INTEGRAL observations of five sources in the Galactic Center region

¹ Space Research Institute, Russian Academy of Sciences, Profsoyuznaya 84/32, 117810 Moscow, Russia e-mail: lutovinov@hea.iki.rssi.ru
² Max-Planck-Institute für Astrophysik, Karl-Schwarzschild-Str. 1, 85740 Garching bei München, Germany

Received: 16 July 2004
Accepted: 10 September 2004

Abstract

A number of new X-ray sources (IGR J17091-3624, IGR/XTE J17391-3021, IGR J17464-3213 (=XTE J17464-3213 = H 1743-322), IGR J17597-2201, SAX/IGR J18027-2017) have been observed with the INTEGRAL observatory during ultra deep exposure of the Galactic Center region in August-September 2003. Most of them were permanently visible by INTEGRAL at energies higher than ∼20 keV, but IGR/XTE J17391-3021 was observed only during its flaring activity with a flux maximum of ~120 mCrab. IGR J17091-3624, IGR J17464-3213 and IGR J17597-2201 were detected up to ∼100–150 keV. In this paper we present the analysis of INTEGRAL observations of these sources to determine the nature of these objects. We conclude that all of them have a galactic origin. Two sources are black hole candidates (IGR J17091-3624 and IGR J17464-3213), one (IGR J17597-2201) is an LMXB neutron star binary (presumably an X-ray burster) and two other sources (IGR J17391-3021 and SAX/IGR J18027-2017) are neutron stars in high mass binaries; one of them (SAX/IGR J18027-2017) is an accreting X-ray pulsar.