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

• Published in: Astronomy and astrophysics (Berlin) 2006-03, Vol.447 (3), p.1027-1034
• Main Authors: Bodaghee, A., Walter, R., Zurita Heras, J. A., Bird, A. J., Courvoisier, T. J.-L., Malizia, A., Terrier, R., Ubertini, P.
• Format: Article
• Language: English
• Subjects: Astronomy; Astrophysics; Cosmology and Extra-Galactic Astrophysics; Earth, ocean, space; Exact sciences and technology; gamma-rays: observations; Physics; pulsars: individuals: AX J1639.0-4642; pulsars: individuals: IGR J16393-4643; X-rays: binaries
• ISSN: 0004-6361; 1432-0746; 1432-0756
• DOI: 10.1051/0004-6361:20053809

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 $5.1\times10^{-11}$ 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 ($N_{\mathrm{H}}=(2.5\pm0.2)\times10^{23}$ 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 $7\times10^{-15}$ 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$)=16^{\mathrm{h}}39^{\mathrm{m}}05.4^{\mathrm{s}}$ and $\rm Dec=-46^{\circ}42'12''$ ($4''$ uncertainty) which is compatible with that of 2MASS J16390535-4642137.