IGR J16393-4643: a new heavily-obscured X-ray pulsar

¹ INTEGRAL Science Data Centre, Chemin d'Ecogia 16, 1290 Versoix, Switzerland e-mail: arash.bodaghee@obs.unige.ch
² Observatoire de Genève, Chemin des Maillettes 51, 1290 Sauverny, Switzerland
³ School of Physics and Astronomy, University of Southampton, Highfield, Southampton, SO17 1BJ, UK
⁴ IASF/CNR, Via Gobetti 101, 40129 Bologna, Italy
⁵ CEA-Saclay, DAPNIA/Service d'Astrophysique, 91191 Gif-sur-Yvette Cedex, France
⁶ Fédération de recherche APC, Collège de France, 11 place Marcelin Berthelot, 75231 Paris, France
⁷ IASF/CNR, Via Fosso del Cavaliere 100, 00133 Rome, Italy

Received: 11 July 2005
Accepted: 27 September 2005

Abstract

An analysis of the high-energy emission from IGR J16393-4643 (=AX J1639.0-4642) is presented using data from INTEGRAL and XMM-Newton. The source is persistent in the 20–40 keV band at an average flux of  erg cm^-2 s^-1, with variations in intensity by at least an order of magnitude. A pulse period of 912.0±0.1 s was discovered in the ISGRI and EPIC light curves. The source spectrum is a strongly-absorbed ( cm^-2) power law that features a high-energy cutoff above 10 keV. Two iron emission lines at 6.4 and 7.1 keV, an iron absorption edge ≳7.1 keV, and a soft excess emission of  erg cm^-2 s^-1 between 0.5–2 keV, are detected in the EPIC spectrum. The shape of the spectrum does not change with the pulse. Its persistence, pulsation, and spectrum place IGR J16393-4643 among the class of heavily-absorbed HMXBs. The improved position from EPIC is RA (J2000 and ( uncertainty) which is compatible with that of 2MASS J16390535-4642137.