This Letter presents the first results of an observational campaign to study the Galactic center with INTEGRAL , the Internaltional Gamma-Ray Astrophysics Laboratory .
Mosaicked images were constructed using data obtained with ISGRI , the soft gamma-ray instrument of the coded aperture IBIS imager , in the energy ranges 20–40 and 40–100 \mathrm { keV } .
These give a yet unseen view of the high-energy sources of this region in hard X-rays and gamma-rays with an angular resolution of 12 ^ { \prime } ( FWHM ) .
We report on the discovery of a source , IGR J1745.6–2901 , coincident with the Galactic nucleus Sgr A ^ { * } to within 0 ^ { \prime } .9 .
Located at R.A. ( J2000.0 ) = \mathrm { 17 ^ { h } 45 ^ { m } 38 ^ { s } \hskip { -2.0 pt } .5 } , decl .
( J2000.0 ) = -29 ^ { \circ } 01 ^ { \prime } 15 ^ { \prime \prime } , the source is visible up to about 100 \mathrm { keV } with a 20–100 \mathrm { keV } luminosity at 8 \mathrm { kpc } of ( 2.89 \pm 0.41 ) \times 10 ^ { 35 } \mathrm { ergs s ^ { -1 } } .
Although the new INTEGRAL source can not unequivocally be associated to the Galactic nucleus , this is the first report of significant hard X-ray emission from within the inner 10 ^ { \prime } of the Galaxy and a contribution from the Galactic supermassive black hole itself can not be excluded .