SDWFS-MT-1: A Self-Obscured Luminous Supernova At z ~= 0.2
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Date
2010-10-20
Journal Title
Journal ISSN
Volume Title
Publisher
American Astronomical Society
Abstract
We report the discovery of a 6 month long mid-infrared transient, SDWFS-MT-1 (aka SN 2007va), in the Spitzer Deep, Wide-Field Survey of the NOAO Deep Wide-Field Survey Boötes field. The transient, located in a z = 0.19 low-luminosity (M_[4.5] ~= –18.6 mag, L/L star ~= 0.01) metal-poor (12 + log(O/H) ~= 7.8) irregular galaxy, peaked at a mid-infrared absolute magnitude of M_[4.5] ~= –24.2 in the 4.5 μm Spitzer/IRAC band and emitted a total energy of at least 1051 erg. The optical emission was likely fainter than the mid-infrared, although our constraints on the optical emission are poor because the transient peaked when the source was "behind" the Sun. The Spitzer data are consistent with emission by a modified blackbody with a temperature of ~1350 K. We rule out a number of scenarios for the origin of the transient such as a Galactic star, active galactic nucleus activity, γ-ray burst, tidal disruption of a star by a black hole, and gravitational lensing. The most plausible scenario is a supernova (SN) exploding inside a massive, optically thick circumstellar medium, composed of multiple shells of previously ejected material. If the proposed scenario is correct, then a significant fraction (~10%) of the most luminous SN may be self-enshrouded by dust not only before but also after the SN occurs. The spectral energy distribution of the progenitor of such an SN would be a slightly cooler version of η Carinae peaking at 20-30 μm.
Description
Keywords
galaxies: irregular, infrared: galaxies, supernovae: general, supernovae: individual (SDWFS-MT-1, SN 2007va)
Citation
Szymon Kozłowski et al, "SDWFS-MT-1: A Self-Obscured Luminous Supernova At z ~= 0.2," The Astrophysical Journal 722, no. 2 (2010), doi:10.1088/0004-637X/722/2/1624