Browsing by Author "Kim, D. -C."

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    A Potential Recoiling Supermassive Black Hole, CXO J101527.2+625911
    (2017) Kim, D. -C.; Yoon, Ilsang; Privon, G. C.; Evans, A. S.; Harvey, D.; Stierwalt, S.; Kim, Ji Hoon
    We have carried out a systematic search for recoiling supermassive black holes (rSMBH) using the Chandra Source and SDSS Cross-Match Catalog. From the survey, we have detected a potential rSMBH, CXO J101527.2 +625911, at z = 0.3504. The source CXO J101527.2+625911 has a spatially offset (1.26 +/- 0.05 kpc) active SMBH and kinematically offset broad emission lines (175 +/- 25 km s(-1) relative to the systemic velocity). The observed spatial and velocity offsets suggest that this galaxy could be an rSMBH, but we have also considered the possibility of a dual SMBH scenario. The column density toward the galaxy center was found to be Compton thin, but no X-ray source was detected. The non-detection of the X-ray source in the nucleus suggests that either there is no obscured actively accreting SMBH or that there exists an SMBH, but it has a low accretion rate (i.e., a low luminosity AGN (LLAGN)). The possibility of the LLAGN was investigated and found to be unlikely based on the Ha luminosity, radio power, and kinematic arguments. This, along with the null detection of an X-ray source in the nucleus, supports our hypothesis that CXO J101527.2+625911 is an rSMBH. Our GALFIT analysis shows the host galaxy to be a bulge-dominated elliptical. The weak morphological disturbance and small spatial and velocity offsets suggest that CXO J101527.2+625911 could be in the final stage of a merging process and about to turn into a normal elliptical galaxy.
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    KINEMATICALLY IDENTIFIED RECOILING SUPERMASSIVE BLACK HOLE CANDIDATES IN SDSS QSOs WITH z < 0.25
    (2016) Kim, D. -C.; Evans, A. S.; Stierwalt, S.; Privon, G. C.
    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(-1) with a mean of -149 +/- 58 km s(-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-BH of the rSMBH candidates are on average similar to 5 times smaller than those of their stationary counterparts and cause a scatter in the M-BH -sigma(*) 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(-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.