Luminous Radio Emission from the Superluminous Supernova 2017ens at 3.3 Yr After Explosion

Authors

Raffaella Margutti, University of California
J. S. Bright, University of California
D. J. Matthews, University of California
D. L. Coppejans, University of Warwick
K. D. Alexander, Steward Observatory
E. Berger, Harvard & Smithsonian
M. Bietenholz, South African Radio Astronomy Observatory
R. Chornock, University of California
L. DeMarchi, Boise State University
M. R. Drout, University of Toronto
T. Eftekhari, Northwestern University
W. V. Jacobson-Galán, University of California
T. Laskar, University of Utah
D. Milisavljevic, Purdue University
K. Murase, Pennsylvania State University
M. Nicholl, Queens University Belfast
C. M. B. Omand, Stockholm University, AlbaNova
M. Stroh, Northwestern University
G. Terreran, Las Cumbres Observatory
B. A. VanderLey, National Science Foundation

Document Type

Article

Publication Date

9-10-2023

Abstract

We present the results from a multiyear radio campaign of the superluminous supernova (SLSN) SN 2017ens, which yielded the earliest radio detection of an SLSN to date at the age of ∼3.3 yr after explosion. SN 2017ens was not detected at radio frequencies in the first ∼300 days but reached L_ν ≈ 10²⁸ erg s⁻¹ cm⁻² Hz⁻¹ at ν ∼ 6 GHz, ∼1250 days post explosion. Interpreting the radio observations in the context of synchrotron radiation from the supernova shock interaction with the circumstellar medium (CSM), we infer an effective mass-loss rate Ṁ ≈ 10⁻⁴ M_☉ yr⁻¹ at r ∼ 10¹⁷ cm from the explosion's site, for a wind speed of v_w = 50–60 km s⁻¹ as measured from optical spectra. These findings are consistent with the spectroscopic metamorphosis of SN 2017ens from hydrogen poor to hydrogen rich ∼190 days after explosion reported by Chen et al. SN 2017ens is thus an addition to the sample of hydrogen-poor massive progenitors that explode shortly after having lost their hydrogen envelope. The inferred circumstellar densities, implying a CSM mass up to ∼0.5 M_☉, and low velocity of the ejection suggest that binary interactions (in the form of common-envelope evolution and subsequent envelope ejection) play a role in shaping the evolution of the stellar progenitors of SLSNe in the ≲ 500 yr preceding core collapse.

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This work is licensed under a Creative Commons Attribution 4.0 International License.

Publication Information

Margutti, Raffaella; Bright, J. S.; Matthews, D. J.; Coppejans, D. L.; Alexander, K. D.; Berger, E.; . . . and VanderLey, B. A. (2023). "Luminous Radio Emission from the Superluminous Supernova 2017ens at 3.3 Yr After Explosion". The Astrophysical Journal Letters, 954(2), L45. https://doi.org/10.3847/2041-8213/acf1fd