Black hole masses of tidal disruption event host galaxies

Thomas Wevers; Sjoert van Velzen; Peter G. Jonker; Nicholas C. Stone; Tiara Hung; Francesca Onori; Suvi Gezari; Nadejda Blagorodnova

doi:10.1093/MNRAS/STX1703

Black hole masses of tidal disruption event host galaxies

Thomas Wevers^*, Sjoert van Velzen, Peter G. Jonker, Nicholas C. Stone, Tiara Hung, Francesca Onori, Suvi Gezari, Nadejda Blagorodnova

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

91 Scopus citations

Abstract

The mass of the central black hole in a galaxy that hosted a tidal disruption event (TDE) is an important parameter in understanding its energetics and dynamics.We present the first homogeneously measured black hole masses of a complete sample of 12 optically/UV-selected TDE host galaxies (down to g_host ≤ 22 mag and z = 0.37) in the Northern sky. The mass estimates are based on velocity dispersion measurements, performed on late time optical spectroscopic observations. We find black hole masses in the range of 3 × 10⁵ M_⊙ ≤ M_BH ≤ 2 × 10⁷ M_⊙. The TDE host galaxy sample is dominated by low-mass black holes (~ 10⁶ M_⊙), as expected from theoretical predictions. The blackbody peak luminosity of TDEs with M_BH =≤10^7.1 M_⊙ is consistent with the Eddington limit of the supermassive black hole (SMBH), whereas the two TDEs with M_BH ≥ 10^7.1 M_⊙ have peak luminosities below their SMBH Eddington luminosity, in line with the theoretical expectation that the fallback rate for M_BH ≥ 10^7.1 M_⊙ is sub-Eddington. In addition, our observations suggest that TDEs around lower mass black holes evolve faster. These findings corroborate the standard TDE picture in 106 M_⊙ black holes. Our results imply an increased tension between observational and theoretical TDE rates. By comparing the blackbody emission radius with theoretical predictions, we conclude that the optical/UV emission is produced in a region consistent with the stream self-intersection radius of shallow encounters, ruling out a compact accretion disc as the direct origin of the blackbody radiation at peak brightness.

Original language	American English
Pages (from-to)	1694-1708
Number of pages	15
Journal	Monthly Notices of the Royal Astronomical Society
Volume	471
Issue number	2
DOIs	https://doi.org/10.1093/MNRAS/STX1703
State	Published - 2017
Externally published	Yes

Bibliographical note

Funding Information:
We would like to thank the anonymous referee for suggestions that improved the manuscript. TW wishes to thank D. Lena for assisting in the observing runs and is grateful to D. Lena and M. Torres for useful discussions. SvV is supported by NASA through a Hubble Fellowship (HSTHF2-51350). PGJ acknowledges support from European Research Council Consolidator Grant 647208. NCS acknowledges support through NASA from Einstein Postdoctoral Fellowship Award Number PF5-160145. The research leading to these results has received funding from the European Union's Horizon 2020 Programme under the AHEAD project (grant agreement no. 654215). SG is supported in part by NSF CAREER grant 1454816 and NASA Keck Grant 1568615. Part of this work was inspired by discussions within International Team #371 Using Tidal Disruption Events to Study Super-Massive Black Holes at the International Space Science Institute in Bern, Switzerland. We thank Tom Marsh for developing the software package MOLLY. TheWHT is operated on the island of La Palma by the Isaac Newton Group of Telescopes in the SpanishObservatorio del Roque de losMuchachos of the Instituto de Astrofisica de Canarias. The ISIS spectroscopy was obtained as part of programmes W15BN010 and W16AN007. Based on observations made with ESO Telescopes at the La Silla Paranal Observatory with the director's discretionary time, programme ID 297.B-5062(A) (P. I. Jonker). Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of theW. M. Keck Foundation. We wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community.We are most fortunate to have the opportunity to conduct observations from this mountain.

Publisher Copyright:
© 2017 The Authors.

