Reverberation mapping of two luminous quasars: the broad-line region structure and black hole mass

SS Li, S Yang, ZX Yang, YJ Chen, YY Songsheng, HZ Liu, P Du, B Luo, Z Yu, C Hu, BW Jiang, DW Bao, WJ Guo, ZX Zhang, YR Li, M Xiao, KX Lu, LC Ho, JM Bai, WH BianJ Aceituno, T Minezaki, K Horne, M Kokubo, JM Wang

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23 Citations (Scopus)


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 10(45) 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 H beta, H gamma, and Fe ii lines with respect to those of the 5100 angstrom 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 (BLR) = 1 and FWHM line widths, we measure the black hole mass to be 118(-16)(+11)x10(7)M(circle dot) for PG 0923+201 and 3.33(-0.54)(+0.62) x 10(7)M(circle dot) for PG 1001+291. Their respective accretion rates are estimated to be 0.21(-0.07)(+0.06) x L(Edd)c(-2) and 679(-227)(+259) x 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 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 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.
Original languageEnglish
Number of pages17
JournalAstrophysical Journal
Issue number1
Early online date6 Oct 2021
Publication statusPublished - 10 Oct 2021


  • Supermassive black holes
  • Quasars
  • Reverberation mapping


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