Taking a Long Look: A Two-decade Reverberation Mapping Study of High-luminosity Quasars

Shai Kaspi, W. N. Brandt, Dan Maoz, Hagai Netzer, Donald P. Schneider, Ohad Shemmer, C. J. Grier

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


Reverberation mapping (RM) of active galactic nuclei (AGNs) has been used over the past three decades to determine AGN broad-line region (BLR) sizes and central black hole masses, and their relations with the AGN luminosity. Until recently, the sample of objects with RM data was limited to low-luminosity AGNs (L opt ≲ 1046 erg s-1) and low redshifts (z ≲ 0.5). Here we present results from an RM project of some of the most luminous and highest-redshift quasars that have been mapped to date. The study is based on almost 20 years of photometric monitoring of 11 quasars, 6 of which were monitored spectrophotometrically for 13 yr. This is the longest RM project carried out so far on this type of AGNs. We successfully measure a time lag between the C iv λ 1549 broad emission line and the quasar continuum in three objects, and measure a C iii] λ 1909 lag in one quasar. Together with recently published data on C iv RM, the BLR size is found to scale as the square root of the UV luminosity over eight orders of magnitude in AGN luminosity. There is a significant scatter in the relation, part of which may be intrinsic to the AGNs. Although the C iv line is probably less well suited than Balmer lines for determination of the mass of the black hole, virial masses are tentatively computed, and in spite of a large scatter, we find that the mass of the black hole scales as the square root of the UV luminosity.

Original languageEnglish (US)
Article number129
JournalAstrophysical Journal
Issue number2
StatePublished - Jul 10 2021

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'Taking a Long Look: A Two-decade Reverberation Mapping Study of High-luminosity Quasars'. Together they form a unique fingerprint.

Cite this