G17.8 + 16.7: A new supernova remnant

Abstract

Non-thermal radio emission is detected in the region of the gamma-ray source FHES J1723.5 − 0501. The emission has an approximately circular shape 0.8° in diameter. The observations confirm its nature as a new supernova remnant, G 17.8 + 16.7. We derive constraints on the source parameters using the radio data and gamma-ray observations of the region. The distance to the object is possibly in the range 1.4–3.5 kpc. An SNR age of the order of 10 kyr is compatible with the radio and GeV features, but an older or younger SNR cannot be ruled out. A simple one-zone leptonic model naturally explains the multi-wavelength non-thermal fluxes of the source at its location outside the Galactic plane.