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TOPIC: High Mass X-ray Binary System (HMXB)

Blobrana

L

Posts: 131433

Date: May 11 17:58 2012

IGR J16318-4848	Permalink

Title: Broadband ESO/VISIR-Spitzer infrared spectroscopy of the obscured supergiant X-ray Binary IGR J16318-4848 Authors: Sylvain Chaty, Farid Rahoui A new class of X-ray binaries has been recently discovered by the high energy observatory, INTEGRAL. It is composed of intrinsically obscured supergiant high mass X-ray binaries, unveiled by means of multi-wavelength X-ray, optical, near- and mid-infrared observations, in particular photometric and spectroscopic observations using ESO facilities. However the fundamental questions about these intriguing sources, namely their formation, evolution, and the nature of their environment, are still unsolved. Among them, IGR J16318-4848 - a compact object orbiting around a supergiant B[e] star - seems to be one of the most extraordinary celestial sources of our Galaxy. We present here new ESO/VLT VISIR mid-infrared (MIR) spectroscopic observations of this source. First, line diagnostics allow us to confirm the presence of absorbing material (dust and cold gas) enshrouding the whole binary system, and to characterise the nature of this material. Second, by fitting broadband near to mid-infrared Spectral Energy Distribution - including ESO NTT/SofI, VLT/VISIR and Spitzer data - with a phenomenological model for sgB[e] stars, we show that the star is surrounded by an irradiated rim heated to a temperature of 3800-5500 K, along with a viscous disk component at an inner temperature of 750 K. VISIR data allow us to exclude the spherical geometry for the dust component. This detailed study will allow us in the future to get better constraints on the formation and evolution of such rare and short-living high mass X-ray binary systems in our Galaxy. Read more (232kb, PDF) __________________

Blobrana

L

Posts: 131433

Date: Feb 8 12:09 2007

High Mass X-ray Binary System (HMXB)	Permalink

IGR J16318-4848 Astronomers have found a new class of objects in space: a neutron star orbiting inside a cocoon of cold gas and/or dust that hides a bloated supergiant star. In a strange twist of fate, these objects may be tremendously luminous, but the enshrouding cocoon absorbs almost all their emission, making them nearly invisible to telescopes on Earth until now. These findings were presented on Feb. 5, 2007 by Dr. Sylvain Chaty of the University Paris 7 and Service d'Astrophysique, CEA, France, at the first Gamma Ray Large-Area Space Telescope (GLAST) scientific Symposium meeting in Palo Alto, California. This result, obtained through multi-wavelength observations, is of special interest because it revolutionizes the view scientists have on the formation, evolution, and fate of massive stars in close binary (twin star) systems. Furthermore, this clearly demonstrates that the GLAST satellite will likely discover more of these new and unexpected celestial objects. This new class of objects was discovered using the European ”INTErnational Gamma-Ray Astrophysics Laboratory” (INTEGRAL) satellite. Twenty of these binary systems were found, with estimated distances lying between 7,000 and 25,000 light years from Earth, putting them all inside of our own Milky Way Galaxy. The nature of these sources was revealed through multi-wavelength observations, mainly from optical to mid-infrared (MIR) wavelengths, using European Southern Observatory (ESO) facilities. Read more __________________

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