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9th of November 2023
Gamma-ray detection of newly discovered ASKAP supernova remnant
by Burger-Scheidlin et al.
The supernova remnant (SNR) G288.8–6.3 was recently discovered with ASKAP as a faint radio shell at a high Galactic latitude. Burger-Scheidlin et al. have made the first detailed investigation of the gamma-ray emission from the G288.8–6.3 region, aiming to characterise the high-energy emission in the GeV regime from the newly discovered SNR, which has been dubbed Ancora (for reasons to be explained in tomorrow's ADAP). Fifteen years of Fermi-Large Area Telescope (LAT) data were analysed at energies between 400 MeV and 1 TeV with the detection of spatially extended gamma-ray emission coinciding with the radio SNR. The gamma-ray excess was modelled using different spatial and spectral models, with a radial disk spatial model in combination with a power-law spectral model found to be the preferred model. Morphologically, hotspots seen above 1 GeV are well-correlated with the bright western part of the radio shell. The figure above shows the significance map of the G288.8–6.3 region as seen with Fermi-LAT after fitting with a RadialDisk spatial model and a PowerLaw spectral model, including modelling of the Fermi source 4FGL J1028.7-6431c, overlaid with Fermi contours for significance above 1 GeV, and the smoothed radio contours from the ASKAP instrument at 954 MHz. It is not clear whether 4FGL J1028.7-6431c is actually associated with Ancora, or is an unrelated source overlapping with the SNR. Ancora is the eighth SNR detected at high Galactic latitude with Fermi-LAT. This new population of remnants has the potential to constrain the physics of particle diffusion and escape from SNRs into the Galaxy.

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