Revealing the nature of the highly obscured galactic source IGR J16318-4848

The X-ray source IGR J16318-4848 was the first source discovered by INTEGRAL on 2003, January 29. We carried out optical and near-infrared (NIR) observations at the European Southern Observatory (ESO La Silla) in the course of a Target of Opportunity (ToO) programme. We discovered the optical counterpart and confirmed an already proposed NIR candidate. NIR spectroscopy revealed a large amount of emission lines, including forbidden iron lines and P-Cygni profiles. The spectral energy distribution of the source points towards a high luminosity and a high temperature, with an absorption greater than the interstellar absorption, but two orders of magnitude lower than the X-ray absorption. We show that the source is an High Mass X-ray binary (HMXB) at a distance between ~1 and 6 kpc, the mass donor being an early-type star, probably a sgB[e] star, surrounded by a rich and absorbing circumstellar material. This would make the second High Mass X-ray Binary (HMXB) with a sgB[e] star after CI Cam, indicating that a new class of strongly absorbed X-ray binaries is being unveiled by INTEGRAL.Comment: to appear in proceedings of the IAU conference #194, Compact Binaries in the Galaxy and beyond, La Paz, Mexico, 17-22 November 2003, ed. G. Tovmassian & E. Sion, RevMexAA (CS

Assessment of fissionable material behaviour in fission chambers

A comprehensive study is performed in order to assess the pertinence of fission chambers coated with different fissile materials for high neutron flux detection. Three neutron scenarios are proposed to study the fast component of a high neutron flux: (i) high neutron flux with a significant thermal contribution such as BR2, (ii) DEMO magnetic fusion reactor, and (iii) IFMIF high flux test module. In this study, the inventory code ACAB is used to analyze the following questions: (i) impact of different deposits in fission chambers; (ii) effect of the irradiation time/burn-up on the concentration; (iii) impact of activation cross-section uncertainties on the composition of the deposit for all the range of burn-up/irradiation neutron fluences of interest. The complete set of nuclear data (decay, fission yield, activation cross-sections, and uncertainties) provided in the EAF2007 data library are used for this evaluation

A Deductive Verification Platform for Cryptographic Software

In this paper we describe a deductive verification platform for the CAO language. CAO is a domain-specific language for cryptography. We show that this language presents interesting challenges for formal verification, not only in the rich mathematical type system that it introduces, but also in the cryptography-oriented language constructions that it offers. We describe how we tackle these problems, and also demonstrate that, by relying on the Jessie plug-in included in the Frama-C framework, the development time of such a complex verification tool could be greatly reduced. We base our presentation on real-world examples of CAO code, extracted from the open-source code of the NaCl cryptographic library, and illustrate how various cryptography-relevant security properties can be verified

Formal Verification of Floating-Point Programs

This paper introduces a methodology to perform formal verification of floating-point C programs. It extends an ex-isting tool for the verification of C programs, Caduceus, with new annotations specific to floating-point arithmetic. The Caduceus first-order logic model for C programs is ex-tended accordingly. Then verification conditions expressing the correctness of the programs are obtained in the usual way and can be discharged interactively with the Coq proof assistant, using an existing Coq formalization of floating-point arithmetic. This methodology is already implemented and has been successfully applied to several short floating-point programs, which are presented in this paper

Unveiling the nature of IGR J16283-4838

Context. One of the most striking discoveries of the INTEGRAL observatory is the existence of a previously unknown population of X-ray sources in the inner arms of the Galaxy. The investigations of the optical/NIR counterparts of some of them have provided evidence that they are highly absorbed high mass X-ray binaries hosting supergiants. Aims. We aim to identify the optical/NIR counterpart of one of the newly discovered INTEGRAL sources, IGR J16283-4838, and determine the nature of this system. Methods. We present optical and NIR observations of the field of IGR J16283-4838, and use the astrometry and photometry of the sources within it to identify its counterpart. We obtain its NIR spectrum, and its optical/NIR spectral energy distribution by means of broadband photometry. We search for the intrinsic polarization of its light, and its short and long-term photometric variability. Results. We demonstrate that this source is a highly absorbed HMXB located beyond the Galactic center, and that it may be surrounded by a variable circumstellar medium.Comment: 6 pages, 5 figures, accepted for publication in Astronomy & Astrophysic

Recent advances in the first-line treatment of follicular non-Hodgkin lymphoma [version 1; referees: 2 approved]

