High-excitation OH and H_2O lines in Markarian 231: the molecular signatures of compact far-infrared continuum sources

The ISO/LWS far-infrared spectrum of the ultraluminous galaxy Mkn 231 shows OH and H_2O lines in absorption from energy levels up to 300 K above the ground state, and emission in the [O I] 63 micron and [C II] 158 micron lines. Our analysis shows that OH and H_2O are radiatively pumped by the far-infrared continuum emission of the galaxy. The absorptions in the high-excitation lines require high far-infrared radiation densities, allowing us to constrain the properties of the underlying continuum source. The bulk of the far-infrared continuum arises from a warm (T_dust=70-100 K), optically thick (tau_100micron=1-2) medium of effective diameter 200-400 pc. In our best-fit model of total luminosity L_IR, the observed OH and H2O high-lying lines arise from a luminous (L/L_IR~0.56) region with radius ~100 pc. The high surface brightness of this component suggests that its infrared emission is dominated by the AGN. The derived column densities N(OH)>~10^{17} cm^{-2} and N(H_2O)>~6x10^{16} cm^{-2} may indicate XDR chemistry, although significant starburst chemistry cannot be ruled out. The lower-lying OH, [C II] 158 micron, and [O I] 63 micron lines arise from a more extended (~350 pc) starburst region. We show that the [C II] deficit in Mkn 231 is compatible with a high average abundance of C+ because of an extreme overall luminosity to gas mass ratio. Therefore, a [C II] deficit may indicate a significant contribution to the luminosity by an AGN, and/or by extremely efficient star formation.Comment: 16 pages, 6 figures, accepted for publication in The Astrophysical Journa

Atomic Diagnostics of X-ray Irradiated Protoplanetary Disks

We study atomic line diagnostics of the inner regions of protoplanetary disks with our model of X-ray irradiated disk atmospheres which was previously used to predict observable levels of the NeII and NeIII fine-structure transitions at 12.81 and 15.55mum. We extend the X-ray ionization theory to sulfur and calculate the fraction of sulfur in S, S+, S2+ and sulfur molecules. For the D'Alessio generic T Tauri star disk, we find that the SI fine-structure line at 25.55mum is below the detection level of the Spitzer Infrared Spectrometer (IRS), in large part due to X-ray ionization of atomic S at the top of the atmosphere and to its incorporation into molecules close to the mid-plane. We predict that observable fluxes of the SII 6718/6732AA forbidden transitions are produced in the upper atmosphere at somewhat shallower depths and smaller radii than the neon fine-structure lines. This and other forbidden line transitions, such as the OI 6300/6363AA and the CI 9826/9852AA lines, serve as complementary diagnostics of X-ray irradiated disk atmospheres. We have also analyzed the potential role of the low-excitation fine-structure lines of CI, CII, and OI, which should be observable by SOFIA and Herschel.Comment: Accepted by Ap

Outcomes in antiretroviral-naive HIV-infected patients initiating therapy with TDF/FTC plus either atazanavir/r or another third recommended drug

POSTER PRESENTATIONInternational audienceN.

A model for atomic and molecular interstellar gas: The Meudon PDR code

We present the revised ``Meudon'' model of Photon Dominated Region (PDR code), presently available on the web under the Gnu Public Licence at: http://aristote.obspm.fr/MIS. General organisation of the code is described down to a level that should allow most observers to use it as an interpretation tool with minimal help from our part. Two grids of models, one for low excitation diffuse clouds and one for dense highly illuminated clouds, are discussed, and some new results on PDR modelisation highlighted.Comment: accepted in ApJ sup

The gas temperature in flaring disks around pre-main sequence stars

A model is presented which calculates the gas temperature and chemistry in the surface layers of flaring circumstellar disks using a code developed for photon-dominated regions. Special attention is given to the influence of dust settling. It is found that the gas temperature exceeds the dust temperature by up to several hundreds of Kelvins in the part of the disk that is optically thin to ultraviolet radiation, indicating that the common assumption that Tgas=Tdust is not valid throughout the disk. In the optically thick part, gas and dust are strongly coupled and the gas temperature equals the dust temperature. Dust settling has little effect on the chemistry in the disk, but increases the amount of hot gas deeper in the disk. The effects of the higher gas temperature on several emission lines arising in the surface layer are examined. The higher gas temperatures increase the intensities of molecular and fine-structure lines by up to an order of magnitude, and can also have an important effect on the line shapes.Comment: 14 pages, 10 figures, accepted for publication in A&

