Radio study of HESS J1857+026: Gamma-rays from a superbubble?

Aims. We provide new insights into the nature of HESS J1857+026, a very-high-energy γ -ray source whose complex morphology in TeV band was attributed to superposition two distinct sources. Methods. performed radio continuum observations look for pulsar wind nebula and supernova remnant associated with PSR J1856+0245, which might be powering part emission. observed J1857+026 Karl G. Jansky Very Large Array (VLA) at 1.5 GHz C configuration. In addition, using same array configuration, we region 0.4° × towards J1856+0245 6.0 GHz. obtained complementary data neutral hydrogen molecular gas emission from public surveys order investigate properties interstellar medium direction J1857+026. Results. The do not show evidence above noise level 0.7 mJy beam −1 that could either or J1856+0245. Also, image detect powered by analysis shows existence superbubble source. suggest this structure is located ~5.5 kpc, compatible distance Conclusions. conclude originates superbubble, arguing favour single rather than also contributing as -rays within bubble.