[en] To date, mid-infrared properties of Galactic black hole binaries have barely been investigated in the framework of multi-wavelength campaigns. Yet, studies in this spectral domain are crucial to get complementary information on the presence of dust and/or on the physical processes such as dust heating and thermal bremsstrahlung. Here, we report a long-term multi-wavelength study of the microquasar GRS 1915+105. On the one hand, we aimed at understanding the origins of the mid-infrared emission, and on the other hand, at searching for correlation with the high-energy and/or radio activities. We observed the source at several epochs between 2004 and 2006 with the photometer IRAC and spectrometer IRS, both mounted on the Spitzer Space Telescope. When available, we completed our set of data with quasi-simultaneous RXTE/INTEGRAL high-energy and/or Ryle radio observations from public archives. We then studied the mid-infrared environment and activities of GRS 1915+105 through spectral analysis and broadband fitting of its radio to X-ray spectral energy distributions. We detected polycyclic aromatic hydrocarbon molecules in all but one IRS spectra of GRS 1915+105 which unambiguously proves the presence of a dust component, likely photoionized by the high-energy emission. We also argue that this dust is distributed in a disk-like structure heated by the companion star, as observed in some Herbig Ae/Be and isolated cool giant stars. Moreover, we show that some of the soft X-ray emission emanating from the inner regions of the accretion disk is reprocessed and thermalized in the outer part. This leads to a mid-infrared excess that is very likely correlated to the soft X-ray emission. We exclude thermal bremsstrahlung as contributing significantly in this spectral domain.

[en] The IBIS Telescope is the high angular resolution Gamma-Ray imager on-Board the INTEGRAL Satellite. IBIS features a coded aperture mask and a novel large area (∼3,000 cm2) multilayer detector which utilises both Cadmium Telluride (16,384 detectors) and Caesium Iodide elements (4,096 detectors) to provide the fine angular resolution ∼12 arcmin, wide spectral response (20 keV to 10 MeV), high resolution timing (61 μs) and spectroscopy (6% at 100 keV) required to satisfy the mission's imaging objectives. This paper will focus on the IBIS hardware characteristics while the Scientific Performance of the telescope have been recently addressed elsewhere [1]

[en] We present a new, detailed analysis of the morphologies and molecular gas fractions (MGFs) for a complete sample of 65 local luminous infrared galaxies from Great Observatories All-Sky Luminous Infrared Galaxies (LIRG) Survey using high resolution I-band images from The Hubble Space Telescope, the University of Hawaii 2.2 m Telescope and the Pan-STARRS1 Survey. Our classification scheme includes single undisturbed galaxies, minor mergers, and major mergers, with the latter divided into five distinct stages from pre-first pericenter passage to final nuclear coalescence. We find that major mergers of molecular gas-rich spirals clearly play a major role for all sources with $L_{\mathrm{I}\mathrm{R}}><!--\; >\; -->{10}^{11.5}{L}_{\odot <!--\; ???\; -->};$ however, below this luminosity threshold, minor mergers and secular processes dominate. Additionally, galaxies do not reach $L_{\mathrm{I}\mathrm{R}}><!--\; >\; -->{10}^{12.0}{L}_{\odot <!--\; ???\; -->}$ until late in the merger process when both disks are near final coalescence. The mean MGF ($\mathrm{M}\mathrm{G}\mathrm{F}=M_{{\mathrm{H}}_2}/(M_{\ast <!--\; ???\; -->}+M_{{\mathrm{H}}_2})$) for non-interacting and early-stage major merger LIRGs is 18 ± 2%, which increases to 33 ± 3%, for intermediate stage major merger LIRGs, consistent with the hypothesis that, during the early-mid stages of major mergers, most of the initial large reservoir of atomic gas (HI) at large galactocentric radii is swept inward where it is converted into molecular gas (H₂).