108 research outputs found
Acute life-threatening extrinsic allergic alveolitis in a paint controller
Background Occupational diisocyanate-induced extrinsic allergic alveolitis (EAA) is a rare and probably underestimated diagnosis. Two acute occupational EAA cases have been described in this context, but neither of them concerned hexamethylene diisocyanate (HDI) exposure. Aims To investigate the cause of a life-threatening EAA arising at work in a healthy 30-year-old female paint quality controller. Methods Occupational medical assessment, workplace evaluation, airborne and biological monitoring and immunodermatological tests. Results Diagnosis of EAA relied on congruent clinical and radiological information, confirmed occupational HDI exposure and positive IgG antibodies and patch tests. The patient worked in a small laboratory for 7 years, only occasionally using HDI-containing hardeners. While working with HDI for 6 h, she developed breathlessness, rapidly progressing to severe respiratory failure. Workplace HDI airborne exposure values ranged from undetectable levels to 4.25 p.p.b. Biological monitoring of urinary hexamethylene diamine in co-workers ranged from <1.0 to 15.4 μg/g creatinine. Patch tests 8 months later showed delayed skin reaction to HDI at 48 h. Subsequent skin biopsy showed spongiotic dermatitis with infiltration of CD4+ and CD8+ T cells. Conclusions We believe this is the first reported case of acute life-threatening EAA following exposure to HDI. Low concentrations of airborne HDI and relatively high urinary hexamethylene diamine suggest significant skin absorption of HDI could have significantly contributed to the development of this acute occupational EA
The EMPIRE Survey: Systematic Variations in the Dense Gas Fraction and Star Formation Efficiency from Full-Disk Mapping of M51
We present the first results from the EMPIRE survey, an IRAM large program
that is mapping tracers of high density molecular gas across the disks of nine
nearby star-forming galaxies. Here, we present new maps of the 3-mm transitions
of HCN, HCO+, and HNC across the whole disk of our pilot target, M51. As
expected, dense gas correlates with tracers of recent star formation, filling
the "luminosity gap" between Galactic cores and whole galaxies. In detail, we
show that both the fraction of gas that is dense, f_dense traced by HCN/CO, and
the rate at which dense gas forms stars, SFE_dense traced by IR/HCN, depend on
environment in the galaxy. The sense of the dependence is that high surface
density, high molecular gas fraction regions of the galaxy show high dense gas
fractions and low dense gas star formation efficiencies. This agrees with
recent results for individual pointings by Usero et al. 2015 but using unbiased
whole-galaxy maps. It also agrees qualitatively with the behavior observed
contrasting our own Solar Neighborhood with the central regions of the Milky
Way. The sense of the trends can be explained if the dense gas fraction tracks
interstellar pressure but star formation occurs only in regions of high density
contrast.Comment: 7 pages, 5 figures, ApJL accepte
The history of star-forming regions in the tails of 6 GASP jellyfish galaxies observed with the Hubble Space Telescope
Using images collected with the WFC3 camera on board of the Hubble Space
Telescope, we detect stellar clumps in continuum-subtracted and
ultraviolet (F275W filter), such clumps are often embedded in larger regions
(star-forming complexes) detected in the optical (F606W filter). We model the
photometry of these objects using BAGPIPES to obtain their stellar population
parameters. The median mass-weighted stellar ages are 27 Myr for
clumps and 39 Myr for F275W clumps and star-forming complexes, the oldest stars
in the complexes can be older than 300 Myr which indicates that
star-formation is sustained for long periods of time. Stellar masses vary from
10 to 10 , with star-forming complexes being more
massive objects in the sample. Clumps and complexes found further away from the
host galaxy are younger, less massive and less obscured by dust. We interpret
these trends as due to the effect of ram-pressure in different phases of the
interstellar medium. clumps form a well-defined sequence in the
stellar mass--SFR plane with slope 0.73. Some F275W clumps and star-forming
complexes follow the same sequence while others stray away from it and
passively age. The difference in stellar age between a complex and its youngest
embedded clump scales with the distance between the clump and the center of the
complex, with the most displaced clumps being hosted by the most elongated
complexes. This is consistent with a fireball-like morphology, where
star-formation proceeds in a small portion of the complex while older stars are
left behind producing a linear stellar population gradient. The stellar masses
of star-forming complexes are consistent with the ones of globular clusters,
but stellar mass surface densities are lower by 2 dex, and their properties are
more consistent with the population of dwarf galaxies in clusters.Comment: Accepted for publication in A&
GASP XXXIV: Unfolding the thermal side of ram pressure stripping in the jellyfish galaxy JO201
X-ray studies of jellyfish galaxies play a crucial role in understanding the
