NuSTAR Non-detection of a Faint Active Galactic Nucleus in an Ultraluminous Infrared Galaxy with Kpc-scale Fast Wind
Abstract
Large-scale outflows are generally considered to be possible evidence that active galactic nuclei (AGNs) can severely affect their host galaxies. Recently, an ultraluminous infrared galaxy (ULIRG) at z = 0.49, AKARI J0916248+073034, was found to have a galaxy-scale [O III] λ5007 outflow with one of the highest energy-ejection rates at z < 1.6. However, the central AGN activity estimated from its torus mid-infrared (MIR) radiation is weak relative to the luminous [O III] emission. In this work we report the first NuSTAR hard X-ray follow-up of this ULIRG to constrain its current AGN luminosity. The intrinsic 2-10 keV luminosity shows a 90% upper limit of 3.0 × 1043 erg s-1 assuming Compton-thick obscuration (NH = 1.5 × 1024 cm-2), which is only 3.6% of the luminosity expected from the extinction-corrected [O III] luminosity. Using the NuSTAR observation, we successfully identify that this ULIRG has a very extreme case of X-ray deficit among local ULIRGs. A possible scenario to explain the drastic decline in both the corona (X-ray) and torus (MIR) is that the primary radiation from the AGN accretion disk is currently in a fading status, as a consequence of a powerful nuclear wind suggested by powerful ionized outflow in a galaxy scale.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 2020
- DOI:
- 10.3847/2041-8213/abca30
- arXiv:
- arXiv:2011.06914
- Bibcode:
- 2020ApJ...905L...2C
- Keywords:
-
- Active galaxies;
- X-ray active galactic nuclei;
- Ultraluminous infrared galaxies;
- 17;
- 2035;
- 1735;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 8 pages, 2 figures, accepted for publication in The Astrophysical Journal Letters