Multichannel quantum-defect theory for ultracold atom-ion collisions

We develop an analytical model for ultracold atom-ion collisions using the multichannel quantum-defect formalism. The model is based on the analytical solutions of the r^-4 long-range potential and on the application of a frame transformation between asymptotic and molecular bases. This approach allows the description of the atom-ion interaction in the ultracold domain in terms of three parameters only: the singlet and triplet scattering lengths, assumed to be independent of the relative motion angular momentum, and the lead dispersion coefficient of the asymptotic potential. We also introduce corrections to the scattering lengths that improve the accuracy of our quantum-defect model for higher order partial waves, a particularly important result for an accurate description of shape and Feshbach resonances at finite temperature. The theory is applied to the system composed of a 40Ca+ ion and a Na atom, and compared to numerical coupled-channel calculations carried out using ab initio potentials. For this particular system, we investigate the spectrum of bound states, the rate of charge-transfer processes, and the collision rates in the presence of magnetic Feshbach resonances at zero and finite temperature.Comment: 39 pages, 21 figure

An Interstellar Conduction Front Within a Wolf-Rayet Ring Nebula Observed with the GHRS

With the High Resolution Spectrograph aboard the Hubble Space Telescope we obtained high signal-to-noise (S/N > 200 - 600 per 17 km/s resolution element) spectra of narrow absorption lines toward the Wolf-Rayet star HD 50896. The ring nebula S308 that surrounds this star is thought to be caused by a pressure-driven bubble bounded by circumstellar gas (most likely from a red supergiant or luminous blue variable progenitor) pushed aside by a strong stellar wind. Our observation has shown for the first time that blueshifted (approximately 70 km/s relative to the star) absorption components of C IV and N V arise in a conduction front between the hot interior of the bubble and the cold shell of swept-up material. These lines set limits on models of the conduction front. Nitrogen in the shell appears to be overabundant by a factor ~10. The P Cygni profiles of N V and C IV are variable, possibly due to a suspected binary companion to HD 50896.Comment: 32 pages, Latex, to appear in the Astrophysical Journal, April, 199

Virological outcomes in ARV-naïve patients switching or not from a first successful boosted PI-regimen to efavirenz, nevirapine or abacavir regimens

International audiencen.

Field-linked States of Ultracold Polar Molecules

We explore the character of a novel set of ``field-linked'' states that were predicted in [A. V. Avdeenkov and J. L. Bohn, Phys. Rev. Lett. 90, 043006 (2003)]. These states exist at ultralow temperatures in the presence of an electrostatic field, and their properties are strongly dependent on the field's strength. We clarify the nature of these quasi-bound states by constructing their wave functions and determining their approximate quantum numbers. As the properties of field-linked states are strongly defined by anisotropic dipolar and Stark interactions, we construct adiabatic surfaces as functions of both the intermolecular distance and the angle that the intermolecular axis makes with the electric field. Within an adiabatic approximation we solve the 2-D Schrodinger equation to find bound states, whose energies correlate well with resonance features found in fully-converged multichannel scattering calculations

Value of systolic pulmonary arterial pressure as a prognostic factor of death in the systemic sclerosis EUSTAR population.

The aim of this study was to assess the prognostic value of systolic pulmonary artery pressure (sPAP) estimated by echocardiography in the multinational European League Against Rheumatism Scleroderma Trial and Research (EUSTAR) cohort.Data for patients with echocardiography documented between 1 January 2005 and 31 December 2011 were extracted from the EUSTAR database. Stepwise forward multivariable statistical Cox pulmonary hypertension analysis was used to examine the independent effect on survival of selected variables.Based on our selection criteria, 1476 patients were included in the analysis; 87\% of patients were female, with a mean age of 56.3 years (s.d. 13.5) and 31\% had diffuse SSc. The mean duration of follow-up was 2.0 years (s.d. 1.2, median 1.9). Taking index sPAP of 50 mmHg. In a multivariable Cox model, sPAP and the diffusing capacity for carbon monoxide (DLCO) were independently associated with the risk of death [HR 1.833 (95\% CI 1.035, 3.247) and HR 0.973 (95\% CI 0.955, 0.991), respectively]. sPAP was an independent risk factor for death with a HR of 3.02 (95\% CI 1.91, 4.78) for sPAP ≥36 mmHg.An estimated sPAP >36 mmHg at baseline echocardiography was significantly and independently associated with reduced survival, regardless of the presence of pulmonary hypertension based on right heart catheterization