TY - JOUR
T1 - Live to Die Another Day
T2 - The Rebrightening of AT 2018fyk as a Repeating Partial Tidal Disruption Event
AU - Wevers, T.
AU - Coughlin, E. R.
AU - Pasham, D. R.
AU - Guolo, M.
AU - Sun, Y.
AU - Wen, S.
AU - Jonker, P. G.
AU - Zabludoff, A.
AU - Malyali, A.
AU - Arcodia, R.
AU - Liu, Z.
AU - Merloni, A.
AU - Rau, A.
AU - Grotova, I.
AU - Short, P.
AU - Cao, Z.
N1 - Funding Information:
We thank the anonymous referee for thoughtful comments and suggestions that helped to improve the manuscript. We thank the XMM, Swift, and NICER PIs (Norbert Schartel, Bradley Cenko, and Keith Gendreau) and their operations teams for approving and promptly scheduling the requested observations. We warmly thank M.I. Saladino for help in creating Figure . E.R.C. thanks Chris Nixon for useful discussions and acknowledges support from the National Science Foundation through grant AST-2006684 and the Oakridge Associated Universities through a Ralph E. Powe Junior Faculty Enhancement Award. Raw optical/UV/X-ray observations are available in the NASA/Swift archive ( http://heasarc.nasa.gov/docs/swift/archive ; target names: AT 2018fyk, ASASSN-18UL) and XMM-Newton Science Archive ( http://nxsa.esac.esa.int ; ObsID: 0911790601, 0911791601); NICER data are publicly available through the HEASARC: https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3browse.pl . Based on observations collected at the European Southern Observatory under ESO programs 0103.D-0440(B) and 0106.21SS.
Funding Information:
This work is based on data from eROSITA, the soft X-ray instrument on board SRG, a joint Russian–German science mission supported by the Russian Space Agency (Roskosmos), in the interests of the Russian Academy of Sciences represented by its Space Research Institute (IKI), and the Deutsches Zentrum für Luft- und Raumfahrt (DLR). The SRG spacecraft was built by Lavochkin Association (NPOL) and its subcontractors and is operated by NPOL with support from the Max Planck Institute for Extraterrestrial Physics (MPE).
Funding Information:
We thank the anonymous referee for thoughtful comments and suggestions that helped to improve the manuscript. We thank the XMM, Swift, and NICER PIs (Norbert Schartel, Bradley Cenko, and Keith Gendreau) and their operations teams for approving and promptly scheduling the requested observations. We warmly thank M.I. Saladino for help in creating Figure 4. E.R.C. thanks Chris Nixon for useful discussions and acknowledges support from the National Science Foundation through grant AST-2006684 and the Oakridge Associated Universities through a Ralph E. Powe Junior Faculty Enhancement Award. Raw optical/UV/X-ray observations are available in the NASA/Swift archive (http://heasarc.nasa.gov/docs/swift/archive; target names: AT 2018fyk, ASASSN-18UL) and XMM-Newton Science Archive (http://nxsa.esac.esa.int; ObsID: 0911790601, 0911791601); NICER data are publicly available through the HEASARC: https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3browse.pl. Based on observations collected at the European Southern Observatory under ESO programs 0103.D-0440(B) and 0106.21SS.
Publisher Copyright:
© 2023. The Author(s). Published by the American Astronomical Society.
PY - 2023/1/1
Y1 - 2023/1/1
N2 - Stars that interact with supermassive black holes (SMBHs) can be either completely or partially destroyed by tides. In a partial tidal disruption event (TDE), the high-density core of the star remains intact, and the low-density outer envelope of the star is stripped and feeds a luminous accretion episode. The TDE AT 2018fyk, with an inferred black hole mass of 107.7±0.4 M ⊙, experienced an extreme dimming event at X-ray (factor of >6000) and UV (factor of ∼15) wavelengths ∼500-600 days after discovery. Here we report on the reemergence of these emission components roughly 1200 days after discovery. We find that the source properties are similar to those of the predimming accretion state, suggesting that the accretion flow was rejuvenated to a similar state. We propose that a repeated partial TDE, where the partially disrupted star is on an ∼1200 day orbit about the SMBH and periodically stripped of mass during each pericenter passage, powers its unique light curve. This scenario provides a plausible explanation for AT 2018fyk’s overall properties, including the rapid dimming event and the rebrightening at late times. We also provide testable predictions for the behavior of the accretion flow in the future; if the second encounter was also a partial disruption, then we predict another strong dimming event around day 1800 (2023 August) and a subsequent rebrightening around day 2400 (2025 March). This source provides strong evidence of the partial disruption of a star by an SMBH.
AB - Stars that interact with supermassive black holes (SMBHs) can be either completely or partially destroyed by tides. In a partial tidal disruption event (TDE), the high-density core of the star remains intact, and the low-density outer envelope of the star is stripped and feeds a luminous accretion episode. The TDE AT 2018fyk, with an inferred black hole mass of 107.7±0.4 M ⊙, experienced an extreme dimming event at X-ray (factor of >6000) and UV (factor of ∼15) wavelengths ∼500-600 days after discovery. Here we report on the reemergence of these emission components roughly 1200 days after discovery. We find that the source properties are similar to those of the predimming accretion state, suggesting that the accretion flow was rejuvenated to a similar state. We propose that a repeated partial TDE, where the partially disrupted star is on an ∼1200 day orbit about the SMBH and periodically stripped of mass during each pericenter passage, powers its unique light curve. This scenario provides a plausible explanation for AT 2018fyk’s overall properties, including the rapid dimming event and the rebrightening at late times. We also provide testable predictions for the behavior of the accretion flow in the future; if the second encounter was also a partial disruption, then we predict another strong dimming event around day 1800 (2023 August) and a subsequent rebrightening around day 2400 (2025 March). This source provides strong evidence of the partial disruption of a star by an SMBH.
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UR - http://www.scopus.com/inward/citedby.url?scp=85146393160&partnerID=8YFLogxK
U2 - 10.3847/2041-8213/ac9f36
DO - 10.3847/2041-8213/ac9f36
M3 - Article
AN - SCOPUS:85146393160
SN - 2041-8205
VL - 942
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 2
ER -