Preliminary Results of the NuSTAR Galactic Center Mini-survey

In October 2012, the Nuclear Spectroscopic Telescope Array (NuSTAR) observed the Galactic Center region. This observation, with 150 ksec total exposure time and 6 pointings between Sgr A* and 1E1743.1-2843, was conducted as the first part of the 2x0.8 degree Galactic Center survey. NuSTAR's Galactic Center survey will address some of the long-standing questions in high-energy astrophysics - the nature of numerous X-ray sources discovered by Chandra, the origin of hard X-ray emission from Sgr A* and its vicinity, the nature of the Galactic diffuse X-ray background and the question of whether the Galactic Center molecular clouds are illuminated by cosmic-ray bombardment or Sgr A* flares in the past. In this talk, I will present the first high-resolution image of the Galactic Center region above 10 keV. With NuSTAR's sub-arcminute angular resolution, we can unambiguously resolve and identify various sources such as Sgr A East, the Plume, the Sgr A-E knot, the Arches cluster and various molecular clouds. Combined with high-resolution spectral analysis from 3 to 40 keV, NuSTAR elucidates the origin of the hard X-ray emission from the Sgr A* region and several bright molecular clouds in the Sgr A complex. We did not find the putative hard X-ray source J17456-2901 discovered by INTEGRAL. Some preliminary results from point source detection and diffuse X-ray background analysis will be also presented.