A SEARCH FOR RADIO SUPERNOVA REMNANTS IN FOUR IRREGULAR GALAXIES
We survey four nearby irregular galaxies for radio supernova remnants (SNRs) using deep (1{sigma} {approx} 20 {mu}Jy), high-resolution ({approx}20 pc) Very Large Array continuum data at 20, 6, and 3.6 cm. We identify discrete sources in these galaxies and use radio spectral indices and H{alpha} images to categorize them as SNRs, H II regions, or background radio galaxies. Our classifications are generally in good agreement with the literature. We identify a total of 43 SNR candidates: 23 in NGC 1569, seven in NGC 4214, five in NGC 2366, and eight in NGC 4449. Only one SNR-the well-studied object J1228+441 in NGC 4449-is more luminous at 20 cm than Cas A. By comparing the total thermal flux density in each galaxy with that localized in H II regions, we conclude that a significant fraction must be in a diffuse component or in low-luminosity H II regions.
- OSTI ID:
- 21269243
- Journal Information:
- Astronomical Journal (New York, N.Y. Online), Vol. 137, Issue 4; Other Information: DOI: 10.1088/0004-6256/137/4/3869; Country of input: International Atomic Energy Agency (IAEA); ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
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