Multi-wavelength observations of Galactic hard X-ray sources discovered by INTEGRAL. I. The nature of the companion star

Abstract

Context: The INTEGRAL hard X-ray observatory has revealed an emerging population of highly obscured X-ray binary systems through multi-wavelength observations. Previous studies have shown that many of these sources are high-mass X-ray binaries hosting neutron stars orbiting around luminous and evolved companion stars. Aims: To better understand this newly-discovered population, we have selected a sample of sources for which an accurate localisation is available to identify the stellar counterpart and reveal the nature of the companion star and of the binary system. Methods: We performed an intensive study of a sample of thirteen INTEGRAL sources, through multi-wavelength optical to NIR photometric and spectroscopic observations, using EMMI and SofI instruments at the ESO NTT telescope. We performed accurate astrometry and identified candidate counterparts for which we give the optical and NIR magnitudes. We detected many spectral lines allowing us to determine the spectral type of the companion star. We fitted with stellar black bodies the mid-infrared to optical spectral energy distributions of these sources. From the spectral analysis and SED fitting we identified the nature of the companion stars and of the binary systems. (abridged).

A&A in press; The official date of acceptance is 15/12/2007; 25 pages, 6 figures, 8 tables. New version with language editing required by editor

References in corpus (8)

• Catalogue of high-mass X-ray binaries in the Galaxy ($4^{th}$ edition)
• The 3rd IBIS/ISGRI soft gamma-ray survey catalog
• Multi-wavelength observations of Galactic hard X-ray sources discovered by INTEGRAL. I. The nature of the companion star
• Multi-wavelength observations of Galactic hard X-ray sources discovered by INTEGRAL. II. The environment of the companion star
• A description of sources detected by INTEGRAL during the first 4 years of observations
• A search for counterparts to massive X-ray binaries using photometric catalogues
• The 1 - 50 keV spectral and timing analysis of IGR J18027-2016: an eclipsing, high mass X-ray binary
• A Possible Magnetar Nature for IGR J16358-4726

Cited by in corpus (10)

• Multi-wavelength observations of Galactic hard X-ray sources discovered by INTEGRAL. I. The nature of the companion star
• Multi-wavelength observations of Galactic hard X-ray sources discovered by INTEGRAL. II. The environment of the companion star
• Unveiling the nature of INTEGRAL objects through optical spectroscopy. VII. Identification of 20 Galactic and extragalactic hard X-ray sources
• Chandra Localizations and Spectra of INTEGRAL Sources in the Galactic Plane: The Cycle 9 Sample
• Chandra Localizations and Spectra of INTEGRAL Sources in the Galactic Plane
• Discovery of slow X-ray pulsations in the high-mass X-ray binary 4U 2206+54
• IGR J18483-0311: a new intermediate supergiant fast X-ray transient
• Discovery of an eccentric 30 days period in the supergiant X-ray binary SAX J1818.6-1703 with INTEGRAL
• On the Origin of the 511 keV Emission in the Galactic Centre
• Swift follow-up observations of 17 INTEGRAL sources of uncertain or unknown nature