1,513 research outputs found
Resolving the molecular gas around the lensed quasar RXJ0911.4+0551
We report on high angular resolution observations of the CO(7-6) line and
millimeter continuum in the host galaxy of the gravitationally lensed (z~2.8)
quasar RXJ0911.4+0551 using the Plateau de Bure Interferometer. Our CO
observations resolve the molecular disk of the source. Using a lens model based
on HST observations we fit source models to the observed visibilities. We
estimate a molecular disk radius of 10.2 kpc and an inclination of
696\deg, the continuum is more compact and is only marginally resolved by
our observations. The relatively low molecular gas mass, Msolar, and far infrared luminosity, Lsolar, of this quasar could be explained by its relatively low
dynamical mass, Msolar. It would be a
scaled-down version the QSOs usually found at high-z. The FIR and CO
luminosities lie on the correlation found for QSOs from low to high redshifts
and the gas-to-dust ratio () is similar to the one measured in the
z=6.4 QSO, SDSS J1148+5251. Differential magnification affects the
continuum-to-line luminosity ratio, the line profile and possibly the spectral
energy distribution.Comment: Accepted for publication in A&A, revised after language editin
Constraining the Thermal Dust Content of Lyman-Break Galaxies in an Overdense Field at z~5
We have carried out 870 micron observations in the J1040.7-1155 field, known
to host an overdensity of Lyman break galaxies at z=5.16 +/- 0.05. We do not
detect any individual source at the S(870)=3.0 mJy/beam (2 sigma) level. A
stack of nine spectroscopically confirmed z>5 galaxies also yields a
non-detection, constraining the submillimeter flux from a typical galaxy at
this redshift to S(870)<0.85 mJy, which corresponds to a mass limit
M(dust)<1.2x10^8 M_sun (2 sigma). This constrains the mass of thermal dust in
distant Lyman break galaxies to less than one tenth of their typical stellar
mass. We see no evidence for strong submillimeter galaxies associated with the
ultraviolet-selected galaxy overdensity, but cannot rule out the presence of
fainter, less massive sources.Comment: 5 pages, 2 figures. MNRAS in pres
Culture of human bone marrow in the Teflon culture bag : Identification of the human monoblast
Contains fulltext :
4419.pdf (publisher's version ) (Open Access
A Novel Mouse Model of Peritoneal Dialysis: Combination of Uraemia and Long-Term Exposure to PD Fluid
Different animal models for peritoneal dialysis (PD) have been used in the past decades to develop PD fluids compatible with patient life and to identify markers of peritoneal fibrosis and inflammation. Only few of those studies have taken into account the importance of uraemia-induced alterations at both systemic and peritoneal levels. Moreover, some animal studies which have reported about PD in a uremic setting did not always entirely succeed in terms of uraemia establishment and animal survival. In the present study we induced uraemia in the recently established mouse PD exposure model in order to obtain a more clinically relevant mouse model for kidney patients. This new designed model reflected both the slight thickening of peritoneal membrane induced by uraemia and the significant extracellular matrix deposition due to daily PD fluid instillation. In addition the model offers the opportunity to perform long-term exposure to PD fluids, as it is observed in the clinical setting, and gives the advantage to knock out candidate markers for driving peritoneal inflammatory mechanisms.Marie Curie actionsPeer Reviewe
Structure formation in a colliding flow: The Herschel view of the Draco nebula
The Draco nebula is a high Galactic latitude interstellar cloud likely to
have been formed by the collision of a Galactic halo cloud entering the disk of
the Milky Way. Such conditions are ideal to study the formation of cold and
dense gas in colliding flows of warm gas. We present Herschel-SPIRE
observations that reveal the fragmented structure of the interface between the
infalling cloud and the Galactic layer. This front is characterized by a
Rayleigh-Taylor instability structure. From the determination of the typical
length of the periodic structure (2.2 pc) we estimated the gas kinematic
