A spatial template is important to study nearby supernova remnants(SNRs).For SNR G332.5-5.6,we report a Gaussian disk with a radius of about 1°.06 to be a potential good spatial model in the γ-ray band.Employing...A spatial template is important to study nearby supernova remnants(SNRs).For SNR G332.5-5.6,we report a Gaussian disk with a radius of about 1°.06 to be a potential good spatial model in the γ-ray band.Employing this new Gaussian disk,its GeV lightcurve shows a significant variability of about seven sigma.The γ-ray observations of this SNR could be explained well either by a leptonic model or a hadronic model,in which a flat spectrum for the ejected electrons/protons is required.展开更多
Based on the first 13.4 yr of Fermi science data in the energy range from 300 Me V to 500 Ge V,we discovered a bright Ge V gamma-ray source with a ~5.64σ detection,named Fermi J1242.5+3236,which has an offset of abou...Based on the first 13.4 yr of Fermi science data in the energy range from 300 Me V to 500 Ge V,we discovered a bright Ge V gamma-ray source with a ~5.64σ detection,named Fermi J1242.5+3236,which has an offset of about0°.0996 from a nearby star-forming galaxy NGC 4631.When using the 12 yr’ data,the detection significance of Fermi J1242.5+3236 is about 4.72σ.Fermi J1242.5+3236 is a steady point source without significant temporal variability and has a hard gamma-ray photon index of about-1.60 ± 0.24.The spatial offset and the hard gammaray spectrum disfavor this source as the diffuse gamma-ray emission from this galaxy.This new source might have a possible origin of an unidentified background blazar,which is more likely a high-synchrotron-peaked blazar for its hard gamma-ray photon index.A follow-up optical observation would help distinguish origin of Fermi J1242.5+3236.展开更多
基金supported by the National Natural Science Foundation of China under grant 12065017the Jiangxi Provincial Natural Science Foundation of China under grant Nos.20224ACB211001 and 20212BAB201029。
文摘A spatial template is important to study nearby supernova remnants(SNRs).For SNR G332.5-5.6,we report a Gaussian disk with a radius of about 1°.06 to be a potential good spatial model in the γ-ray band.Employing this new Gaussian disk,its GeV lightcurve shows a significant variability of about seven sigma.The γ-ray observations of this SNR could be explained well either by a leptonic model or a hadronic model,in which a flat spectrum for the ejected electrons/protons is required.
基金supported by the Jiangxi Provincial Natural Science Foundation under grant 20212BAB201029the National Natural Science Foundation of China under grants 11903017,11975116,12065017,and U2031105。
文摘Based on the first 13.4 yr of Fermi science data in the energy range from 300 Me V to 500 Ge V,we discovered a bright Ge V gamma-ray source with a ~5.64σ detection,named Fermi J1242.5+3236,which has an offset of about0°.0996 from a nearby star-forming galaxy NGC 4631.When using the 12 yr’ data,the detection significance of Fermi J1242.5+3236 is about 4.72σ.Fermi J1242.5+3236 is a steady point source without significant temporal variability and has a hard gamma-ray photon index of about-1.60 ± 0.24.The spatial offset and the hard gammaray spectrum disfavor this source as the diffuse gamma-ray emission from this galaxy.This new source might have a possible origin of an unidentified background blazar,which is more likely a high-synchrotron-peaked blazar for its hard gamma-ray photon index.A follow-up optical observation would help distinguish origin of Fermi J1242.5+3236.