Follicular lymphoma (FL) is the most common type of indolent B-cell lymphoma. Twenty years ago, FL was considered an indolent lymphoma with a long survival time but without a high rate of complete remission with chemotherapies. The use of rituximab has improved the response and survival of patients with this lymphoma. More recently, development of biological knowledge and use of targeted drugs have offered new perspectives, including improvement of response rates and survival with chemo-free treatment strategies. In 2019, patients have a 10-year overall survival probability of over 70%. Histological transformation to more aggressive lymphoma and treatment relapses remain a medical challenge, especially for patients relapsing within two years. This article will review the recent advances in the treatment of FL. As the use of new drugs is directly related to the development of biological aspects, we will first summarize recent advances in biological aspects of FL

IGR J17544-2619: A new supergiant fast X-ray transient revealed by optical/infrared observations

One of the most recent discoveries of the INTEGRAL observatory is the existence of a previously unknown population of X-ray sources in the inner arms of the Galaxy. IGR J17544-2619, IGR J16465-4507 and XTE J1739-302 are among these sources. Although the nature of these systems is still unexplained, the investigations of the optical/NIR counterparts of the two last sources, combined with high energy data, have provided evidence of them being highly absorbed high mass X-ray binaries with blue supergiant secondaries and displaying fast X-ray transient behaviour. In this work we present our optical/NIR observations of IGR J17544-2619, aimed at identifying and characterizing its counterpart. We show that the source is a high mass X-ray binary at a distance of 2-4 kpc with a strongly absorbed O9Ib secondary, and discuss the nature of the system.Comment: 7 pages, 4 figures. Accepted for publication in A&

Multi-wavelength properties of the high-energy bright Seyfert 1 galaxy IGR J18027-1455

A new sample of hard X-ray sources in the Galactic Plane is being revealed by the regular observations performed by the INTEGRAL satellite. The full characterization of these sources is mandatory to understand the hard X-ray sky. Here we report new multifrequency radio, infrared and optical observations of the source IGR J18027-1455, as well as a multi-wavelength study from radio to hard X-rays. The radio counterpart of IGR J18027-1455 is not resolved at any observing frequency. The radio flux density is well fitted by a simple power law with a spectral index alpha=-0.75+/-0.02. This value is typical of optically thin non-thermal synchrotron emission originated in a jet. The NIR and optical spectra show redshifted emission lines with z=0.034, and a broad Halpha line profile with FWHM ~3400 km/s. This suggests an Active Galactic Nucleus (AGN) of type 1 as the optical counterpart of IGR J18027-1455. We confirm the Seyfert 1 nature of the source, which is intrinsically bright at high energies both in absolute terms and when scaled to a normalized 6 cm luminosity. Finally, comparing its X-ray luminosity with isotropic indicators, we find that the source is Compton thin and AGN dominated. This indicates that INTEGRAL might have just seen the tip of the iceberg, and several tens of such sources should be unveiled during the course of its lifetime.Comment: 6 pages, 6 figures. Accepted for publication in A&A. Minor changes according to referee repor

Microquasar models for 3EG J1828+0142 and 3EG J1735-1500

Microquasars are promising candidates to emit high-energy gamma-rays. Moreover, statistical studies show that variable EGRET sources at low galactic latitudes could be associated with the inner spiral arms. The variable nature and the location in the Galaxy of the high-mass microquasars, concentrated in the galactic plane and within 55 degrees from the galactic center, give to these objects the status of likely counterparts of the variable low-latitude EGRET sources. We consider in this work the two most variable EGRET sources at low-latitudes: 3EG J1828+0142 and 3EG J1735-1500, proposing a microquasar model to explain the EGRET data in consistency with the observations at lower energies (from radio frequencies to soft gamma-rays) within the EGRET error box.Comment: (1)Universitat de Barcelona, (2)Instituto Argentino de Radioastronomia (3) Facultad de Ciencias Astronomicas y Geofisicas (4)Lawrence Livermore National Laboratory 6 pages, 2 figures. Presented as a poster at the V Microquasar Workshop, Beijing, June 2004. Accepted for publication in the Chinese Journal of Astronomy & Astrophysic

Open issues in gamma-ray bursts: polarimetry and dark GRBs

We review some open problems in the physics of afterglows, namely their polarization properties and the existence of dark/faint bursts. Polarization studies yield precious insights in the physical structure and dynamical evolution of GRB jets, revealing their magnetization properties and their energy profile. Polarimetric observations of GRB 020813 already allowed to exclude a homogeneous jet for this event. We then present observations of faint/dark bursts, showing that some of them may be obscured by dust, while others are possibly just intrinsically dim.Comment: 6 pages, 3 figures. Proceedings of the 4th Workshop "Gamma-Ray Bursts in the Afterglow Era", Roma, 2004 October 18-22, eds. L. Piro, L. Amati, S. Covino, and B. Gendre. Il Nuovo Cimento, in pres