SIMBAD references

Considering the hard X-ray spectral similarities of Cyg X-1 with 1E 1740.7-2942 and GRS 1758-258, for which nonthermal radio counterparts with double jet-like morphology have been found, we discuss the possibility that similar parsec scale radio jets could exist in Cyg X-1 as well. This kind of radio structures are expected to be weak and extended at the arcminute level. As a first step to try to detect them, a combined analysis of VLA D configuration archive data has been carried out. Extended arcminute radio emission around Cyg X-1 has been found, with apparently nonthermal spectral index. However, a clear jet morphology or a direct connection with Cyg X-1 itself is not evident and further, more sensitive observations are required. We also discuss the possibility that such extended radio jets could be absent in Cyg X-1 because of disruption by radiation pressure from the supergiant companion.