@article{0fd179db039f4b8d9d0154a19983accc,
title = "Measuring Supermassive Black Hole Peculiar Motion Using H2O Megamasers",
abstract = "H2O megamasers residing in the accretion disks of active galactic nuclei (AGNs) exhibit Keplerian rotation about the central supermassive black hole (SMBH). Such disk maser systems are excellent tools for diagnosing the kinematic status of the SMBH, and they currently provide the only direct and unambiguous measure of SMBH velocities outside the Milky Way. We have measured the galaxy recession velocities for a sample of 10 maser disk systems using a combination of spatially resolved H i disk modeling, spatially integrated H i profile fitting, and optical spectral line and continuum fitting. In comparing the SMBH velocities to those of their host galaxies, we find two (out of 10) systems - J0437+2456 and NGC 6264 - for which the SMBH and galaxy velocities show a statistically significant (>3σ) difference. For NGC 6264 the apparent velocity offset can likely be explained by ionized gas motion within the host galaxy (e.g., from AGN-driven shocks). The velocity measurements for J0437+2456, however, imply a SMBH peculiar velocity of 69.6 ± 12.7 km s-1 (5.5σ). We thus consider J0437+2456 to be a promising candidate for hosting either a recoiling or binary SMBH, though additional observations are necessary to exclude the possibility of a systematic offset between the galactic recession velocity and that measured using the optical spectrum.",
keywords = "galaxies: active, galaxies: nuclei, masers, quasars: supermassive black holes",
author = "Pesce, {D. W.} and Braatz, {J. A.} and Condon, {J. J.} and Greene, {J. E.}",
note = "Funding Information: We acknowledge Shane Davis, Aaron Evans, Jackie Huband, Remy Indebetouw, Cheng-Yu Kuo, Scott Suriano, Nick Troup, Mark Whittle, and Haifeng Yang for many helpful discussions, and Lucas Macri for re-running the 2MRS radial velocity code on their spectrum of J0437+2456. We also thank the anonymous referee for comments that improved the quality of the paper. Support for this work was provided by the NSF through the Grote Reber Fellowship Program administered by Associated Universities, Inc./National Radio Astronomy Observatory. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. This research has made use of the NED, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. Funding Information: Funding for SDSS-III has been 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/. Funding Information: The PanSTARRS1 Surveys (PS1) and the PS1 public science archive have been made possible through contributions by the Institute for Astronomy, the University of Hawaii, the PanSTARRS Project Office, the Max Planck Society and its participating institutes, the Max Planck Institute for Astronomy, Heidelberg and the Max Planck Institute for Extraterrestrial Physics, Garching, The Johns Hopkins University, Durham University, the University of Edinburgh, the Queen{\textquoteright}s University Belfast, the Harvard-Smithsonian Center for Astrophysics, the Las Cumbres Observatory Global Telescope Network Inc., the National Central University of Taiwan, the Space Telescope Science Institute, the National Aeronautics and Space Administration under Grant No. NNX08AR22G issued through the Planetary Science Division of the NASA Science Mission Directorate, the National Science Foundation Grant No. AST-1238877, the University of Maryland, Eotvos Lorand University (ELTE), the Los Alamos National Laboratory, and the Gordon and Betty Moore Foundation. Funding Information: This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. Funding Information: This publication makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, and NEO-WISE, which is a project of the Jet Propulsion Laboratory/ California Institute of Technology. Wide-field Infrared Survey Explorer (WISE) and NEOWISE are funded by the National Aeronautics and Space Administration. Facility: VLA. Software: CASA.",
year = "2018",
month = aug,
day = "20",
doi = "10.3847/1538-4357/aad3c2",
language = "English (US)",
volume = "863",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "2",
}