Transient nature of J195754+353513
  We have searched for transient and/or variable radio sources in the field of
Galactic micro-quasar Cygnus X-1 in 1.4 GHz (L band) using data from the Karl
G. Jansky Very Large Array (JVLA). We used twenty years of data between 1983
and 2003. We found a source J195754+353513 showing transient behavior. The
source was also mentioned earlier in NVSS and WENSS catalog but its transient
nature was not reported earlier. The source is located 23.8 arcminutes far from
Cygnus X-1. It is detected many times during the span of our study and it
varied between less than 0.3 mJy to 201 mJy. J195754+353513 also showed high
intra-day variability. In one occasion, the source rose from ~20 mJy to ~180
mJy 700 second. For limited number of cases circularly polarized emission could
be detected from the source with V/I vary between 0.15 to 0.25. 2MASS
J19575420+3535152 may be the near-infrared counterpart of the source. We
compared the properties of the source with other Galactic transient sources
having similar properties. The nature of the source is still unknown. We
speculate on its possible nature.
