Joint Astrophysics Colloquium

Looking Deep Into (and sometimes through) the Galaxy with INTEGRAL, Chandra, and NuSTAR

John Tomsick

University of California at Berkeley

Hard X-ray observations uncover extreme processes that are occurring in our Galaxy. These processes can be related to accretion of matter onto compact objects, the conversion of spin or magnetic energy into radiation, acceleration of electrons in shocks, and emission from nuclear decays. Hard X-ray surveys above 10 keV provide a relatively unbiased view of the source populations in the Galaxy because the levels of interstellar absorption are very low at such energies. For nearly a decade, the INTEGRAL satellite has been uncovering new hard X-ray sources. However, the positional accuracy obtained by INTEGRAL is not nearly good enough to obtain unique multi-wavelength identifications of sources in the crowded Galactic Plane. Thus, over the past several years, we have been following up INTEGRAL detections with the Chandra X-ray Observatory to determine the nature of these sources. We have identified a large number of them, and I will describe our methods and present our results for some of the more interesting cases. This topic is timely because of the upcoming launch of the NuSTAR hard X-ray satellite, which will provide a huge advance in sensitivity and angular resolution over INTEGRAL. I will also discuss some of the science that we expect the NuSTAR capabilities to enable.