interactions between the interstellar medium (ISM) and the intracluster medium
(ICM). In this paper, we focused on the jellyfish galaxy JO201. By combining
archival Chandra observations, MUSE H cubes, and maps of the emission
fraction of the diffuse ionised gas, we investigated both its high energy
spectral properties and the spatial correlation between its X-ray and optical
emissions. The X-ray emission of JO201 is provided by both the Compton thick
AGN (L=2.710 erg s, not
corrected for intrinsic absorption) and an extended component
(L1.9-4.510 erg
s) produced by a warm plasma (kT1 keV), whose luminosity is
higher than expected from the observed star formation
(L3.8 erg s). The spectral analysis
showed that the X-ray emission is consistent with the thermal cooling of hot
plasma. These properties are similar to the ones found in other jellyfish
galaxies showing extended X-ray emission. A point-to-point analysis revealed
that this X-ray emission closely follows the ISM distribution, whereas CLOUDY
simulations proved that the ionisation triggered by this warm plasma would be
able to reproduce the [OI]/H excess observed in JO201. We conclude that
the galactic X-ray emitting plasma is originated on the surface of the ISM as a
result of the ICM-ISM interplay. This process would entail the cooling and
accretion of the ICM onto the galaxy, which could additionally fuel the star
formation, and the emergence of [OI]/H excess in the optical spectrum.Comment: 21 pages, 6 figures, 5 tables. Manuscript in press in Ap
GASP XXXIV: Unfolding the thermal side of ram pressure stripping in the jellyfish galaxy JO201
X-ray studies of jellyfish galaxies play a crucial role in understanding the interactions between the interstellar medium (ISM) and the intracluster medium (ICM). In this paper, we focused on the jellyfish galaxy JO201. By combining archival Chandra observations, Multi Unit Spectroscopic Explorer Hα cubes, and maps of the emission fraction of the diffuse ionized gas, we investigated both its high-energy spectral properties and the spatial correlation between its X-ray and optical emissions. The X-ray emission of JO201 is provided by both the Compton-thick active galactic nucleus (L0.5X-10keV = 2.7 · 1041 erg s−1, not corrected for intrinsic absorption) and an extended component (L0.5X–10 keV » 1.9–4.5 · 1041 erg s−1) produced by a warm plasma (kT»1 keV), whose luminosity is higher than expected from the observed star formation (LX ~ 3.8 · 1040erg s−1). The spectral analysis showed that the X-ray emission is consistent with the thermal cooling of hot plasma. These properties are similar to the ones found in other jellyfish galaxies showing extended X-ray emission. A point-to-point analysis revealed that this X-ray emission closely follows the ISM distribution, whereas CLOUDY simulations proved that the ionization triggered by this warm plasma would be able to reproduce the [O I]/Hα excess observed in JO201. We conclude that the galactic X-ray emitting plasma originates on the surface of the ISM as a result of the ICM–ISM interplay. This process would entail the cooling and accretion of the ICM onto the galaxy, which could additionally fuel the star formation, and the emergence of [O I]/Hα excess in the optical spectrum
MOKA3D: An innovative approach to 3D gas kinematic modelling. I. Application to AGN ionized outflows
Studying the feedback process of Active Galactic Nuclei (AGN) requires
characterising multiple kinematical components, such as rotating gas and
stellar disks, outflows, inflows, and jets. To compare the observed properties
with theoretical predictions of galaxy evolution and feedback models and to
assess the mutual interaction and energy injection rate into the interstellar
medium (ISM), one usually relies on simplified kinematic models. These models
have several limitations, as they often do not take into account projection
effects, beam smearing and the surface brightness distribution of the emitting
medium. Here, we present MOKA3D, an innovative approach to model the 3D gas
kinematics from integral field spectroscopy observations. In this first paper,
we discuss its application to the case of AGN ionised outflows, whose observed
clumpy emission and apparently irregular kinematics are only marginally
accounted for by existing kinematical models. Unlike previous works, our model
does not assume the surface brightness distribution of the gas, but exploits a
novel procedure to derive it from the observations by reconstructing the 3D
distribution of emitting clouds and providing accurate estimates of the
spatially resolved outflow physical properties (e.g. mass rate, kinetic
energy). As an example, we demonstrate the capabilities of our method by
applying it to three nearby Seyfert-II galaxies observed with MUSE at the VLT
and selected from the MAGNUM survey, showing that the complex kinematic
features observed can be described by a conical outflow with a constant radial
velocity field and a clumpy distribution of clouds.Comment: 17 pages, 14 figure
MOKA3D : an innovative approach to 3D gas kinematic modelling: I. Application to AGN ionised outflows
