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H.A. Kobulnicky (University of Wyoming), C.L. Martin (U.C. Santa Barbara)
We report preliminary results from Chandra X-ray Observatory observations of the prototype Wolf-Rayet galaxy Henize 2-10. A 20-ksec observation with the ACIS-S detector reveals 26 X-ray point sources in the 8' field, seven of which appear to be associated with Henize 2-10 itself. Four of the seven sources have X-ray colors consistent with localized maxima in the hot diffuse interstellar medium with temperatures of T~0.4 keV. Two of the remaining three points sources are consistent absorbed power law spectra with photon indices \Gamma~.5 and unabsorbed luminosities ~1E38 erg/s in the 0.1-6 keV band. These are probable X-ray binaries. The remaining point source dominates the nuclear X-ray emission and is best fit by a combination of thermal plasma and power law contributions with foreground column densities in excess of 6E21 cm-2. This nucleus is spatially coincident with a sub-arcsec (<40 pc diameter) variable radio source seen in VLA 3.6 cm continuum maps over 3 epochs. Given the power law nature of the X-ray spectrum and the radio variability, we propose the existence of a low-level active nucleus embedded within a more extended hot thermal medium heated by generations of star formation and supernovae. Outside the nucleus on kpc scales, Henize 2-10 exhibits a bipolar morphology in the X-ray color images. X-ray features in the soft (0.3-0.7 keV) and medium (0.7-1.1 keV) bands correlate with ionized shells and filaments traced by Halpha emission. The diffuse X-ray emission is detected radially out to the faintest Halpha features, but not convincingly beyond them. Best fit parameters to the global diffuse X-ray spectrum are consistent with solar metal abundances and solar or super-solar \alpha-to-Fe ratios, but the sensitivity of current observations is not sufficient to place more stringent limits on the physical parameters of the hot interstellar medium.
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Bulletin of the American Astronomical Society, 35#5
© 2003. The American Astronomical Soceity.