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Extinction curves flattened by reverse shocks in supernovae
Title: | Extinction curves flattened by reverse shocks in supernovae |
Authors: | Hirashita, Hiroyuki Browse this author | Nozawa, Takaya Browse this author | Takeuchi, Tsutomu T. Browse this author | Kozasa, Takashi Browse this author →KAKEN DB |
Keywords: | supernovae: general | dust, extinction | galaxies: evolution | galaxies: highredshift | galaxies: ISM | quasars: individual: SDSS J104845.05+463718.3 |
Issue Date: | Mar-2008 |
Publisher: | Blackwell Publishing |
Journal Title: | Monthly Notices of the Royal Astronomical Society |
Volume: | 384 |
Issue: | 4 |
Start Page: | 1725 |
End Page: | 1732 |
Publisher DOI: | 10.1111/j.1365-2966.2007.12834.x |
Abstract: | We investigate the extinction curves of young galaxies in which dust is supplied from Type II supernovae (SNe II) and/or pair instability supernovae (PISNe). Since at high redshift (z > 5), low-mass stars cannot be dominant sources for dust grains, SNe II and PISNe, whose progenitors are massive stars with short lifetimes, should govern the dust production. Here, we theoretically investigate the extinction curves of dust produced by SNe II and PISNe, taking into account reverse shock destruction induced by collision with ambient interstellar medium. We find that the extinction curve is sensitive to the ambient gas density around a SN, since the efficiency of reverse shock destruction strongly depends on it. The destruction is particularly efficient for small-sized grains, leading to a flat extinction curve in the optical and ultraviolet wavelengths. Such a large ambient density as nH ≳ 1 cm^[−3] produces too flat an extinction curve to be consistent with the observed extinction curve for SDSS J1048+4637 at z= 6.2. Although the extinction curve is highly sensitive to the ambient density, the hypothesis that the dust is predominantly formed by SNe at z ∼ 6 is still allowed by the current observational constraints. For further quantification, the ambient density should be obtained by some other methods. Finally, we also discuss the importance of our results for observations of high-z galaxies, stressing a possibility of flat extinction curves. |
Rights: | The definitive version is available at www.blackwell-synergy.com |
Type: | article |
URI: | http://hdl.handle.net/2115/42828 |
Appears in Collections: | 理学院・理学研究院 (Graduate School of Science / Faculty of Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 小笹 隆司
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