@article{331b76c2d1d4405ca47fa0a03273d79d,
title = "The sloan digital sky survey reverberation mapping project: MgII lag results from four years of monitoring",
abstract = "We present reverberation mapping results for the Mg II λ2800 {\AA} broad emission line in a sample of 193 quasars at 0.35 < z < 1.7 with photometric and spectroscopic monitoring observations from the Sloan Digital Sky Survey Reverberation Mapping project during 2014-2017. We find significant time lags between the Mg II and continuum lightcurves for 57 quasars, and define a “gold sample” of 24 quasars with the most reliable lag measurements. We estimate false-positive rates for each lag that range from 1% to 24%, with an average false-positive rate of 11% for the full sample and 8% for the gold sample. There are an additional ∼40 quasars with marginal Mg II lag detections, which may yield reliable lags after additional years of monitoring. The Mg II lags follow a radius-luminosity relation with a best-fit slope that is consistent with a = 0.5, but with an intrinsic scatter of 0.36 dex that is significantly larger than found for the Hβ radius-luminosity relation. For targets with SDSS-RM lag measurements of other emission lines, we find that our Mg II lags are similar to the Hβ lags and ∼2-3 times larger than the C IV lags. This work significantly increases the number of Mg II broad-line lags and provides additional reverberation-mapped black hole masses, filling the redshift gap at the peak of supermassive black hole growth between the Hβ and C IV emission lines in optical spectroscopy.",
keywords = "Active galactic nuclei (16), Active galaxies (17), Galaxy nuclei (609), Quasars (1319)",
author = "Y. Homayouni and Trump, {Jonathan R.} and Grier, {C. J.} and Keith Horne and Yue Shen and Brandt, {W. N.} and Dawson, {Kyle S.} and Alvarez, {Gloria Fonseca} and Green, {Paul J.} and Hall, {P. B.} and {Hern{\'a}ndez Santisteban}, {Juan V.} and Ho, {Luis C.} and Karen Kinemuchi and Kochanek, {C. S.} and Li, {Jennifer I.Hsiu} and Peterson, {B. M.} and P. Schneider and Starkey, {D. A.} and Dmitry Bizyaev and Kaike Pan and Daniel Oravetz and Audrey Simmons",
note = "Funding Information: Y. H., J. R. T., and G. F. A. acknowledge support from NASA grants HST-GO-15650 and 18-2ADAP18-0177 and NSF grant CAREER-1945546. Y. S., D. A. S., and J. L. acknowledge support from an Alfred P. Sloan Research Fellowship (Y. S.) and NSF grant AST-1715579. K. H. and J. V. H. S. acknowledge support from STFC grant ST/ R000824/1. P. H. acknowledges support from the Natural Sciences and Engineering Research Council of Canada (NSERC), funding reference number 2017-05983, and from the National Research Council Canada during his sabbatical at NRC Herzberg Astronomy & Astrophysics. L. C. H. was supported by the National Key R&D Program of China (2016YFA0400702) and the National Science Foundation of China (11473002, 11721303). C. S. K. acknowledges support from NSF grants AST-1908952 and AST-1814440. Funding for SDSS-III was provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, and the U.S. Department of Energy Office of Science. The SDSS-III website is http://www.sdss3.org/. SDSS-III was managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS-III Collaboration including the University of Arizona, the Brazilian Participation Group, Brookhaven National Laboratory, Carnegie Mellon University, University of Florida, the French Participation Group, the German Participation Group, Harvard University, the Instituto de Astrofisica de Canarias, the Michigan State/Notre Dame/JINA Participation Group, The Johns Hopkins University, Lawrence Berkeley National Laboratory, Max Planck Institute for Astrophysics, Max Planck Institute for Extraterrestrial Physics, New Mexico State University, New York University, Ohio State University, Pennsylvania State University, University of Portsmouth, Princeton University, the Spanish Participation Group, University of Tokyo, University of Utah, Vanderbilt University, University of Virginia, University of Washington, and Yale University. Funding for SDSS-IV has been provided by the Alfred P. Sloan Foundation, the U.S. Department of Energy Office of Science, and the Participating Institutions. SDSS acknowledges support and resources from the Center for High-Performance Computing at the University of Utah. The SDSS website is www.sdss.org. SDSS is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS Collaboration including the Brazilian Participation Group, the Carnegie Institution for Science, Carnegie Mellon University, the Chilean Participation Group, the French Participation Group, Harvard-Smithsonian Center for Astrophysics, Instituto de Astrof{\'i}sica de Canarias, The Johns Hopkins University, Kavli Institute for the Physics and Mathematics of the Universe (IPMU)/University of Tokyo, the Korean Participation Group, Lawrence Berkeley National Laboratory, Leibniz Institut f{\"u}r Astrophysik Potsdam (AIP), Max-Planck-Institut f{\"u}r Astronomie (MPIA Heidelberg), Max-Planck-Institut f{\"u}r Astrophysik (MPA Garching), Max-Planck-Institut f{\"u}r Extraterrestrische Physik (MPE), National Astronomical Observatories of China, New Mexico State University, New York University, University of Notre Dame, Observat{\'o}rio Nacional/MCTI, The Ohio State University, Pennsylvania State University, Shanghai Astronomical Observatory, United Kingdom Participation Group, Universidad Nacional Aut{\'o}noma de M{\'e}xico, University of Arizona, University of Colorado Boulder, University of Oxford, University of Portsmouth, University of Utah, University of Virginia, University of Washington, University of Wisconsin, Vanderbilt University, and Yale University. We thank the Bok and CFHT Canadian, Chinese, and French TACs for their support. This research uses Bok data obtained through the Telescope Access Program (TAP), which is funded by the National Astronomical Observatories, Chinese Academy of Sciences, and the Special Fund for Astronomy from the Ministry of Finance in China. This work is based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. The astronomical community is most fortunate to have the opportunity to conduct observations from this mountain. Publisher Copyright: {\textcopyright} 2020. The American Astronomical Society. All rights reserved.",
year = "2020",
month = sep,
day = "20",
doi = "10.3847/1538-4357/ababa9",
language = "English (US)",
volume = "901",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "1",
}