The case of AT2022wtn: a tidal disruption event in an interacting galaxy

ABSTRACT We present the results from our multiwavelength monitoring campaign of the transient AT 2022wtn, discovered by the Zwicky Transient Facility in the nucleus of SDSS J232323.79 + 104107.7, the less-massive galaxy in an active merging pair with a mass ratio of $\sim$10:1. AT 2022wtn shows spectroscopic and photometric properties consistent with a X-ray faint N-strong TDE-H + He with a number of peculiarities. Specifically, a 30-d long plateau at maximum luminosity, a corresponding dip in temperature and the development of a double-horned N iii + He ii line profile. Strong and time-evolving velocity offsets in the tidal disruption event (TDE) broad emission lines and the detection of a transient radio emission, indicate the presence of outflows. Overall, the observed properties are consistent with the full disruption of a low-mass star by a $\sim 10^{6}$ M$_{\odot }$ supermassive black hole followed by an efficient disc formation and the launch of a quasi-spherical reprocessing envelope of fast expanding outflowing material. The observed differences between the He ii and the Hydrogen and N iii lines can be explained either with a spatial separation of the lines emitting region or with a late-time reveal of shocks from the returning debris streams, as the photosphere recedes. Finally, we present an extensive analysis of the hosting environment and discuss the implications for the discovery of two TDEs in interacting galaxy pairs, finding indication for an over-representation of TDEs in these systems. The AT 2022wtn host galaxy properties suggest that it is in the early stages of the merger, therefore we may be witnessing the initial enhanced rate of TDEs in interacting galaxies before the post-starburst phase.

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Journal
Monthly Notices of the Royal Astronomical Society
Published
2025-05-08
DOI
https://doi.org/10.1093/mnras/staf746
Citations
4
Primary Topic
Astronomy and Astrophysical Research
Type
article
Field-Weighted Citation Impact
4.77

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article

The case of AT2022wtn: a tidal disruption event in an interacting galaxy

Erica Hammerstein, E. Kankare, J. P. Anderson, T. Wevers et al.
4 citations
Monthly Notices of the Royal Astronomical Society
Astronomy and Astrophysical Research
4.77
article

The case of AT2022wtn: a tidal disruption event in an interacting galaxy

Erica Hammerstein, E. Kankare, J. P. Anderson, T. Wevers, G. Pignata, M. Bronikowski, P. Ramsden, E. Brocato, M. Gromadzki, T. E. Müller-Bravo, D. Flammini, R. Roy, S. González–Gaitán, J. Farah, D. R. Young, Yuhan Yao, F. Onori, Robert Stein, I. Arcavi, S. Mattila, K-Ryan Hinds, P. Clark, T. Reynolds, S. Piranomonte, L. Makrygianni, Sean McGee, Amit Kumar, S. B. Cenko, K. C. Chambers, C. P. Gutiérrez, M. Nicholl, Wenxiong Li, K. Matilainen, C. Inserra, Yanan Wang, T. W. Chen, T. Petrushevska, E. Concepcion
article en
4 citations

Abstract

ABSTRACT We present the results from our multiwavelength monitoring campaign of the transient AT 2022wtn, discovered by the Zwicky Transient Facility in the nucleus of SDSS J232323.79 + 104107.7, the less-massive galaxy in an active merging pair with a mass ratio of $\sim$10:1. AT 2022wtn shows spectroscopic and photometric properties consistent with a X-ray faint N-strong TDE-H + He with a number of peculiarities. Specifically, a 30-d long plateau at maximum luminosity, a corresponding dip in temperature and the development of a double-horned N iii + He ii line profile. Strong and time-evolving velocity offsets in the tidal disruption event (TDE) broad emission lines and the detection of a transient radio emission, indicate the presence of outflows. Overall, the observed properties are consistent with the full disruption of a low-mass star by a $\sim 10^{6}$ M$_{\odot }$ supermassive black hole followed by an efficient disc formation and the launch of a quasi-spherical reprocessing envelope of fast expanding outflowing material. The observed differences between the He ii and the Hydrogen and N iii lines can be explained either with a spatial separation of the lines emitting region or with a late-time reveal of shocks from the returning debris streams, as the photosphere recedes. Finally, we present an extensive analysis of the hosting environment and discuss the implications for the discovery of two TDEs in interacting galaxy pairs, finding indication for an over-representation of TDEs in these systems. The AT 2022wtn host galaxy properties suggest that it is in the early stages of the merger, therefore we may be witnessing the initial enhanced rate of TDEs in interacting galaxies before the post-starburst phase.

Monthly Notices of the Royal Astronomical SocietyVol. 540(1)
National Agency for New Technologies, Energy and Sustainable Economic Development (IT), California Institute of Technology (US), University of Copenhagen (DK), Queen's University Belfast (GB), Las Cumbres Observatory Global Telescope Network (US), Space Telescope Science Institute (US), Goddard Space Flight Center (US), Institute of Space Sciences (ES), University of Hawaii System (US), University of Lisbon (PT), University of California, Santa Barbara (US), University of Turku (FI), Tel Aviv University (IL), Manipal Academy of Higher Education (IN), Royal Holloway University of London (GB), University of Tarapacá (CL), University of Nova Gorica (SI), Chinese Academy of Sciences (CN), European University Cyprus (CY), National Central University (TW), Astronomical Observatory of Rome (IT), Miller College (US), Dawn Research (United States) (US), Institute of Astrophysics and Space Sciences (PT), Institut d'Estudis Espacials de Catalunya (ES), Millennium Institute of Astrophysics (CL), Queens University (BD), DAWN Center for Independent Living (US), Joint Space Science Institute (US), Université Bourgogne Franche-Comté (FR), Institute of Astronomy (RU), Collurania Teramo Observatory (IT), European Southern Observatory (CL), Astronomical Observatory (RS), National Astronomical Observatories (CN), Deleted Institution, University of Warsaw (PL), University of Portsmouth (GB), Liverpool John Moores University (GB), University of Maryland, College Park (US), Lancaster University (GB), Cardiff University (GB), University of Birmingham (GB), University of California, Berkeley (US), Universitat Politècnica de Catalunya (ES)
National Science Foundation, National Aeronautics and Space Administration, Yale University, California Institute of Technology, Northern Arizona University, Space Telescope Science Institute, European Commission, Queen's University Belfast, National Research Foundation, Danmarks Grundforskningsfond, United States-Israel Binational Science Foundation, Generalitat de Catalunya, Queen's University, Ministero dell’Istruzione, dell’Università e della Ricerca, Nuclear Safety and Security Commission, Liverpool John Moores University, Javna Agencija za Raziskovalno Dejavnost RS, Ministry of Education, India, Ministerio de Ciencia e Innovación, PAZY Foundation, Agencia Nacional de Investigación y Desarrollo, Goddard Space Flight Center, Science and Technology Facilities Council, Agencia Estatal de Investigación
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Astronomy and Astrophysical Research
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