X-Ray Emission from the Supergiant Shell in IC 2574
  The M81 group member dwarf galaxy IC 2574 hosts a supergiant shell of current
and recent star-formation activity surrounding a 1000 x 500 pc hole in the
ambient Hi gas distribution. Chandra X-ray Observatory imaging observations
reveal a luminous, L_x ~ 6.5 x 10^{38} erg/s in the 0.3 - 8.0 keV band,
point-like source within the hole but offset from its center and fainter
diffuse emission extending throughout and beyond the hole. The star formation
history at the location of the point source indicates a burst of star formation
beginning ~25 Myr ago and currently weakening and there is a young nearby star
cluster, at least 5 Myr old, bracketing the likely age of the X-ray source at
between 5 and ~25 Myr. The source is thus likely a bright high-mass X-ray
binary --- either a neutron star or black hole accreting from an early B star
undergoing thermal-timescale mass transfer through Roche lobe overflow. The
properties of the residual diffuse X-ray emission are consistent with those
expected from hot gas associated with the recent star-formation activity in the
region.
