Visibility of Old Supernova Remnants in HI 21-cm Emission Line
arXiv:astro-ph/0312642 · doi:10.1111/j.1365-2966.2004.07579.x
Abstract
We estimate the number of old, radiative supernova remnants (SNRs) detectable in HI 21-cm emission line in the Galaxy. According to our result, the contamination due to the Galactic background HI emission limits the number of visible SNRs to 270, or 9% of the total HI SNRs. The telescope sensitivity further limits the number. We compare the result with observations to find that the observed number (< 25) of HI SNRs is much less than the expected. A plausible explanation is that previous observational studies, which were made toward the SNRs identified mostly in radio continuum, missed most of the HI SNRs because they are too faint to be visible in radio continuum. We propose that the faint, extended HI 21-cm emission line wings protruding from the Galactic background HI emission in large-scale (l, v) diagrams could be possible candidates for HI SNRs, although our preliminary result shows that their number is considerably less than the expected in the inner Galaxy. We conclude that a possible explanation for the small number of \schi SNRs in the inner Galaxy is that the interstellar space there is largely filled with a very tenuous gas as in the three-phase ISM model.
arXiv comment10 pages, 9 figures, accepted for publication in MNRAS
References in corpus (7)
- The Millennium Arecibo 21-CM Absorption Line Survey. II. Properties of the Warm and Cold Neutral Media
- Three Dimensional Structure of the Milky Way Disk
- COBE's Galactic Bar and Disk
- Old stellar Galactic disc in near-plane regions according to 2MASS: scales, cut-off, flare and warp
- Extinction and the Radial Distribution of Supernova Properties in Their Parent Galaxies
- Distribution of Supernovae in Spiral Galaxies
- Radiative instabilities in simulations of spherically symmetric supernova blast waves
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