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Published December 4, 2015 | Submitted
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The Double Peaked SN2013ge: a Type Ib/c SN with an Early Asymmetric Mass Ejection or an Extended Progenitor Envelope


We present extensive multiwavelength (radio to X-ray) observations of the Type Ib/c SN2013ge from −13 to +457 days relative to maximum light, including a series of optical spectra and Swift UV-optical photometry beginning 2 − 4 days post explosion. This makes SN2013ge one of the best observed normal Type Ib/c SN at early times, when the light curve is particularly sensitive to the progenitor configuration and mixing of radioactive elements. These early observations reveal two distinct light curve components in the UV bands. The first component rises over 4 − 5 days and is visible for the first week post-explosion. Spectra of the first component have a blue continuum and show a plethora of high velocity (~ 14,000 km s^(−1)) but narrow (~ 3500 km s^(−1)) spectroscopic features, indicating that the line forming region is restricted. The explosion parameters estimated for the bulk explosion (M_(ej) ~ 2 − 3 M_⊙; EK ~ 1 − 2 × 10^(51) ergs) are standard for Type Ib/c SN, while detailed analysis of optical and NIR spectra identify weak He features at early times (in an object which would have otherwise been classified as Type Ic), and nebular spectra show evidence for mixing and asymmetry in the bulk ejecta. In addition, SN2013ge exploded in a low metallicity environment (~ 0.5 Z_⊙) and we have obtained some of the deepest radio and X-ray limits for a Type Ib/c SN to date that constrain the progenitor mass-loss rate to be M < 4 × 10^(−6) M_⊙ yr^(−1). We are left with two distinct progenitor scenarios for SN2013ge depending on our interpretation of the early emission. If the first component is cooling envelope emission, then the progenitor of SN2013ge possessed a low-mass extended (≳ 30 R_⊙) envelope. Alternatively, if the first component is due to outwardly mixed 56Ni then our observations are consistent with the asymmetric ejection of a small amount of mass (~ 0.05 M_⊙) ahead of the bulk explosion. Current models for the collision of a SN shock with a binary companion cannot reproduce both the timescale and luminosity of the early emission in SN2013ge. Finally, we find that the spectra of the first component of SN2013ge are similar to those of the rapidly-declining SN2002bj.

Additional Information

M. R. D. thanks L. Z. Kelley, D. Kasen, and E. Ramirez-Ruiz for useful discussions regarding this manuscript. We thank N. Morrell for obtaining some of the observations reported here. M. R. D. is supported in part by the NSF Graduate Research Fellowship. M.L.G.s position in the supernova research group at U.C. Berkeley is supported by Gary and Cynthia Bengier and NSF grant AST-1211916. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile. Some observations reported here were obtained at the MMT observatory, a joint facility of the Smithsonian Institution and the University of Arizona. This paper uses data taken with the MODS spectrographs built with funding from NSF grant AST-9987045 and the NSF Telescope System Instrumentation Program(TSIP), with additional funds from the Ohio Board of Regents and the Ohio State University Office of Research. Facilities: Swift -UVOT, Magellan:Baade (IMACS, FIRE), Magellan:Clay (LDSS3), MMT (Blue Channel spectrograph, Hectospec, MMTCam), LBT (MODS), CAO, FLWO (FAST, KeplerCam), Chandra, VLA, Lick:Shane (Kast), MDM (OSMOS)

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August 22, 2023
August 22, 2023