In this work, we present the first results of the long-term high-cadence spectroscopic monitoring of 15 PG quasars with relatively strong Fe ii emission, as a part of a broader reverberation mapping campaign performed using the Calar Alto Observatory’s 2.2 m telescope. The V-band, 5100 Å continuum, and Hβ broad emission line light curves are measured for a set of quasars for periods ranging from dozens to more than a hundred epochs between 2017 May and 2020 July. Accurate time lags between the variations of the Hβ broad-line fluxes and the optical continuum strength are obtained for all 15 quasars, ranging from 17.0 − 3.2 + 2.5 to 95.9 − 23.9 + 7.1 days in the rest frame. The virial masses of the central supermassive black holes are derived for all 15 quasars, ranging between 0.50 − 0.19 + 0.18 and 19.17 − 2.73 + 2.98 in units of 107 M ⊙. For 11 of the objects in our sample, this is the first reverberation analysis to be published. Of the rest, two objects have been the subject of previous reverberation studies, but we determine time lags for these that are only half as long as those found in the earlier investigations, which had only been able to sample much more sparsely. The remaining two objects have previously been monitored with high sampling rates. Our results here are consistent with the earlier findings, in the sense that the time lag and the line width vary inversely, consistent with virialization.
We report the results of a multiyear 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 1045 erg s−1. PG 0923+201 is monitored for the first time, while PG 1001+291 was previously monitored but our campaign has a much longer temporal baseline. We detect time lags of variations of the broad Hβ, Hγ, and Fe ii lines with respect to those of the 5100 Å continuum. The velocity-resolved delay map of Hβ in PG 0923+201 indicates a complicated structure with a mix of Keplerian disk-like motion and outflow, and the map of Hβ in PG 1001+291 shows a signature of Keplerian disk-like motion. Assuming a virial factor of f BLR = 1 and FWHM line widths, we measure the black hole mass to be 118 − 16 + 11 × 10 7 M ⊙ for PG 0923+201 and 3.33 − 0.54 + 0.62 × 10 7 M ⊙ for PG 1001+291. Their respective accretion rates are estimated to be 0.21 − 0.07 + 0.06 × L Edd c − 2 and 679 − 227 + 259 × L Edd c − 2 , indicating that PG 0923+201 is a sub-Eddington accretor and PG 1001+291 is a super-Eddington accretor. While the Hβ 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 active galactic nuclei (AGNs), the BLR size depends on both luminosity and Eddington ratio. Black hole mass estimates from single-AGN spectra will be overestimated at high luminosities and redshifts if this effect is not taken into account.
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