NGC 2276: a remarkable galaxy with a large number of ULXs
  The starbusting, nearby (D = 32.9 Mpc) spiral (Sc) galaxy NGC2276 belongs to
the sparse group dominated by the elliptical galaxy NGC2300. NGC2276 is a
remarkable galaxy, as it displays a disturbed morphology at many wavelengths.
This is possibly due to gravitational interaction with the central elliptical
galaxy of the group. Previous ROSAT and XMM-Newton observations resulted in the
detection of extended hot gas emission and of a single very bright (~1.e41
erg/s) ultraluminous X-ray source (ULX) candidate. Here we report on a study of
the X-ray sources of NGC2276 based on CHANDRA data taken in 2004. CHANDRA was
able to resolve 16 sources, 8 of which are ULXs, and to reveal that the
previous ULX candidate is actually composed of a few distinct objects. We
construct the luminosity function of NGC2276, which can be interpreted as
dominated by high mass X-ray binaries, and estimate the star formation rate
(SFR) to be ~5-15 Msun/yr, consistent with the values derived from optical and
infrared observations. By means of numerical simulations, we show that both ram
pressure and viscous transfer effects are necessary to produce the distorted
morphology and the high SFR observed in NGC2276, while tidal interaction have a
marginal effect.
