Detection of hard X-ray emission from the Galactic nuclear region with INTEGRAL

G. Belanger (1) , A. Goldwurm (1) , P. Goldoni (1) , J. C. Paul (1) , R. Terrier (1) , M. Falanga (1) , P. Ubertini , A. Bazzano , M. del Santo , C. Winkler , A. N. Parmar , E. Kuulkers , K. Ebisawa , J. P. Roques (2) , N. Lund , F. Melia

1 DAPNIA - Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée
2 CESR - Centre d'étude spatiale des rayonnements

This letter presents the first results of an observational campaign to study the Galactic Centre with INTEGRAL. The mosaicked images obtained with the IBIS/ISGRI coded aperture instrument in the energy ranges 20-40 and 40-100 keV, give a yet unseen view of the high-energy sources of this region in hard X- and gamma-rays with an angular resolution of 12 arcmin (FWHM). We report on the discovery of a source, IGR J17456-2901, coincident with the Galactic Nucleus SgrA* to within 0.9 arcmin. Located at R.A.(J2000.0) = 17h45m38.5s, Dec.(J2000.0) = -29:01:15, the source is visible up to about 100 keV with a 20-100 keV luminosity at 8 kpc of (2.89 +/- 0.41) x 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 arcmin of the Galaxy and a contribution from the galactic supermassive black hole itself cannot be excluded.

Domaines: Cosmologie et astrophysique extra-galactique [astro-ph.CO]

G. Belanger, A. Goldwurm, P. Goldoni, J. C. Paul, R. Terrier, et al.. Detection of hard X-ray emission from the Galactic nuclear region with INTEGRAL. The Astrophysical Journal, 2004, 601, pp.L163-L166. ⟨hal-00009065⟩