Chandra X-ray and hubble space telescope imaging of optically selected kiloparsec-scale binary active galactic nuclei. II. Host galaxy morphology and AGN activity

Jinyi Shangguan, Xin Liu, Luis C. Ho, Yue Shen, Chien Y. Peng, Jenny E. Greene, Michael A. Strauss

Research output: Contribution to journalArticlepeer-review

25 Scopus citations

Abstract

Binary active galactic nuclei (AGNs) provide clues to how gas-rich mergers trigger and fuel AGNs and how supermassive black hole (SMBH) pairs evolve in a gas-rich environment. While significant effort has been invested in their identification, the detailed properties of binary AGNs and their host galaxies are still poorly constrained. In a companion paper, we examined the nature of ionizing sources in the double nuclei of four kiloparsec-scale binary AGNs with redshifts between 0.1 and 0.2. Here, we present their host galaxy morphology based on F336W (U-band) and F105W (Y-band) images taken by the Wide Field Camera 3 on board the Hubble Space Telescope. Our targets have double-peaked narrow emission lines and were confirmed to host binary AGNs with follow-up observations. We find that kiloparsec-scale binary AGNs occur in galaxy mergers with diverse morphological types. There are three major mergers with intermediate morphologies and a minor merger with a dominant disk component. We estimate the masses of the SMBHs from their host bulge stellar masses and obtain Eddington ratios for each AGN. Compared with a representative control sample drawn at the same redshift and stellar mass, the AGN luminosities and Eddington ratios of our binary AGNs are similar to those of single AGNs. The U - Y color maps indicate that clumpy star-forming regions could significantly affect the X-ray detection of binary AGNs, e.g., the hardness ratio. Considering the weak X-ray emission in AGNs triggered in merger systems, we suggest that samples of X-ray-selected AGNs may be biased against gas-rich mergers.

Original languageEnglish (US)
Article number50
JournalAstrophysical Journal
Volume823
Issue number1
DOIs
StatePublished - May 20 2016

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • X-rays: galaxies
  • black hole physics
  • galaxies: Seyfert
  • galaxies: active
  • galaxies: interactions
  • galaxies: stellar content

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