The X-ray binary, black hole candidate, and microquasar H1743-322 exhibited a series of X-ray outbursts between 2003 and 2008. We took optical/infrared (OIR) observations with the ESO/NTT telescope during 3 of these outbursts (2003, 2004, and 2008),
to study its spectral energy distribution (SED). We detect rapid flares of duration ~5 mn in the high time-resolution IR lightcurve. We identify H and He emission lines in the IR spectra, coming from the accretion disk. The IR SED exhibits the spectral index typically associated with the X-ray high, soft state in our observations taken during the 2003 and 2004 outbursts, while the index changes to one that is typical of the X-ray low, hard state during the 2008 outburst. During this last outburst, we detected a change of slope in the NIR spectrum between the J and Ks bands, where the JH part is characteristic of an optically thick disk emission, while the HKs part is typical of optically thin synchrotron emission. Furthermore, the comparison of our IR data with radio and X-ray data shows that H1743-322 exhibits a faint jet both in radio and NIR domains. Finally, we suggest that the companion star is a late-type main sequence star located in the Galactic bulge. These OIR photometric and spectroscopic observations of the microquasar H1743-322, the first of this source to be published in a broad multiwavelength context, allow us to unambiguously identify two spectra of different origins in the OIR domain, evolving from optically thick thermal emission to optically thin synchrotron emission toward longer wavelengths. Comparing these OIR observations with other black hole candidates suggests that H1743-322 behaves like a radio-quiet and NIR-dim black hole in the low, hard state. This study will be useful when quantitatively comparing the overall contribution of the compact jet and accretion flow in the energy budget of microquasars.
In this review I first describe the nature of the three kinds of High-Mass X-ray Binaries (HMXBs), accreting through: (i) Be circumstellar disc, (ii) supergiant stellar wind, and (iii) Roche lobe filling supergiants. I then report on the discovery of
two new populations of HMXBs hosting supergiant stars, recently revealed by a wealth of new observations, coming from the high energy side (INTEGRAL, Swift, XMM, Chandra satellites), and complemented by multi-wavelength optical/infrared observations (mainly ESO facilities). The first population is constituted of obscured supergiant HMXBs, the second one of supergiant fast X-ray transients (SFXTs), exhibiting short and intense X-ray flares. I finally discuss the formation and evolution of HMXBs, constrain the accretion models (e.g. clumpy winds, transitory accretion disc, magneto-centrifugal barrier), show evidences suggesting the existence of an evolutionary link, include comparisons with population synthesis models, and finally build a consistent scenario explaining the various characteristics of these extreme celestial sources. Because they are the likely progenitors of Luminous Blue Variables (LBVs), and also of neutron star/black hole binary mergers, related to short/hard gamma-ray bursts, the knowledge of the nature, formation and evolution of these HMXB populations is of prime importance.
We describe here the nature, formation and evolution of the supergiant high mass X-ray binary (HMXB) population, i.e. systems accreting the stellar wind of supergiant stars. There are now many new observations, from the high-energy side (mainly from
the INTEGRAL satellite), complemented by multi-wavelength observations (mainly in the optical, near and mid-infrared from ESO facilities), showing that a new population of supergiant HMXBs has been recently revealed. We report here on the observational facts about the different categories of HMXBs, allowing to build a consistent scenario explaining the various characteristics of these sources, based on models of accretion in these sources (e.g. transitory accretion disc versus clumpy winds). We also mention new observations suggesting the existence of evolutionary links between Be and stellar wind accreting supergiant X-ray binaries.
We present preliminary results on Herschel/PACS mid/far-infrared photometric observations of INTEGRAL supergiant High Mass X-ray Binaries (HMXBs), with the aim of detecting the presence and characterizing the nature of absorbing material (dust and/or
cold gas), either enshrouding the whole binary systems, or surrounding the sources within their close environment. These unique observations allow us to better characterize the nature of these HMXBs, to constrain the link with their environment (impact and feedback), and finally to get a better understanding of the formation and evolution of such rare and short-living supergiant HMXBs in our Galaxy.
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-inf
rared 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.
The aim of this review is to describe the nature, formation and evolution of the three kinds of high mass X-ray binary (HMXB) population: i. systems hosting Be stars (BeHMXBs), ii. systems accreting the stellar wind of supergiant stars (sgHMXBs), and
iii. supergiant stars overflowing their Roche lobe. There are now many new observations, from the high-energy side (mainly from the INTEGRAL satellite), complemented by multi-wavelength observations (mainly in the optical, near and mid-infrared from ESO facilities), showing that a new population of supergiant HMXBs has been recently revealed. New observations also suggest the existence of evolutionary links between Be and stellar wind accreting supergiant X-ray binaries. I describe here the observational facts about the different categories of HMXBs, discuss the different models of accretion in these sources (e.g. transitory accretion disc versus clumpy winds), show the evidences of a link between different kinds of HMXBs, and finally compare observations with population synthesis models.
