Reverberation Mapping of Changing-look Active Galactic Nucleus NGC 3516. (arXiv:2012.15572v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Feng_H/0/1/0/all/0/1">Hai-Cheng. Feng</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hu_C/0/1/0/all/0/1">Chen. Hu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Li_S/0/1/0/all/0/1">Sha-Sha. Li</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_H/0/1/0/all/0/1">H. T. Liu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bai_J/0/1/0/all/0/1">J. M. Bai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Xing_L/0/1/0/all/0/1">Li-Feng. Xing</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_W/0/1/0/all/0/1">Wei-Yang. Wang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yang_Z/0/1/0/all/0/1">Zi-Xu. Yang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Xiao_M/0/1/0/all/0/1">Ming. Xiao</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lu_K/0/1/0/all/0/1">Kai-Xing. Lu</a>
The changes of broad emission lines should be a crucial issue to
understanding the physical properties of changing-look active galactic nucleus
(CL-AGN). Here, we present the results of an intensive and homogeneous 6-month
long reverberation mapping (RM) monitoring campaign during a low-activity state
of the CL-AGN Seyfert galaxy NGC 3516. Photometric and spectroscopic monitoring
was carried out during 2018–2019 with the Lijiang 2.4 m telescope. The
sampling is 2 days in most nights, and the average sampling is $sim$3 days.
The rest frame time lags of H$alpha$ and H$beta$ are
$tau_{rm{H}alpha}=7.56^{+4.42}_{-2.10}$ days and
$tau_{rm{H}beta}=7.50^{+2.05}_{-0.77}$ days, respectively. From a RMS
H$beta$ line dispersion of $sigma_{rm{line}} = 1713.3 pm 46.7$ $rm{km}$
$rm{s^{-1}}$ and a virial factor of $f_{sigma}$ = 5.5, the central black hole
mass of NGC 3516 is estimated to be $M_{rm{BH}}= 2.4^{+0.7}_{-0.3} times
10^{7} M_{odot}$, which is in agreement with previous estimates. The
velocity-resolved delays show that the time lags increase towards negative
velocity for both H$alpha$ and H$beta$. The velocity-resolved RM of H$alpha$
is done for the first time. These RM results are consistent with other
observations before the spectral type change, indicating a basically constant
BLR structure during the changing-look process. The CL model of changes of
accretion rate seems to be favored by long-term H$beta$ variability and RM
observations of NGC 3516.
The changes of broad emission lines should be a crucial issue to
understanding the physical properties of changing-look active galactic nucleus
(CL-AGN). Here, we present the results of an intensive and homogeneous 6-month
long reverberation mapping (RM) monitoring campaign during a low-activity state
of the CL-AGN Seyfert galaxy NGC 3516. Photometric and spectroscopic monitoring
was carried out during 2018–2019 with the Lijiang 2.4 m telescope. The
sampling is 2 days in most nights, and the average sampling is $sim$3 days.
The rest frame time lags of H$alpha$ and H$beta$ are
$tau_{rm{H}alpha}=7.56^{+4.42}_{-2.10}$ days and
$tau_{rm{H}beta}=7.50^{+2.05}_{-0.77}$ days, respectively. From a RMS
H$beta$ line dispersion of $sigma_{rm{line}} = 1713.3 pm 46.7$ $rm{km}$
$rm{s^{-1}}$ and a virial factor of $f_{sigma}$ = 5.5, the central black hole
mass of NGC 3516 is estimated to be $M_{rm{BH}}= 2.4^{+0.7}_{-0.3} times
10^{7} M_{odot}$, which is in agreement with previous estimates. The
velocity-resolved delays show that the time lags increase towards negative
velocity for both H$alpha$ and H$beta$. The velocity-resolved RM of H$alpha$
is done for the first time. These RM results are consistent with other
observations before the spectral type change, indicating a basically constant
BLR structure during the changing-look process. The CL model of changes of
accretion rate seems to be favored by long-term H$beta$ variability and RM
observations of NGC 3516.
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