Kinematically identified recoiling supermassive black hole candidates in SDSS QSOs with z < 0.25

Journal Article · Mon Jun 20 04:00:00 EDT 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/0004-637X/824/2/122· OSTI ID:22868974

Kim, D. -C.; Evans, A. S.; Stierwalt, S. ^[1]

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1. National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States)

We have performed a spectral decomposition to search for recoiling supermassive black holes (rSMBHs) in Sloan Digital Sky Survey (SDSS) quasi-stellar objects (QSOs) with z < 0.25. Out of 1271 QSOs, we have identified 26 rSMBH candidates that are recoiling toward us. The projected recoil velocities range from −76 to −307 km s{sup −1} with a mean of −149 ± 58 km s{sup −1}. Most of the rSMBH candidates are hosted by gas-rich luminous infrared galaxies (LIRGs)/ultra-luminous infrared galaxies (ULIRGs), but only 23% of them show signs of tidal features, which suggests that a majority of them are advanced mergers. We find that the black hole masses M {sub BH} of the rSMBH candidates are on average ∼5 times smaller than those of their stationary counterparts and cause a scatter in the M{sub BH}−σ{sub ∗} relation. The Eddington ratios of all of the rSMBH candidates are larger than 0.1, with a mean of 0.52 ± 0.27, suggesting that they are actively accreting mass. Velocity shifts in high-excitation coronal lines suggest that the rSMBH candidates are recoiling with an average velocity of about −265 km s{sup −1}. The electron density in the narrow line region of the H ii rSMBH candidates is about 1/10 of that in active galactic nucleus (AGN) rSMBH candidates, probably because the AGN in the former was more spatially offset than that in the latter. The estimated spatial offsets between the rSMBH candidate and the center of the host galaxy range from 0.″21 to 1.″97 and need to be confirmed spatially with high-resolution adaptive optics imaging observations.

• OSTI ID: 22868974
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 824; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
BLACK HOLES
ELECTRON DENSITY
EXCITATION
GALACTIC EVOLUTION
GALAXIES
INFRARED RADIATION
MASS
QUASARS
RESOLUTION
SPECTRA
STARS
VELOCITY