Keywords

Accretion
Accretion discs
Galaxies: bulges
Galaxies: fundamental parameters
Galaxies: kinematics and dynamics
Galaxies: nuclei

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10.1093/MNRAS/STX1703

Cite this

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title = "Black hole masses of tidal disruption event host galaxies",

abstract = "The mass of the central black hole in a galaxy that hosted a tidal disruption event (TDE) is an important parameter in understanding its energetics and dynamics.We present the first homogeneously measured black hole masses of a complete sample of 12 optically/UV-selected TDE host galaxies (down to ghost ≤ 22 mag and z = 0.37) in the Northern sky. The mass estimates are based on velocity dispersion measurements, performed on late time optical spectroscopic observations. We find black hole masses in the range of 3 × 105 M⊙ ≤ MBH ≤ 2 × 107 M⊙. The TDE host galaxy sample is dominated by low-mass black holes (~ 106 M⊙), as expected from theoretical predictions. The blackbody peak luminosity of TDEs with MBH =≤107.1 M⊙ is consistent with the Eddington limit of the supermassive black hole (SMBH), whereas the two TDEs with MBH ≥ 107.1 M⊙ have peak luminosities below their SMBH Eddington luminosity, in line with the theoretical expectation that the fallback rate for MBH ≥ 107.1 M⊙ is sub-Eddington. In addition, our observations suggest that TDEs around lower mass black holes evolve faster. These findings corroborate the standard TDE picture in 106 M⊙ black holes. Our results imply an increased tension between observational and theoretical TDE rates. By comparing the blackbody emission radius with theoretical predictions, we conclude that the optical/UV emission is produced in a region consistent with the stream self-intersection radius of shallow encounters, ruling out a compact accretion disc as the direct origin of the blackbody radiation at peak brightness.",

keywords = "Accretion, Accretion discs, Galaxies: bulges, Galaxies: fundamental parameters, Galaxies: kinematics and dynamics, Galaxies: nuclei",

author = "Thomas Wevers and {van Velzen}, Sjoert and Jonker, {Peter G.} and Stone, {Nicholas C.} and Tiara Hung and Francesca Onori and Suvi Gezari and Nadejda Blagorodnova",

note = "Funding Information: We would like to thank the anonymous referee for suggestions that improved the manuscript. TW wishes to thank D. Lena for assisting in the observing runs and is grateful to D. Lena and M. Torres for useful discussions. SvV is supported by NASA through a Hubble Fellowship (HSTHF2-51350). PGJ acknowledges support from European Research Council Consolidator Grant 647208. NCS acknowledges support through NASA from Einstein Postdoctoral Fellowship Award Number PF5-160145. The research leading to these results has received funding from the European Union's Horizon 2020 Programme under the AHEAD project (grant agreement no. 654215). SG is supported in part by NSF CAREER grant 1454816 and NASA Keck Grant 1568615. Part of this work was inspired by discussions within International Team #371 Using Tidal Disruption Events to Study Super-Massive Black Holes at the International Space Science Institute in Bern, Switzerland. We thank Tom Marsh for developing the software package MOLLY. TheWHT is operated on the island of La Palma by the Isaac Newton Group of Telescopes in the SpanishObservatorio del Roque de losMuchachos of the Instituto de Astrofisica de Canarias. The ISIS spectroscopy was obtained as part of programmes W15BN010 and W16AN007. Based on observations made with ESO Telescopes at the La Silla Paranal Observatory with the director's discretionary time, programme ID 297.B-5062(A) (P. I. Jonker). Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of theW. M. Keck Foundation. We wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community.We are most fortunate to have the opportunity to conduct observations from this mountain. Publisher Copyright: {\textcopyright} 2017 The Authors.",

year = "2017",

doi = "10.1093/MNRAS/STX1703",

language = "American English",

volume = "471",

pages = "1694--1708",

journal = "Monthly Notices of the Royal Astronomical Society",

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T1 - Black hole masses of tidal disruption event host galaxies

AU - Wevers, Thomas

AU - van Velzen, Sjoert

AU - Jonker, Peter G.

AU - Stone, Nicholas C.

