The 0.3-30 keV spectra of Powerful Starburst Galaxies: NuSTAR and Chandra observations ofNGC 3256 and NGC 3310

摘要: We present nearly simultaneous Chandra and NuSTAR observations of two actively star-forming galaxies: NGC 3256 and NGC 3310. The NuSTAR galaxy-wide spectra of both galaxies follow steep power law distributions, similar to the spectra of bright individual ultra-luminous X-ray sources (ULXs) that have been studied by NuSTAR. The X-ray emission from both galaxies is spatially resolved by Chandra, which indicates that hot gas dominates the E< 1-3 keV emission, while ULXs make up a majority of the emission at E> 1-3 keV. Using new and archival Chandra data we found that both galaxies have candidate AGNs coincident with nuclear regions. However, the steep NuSTAR spectra of both galaxies restricts these candidates to be low luminosity AGN, and a non-AGN nature cannot be ruled out. We find the average 0.3-30 keV SFR-normalized spectra of NGC 3256 and NGC 3310, combined with equivalent …