分类： 天文学 >> 天文学 提交时间： 2023-02-19
Dong-Wei Bao
Michael S. Brotherton
Pu Du
Jacob N. McLane
T. E. Zastrocky
Kianna A. Olson
Feng-Na Fang
Shuo Zhai
Zheng-Peng Huang
Kai Wang
Bi-Xuan Zhao
Sha-Sha Li
Sen Yang
Yong-Jie Chen
Jun-Rong Liu
Zhu-Heng Yao
Yue-Chang Peng
Wei-Jian Guo
Yu-Yang Songsheng
Yan-Rong Li
摘要： In this third paper of the series reporting on the reverberation mapping (RM) campaign of active galactic nuclei with asymmetric H$\beta$ emission-line profiles, we present results for 15 Palomar-Green (PG) quasars using spectra obtained between the end of 2016 to May 2021. This campaign combines long time spans with relatively high cadence. For 8 objects, both the time lags obtained from the entire light curves and the measurements from individual observing seasons are provided. Reverberation mapping of 9 of our targets has been attempted for the first time, while the results for 6 others can be compared with previous campaigns. We measure the H$\beta$ time lags over periods of years and estimate their black hole masses. The long duration of the campaign enables us to investigate their broad line region (BLR) geometry and kinematics for different years by using velocity-resolved lags, which demonstrate signatures of diverse BLR geometry and kinematics. The BLR geometry and kinematics of individual objects are discussed. In this sample, the BLR kinematics of Keplerian/virialized motion and inflow is more common than outflow.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Fergus R. Donnan
Juan V. Hernández Santisteban
Keith Horne
Chen Hu
Pu Du
Yan-Rong Li
Ming Xiao
Luis C. Ho
Jesús Aceituno
Jian-Min Wang
Wei-Jian Guo
Sen Yang
Bo-Wei Jiang
Zhu-Heng Yao
摘要： We measure the black hole mass and investigate the accretion flow around the local ($z=0.0502$) quasar PG 1119+120. Spectroscopic monitoring with Calar Alto provides H$\beta$ lags and linewidths from which we estimate a black hole mass of $\log \left(M_{\bullet}/\mathrm{M}_{\odot} \right) = 7.0$, uncertain by $\sim0.4$ dex. High cadence photometric monitoring over two years with the Las Cumbres Observatory provides lightcurves in 7 optical bands suitable for intensive continuum reverberation mapping. We identify variability on two timescales. Slower variations on a 100-day timescale exhibit excess flux and increased lag in the $u'$ band and are thus attributable to diffuse bound-free continuum emission from the broad line region. Faster variations that we attribute to accretion disc reprocessing lack a $u'$-band excess and have flux and delay spectra consistent with either $\tau \propto \lambda^{4/3}$, as expected for a temperature structure of $T(R) \propto R^{-3/4}$ for a thin accretion disc, or $\tau \propto \lambda^{2}$ expected for a slim disc. Decomposing the flux into variable (disc) and constant (host galaxy) components, we find the disc SED to be flatter than expected with $f_{\nu} \sim \rm{const}$. Modelling the SED predicts an Eddington ratio of $\lambda_{\rm Edd} > 1$, where the flat spectrum can be reproduced by a slim disc with little dust extinction or a thin disc which requires more dust extinction. While this accretion is super-Eddington, the geometry is still unclear, however a slim disc is expected due to the high radiation pressure at these accretion rates, and is entirely consistent with our observations.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Sha-Sha Li
Sen Yang
Zi-Xu Yang
Yong-Jie Chen
Yu-Yang Songsheng
He-Zhen Liu
Pu Du
Bin Luo
Zhe Yu
Chen Hu
Bo-Wei Jiang
Dong-Wei Bao
Wei-Jian Guo
Zhi-Xiang Zhang
Yan-Rong Li
Ming Xiao
Kai-Xing Lu
Luis C. Ho
Jing-Min Bai
Wei-Hao Bian
摘要： We report the results of a multi-year spectroscopic and photometric monitoring campaign of two luminous quasars, PG~0923+201 and PG~1001+291, both located at the high-luminosity end of the broad-line region (BLR) size-luminosity relation with optical luminosities above $10^{45}~{\rm erg~s^{-1}}$. PG~0923+201 is for the first time monitored, and PG~1001+291 was previously monitored but our campaign has a much longer temporal baseline. We detect time lags of variations of the broad H$\beta$, H$\gamma$, Fe {\sc ii} lines with respect to those of the 5100~{\AA} continuum. The velocity-resolved delay map of H$\beta$ in PG~0923+201 indicates a complicated structure with a mix of Keplerian disk-like motion and outflow, and the map of H$\beta$ in PG~1001+291 shows a signature of Keplerian disk-like motion. Assuming a virial factor of $f_{\rm BLR}=1$ and FWHM line widths, we measure the black hole mass to be $118_{-16}^{+11}\times 10^7 M_{\odot}$ for PG~0923+201 and $3.33_{-0.54}^{+0.62}\times 10^7 M_{\odot}$ for PG~1001+291. Their respective accretion rates are estimated to be $0.21_{-0.07}^{+0.06} \times L_{\rm Edd}\,c^{-2}$ and $679_{-227}^{+259}\times L_{\rm Edd}\,c^{-2}$, indicating that PG~0923+201 is a sub-Eddington accretor and PG~1001+291 is a super-Eddington accretor. While the H$\beta$ time lag of PG~0923+201 agrees with the size-luminosity relation, the time lag of PG~1001+291 shows a significant deviation, confirming that in high-luminosity AGN the BLR size depends on both luminosity and Eddington ratio. Black hole mass estimates from single AGN spectra will be over-estimated at high luminosities and redshifts if this effect is not taken into account.
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