The Black Hole Mass of the z = 2.805 Multiply Imaged Quasar SDSS J2222+2745 from Velocity-resolved Time Lags of the C IV Emission Line
Abstract
We present the first results of a 4.5 yr monitoring campaign of the three bright images of multiply imaged z = 2.805 quasar SDSS J2222+2745 using the Gemini North Multi-Object Spectrograph and the Nordic Optical Telescope. We take advantage of gravitational time delays to construct light curves surpassing 6 yr in duration in the observed frame and achieve an average spectroscopic cadence of 10 days during the 8 months of visibility per season. Using multiple secondary calibrators and advanced reduction techniques, we achieve percent-level spectrophotometric precision and carry out an unprecedented reverberation mapping analysis, measuring both integrated and velocity-resolved time lags for the C IV emission line. The full line lags the continuum by ${\tau }_{\mathrm{cen}}={36.5}_{-3.9}^{+2.9}$ rest-frame days. We combine our measurement with published C IV emission line lags and derive the rBLR - L relationship ${\mathrm{log}}_{10}(\tau /{\rm{d}}{\rm{a}}{\rm{y}})=(0.99\,\pm 0.07)+(0.48\pm 0.03){\mathrm{log}}_{10}[\lambda {L}_{\lambda }(1350\,{\rm{A}}{\rm{A}})/{10}^{44}\,{{\rm{e}}{\rm{r}}{\rm{g}}{\rm{s}}}^{-1}]$ with 0.30 ± 0.06 dex intrinsic scatter. The velocity-resolved lags are consistent with circular Keplerian orbits, with ${\tau }_{\mathrm{cen}}={86.2}_{-5.0}^{+4.5}$ , ${25}_{-15}^{+11}$ , and ${7.5}_{-3.5}^{+4.2}$ rest-frame days for the core, blue wing, and red wing, respectively. Using σline with the mean spectrum and assuming ${\mathrm{log}}_{10}({f}_{\mathrm{mean},\sigma })=0.52\pm 0.26$ , we derive ${\mathrm{log}}_{10}({M}_{\mathrm{BH}}/{M}_{\odot })=8.63\pm 0.27$ . Given the quality of the data, this system represents a unique benchmark for calibration of MBH estimators at high redshift. Future work will present dynamical modeling of the data to constrain the virial factor f and MBH.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 2021
- DOI:
- 10.3847/1538-4357/abe943
- arXiv:
- arXiv:2011.02007
- Bibcode:
- 2021ApJ...911...64W
- Keywords:
-
- Active galactic nuclei;
- Strong gravitational lensing;
- Reverberation mapping;
- Supermassive black holes;
- 16;
- 1643;
- 2019;
- 1663;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 21 pages, 16 figures, 3 tables, submitted to ApJ