AU - Hung, Tiara

AU - Onori, Francesca

AU - Gezari, Suvi

AU - Blagorodnova, Nadejda

N1 - Funding Information: We would like to thank the anonymous referee for suggestions that improved the manuscript. TW wishes to thank D. Lena for assisting in the observing runs and is grateful to D. Lena and M. Torres for useful discussions. SvV is supported by NASA through a Hubble Fellowship (HSTHF2-51350). PGJ acknowledges support from European Research Council Consolidator Grant 647208. NCS acknowledges support through NASA from Einstein Postdoctoral Fellowship Award Number PF5-160145. The research leading to these results has received funding from the European Union's Horizon 2020 Programme under the AHEAD project (grant agreement no. 654215). SG is supported in part by NSF CAREER grant 1454816 and NASA Keck Grant 1568615. Part of this work was inspired by discussions within International Team #371 Using Tidal Disruption Events to Study Super-Massive Black Holes at the International Space Science Institute in Bern, Switzerland. We thank Tom Marsh for developing the software package MOLLY. TheWHT is operated on the island of La Palma by the Isaac Newton Group of Telescopes in the SpanishObservatorio del Roque de losMuchachos of the Instituto de Astrofisica de Canarias. The ISIS spectroscopy was obtained as part of programmes W15BN010 and W16AN007. Based on observations made with ESO Telescopes at the La Silla Paranal Observatory with the director's discretionary time, programme ID 297.B-5062(A) (P. I. Jonker). Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of theW. M. Keck Foundation. We wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community.We are most fortunate to have the opportunity to conduct observations from this mountain. Publisher Copyright: © 2017 The Authors.

PY - 2017

Y1 - 2017

N2 - The mass of the central black hole in a galaxy that hosted a tidal disruption event (TDE) is an important parameter in understanding its energetics and dynamics.We present the first homogeneously measured black hole masses of a complete sample of 12 optically/UV-selected TDE host galaxies (down to ghost ≤ 22 mag and z = 0.37) in the Northern sky. The mass estimates are based on velocity dispersion measurements, performed on late time optical spectroscopic observations. We find black hole masses in the range of 3 × 105 M⊙ ≤ MBH ≤ 2 × 107 M⊙. The TDE host galaxy sample is dominated by low-mass black holes (~ 106 M⊙), as expected from theoretical predictions. The blackbody peak luminosity of TDEs with MBH =≤107.1 M⊙ is consistent with the Eddington limit of the supermassive black hole (SMBH), whereas the two TDEs with MBH ≥ 107.1 M⊙ have peak luminosities below their SMBH Eddington luminosity, in line with the theoretical expectation that the fallback rate for MBH ≥ 107.1 M⊙ is sub-Eddington. In addition, our observations suggest that TDEs around lower mass black holes evolve faster. These findings corroborate the standard TDE picture in 106 M⊙ black holes. Our results imply an increased tension between observational and theoretical TDE rates. By comparing the blackbody emission radius with theoretical predictions, we conclude that the optical/UV emission is produced in a region consistent with the stream self-intersection radius of shallow encounters, ruling out a compact accretion disc as the direct origin of the blackbody radiation at peak brightness.

AB - The mass of the central black hole in a galaxy that hosted a tidal disruption event (TDE) is an important parameter in understanding its energetics and dynamics.We present the first homogeneously measured black hole masses of a complete sample of 12 optically/UV-selected TDE host galaxies (down to ghost ≤ 22 mag and z = 0.37) in the Northern sky. The mass estimates are based on velocity dispersion measurements, performed on late time optical spectroscopic observations. We find black hole masses in the range of 3 × 105 M⊙ ≤ MBH ≤ 2 × 107 M⊙. The TDE host galaxy sample is dominated by low-mass black holes (~ 106 M⊙), as expected from theoretical predictions. The blackbody peak luminosity of TDEs with MBH =≤107.1 M⊙ is consistent with the Eddington limit of the supermassive black hole (SMBH), whereas the two TDEs with MBH ≥ 107.1 M⊙ have peak luminosities below their SMBH Eddington luminosity, in line with the theoretical expectation that the fallback rate for MBH ≥ 107.1 M⊙ is sub-Eddington. In addition, our observations suggest that TDEs around lower mass black holes evolve faster. These findings corroborate the standard TDE picture in 106 M⊙ black holes. Our results imply an increased tension between observational and theoretical TDE rates. By comparing the blackbody emission radius with theoretical predictions, we conclude that the optical/UV emission is produced in a region consistent with the stream self-intersection radius of shallow encounters, ruling out a compact accretion disc as the direct origin of the blackbody radiation at peak brightness.

KW - Accretion

KW - Accretion discs

KW - Galaxies: bulges

KW - Galaxies: fundamental parameters

KW - Galaxies: kinematics and dynamics

KW - Galaxies: nuclei

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JO - Monthly Notices of the Royal Astronomical Society

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Black hole masses of tidal disruption event host galaxies

Abstract

Bibliographical note

Keywords

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