An Ultraviolet Spectrum of the Tidal Disruption Flare ASASSN-14li
Creators
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Cenko, S. Bradley1
- Cucchiara, Antonino2
- Roth, Nathaniel3
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Veilleux, Sylvain1
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Prochaska, J. Xavier4
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Yan, Lin5
- Guillochon, James6
- Maksym, W. Peter6, 7
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Arcavi, Iair8
- Butler, Nathaniel R.9
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Filippenko, Alexei V.3
- Fruchter, Andrew S.2
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Gezari, Suvi1
- Kasen, Daniel3, 10
- Levan, Andrew J.11
- Miller, Jon M.12
- Pasham, Dheeraj R.1
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Ramirez-Ruiz, Enrico4
- Strubbe, Linda E.13
- Tanvir, Nial R.14
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Tombesi, Francesco1, 15
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1.
University of Maryland, College Park
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2.
Space Telescope Science Institute
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3.
University of California, Berkeley
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4.
University of California, Santa Cruz
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5.
Infrared Processing and Analysis Center
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6.
Harvard-Smithsonian Center for Astrophysics
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7.
University of Alabama
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8.
Las Cumbres Observatory Global Telescope Network
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9.
Arizona State University
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10.
Lawrence Berkeley National Laboratory
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11.
University of Warwick
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12.
University of Michigan–Ann Arbor
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13.
University of British Columbia
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14.
University of Leicester
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15.
Goddard Space Flight Center
Abstract
We present a Hubble Space Telescope Space Telescope Imaging Spectrograph spectrum of ASASSN-14li, the first rest-frame ultraviolet (UV) spectrum of a tidal disruption flare (TDF). The underlying continuum is well fit by a blackbody with T_(UV) = 3.5 x 10^4 K, an order of magnitude smaller than the temperature inferred from X-ray spectra (and significantly more precise than previous efforts based on optical and near-UV photometry). Superimposed on this blue continuum, we detect three classes of features: narrow absorption from the Milky Way (probably a high-velocity cloud), and narrow absorption and broad (~2000–8000 km s^(−1)) emission lines at or near the systemic host velocity. The absorption lines are blueshifted with respect to the emission lines by Δv = −(250–400) km s^(−1). Due both to this velocity offset and the lack of common low-ionization features (Mg ii, Fe ii), we argue these arise from the same absorbing material responsible for the low-velocity outflow discovered at X-ray wavelengths. The broad nuclear emission lines display a remarkable abundance pattern: N iii], N iv], and He ii are quite prominent, while the common quasar emission lines of C iii] and Mg ii are weak or entirely absent. Detailed modeling of this spectrum will help elucidate fundamental questions regarding the nature of the emission processes at work in TDFs, while future UV spectroscopy of ASASSN-14li would help to confirm (or refute) the previously proposed connection between TDFs and "N-rich" quasars.
Additional Information
© 2016 American Astronomical Society. Received 2016 January 12; accepted 2016 February 2; published 2016 February 18. We thank R. Chornock, M. Eracleous, P. Hall, and C. Kochanek for valuable discussions, and the HST staff for the prompt scheduling of these ToO observations. S.B.C. acknowledges the Aspen Center for Physics and NSF Grant #1066293 for hospitality. AVF's research was funded by NSF grant AST-1211916, the TABASGO Foundation, and the Christopher R. Redlich Fund. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Data Archive at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. Facility: HST (STIS) - .Attached Files
Published - Cenko_2016pL32.pdf
Submitted - 1601.03331v2.pdf
Files
1601.03331v2.pdf
Additional details
Identifiers
- Eprint ID
- 65332
- Resolver ID
- CaltechAUTHORS:20160314-095808701
Related works
- Describes
- http://arxiv.org/abs/1601.03331 (URL)
Funding
- NSF
- PHY-1066293
- NSF
- AST-1211916
- TABASGO Foundation
- Christopher R. Redlich Fund
- NASA
- NAS 5-26555
Dates
- Created
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2016-03-14Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field
Caltech Custom Metadata
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)