2013/03/08 by G. Pivato, Pivato, G., J. W. Hewitt +3
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #FOS: Physical sciences #Gamma-ray bursts and supernovae #High Energy Astrophysical Phenomena (astro-ph.HE) #Neutrino Physics Research
paper · pdf · doi:10.48550/arxiv.1303.2091
openalex publication_date 2013/03/08 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We present the analysis of Fermi Large Area Telescope (LAT) γ-ray observations of HB 21, a mixed-morphology supernova remnant. Such supernova remnants are characterized by an interior thermal X-ray plasma, surrounded by a wider nonthermal shell emitting at radio frequencies. HB 21 has a large angular size, making it a good candidate for detailed morphological and spectral studies with the LAT. The radio extension is 2°x1°.5, compared to the LAT 68% containment angle of ~1° at 1 GeV. To understand the origin of γ-ray emission, we compare LAT observations with other wavelengths that trace non-thermal radio synchrotron, nearby molecular clouds, shocked molecular clumps, and the central X-ray plasma. Finally, we model possible hadronic and leptonic emission mechanisms. We conclude that γ-rays from HB 21 are likely the result of electron bremsstrahlung or proton-proton collisions with dense material due to interaction with the nearby clouds.