Studying the feedback process of active galactic nuclei (AGN) requires the characterisation of multiple kinematical components, such as rotating gas and stellar discs, outflows, inflows, and jets. The usual approach to compare the observed galaxy properties with feedback theoretical predictions relies on simplified kinematic models. This allows us to assess the mutual interaction between the galaxy components and determine the energy injection rate into the interstellar medium. However, these models have several limitations, as they often do not take into account projection effects, beam smearing, or the surface brightness distribution of the emitting medium. Here, we present MOKA3D, an innovative approach to modelling the 3D gas kinematics from integral field spectroscopy observations. In this first paper, we discuss its application to the case of AGN ionised outflows, whose observed clumpy emission and apparently irregular kinematics are only marginally accounted for by the existing kinematical models. Unlike previous works, our model does not assume the surface brightness distribution of the gas, but exploits a novel procedure to derive it from observations by reconstructing the 3D distribution of emitting clouds and providing accurate estimates of the physical properties of spatially resolved outflow (e.g., mass rate, kinetic energy). We demonstrate the capabilities of our method by applying it to three nearby Seyfert-II galaxies observed with the Multi Unit Spectroscopic Explorer (MUSE) at the VLT and selected from the Measuring Active Galactic Nuclei Under MUSE Microscope (MAGNUM) survey, showing that the complex kinematic features observed can be described by a conical outflow with a constant radial velocity field and a clumpy distribution of clouds
Feedback and ionized gas outflows in four low-radio power AGN at <em>z</em> ∼ 0.15
\ua9 2024 EDP Sciences. All rights reserved. An increasing number of observations and simulations suggests that low-power (< 1044 erg s1) jets may be a significant channel of feedback produced by active galactic nuclei (AGN), but little is known about their actual effect on their host galaxies from the observational point of view. We targeted four luminous type 2 AGN hosting moderately powerful radio emission (∼1044 erg s1), two of which and possibly a third are associated with jets, with optical integral field spectroscopy observations from the Multi Unit Spectroscopic Explorer (MUSE) at the Very Large Telescope (VLT) to analyze the properties of their ionized gas as well as the properties and effects of ionized outflows. We combined these observations with Very Large Array (VLA) and e-MERLIN data to investigate the relations and interactions between the radio jets and host galaxies. We detected ionized outflows as traced by the fast bulk motion of the gas. The outflows extended over kiloparsec scales in the direction of the jet, when present. In the two sources with resolved radio jets, we detected a strong enhancement in the emission-line velocity dispersion (up to 1000 km s1) perpendicular to the direction of the radio jets. We also found a correlation between the mass and the energetics of this high-velocity dispersion gas and the radio power, which supports the idea that the radio emission may cause the enhanced turbulence. This phenomenon, which is now being observed in an increasing number of objects, might represent an important channel for AGN feedback on galaxie
Sublittoral soft bottom communities and diversity of Mejillones Bay in northern Chile (Humboldt Current upwelling system)
The macrozoobenthos of Mejillones Bay (23°S; Humboldt Current) was quantitatively investigated over a 7-year period from austral summer 1995/1996 to winter 2002. About 78 van Veen grab samples taken at six stations (5, 10, 20 m depth) provided the basis for the analysis of the distribution of 60 species and 28 families of benthic invertebrates, as well as of their abundance and biomass. Mean abundance (2,119 individuals m-2) was in the same order compared to a previous investigation; mean biomass (966 g formalin wet mass m-2), however, exceeded prior estimations mainly due to the dominance of the bivalve Aulacomya ater. About 43% of the taxa inhabited the complete depth range. Mean taxonomic Shannon diversity (H', Log e) was 1.54 ± 0.58 with a maximum at 20 m (1.95 ± 0.33); evenness increased with depth. The fauna was numerically dominated by carnivorous gastropods, polychaetes and crustaceans (48%). About 15% of the species were suspensivorous, 13% sedimentivorous, 11% detritivorous, 7% omnivorous and 6% herbivorous. Cluster analyses showed a significant difference between the shallow and the deeper stations. Gammarid amphipods and the polychaete family Nephtyidae characterized the 5-mzone, the molluscs Aulacomya ater, Mitrella unifasciata and gammarids the intermediate zone, while the gastropod Nassarius gayi and the polychaete family Nereidae were most prominent at the deeper stations. The communities of the three depth zones did not appear to be limited by hypoxia during non-El Niño conditions. Therefore, no typical change in community structure occurred during El Niño 1997–1998, in contrast to what was observed for deeper faunal assemblages and hypoxic bays elsewhere in the coastal Humboldt Current system
- …