viscosity and the turbulence dissipation scale (0.1 pc) that is compatible with
that expected if ambipolar diffusion is the main mechanism of energy
dissipation in the WNM. The small-scale structures of the nebula are typical of
that seen in some molecular clouds. The gas density has a log-normal
distribution with an average value of cm. The size of the
structures is 0.1-0.2 pc but this estimate is limited by the resolution of the
observations. The mass ranges from 0.2 to 20 M and the distribution
of the more massive clumps follows a power law . We
identify a mass-size relation with the same exponent as that found in GMCs
() but only 15% of the mass of the cloud is in gravitationally
bound structures. We conclude that the increase of pressure in the collision is
strong enough to trigger the WNM-CNM transition caused by the interplay between
turbulence and thermal instability as self-gravity is not dominating the
dynamics.Comment: 16 pages, A&A, in pres
Studying the first galaxies with ALMA
We discuss observations of the first galaxies, within cosmic reionization, at
centimeter and millimeter wavelengths. We present a summary of current
observations of the host galaxies of the most distant QSOs (). These
observations reveal the gas, dust, and star formation in the host galaxies on
kpc-scales. These data imply an enriched ISM in the QSO host galaxies within 1
Gyr of the big bang, and are consistent with models of coeval supermassive
black hole and spheroidal galaxy formation in major mergers at high redshift.
Current instruments are limited to studying truly pathologic objects at these
redshifts, meaning hyper-luminous infrared galaxies (
L). ALMA will provide the one to two orders of magnitude improvement in
millimeter astronomy required to study normal star forming galaxies (ie.
Ly- emitters) at . ALMA will reveal, at sub-kpc spatial
resolution, the thermal gas and dust -- the fundamental fuel for star formation
-- in galaxies into cosmic reionization.Comment: to appear in Science with ALMA: a new era for Astrophysics}, ed. R.
Bachiller (Springer: Berlin); 5 pages, 7 figure
Planck's Dusty GEMS: Gravitationally lensed high-redshift galaxies discovered with the Planck survey
We present an analysis of 11 bright far-IR/submm sources discovered through a
combination of the Planck survey and follow-up Herschel-SPIRE imaging. Each
source has a redshift z=2.2-3.6 obtained through a blind redshift search with
EMIR at the IRAM 30-m telescope. Interferometry obtained at IRAM and the SMA,
and optical/near-infrared imaging obtained at the CFHT and the VLT reveal
morphologies consistent with strongly gravitationally lensed sources.
Additional photometry was obtained with JCMT/SCUBA-2 and IRAM/GISMO at 850 um
and 2 mm, respectively. All objects are bright, isolated point sources in the
18 arcsec beam of SPIRE at 250 um, with spectral energy distributions peaking
either near the 350 um or the 500 um bands of SPIRE, and with apparent
far-infrared luminosities of up to 3x10^14 L_sun. Their morphologies and sizes,
CO line widths and luminosities, dust temperatures, and far-infrared
luminosities provide additional empirical evidence that these are strongly
gravitationally lensed high-redshift galaxies. We discuss their dust masses and
temperatures, and use additional WISE 22-um photometry and template fitting to
rule out a significant contribution of AGN heating to the total infrared
luminosity. Six sources are detected in FIRST at 1.4 GHz. Four have flux
densities brighter than expected from the local far-infrared-radio correlation,
but in the range previously found for high-z submm galaxies, one has a deficit
of FIR emission, and 6 are consistent with the local correlation. The global
dust-to-gas ratios and star-formation efficiencies of our sources are
predominantly in the range expected from massive, metal-rich, intense,
high-redshift starbursts. An extensive multi-wavelength follow-up programme is
being carried out to further characterize these sources and the intense
star-formation within them.Comment: A&A accepte
Cross-sectional associations between air pollution and chronic bronchitis: an ESCAPE meta-analysis across five cohorts
