Are Narrow-line Seyfert 1 Galaxies Powered by Low-mass Black Holes?
accretion, accretion disks; galaxies: active; galaxies: Seyfert
Narrow-line Seyfert 1 galaxies (NLS1s) are believed to be powered by the accretion of matter onto low-mass black holes (BHs) in spiral host galaxies with BH masses M BH ? 106-108 M o. However, the broadband spectral energy distribution of the ?-ray-emitting NLS1s are found to be similar to flat-spectrum radio quasars. This challenges our current notion of NLS1s having low M BH. To resolve this tension of low M BH values in NLS1s, we fitted the observed optical spectrum of a sample of radio-loud NLS1s (RL-NLS1s), radio-quiet NLS1s (RQ-NLS1s), and radio-quiet broad-line Seyfert 1 galaxies (RQ-BLS1s) of ?500 each with the standard Shakura-Sunyaev accretion disk (AD) model. For RL-NLS1s we found a mean log() of 7.98 0.54. For RQ-NLS1s and RQ-BLS1s we found mean log() of 8.00 0.43 and 7.90 0.57, respectively. While the derived values of RQ-BLS1s are similar to their virial masses, for NLS1s the derived values are about an order of magnitude larger than their virial estimates. Our analysis thus indicates that NLS1s have M BH similar to RQ-BLS1s and their available virial M BH values are underestimated, influenced by their observed relatively small emission line widths. Considering Eddington ratio as an estimation of the accretion rate and using , we found the mean accretion rate of our RQ-NLS1s, RL-NLS1s, and RQ-BLS1s as , and , respectively. Our results therefore suggest that NLS1s have BH masses and accretion rates that are similar to BLS1s. 2019. The American Astronomical Society. All rights reserved.
Viswanath G.; Stalin C.S.; Rakshit S.; Kurian K.S.; Ujjwal K.; Gudennavar S.B.; Kartha S.S.
Astrophysical Journal Letters, Vol-881, No. 1
All Open Access; Bronze Open Access; Green Open Access
https://doi.org/10.3847/2041-8213/ab365e https://www.scopus.com/inward/record.uri?eid=2-s2.0-85071224038&doi=10.3847%2f2041-8213%2fab365e&partnerID=40&md5=2ee9e3e92bbaf0221226e1dc8c52cee8
Viswanath G., Department of Physics and Electronics, CHRIST (Deemed to Be University), Bengaluru, Karnataka, 560029, India; Stalin C.S., Indian Institute of Astrophysics, Block II, Koramangala, Bengaluru, Karnataka, 560034, India; Rakshit S., Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Quantum, Vesilinnantie 5, FI-20014, Finland; Kurian K.S., Indian Institute of Astrophysics, Block II, Koramangala, Bengaluru, Karnataka, 560034, India; Ujjwal K., Department of Physics and Electronics, CHRIST (Deemed to Be University), Bengaluru, Karnataka, 560029, India; Gudennavar S.B., Department of Physics and Electronics, CHRIST (Deemed to Be University), Bengaluru, Karnataka, 560029, India; Kartha S.S., Department of Physics and Electronics, CHRIST (Deemed to Be University), Bengaluru, Karnataka, 560029, India