DUST COOLING IN SUPERNOVA REMNANTS IN THE LARGE MAGELLANIC CLOUD

Journal Article · Wed Jul 01 04:00:00 EDT 2015 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/807/1/100· OSTI ID:22522196

Seok, Ji Yeon ^[1]; Koo, Bon-Chul ^[2]; Hirashita, Hiroyuki ^[3]

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1. Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211 (United States)
2. Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of)
3. Institute for Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China)

The infrared-to-X-ray (IRX) flux ratio traces the relative importance of dust cooling to gas cooling in astrophysical plasma such as supernova remnants (SNRs). We derive IRX ratios of SNRs in the LMC using Spitzer and Chandra SNR survey data and compare them with those of Galactic SNRs. IRX ratios of all the SNRs in the sample are found to be moderately greater than unity, indicating that dust grains are a more efficient coolant than gas although gas cooling may not be negligible. The IRX ratios of the LMC SNRs are systematically lower than those of the Galactic SNRs. As both dust cooling and gas cooling pertain to the properties of the interstellar medium, the lower IRX ratios of the LMC SNRs may reflect the characteristics of the LMC, and the lower dust-to-gas ratio (a quarter of the Galactic value) is likely to be the most significant factor. The observed IRX ratios are compared with theoretical predictions that yield IRX ratios an order of magnitude larger. This discrepancy may originate from the dearth of dust in the remnants due to either the local variation of the dust abundance in the preshock medium with respect to the canonical abundance or the dust destruction in the postshock medium. The non-equilibrium ionization cooling of hot gas, in particular for young SNRs, may also cause the discrepancy. Finally, we discuss implications for the dominant cooling mechanism of SNRs in low-metallicity galaxies.

• OSTI ID: 22522196
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 807; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ASTROPHYSICS
COMPARATIVE EVALUATIONS
COSMIC DUST
EQUILIBRIUM
GAS COOLING
INTERSTELLAR GRAINS
INTERSTELLAR SPACE
IONIZATION
MAGELLANIC CLOUDS
METALLICITY
PLASMA
SUPERNOVA REMNANTS
X RADIATION