Abstract
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 measurements for M83 and NGC 253, show sharpening power-law
slopes at energies above 3 - 6 keV due to
Original language | English |
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State | Published - Jan 2015 |