NuSTAR Galactic Plane Survey and Galactic Binaries Program
Abstract
The NuSTAR Galactic science program includes a Galactic plane survey and observations of specific Galactic binaries. The survey includes a 2x0.8 degree field near Sgr A*, in which Chandra uncovered a large population of unidentified sources, possibly CVs. NuSTAR should detect hundreds of these sources in the hard X-ray band, helping identify their nature. A similar survey of the Norma region will be done for comparative studies. NuSTAR will observe Sgr A*, in coordination with Chandra and other observatories, to search for hard X-ray flaring. The same observations will provide an image of the central few tens of parsecs of the Galaxy with more than an order of magnitude better sensitivity than INTEGRAL. NuSTAR will spatially resolve the hard X-ray emission in the molecular cloud Sgr B2 to better understand its origin. An observation of the Limiting Window, which holds a possible new class of CVs, will yield information on their nature through the fraction of hard X-ray emitters. NuSTAR’s planned observation of the G2 molecular cloud - Sgr A* infall in the spring of 2013 will be discussed. Finally, with its superb hard X-ray sensitivity, NuSTAR will detect and map the low energy extension of the diffuse gamma-ray background observed by INTEGRAL, helping to resolve the long-standing mystery of the diffuse Galactic X-ray background. For Galactic binaries, NuSTAR's hard X-ray sensitivity will permit detailed studies of the fainter part of this population. NuSTAR will obtain the first hard X-ray measurements of black hole and neutron star transients in and approaching quiescence, providing new insights into how the X-ray emission is produced. NuSTAR will follow up on recently discovered types of High-Mass X-ray Binaries to search for pulsations, cyclotron lines, or spectral breaks, constraining the properties of their compact objects. We also plan to target gamma-ray binaries to understand whether the emission is powered by accretion or neutron star rotation. For bright X-ray binaries, we will use NuSTAR’s superb energy resolution at >10 keV to study cyclotron lines from accreting pulsars and to search for absorption edges in type I X-ray bursts that, if found, provide a new window on neutron star physics.
- Publication:
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American Astronomical Society Meeting Abstracts #221
- Pub Date:
- January 2013
- Bibcode:
- 2013AAS...22120902H