A Mildly Relativistic Outflow from the Energetic, Fast-rising Blue Optical Transient CSS161010 in a Dwarf Galaxy
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Author
Coppejans, D. L.Margutti, R.

Terreran, G.
Nayana, A. J.
Coughlin, E. R.
Laskar, T.

Alexander, K. D.
Bietenholz, M.

Caprioli, D.
Chandra, P.
Drout, M. R.
Frederiks, D.
Frohmaier, C.
Hurley, K. H
Kochanek, C. S.
MacLeod, M.
Meisner, A.
Nugent, P. E.
Ridnaia, A.
Sand, D. J.
Svinkin, D.
Ward, C.
Yang, S.
Baldeschi, A.
Chilingarian, I. V.
Dong, Y.
Esquivia, C.
Fong, W.

Guidorzi, C.
Lundqvist, P.

Milisavljevic, D.
Paterson, K.
Reichart, D. E.
Shappee, B.
Stroh, M. C.
Valenti, S.

Zauderer, B. A.

Zhang, B.
Affiliation
Univ Arizona, Steward ObservIssue Date
2020-05-26
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Coppejans, D. L., Margutti, R., Terreran, G., Nayana, A. J., Coughlin, E. R., Laskar, T., ... & Zhang, B. (2020). A mildly relativistic outflow from the energetic, fast-rising Blue Optical Transient CSS161010 in a dwarf galaxy. The Astrophysical Journal Letters, 895(1), L23.Journal
ASTROPHYSICAL JOURNAL LETTERSRights
© 2020. The American Astronomical Society. All rights reserved.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
We present X-ray and radio observations of the Fast Blue Optical Transient CRTS-CSS161010 J045834-081803 (CSS161010 hereafter) at t = 69-531 days. CSS161010 shows luminous X-ray (L-x similar to 5 x 10(39) erg s(-1)) and radio (L-nu similar to 10(29) erg s(-1) Hz(-1)) emission. The radio emission peaked at similar to 100 days post-transient explosion and rapidly decayed. We interpret these observations in the context of synchrotron emission from an expanding blast wave. CSS161010 launched a mildly relativistic outflow with velocity Gamma beta c >= 0.55c at similar to 100 days. This is faster than the non-relativistic AT 2018cow (Gamma beta c similar to 0.1c) and closer to ZTF18abvkwla (Gamma beta c >= 0.3c at 63 days). The inferred initial kinetic energy of CSS161010 (E-k greater than or similar to 10(51) erg) is comparable to that of long gamma-ray bursts, but the ejecta mass that is coupled to the mildly relativistic outflow is significantly larger (similar to 0.01-.1 M-circle dot). This is consistent with the lack of observed gamma-rays. The luminous X-rays were produced by a different emission component to the synchrotron radio emission. CSS161010 is located at similar to 150 Mpc in a dwarf galaxy with stellar mass M-* similar to 10(7) M-circle dot and specific star formation rate sSFR similar to 0.3 Gyr(-1). This mass is among the lowest inferred for host galaxies of explosive transients from massive stars. Our observations of CSS161010 are consistent with an engine-driven aspherical explosion from a rare evolutionary path of a H-rich stellar progenitor, but we cannot rule out a stellar tidal disruption event on a centrally located intermediate-mass black hole. Regardless of the physical mechanism, CSS161010 establishes the existence of a new class of rare (rate < 0.4% of the local core-collapse supernova rate) H-rich transients that can launch mildly relativistic outflows.ISSN
2041-8205EISSN
2041-8213Version
Final published versionSponsors
National Aeronautics and Space Administrationae974a485f413a2113503eed53cd6c53
10.3847/2041-8213/ab8cc7