Reverberation Mapping of the Narrow-line Seyfert 1 Galaxy I Zwicky 1: Black Hole Mass
Ho, Luis C.; Bian, Wei-Hao; Zhang, Zhi-Xiang; Du, Pu; Hu, Chen; Wang, Jian-Min; Wang, Kai; Li, Yan-Rong; Bai, Jin-Ming; Lu, Kai-Xing; Huang, Ying-Ke; Yuan, Ye-Fei; Zhao, Yu-Lin; Zhang, Yue
China
Abstract
We report results of the first reverberation mapping campaign of I Zwicky 1 during 2014-2016, which showed unambiguous reverberations of the broad Hβ line emission in the varying optical continuum. From analysis using several methods, we obtain a reverberation lag of {τ }{{H}β }={37.2}-4.9+4.5 {days}. Taking a virial factor of {f}{BLR}}=1, we find a black hole mass of {M}\bullet ={9.30}-1.38+1.26× {10}6{M}⊙ from the mean spectra. The accretion rate is estimated to be {203.9}-65.8+61.0 {L}Edd}{c}-2, suggesting a super-Eddington accretor, where L Edd is the Eddington luminosity and c is the speed of light. By decomposing Hubble Space Telescope images, we find that the stellar mass of the bulge of its host galaxy is {log}({M}bulge}/{M}⊙ )=10.92+/- 0.07. This leads to a black hole to bulge mass ratio of ∼10-4, which is significantly smaller than that of classical bulges and elliptical galaxies. After subtracting the host contamination from the observed luminosity, we find that I Zw 1 follows the empirical {R}BLR}\propto {L}51001/2 relation.