We present an analysis of archival Chandra X-ray observations of a sample of six nearby dwarf starburst galaxies (DDO 165, NGC 625, NGC 1569, NGC 4214, NGC 4449, NGC 5253). This work presents maps of diffuse X-ray emission with point sources removed. We find evidence of diffuse X-ray emission extended beyond the optical disc in four of six galaxies in the sample. The diffuse emission is best fit to single or two temperature thermal plasma models with temperatures of 0.14-0.8 keV. In galaxies with extended emission detected, emission extends up to 5 kpc from the nuclei of the galaxies, and all show unique morphologies. We compare X-ray data to ancillary UV and optical data from the STARBIRDS project and archival radio wavelengths. Diffuse X-ray emission generally corresponds with star forming regions emitting in the Near UV, and/or with an under-density in the HI disc. Our analysis shows that diffuse X-ray emission is strongly correlated with star formation on both short (~10 Myr) and long timescales (200-400 Myr). The shorter timescales agree with previous studies, however the agreement on long timescales suggest the picture is more complex. Our analysis combined with star formation histories conflict with previous works assuming ~10 Myr burst timescales and constant star formation rates, suggesting that longer, time-varying star formation rates are essential to truly understanding stellar feedback and galactic winds.
University of Minnesota M.S. thesis. December 2015. Major: Astrophysics. Advisor: Evan Skillman. 1 computer file (PDF); vii, 34 pages.
Galactic Outflows in Starburst Dwarf Galaxies Detected in Diffuse X-ray Emission.
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