Kinematics: A Clean Diagnostic for Separating Supernova Remnants from H ii Regions in Nearby Galaxies
| Autor: | William P. Blair, P. Frank Winkler, Sean D. Points, Knox S. Long |
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| Rok vydání: | 2019 |
| Předmět: |
Physics
010504 meteorology & atmospheric sciences FOS: Physical sciences Astronomy and Astrophysics Astrophysics Kinematics Astrophysics - Astrophysics of Galaxies 01 natural sciences Galaxy Interstellar medium Supernova Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) 0103 physical sciences Large Magellanic Cloud 010303 astronomy & astrophysics 0105 earth and related environmental sciences |
| Zdroj: | The Astrophysical Journal. 887:66 |
| ISSN: | 1538-4357 |
| Popis: | Many more supernova remnants (SNRs) are now known in external galaxies than in the Milky Way. Most of these SNRs have been identified using narrow-band imaging, separating SNRs from HII regions on the basis of [SII]:H-alpha ratios that are elevated compared to HII regions. However, the boundary between SNRs and HII regions is not always distinct, especially at low surface brightness. Here we explore velocity structure as a possible criterion for separating SNRs from HII regions, using a sample of well-studied SNRs in the Large Magellanic Cloud (LMC) as well as a small number of SNRs in the galaxy M83. We find, perhaps not surprisingly, that even at large diameters, SNRs exhibit velocity broadening sufficient to readily distinguish them from HII regions. We thus suggest that the purity of most extragalactic samples would be greatly improved through spectroscopic observations with a velocity resolution of order 50~km/s$. Comment: 19 pages, 9 figures. To be published in ApJ |
| Databáze: | OpenAIRE |
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