Black Hole Powered Nebulae and a Case Study of the Ultraluminous X-ray
  Source IC342 X-1
  We present new radio, optical, and X-ray observations of three Ultraluminous
X-ray sources (ULXs) that are associated with large-scale nebulae. We report
the discovery of a radio nebula associated with the ULX IC342 X-1 using the
Very Large Array (VLA). Complementary VLA observations of the nebula around
Holmberg II X-1, and high-frequency Australia Telescope Compact Array (ATCA)
and Very Large Telescope (VLT) spectroscopic observations of NGC5408 X-1 are
also presented. We study the morphology, ionization processes, and the
energetics of the optical/radio nebulae of IC342 X-1, Holmberg II X-1 and
NGC5408 X-1. The energetics of the optical nebula of IC342 X-1 is discussed in
the framework of standard bubble theory. The total energy content of the
optical nebula is 6 x 10^52 erg. The minimum energy needed to supply the
associated radio nebula is 9.2 x 10^50 erg. In addition, we detected an
unresolved radio source at the location of IC342 X-1 at VLA scales. However,
our Very Long Baseline Interferometry (VLBI) observations using the European
VLBI Network likely rule out the presence of any compact radio source at
milli-arcsecond (mas) scales. Using a simultaneous Swift X-ray Telescope
measurement, we estimate an upper limit on the mass of the black hole in IC342
X-1 using the "fundamental plane" of accreting black holes and obtain M_BH <
(1.0\pm0.3) x 10^3 M_Sun. Arguing that the nebula of IC342 X-1 is possibly
inflated by a jet, we estimate accretion rates and efficiencies for the jet of
IC342 X-1 and compare with sources like S26, SS433, IC10 X-1.
