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Title: Superluminous Transients at AGN Centers from Interaction between Black Hole Disk Winds and Broad-line Region Clouds

Abstract

We propose that superluminous transients that appear at central regions of active galactic nuclei (AGNs) such as CSS100217:102913+404220 (CSS100217) and PS16dtm, which reach near- or super-Eddington luminosities of the central black holes, are powered by the interaction between accretion-disk winds and clouds in broad-line regions (BLRs) surrounding them. If the disk luminosity temporarily increases by, e.g., limit–cycle oscillations, leading to a powerful radiatively driven wind, strong shock waves propagate in the BLR. Because the dense clouds in the AGN BLRs typically have similar densities to those found in SNe IIn, strong radiative shocks emerge and efficiently convert the ejecta kinetic energy to radiation. As a result, transients similar to SNe IIn can be observed at AGN central regions. Since a typical black hole disk-wind velocity is ≃0.1 c , where c is the speed of light, the ejecta kinetic energy is expected to be ≃10{sup 52} erg when ≃1 M {sub ⊙} is ejected. This kinetic energy is transformed to radiation energy in a timescale for the wind to sweep up a similar mass to itself in the BLR, which is a few hundred days. Therefore, both luminosities (∼10{sup 44} erg s{sup −1}) and timescales (∼100 days) of the superluminousmore » transients from AGN central regions match those expected in our interaction model. If CSS100217 and PS16dtm are related to the AGN activities triggered by limit–cycle oscillations, they become bright again in coming years or decades.« less

Authors:
; ;  [1];  [2]
  1. Division of Theoretical Astronomy, National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)
  2. Institute of Astronomy, Graduate School of Science, The University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan)
Publication Date:
OSTI Identifier:
22654443
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 843; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCRETION DISKS; BLACK HOLES; CLOUDS; DENSITY; GALAXIES; GALAXY NUCLEI; INTERACTIONS; LIMIT CYCLE; LUMINOSITY; MASS; OSCILLATIONS; SHOCK WAVES; STELLAR WINDS; VELOCITY; VISIBLE RADIATION

Citation Formats

Moriya, Takashi J., Tanaka, Masaomi, Ohsuga, Ken, and Morokuma, Tomoki, E-mail: takashi.moriya@nao.ac.jp. Superluminous Transients at AGN Centers from Interaction between Black Hole Disk Winds and Broad-line Region Clouds. United States: N. p., 2017. Web. doi:10.3847/2041-8213/AA7AF3.
Moriya, Takashi J., Tanaka, Masaomi, Ohsuga, Ken, & Morokuma, Tomoki, E-mail: takashi.moriya@nao.ac.jp. Superluminous Transients at AGN Centers from Interaction between Black Hole Disk Winds and Broad-line Region Clouds. United States. doi:10.3847/2041-8213/AA7AF3.
Moriya, Takashi J., Tanaka, Masaomi, Ohsuga, Ken, and Morokuma, Tomoki, E-mail: takashi.moriya@nao.ac.jp. Mon . "Superluminous Transients at AGN Centers from Interaction between Black Hole Disk Winds and Broad-line Region Clouds". United States. doi:10.3847/2041-8213/AA7AF3.
@article{osti_22654443,
title = {Superluminous Transients at AGN Centers from Interaction between Black Hole Disk Winds and Broad-line Region Clouds},
author = {Moriya, Takashi J. and Tanaka, Masaomi and Ohsuga, Ken and Morokuma, Tomoki, E-mail: takashi.moriya@nao.ac.jp},
abstractNote = {We propose that superluminous transients that appear at central regions of active galactic nuclei (AGNs) such as CSS100217:102913+404220 (CSS100217) and PS16dtm, which reach near- or super-Eddington luminosities of the central black holes, are powered by the interaction between accretion-disk winds and clouds in broad-line regions (BLRs) surrounding them. If the disk luminosity temporarily increases by, e.g., limit–cycle oscillations, leading to a powerful radiatively driven wind, strong shock waves propagate in the BLR. Because the dense clouds in the AGN BLRs typically have similar densities to those found in SNe IIn, strong radiative shocks emerge and efficiently convert the ejecta kinetic energy to radiation. As a result, transients similar to SNe IIn can be observed at AGN central regions. Since a typical black hole disk-wind velocity is ≃0.1 c , where c is the speed of light, the ejecta kinetic energy is expected to be ≃10{sup 52} erg when ≃1 M {sub ⊙} is ejected. This kinetic energy is transformed to radiation energy in a timescale for the wind to sweep up a similar mass to itself in the BLR, which is a few hundred days. Therefore, both luminosities (∼10{sup 44} erg s{sup −1}) and timescales (∼100 days) of the superluminous transients from AGN central regions match those expected in our interaction model. If CSS100217 and PS16dtm are related to the AGN activities triggered by limit–cycle oscillations, they become bright again in coming years or decades.},
doi = {10.3847/2041-8213/AA7AF3},
journal = {Astrophysical Journal Letters},
number = 2,
volume = 843,
place = {United States},
year = {Mon Jul 10 00:00:00 EDT 2017},
month = {Mon Jul 10 00:00:00 EDT 2017}
}