We present the first survey results of hard X-ray point sources in the Galactic Center ( GC ) region by NuSTAR .
We have discovered 70 hard ( 3–79 keV ) X-ray point sources in a 0.6 deg { } ^ { 2 } region around Sgr A* with a total exposure of 1.7 Ms , and 7 sources in the Sgr B2 field with 300 ks .
We identify clear Chandra counterparts for 58 NuSTAR sources and assign candidate counterparts for the remaining 19 .
The NuSTAR survey reaches X-ray luminosities of \sim 4 \times and \sim 8 \times 10 { } ^ { 32 } erg s { } ^ { -1 } at the GC ( 8 kpc ) in the 3–10 and 10–40 keV bands , respectively .
The source list includes three persistent luminous X-ray binaries and the likely run-away pulsar called the Cannonball .
New source-detection significance maps reveal a cluster of hard ( > 10 keV ) X-ray sources near the Sgr A diffuse complex with no clear soft X-ray counterparts .
The severe extinction observed in the Chandra spectra indicates that all the NuSTAR sources are in the central bulge or are of extragalactic origin .
Spectral analysis of relatively bright NuSTAR sources suggests that magnetic cataclysmic variables constitute a large fraction ( > 40–60 % ) .
Both spectral analysis and log N -log S distributions of the NuSTAR sources indicate that the X-ray spectra of the NuSTAR sources should have kT > 20 keV on average for a single temperature thermal plasma model or an average photon index of \Gamma = 1.5 – 2 for a power-law model .
These findings suggest that the GC X-ray source population may contain a larger fraction of X-ray binaries with high plasma temperatures than the field population .