iPTF15eqv: Multi-wavelength exposé of a peculiar calcium-rich transient

Dan Milisavljevic, Daniel J. Patnaude, John C. Raymond, Maria R. Drout, Raffaella Margutti, Atish Kamble, Ryan Chornock, James Guillochon, Nathan E. Sanders, Jerod T. Parrent, Lorenzo Lovisari, Igor V. Chilingarian, Peter Challis, Robert P. Kirshner, Matthew T. Penny, Koichi Itagaki, J. J. Eldridge, Takashi J. Moriya

Research output: Contribution to journalArticlepeer-review

Abstract

The progenitor systems of the class of “Ca-rich transients” is a key open issue in time domain astrophysics. These intriguing objects exhibit unusually strong calcium line emissions months after explosion, fall within an intermediate luminosity range, are often found at large projected distances from their host galaxies, and may play a vital role in enriching galaxies and the intergalactic medium. Here we present multi-wavelength observations of iPTF15eqv in NGC 3430, which exhibits a unique combination of properties that bridge those observed in Ca-rich transients and Type Ib/c supernovae. iPTF15eqv has among the highest [Ca II]/[O I] emission line ratios observed to date, yet is more luminous and decays more slowly than other Ca-rich transients. Optical and near-infrared photometry and spectroscopy reveal signatures consistent with the supernova explosion of a ≲ 10 M⊙ star that was stripped of its H-rich envelope via binary interaction. Distinct chemical abundances and ejecta kinematics suggest that the core collapse occurred through electron capture processes. Deep limits on possible radio emission made with the Jansky Very Large Array imply a clean environment (n ≲ 0.1 cm3) within a radius of ∼ 1017 cm. Chandra X-ray Observatory observations rule out alternative scenarios involving tidal disruption of a white dwarf by a black hole, for masses > 100 M⊙. Our results challenge the notion that spectroscopically classified Ca-rich transients only originate from white dwarf progenitor systems, complicate the view that they are all associated with large ejection velocities, and indicate that their chemical abundances may vary widely between events.

Original languageEnglish (US)
JournalUnknown Journal
StatePublished - Jun 6 2017

Keywords

  • Galaxies: abundances
  • Line: identification
  • Stars: evolution
  • Supernovae: general
  • Supernovae: individual (iPTF15eqv, SN2005E)

ASJC Scopus subject areas

  • General

Fingerprint Dive into the research topics of 'iPTF15eqv: Multi-wavelength exposé of a peculiar calcium-rich transient'. Together they form a unique fingerprint.

Cite this