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Abstract We present the discovery of a luminous X-ray active galactic nucleus (AGN) in the dwarf galaxy merger RGG 66. The black hole is predicted to have a mass ofMBH∼ 105.4M⊙and to be radiating close to its Eddington limit (Lbol/LEdd∼ 0.75). The AGN in RGG 66 is notable both for its presence in a late-stage dwarf–dwarf merger and for its luminosity ofL2–10 keV= 1042.2erg s−1, which is among the most powerful AGNs known in nearby dwarf galaxies. The X-ray spectrum has a best-fit photon index of Γ = 2.4 and an intrinsic absorption ofNH∼ 1021cm−2. These results come from a follow-up Chandra X-ray Observatory study of four irregular/disturbed dwarf galaxies with evidence for hosting AGNs based on optical spectroscopy. The remaining three dwarf galaxies do not have detectable X-ray sources with upper limits ofL2–10 keV≲ 1040erg s−1. Taken at face value, our results on RGG 66 suggest that mergers may trigger the most luminous of AGNs in the dwarf galaxy regime, just as they are suspected to do in more massive galaxy mergers.
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The Most Obscured AGNs in the XMM-SERVS Fields
Abstract We perform X-ray spectral analyses to derive the characteristics (e.g., column density, X-ray luminosity) of ≈10,200 active galactic nuclei (AGNs) in the XMM-Spitzer Extragalactic Representative Volume Survey, which was designed to investigate the growth of supermassive black holes across a wide dynamic range of cosmic environments. Using physical torus models (e.g., Borus02) and a Bayesian approach, we uncover 22 representative Compton-thick (CT;NH> 1.5 × 1024cm−2) AGN candidates with good signal-to-noise ratios as well as a large sample of 136 heavily obscured AGNs. We also find an increasing CT fraction (fCT) from low (z< 0.75) to high (z> 0.75) redshift. Our CT candidates tend to show hard X-ray spectral shapes and dust extinction in their spectral energy distribution fits, which may shed light on the connection between AGN obscuration and host-galaxy evolution.
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- Award ID(s):
- 2106990
- PAR ID:
- 10427232
- Publisher / Repository:
- DOI PREFIX: 10.3847
- Date Published:
- Journal Name:
- The Astrophysical Journal
- Volume:
- 951
- Issue:
- 1
- ISSN:
- 0004-637X
- Format(s):
- Medium: X Size: Article No. 27
- Size(s):
- Article No. 27
- Sponsoring Org:
- National Science Foundation
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