ ). Utilizing the archival data of Chandra, we identify three AGNs at z = 1.06, 2.09, and 2.84 among the 180 millimeter sources securely detected in the ALCS (of which 155 are inside the coverage of Chandra). The X-ray spectral analysis shows that two AGNs are not significantly absorbed ( $\mathrm{log}{N}_{{\rm{H}}}/{\mathrm{cm}}^{-2}\lt 23$ ), while the other shows signs of moderate absorption ( $\mathrm{log}{N}_{{\rm{H}}}/{\mathrm{cm}}^{-2}\sim 23.5$ ). We also perform spectral energy distribution modeling of X-ray to millimeter photometry. We find that our X-ray AGN sample shows both high mass-accretion rates (intrinsic 0.5–8 keV X-ray luminosities of ∼10 ^44–45 erg s ^−1 ) and star formation rates (≳100 M _⊙ yr ^−1 ). This demonstrates that a wide-area survey with ALMA and Chandra can selectively detect intense growth of both galaxies and supermassive black holes in the high-redshift universe.

Keywords

• Active galactic nuclei
• X-ray active galactic nuclei
• Quasars
• Submillimeter astronomy
• Galaxy evolution
• High-redshift galaxies