The HI absorption distance of HESS J1943+213 favours its extragalactic nature
1 Department of Physics & AstronomyUniversity of Calgary, Calgary, Alberta T2N 1N4, Canada
2 National Astronomical Observatories, CAS, Beijing 100012, PR China
Received: 12 December 2011
Accepted: 25 January 2012
Context. The H.E.S.S. Collaboration dicovered a new TeV point-like source HESS J1943+213 in the Galactic plane and suggested three possible low-energy-band counterparts: a γ-ray binary, a pulsar wind nebula (PWN), or a BL Lacertae object.
Aims. We measure the distance to the radio counterpart G57.76-1.29 of HESS J1943+213.
Methods. We analyze Very Large Array observations to obtain a reliable HI absorption spectrum.
Results. The resulting distance limit is ≥ 16 kpc. This distance strongly supports that HESS J1943+213 is an extragalactic source, consistent with the preferred counterpart of the H.E.S.S. Collaboration
Key words: methods: data analysis / ISM: supernova remnants / cosmic rays
© ESO, 2012