BACKGROUND: This study aimed to assess associations of outdoor air pollution on prevalence of chronic bronchitis symptoms in adults in five cohort studies (Asthma-E3N, ECRHS, NSHD, SALIA, SAPALDIA) participating in the European Study of Cohorts for Air Pollution Effects (ESCAPE) project. METHODS: Annual average particulate matter (PM10, PM2.5, PMabsorbance, PMcoarse), NO2, nitrogen oxides (NOx) and road traffic measures modelled from ESCAPE measurement campaigns 2008-2011 were assigned to home address at most recent assessments (1998-2011). Symptoms examined were chronic bronchitis (cough and phlegm for ≥3 months of the year for ≥2 years), chronic cough (with/without phlegm) and chronic phlegm (with/without cough). Cohort-specific cross-sectional multivariable logistic regression analyses were conducted using common confounder sets (age, sex, smoking, interview season, education), followed by meta-analysis. RESULTS: 15 279 and 10 537 participants respectively were included in the main NO2 and PM analyses at assessments in 1998-2011. Overall, there were no statistically significant associations with any air pollutant or traffic exposure. Sensitivity analyses including in asthmatics only, females only or using back-extrapolated NO2 and PM10 for assessments in 1985-2002 (ECRHS, NSHD, SALIA, SAPALDIA) did not alter conclusions. In never-smokers, all associations were positive, but reached statistical significance only for chronic phlegm with PMcoarse OR 1.31 (1.05 to 1.64) per 5 µg/m(3) increase and PM10 with similar effect size. Sensitivity analyses of older cohorts showed increased risk of chronic cough with PM2.5abs (black carbon) exposures. CONCLUSIONS: Results do not show consistent associations between chronic bronchitis symptoms and current traffic-related air pollution in adult European populations
Study of the Quantum Efficiency of CsI Photocathodes Exposed to Oxygen and Water Vapour
The operation of CsI photocathodes in gaseous detectors requires special attention to the purity of the applied gas mixtures.We have studied the influence of oxygen and water vapour contaminations on the performance of CsI photocathodes for theALICE HMPID RICH prototype. Measurements were done through comparison of Cherenkov rings obtained from beamtests. Increased levels of oxygen and water vapour did not show any effect on the performance. The results of this studyfound a direct application in the way of storing CsI photocathodes over long periods nad in particular in the shipment of theHMPID prototype from CERN to the STAR experiment at BNL. (Abstract only available,full text to follow
Far-Infrared Properties of Spitzer-selected Luminous Starbursts
We present SHARC-2 350 micron data on 20 luminous z ~ 2 starbursts with
S(1.2mm) > 2 mJy from the Spitzer-selected samples of Lonsdale et al. and
Fiolet et al. All the sources were detected, with S(350um) > 25 mJy for 18 of
them. With the data, we determine precise dust temperatures and luminosities
for these galaxies using both single-temperature fits and models with power-law
mass--temperature distributions. We derive appropriate formulae to use when
optical depths are non-negligible. Our models provide an excellent fit to the
6um--2mm measurements of local starbursts. We find characteristic
single-component temperatures T1 ~ 35.5+-2.2 K and integrated infrared (IR)
luminosities around 10^(12.9+-0.1) Lsun for the SWIRE-selected sources.
Molecular gas masses are estimated at 4 x 10^(10) Msun, assuming
kappa(850um)=0.15 m^2/kg and a submillimeter-selected galaxy (SMG)-like
gas-to-dust mass ratio. The best-fit models imply >~2 kpc emission scales. We
also note a tight correlation between rest-frame 1.4 GHz radio and IR
luminosities confirming star formation as the predominant power source. The
far-IR properties of our sample are indistinguishable from the purely
submillimeter-selected populations from current surveys. We therefore conclude
that our original selection criteria, based on mid-IR colors and 24 um flux
densities, provides an effective means for the study of SMGs at z ~ 1.5--2.5.Comment: 13 pages, 4 figures, edited to match published version in ApJ 717,
29-39 (2010
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