Seventeen tidal disruption events from the first half of ZTF survey observations: Entering a new Era of population studies

Sjoert Van Velzen, Suvi Gezari, Erica Hammerstein, Nathaniel Roth, Sara Frederick, Charlotte Ward, Tiara Hung, S. Bradley Cenko, Robert Stein, Daniel A. Perley, Kirsty Taggart, Ryan J. Foley, Jesper Sollerman, Nadejda Blagorodnova, Igor Andreoni, Eric C. Bellm, Valery Brinnel, Kishalay De, Richard Dekany, Michael FeeneyChristoffer Fremling, Matteo Giomi, V. Zach Golkhou, Matthew J. Graham, Anna Y.Q. Ho, Mansi M. Kasliwal, Charles D. Kilpatrick, Shrinivas R. Kulkarni, Thomas Kupfer, Russ R. Laher, Ashish Mahabal, Frank J. Masci, Adam A. Miller, Jakob Nordin, Reed Riddle, Ben Rusholme, Jakob Van Santen, Yashvi Sharma, David L. Shupe, Maayane T. Soumagnac

Research output: Contribution to journalArticlepeer-review

48 Scopus citations


While tidal disruption events (TDEs) have long been heralded as laboratories for the study of quiescent black holes, the small number of known TDEs and uncertainties in their emission mechanism have hindered progress toward this promise. Here we present 17 new TDEs that have been detected recently by the Zwicky Transient Facility along with Swift UV and X-ray follow-up observations. Our homogeneous analysis of the optical/UV light curves, including 22 previously known TDEs from the literature, reveals a clean separation of light-curve properties with spectroscopic class. The TDEs with Bowen fluorescence features in their optical spectra have smaller blackbody radii, lower optical luminosities, and higher disruption rates compared to the rest of the sample. The small subset of TDEs that show only helium emission lines in their spectra have the longest rise times, the highest luminosities, and the lowest rates. A high detection rate of Bowen lines in TDEs with small photometric radii could be explained by the high density that is required for this fluorescence mechanism. The stellar debris can provide a source for this dense material. Diffusion of photons through this debris may explain why the rise and fade timescale of the TDEs in our sample are not correlated. We also report, for the first time, the detection of soft X-ray flares from a TDE on ~day timescales. Based on the fact that the X-ray flares peak at a luminosity similar to the optical/UV blackbody luminosity, we attribute them to brief glimpses through a reprocessing layer that otherwise obscures the inner accretion flow.

Original languageEnglish
Article numberabc258
JournalAstrophysical Journal
Issue number1
StatePublished - 10 Feb 2021
Externally publishedYes

Bibliographical note

Funding Information:
S.v.V. is supported by the James Arthur Postdoctoral Fellowship. S.G. is supported in part by NSF CAREER grant 1454816 and NSF AAG grant 1616566. N.R. acknowledges the support of a Joint Space-Science Institute prize postdoctoral fellowship. This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement No. 759194 - USNAC). A. Y.Q.H. is supported by a National Science Foundation Graduate Research Fellowship under grant No. DGE-1144469. This work was supported by the GROWTH project funded by the National Science Foundation under PIRE grant No. 1545949. C.F. gratefully acknowledges support of his research by the Heising- Simons Foundation (#2018-0907). The UCSC transient team is supported in part by NSF grant AST-1518052, NASA/Swift grant 80NSSC19K1386, the Gordon & Betty Moore Foundation, the Heising-Simons Foundation, and by a fellowship from the David and Lucile Packard Foundation to R.J.F.

Publisher Copyright:
© 2021. The American Astronomical Society. All rights reserved.


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