Journal article
Double-peaked Balmer Emission Indicating Prompt Accretion Disk Formation in an X-Ray Faint Tidal Disruption Event
Tiara Hung, Ryan J Foley, Enrico Ramirez-Ruiz, Jane L Dai, Katie Auchettl, Charles D Kilpatrick, Brenna Mockler, Jonathan S Brown, David A Coulter, Georgios Dimitriadis, Thomas W-S Holoien, Jamie AP Law-Smith, Anthony L Piro, Armin Rest, Cesar Rojas-Bravo, Matthew R Siebert
ASTROPHYSICAL JOURNAL | IOP PUBLISHING LTD | Published : 2020
Abstract
We present the multiwavelength analysis of the tidal disruption event (TDE) AT 2018hyz (ASASSN-18zj). From follow-up optical spectroscopy, we detect the first unambiguous case of resolved double-peaked Balmer emission in a TDE. The distinct line profile can be well-modeled by a low eccentricity (e ≈ 0.1) accretion disk extending out to ~100 Rp and a Gaussian component originating from non-disk clouds, though a bipolar outflow origin cannot be completely ruled out. Our analysis indicates that in AT 2018hyz, disk formation took place promptly after the most-bound debris returned to pericenter, which we estimate to be roughly tens of days before the first detection. Redistribution of angular mo..
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Grants
Awarded by NSF
Awarded by NASA/Swift grant
Awarded by Danish National Research Foundation
Awarded by GRF grant from the Hong Kong Government
Awarded by National Science Foundation Graduate Research Fellowship Program
Awarded by Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D)
Funding Acknowledgements
T.H. thanks Prof. Michael Eracleous for discussion on numerical concerns when implementing the elliptical-disk model, Dr. Qian Wang for numerical and algorithmic advice to greatly speed up computation, and Dr. Martin Gaskell for discussion on the absorption and emission features in the spectra. The authors would like to thank the anonymous referee for suggestions that greatly improved the clarity of the paper. 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. K.A.A., J.L.S., E.R.-R., and B.M. are supported by the Danish National Research Foundation (DNRF132), the Heising-Simons Foundation, and NSF grant AST-161588. J.L.D. is supported by the GRF grant from the Hong Kong Government under HKU 27305119. M.R.S. is supported by the National Science Foundation Graduate Research Fellowship Program Under grant No. 1842400.Parts of this research were supported by the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), through project number CE170100013.Research at the Lick Observatory is partially supported by a generous gift from Google.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 the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.