SN 2008jb: A 'Lost' Core-collapse Supernova in a Star-forming Dwarf Galaxy at ~10 Mpc
| Autor: | E. Beshore, R. H. McNaught, Janice C. Lee, M. Catelan, G. Garradd, Krzysztof Z. Stanek, S. G. Djorgovski, D. M. Szczygiel, John F. Beacom, Andrew J. Drake, J. L. Prieto, G. Pojmanski |
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| Jazyk: | angličtina |
| Rok vydání: | 2012 |
| Předmět: |
Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Astrophysics::High Energy Astrophysical Phenomena FOS: Physical sciences Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics 01 natural sciences 0103 physical sciences Astrophysics::Solar and Stellar Astrophysics 010303 astronomy & astrophysics Stellar evolution Solar and Stellar Astrophysics (astro-ph.SR) Astrophysics::Galaxy Astrophysics Physics 010308 nuclear & particles physics Star formation Astronomy and Astrophysics Light curve Type II supernova Galaxy Supernova Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science Astrophysics::Earth and Planetary Astrophysics Small Magellanic Cloud Irregular galaxy Astrophysics - Cosmology and Nongalactic Astrophysics |
| Popis: | We present the discovery and follow-up observations of SN 2008jb, a core-collapse supernova in the dwarf irregular galaxy ESO 302-14 at 9.6 Mpc. This transient was missed by galaxy-targeted surveys and was only found in archival optical images obtained by CRTS and ASAS. It was detected shortly after explosion and reached a bright optical maximum, Vmax = 13.6 mag (M_Vmax ~ -16.5). The shape of the light curve shows a plateau of 100 days, followed by a drop of 1.4 mag in V-band to a decline with the approximate Co 56 decay slope, consistent with 0.04 Msun of Ni 56 synthesized in the explosion. A spectrum obtained 2 years after explosion shows a broad, boxy Halpha emission line, which is unusual for type IIP supernovae. We detect the supernova in archival Spitzer and WISE images obtained 8-14 months after explosion, which show clear signs of warm dust emission. The dwarf irregular host galaxy has a low gas-phase oxygen abundance, 12 + log(O/H) = 8.2 (~1/5 Solar), similar to those of the SMC and the hosts of long gamma-ray bursts and luminous core-collapse supernovae. We study the host environment using GALEX FUV, R-band, and Halpha images and find that the supernova occurred in a large star-formation complex. The morphology of the Halpha emission appears as a large shell (R = 350 pc) surrounding the FUV and optical emission. We estimate an age of ~9 Myr and a total mass of ~2 x 10^5 Msun for the star-formation complex. These properties are consistent with the expanding Halpha supershells observed in well-studied nearby dwarf galaxies, which are tell-tale signs of feedback from the cumulative effect of massive star winds and supernovae. The age estimated for the star-forming region suggests a relatively high-mass progenitor star with initial mass of ~20 Msun. We discuss the implications of these findings in the study of core-collapse supernova progenitors. (Abridged) 41 pages, 10 figures, accepted in ApJ; small changes, conclusions unchanged |
| Databáze: | OpenAIRE |
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