### Résumé du preprint DAPNIA-04-46

DAPNIA-04-46
Detection of Hard X-rays from the Galactic Nuclear Region with INTEGRAL
G. Belanger et al.
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 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\\am (FWHM). We report on the discovery of a source, IGR J1745.6--2901, coincident with the Galactic nucleus \\sgra to within 0.9 arcminutes.
Located at R.A.(J2000.0) = 17h45m38.5s, decl.(J2000.0) = -29deg01\'15\'\', the source is visible up to about 100 keV with a
20--100 keV luminosity at 8 kpc of (2.89 \\pm 0.41) \\times 10^{35} ergs/s. Although the new INTEGRAL source cannot unequivocally be associated to the Galactic nucleus, this is the first report of significant hard X-ray emission from within the inner 10\' of the Galaxy and a contribution from the Galactic supermassive black hole itself cannot be excluded.