VLBI search for the radio counterpart of HESS J1943+213

Abstract

HESS J1943+213, a TeV point source close to the Galactic plane recently discovered by the H.E.S.S. collaboration, was proposed to be an extreme BL Lacertae object, though a pulsar wind nebula (PWN) nature could not be completely discarded. To investigate its nature, we performed high-resolution radio observations with the European Very Long Baseline Interferometry Network (EVN) and reanalyzed archival continuum and H {\sc i} data. The EVN observations revealed a compact radio counterpart of the TeV source. The low brightness temperature and the resolved nature of the radio source are indications against the beamed BL Lacertae hypothesis. The radio/X-ray source appears immersed in a $\sim$ 1\arcmin elliptical feature suggesting a possible galactic origin (PWN nature) for the HESS source. We found that HESS\,J1943+213 is located in the interior of a $\sim1\degr$ diameter H {\sc i} feature, and explored the possibility of they being physically related.

Significantly revised and extended. Accepted for publication in ApJ (ApJ, 762, 63). (4 figures.)

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• The Warped HI Layer of the Outer Galaxy

Cited by in corpus (9)

• Supernova Remnants Interacting with Molecular Clouds: X-ray and Gamma-ray Signatures
• First-Epoch VLBA Imaging of Twenty New TeV Blazars
• Extreme Blazars Studied with Fermi-LAT and Suzaku: 1ES 0347-121 and Blazar Candidate HESS J1943+213
• HESS J1943+213: An Extreme Blazar Shining Through The Galactic Plane
• The host galaxy and Fermi-LAT counterpart of HESS J1943+213
• EVN Observations of HESS J1943+213: Evidence for an Extreme TeV BL Lac Object
• HESS J1943+213: a non-classical high-frequency-peaked BL Lac object
• e-MERLIN observations of the puzzling TeV source HESS J1943+213
• VERITAS and VLBA Observations of HESS J1943+213