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Register a new userBroad-line Region of the Quasar PG 2130+099 from a Two-Year Reverberation Mapping Campaign with High Cadence
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Chen Hu
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As one of the most interesting Seyfert 1 galaxies, PG 2130+099 has been the target of several reverberation mapping (RM) campaigns over the years. However, its measured broad H$beta$ line responses have been inconsistent, with time lags of $sim$200 days, $sim$25 days, and $sim$10 days being reported for different epochs while its optical luminosity changed no more than 40%. To investigate this issue, we conducted a new RM-campaign with homogenous and high cadence (about $sim$3 days) for two years during 2017--2019 to measure the kinematics and structure of the ionized gas. We successfully detected time lags of broad H$beta$, He II, He I, and Fe II lines with respect to the varying 5100AA continuum, revealing a stratified structure that is likely virialized with Keplerian kinematics in the first year of observations, but an inflow kinematics of the broad-line region from the second year. With a central black hole mass of $0.97_{-0.18}^{+0.15}times 10^7~M_{odot}$, PG 2130+099 has an accretion rate of $10^{2.1pm0.5}L_{rm Edd}c^{-2}$, where $L_{rm Edd}$ is the Eddington luminosity and $c$ is speed of light, implying that it is a super-Eddington accretor and likely possesses a slim, rather than thin, accretion disk. The fast changes of the ionization structures of the three broad lines remain puzzling.
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Despite many decades of study, the kinematics of the broad-line region of 3C~273 are still poorly understood. We report a new, high signal-to-noise, reverberation mapping campaign carried out from November 2008 to March 2018 that allows the determination of time lags between emission lines and the variable continuum with high precision. The time lag of variations in H$beta$ relative to those of the 5100 Angstrom continuum is $146.8_{-12.1}^{+8.3}$ days in the rest frame, which agrees very well with the Paschen-$alpha$ region measured by the GRAVITY at The Very Large Telescope Interferometer. The time lag of the H$gamma$ emission line is found to be nearly the same as for H$beta$. The lag of the Fe II emission is $322.0_{-57.9}^{+55.5}$ days, longer by a factor of $sim$2 than that of the Balmer lines. The velocity-resolved lag measurements of the H$beta$ line show a complex structure which can be possibly explained by a rotation-dominated disk with some inflowing radial velocity in the H$beta$-emitting region. Taking the virial factor of $f_{rm BLR} = 1.3$, we derive a BH mass of $M_{bullet} = 4.1_{-0.4}^{+0.3} times 10^8 M_{odot}$ and an accretion rate of $9.3,L_{rm Edd},c^{-2}$ from the H$beta$ line. The decomposition of its $HST$ images yields a host stellar mass of $M_* = 10^{11.3 pm 0.7} M_odot$, and a ratio of $M_{bullet}/M_*approx 2.0times 10^{-3}$ in agreement with the Magorrian relation. In the near future, it is expected to compare the geometrically-thick BLR discovered by the GRAVITY in 3C 273 with its spatially-resolved torus in order to understand the potential connection between the BLR and the torus.
We report on the results of a new spectroscopic monitoring campaign of the quasar PG 0026+129 at the Calar Alto Observatory 2.2m telescope from July 2017 to February 2020. Significant variations in the fluxes of the continuum and broad-emission lines, including H$beta$ and He II, were observed in the first and third years, and clear time lags between them are measured. The broad H$beta$ line profile consists of two Gaussian components: an intermediate-width H$beta_{rm IC}$ with a full width at half-maximum (FWHM) of 1964$pm$18 $rm km~s^{-1}$ and another very broad H$beta_{rm VBC}$ with a FWHM of 7570$pm$83 $rm km~s^{-1}$. H$beta_{rm IC}$ has long time lags of $sim$40--60 days in the rest frame, while H$beta_{rm VBC}$ shows nearly zero time delay with respect to the optical continuum at 5100 AA. The velocity-resolved delays show consistent results: lags of $sim$30--50 days at the core of the broad H$beta$ line and roughly zero lags at the wings. H$beta_{rm IC}$ has a redshift of $sim$400 $rm km~s^{-1}$ which seems to be stable for nearly 30 years by comparing with archived spectra, and may originate from an infall. The root mean square (rms) spectrum of H$beta_{rm VBC}$ shows a double-peaked profile with brighter blue peak and extended red wing in the first year, which matches the signature of a thin disk. Both the double-peaked profile and the near-zero lag suggest that H$beta_{rm VBC}$ comes from a region associated with the part of the accretion disc that emits the optical continuum. Adopting the FWHM (in the rms spectrum) and the time lag measured for the total H$beta$ line, and a virial factor of 1.5, we obtain a virial mass of $2.89_{-0.69}^{+0.60} times10^7 M_{odot}$ for the central black hole in this quasar.
We present the results of a recent reverberation-mapping campaign undertaken to improve measurements of the radius of the broad line region and the central black hole mass of the quasar PG 2130+099. Cross correlation of the 5100 angstrom continuum and H-beta emission-line light curves yields a time lag of 22.9 (+4.4 - 4.3) days, corresponding to a central black hole mass MBH= 3.8 (+/- 1.5) x 10^7 Msun. This value supports the notion that previous measurements yielded an incorrect lag. We re-analyzed previous datasets to investigate the possible sources of the discrepancy and conclude that previous measurement errors were apparently caused by a combination of undersampling of the light curves and long-term secular changes in the H-beta emission-line equivalent width. With our new measurements, PG 2130+099 is no longer an outlier in either the R-L or the MBH-Sigma relationships.
A detailed analysis of the data from a high sampling rate, multi-month reverberation mapping campaign, undertaken primarily at MDM Observatory with supporting observations from telescopes around the world, reveals that the Hbeta emission region within the broad line regions (BLRs) of several nearby AGNs exhibit a variety of kinematic behaviors. While the primary goal of this campaign was to obtain either new or improved Hbeta reverberation lag measurements for several relatively low luminosity AGNs (presented in a separate work), we were also able to unambiguously reconstruct velocity-resolved reverberation signals from a subset of our targets. Through high cadence spectroscopic monitoring of the optical continuum and broad Hbeta emission line variations observed in the nuclear regions of NGC 3227, NGC 3516, and NGC 5548, we clearly see evidence for outflowing, infalling, and virialized BLR gas motions, respectively.
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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