32 research outputs found
L1599B: Cloud Envelope and C+ Emission in a Region of Moderately Enhanced Radiation Field
We study the effects of an asymmetric radiation field on the properties of a
molecular cloud envelope. We employ observations of carbon monoxide (12CO and
13CO), atomic carbon, ionized carbon, and atomic hydrogen to analyze the
chemical and physical properties of the core and envelope of L1599B, a
molecular cloud forming a portion of the ring at approximately 27 pc from the
star Lambda Ori. The O III star provides an asymmetric radiation field that
produces a moderate enhancement of the external radiation field. Observations
of the [CII] fine structure line with the GREAT instrument on SOFIA indicate a
significant enhanced emission on the side of the cloud facing the star, while
the [Ci], 12CO and 13CO J = 1-0 and 2-1, and 12CO J = 3-2 data from the PMO and
APEX telescopes suggest a relatively typical cloud interior. The atomic, ionic,
and molecular line centroid velocities track each other very closely, and
indicate that the cloud may be undergoing differential radial motion. The HI
data from the Arecibo GALFA survey and the SOFIA/GREAT [CII] data do not
suggest any systematic motion of the halo gas, relative to the dense central
portion of the cloud traced by 12CO and 13CO.Comment: 9 Figure
A lambda=3 mm molecular line survey of NGC1068. Chemical signatures of an AGN environment
We aimed to study the molecular composition of the interstellar medium (ISM)
surrounding an Active Galactic Nucleus (AGN), by making an inventory of
molecular species and their abundances, as well as to establish a chemical
differentiation between starburst galaxies and AGN. We used the IRAM-30 m
telescope to observe the central 1.5-2 kpc region of NGC1068, covering the
frequencies between 86.2 GHz and 115.6 GHz. Using Boltzmann diagrams, we
calculated the column densities of the detected molecules. We used a chemical
model to reproduce the abundances found in the AGN, to determine the origin of
each detected species, and to test the influence of UV fields, cosmic rays, and
shocks on the ISM. We identified 24 different molecular species and
isotopologues, among which HC3N, SO, N2H+, CH3CN, NS, 13CN, and HN13C are
detected for the first time in NGC1068. We obtained the upper limits to the
isotopic ratios 12C/13C=49, 16O/18O=177 and 32S/34S=5. Our chemical models
suggest that the chemistry in the nucleus of NGC1068 is strongly influenced by
cosmic rays, although high values of both cosmic rays and far ultraviolet (FUV)
radiation fields also explain well the observations. The gas in the nucleus of
NGC1068 has a different chemical composition as compared to starburst galaxies.
The distinct physical processes dominating galaxy nuclei (e.g. C-shocks, UV
fields, X-rays, cosmic rays) leave clear imprints in the chemistry of the gas,
which allow to characterise the nucleus activity by its molecular abundances.Comment: 16 pages, 6 figures, 7 tables. Accepted for publication in Astronomy
and Astrophysic
Lambda = 3 mm line survey of nearby active galaxies
We used the IRAM 30m telescope to observe the frequency range [86-116]GHz
towards the central regions of the starburst galaxies M83, M82, and NGC253, the
AGNs M51, NGC1068, and NGC7469, and the ULIRGs Arp220 and Mrk231. Assuming LTE
conditions, we calculated the column densities of 27 molecules and 10
isotopologues. Among others, we report the first tentative detections of
CH3CHO, HNCO, and NS in M82 and, for the first time in the extragalactic
medium, HC5N in NGC253. Halpha recombination lines were only found in M82 and
NGC253. Vibrationally excited lines of HC3N were only detected in Arp220.
CH3CCH emission is only seen in the starburst-dominated galaxies. By comparison
of the fractional abundances among the galaxies, we looked for the molecules
that are best suited to characterise the chemistry of starbursts, AGNs and
ULIRGs, as well as the differences among galaxies within the same group.Comment: 24 pages, 6 figures, 12 tables. Accepted for publication in Astronomy
and Astrophysic
Impacts of pure shocks in the BHR71 bipolar outflow
During the formation of a star, material is ejected along powerful jets that
impact the ambient material. This outflow regulates star formation by e.g.
inducing turbulence and heating the surrounding gas. Understanding the
associated shocks is therefore essential to the study of star formation. We
present comparisons of shock models with CO, H2, and SiO observations in a
'pure' shock position in the BHR71 bipolar outflow. These comparisons provide
an insight into the shock and pre-shock characteristics, and allow us to
understand the energetic and chemical feedback of star formation on Galactic
scales. New CO (Jup = 16, 11, 7, 6, 4, 3) observations from the shocked regions
with the SOFIA and APEX telescopes are presented and combined with earlier H2
and SiO data (from the Spitzer and APEX telescopes). The integrated intensities
are compared to a grid of models that were obtained from a
magneto-hydrodynamical shock code which calculates the dynamical and chemical
structure of these regions combined with a radiative transfer module based on
the 'large velocity gradient' approximation. The CO emission leads us to update
the conclusions of our previous shock analysis: pre-shock densities of 1e4 cm-3
and shock velocities around 20-25 km s-1 are still constrained, but older ages
are inferred ( 4000 years). We evaluate the contribution of shocks to the
excitation of CO around forming stars. The SiO observations are compatible with
a scenario where less than 4% of the pre-shock SiO belongs to the grain
mantles. We infer outflow parameters: a mass of 1.8x1e-2 Msun was measured in
our beam, in which a momentum of 0.4 Msun km s-1 is dissipated, for an energy
of 4.2x1e43erg. We analyse the energetics of the outflow species by species.
Comparing our results with previous studies highlights their dependence on the
method: H2 observations only are not sufficient to evaluate the mass of
outflows.Comment: 14 pages, 10 figures, 4 Tables, accepted in A&
The Inception of Star Cluster Formation Revealed by [CII] Emission Around an Infrared Dark Cloud
We present SOFIA-upGREAT observations of [CII] emission of Infrared Dark
Cloud (IRDC) G035.39-00.33, designed to trace its atomic gas envelope and thus
test models of the origins of such clouds. Several velocity components of [CII]
emission are detected, tracing structures that are at a wide range of distances
in the Galactic plane. We find a main component that is likely associated with
the IRDC and its immediate surroundings. This strongest emission component has
a velocity similar to that of the CO(2-1) emission of the IRDC, but
offset by and with a larger velocity width of
. The spatial distribution of the [CII] emission of
this component is also offset predominantly to one side of the dense
filamentary structure of the IRDC. The CII column density is estimated to be of
the order of . We compare these results to
the [CII] emission from numerical simulations of magnetized, dense gas
filaments formed from giant molecular cloud (GMC) collisions, finding similar
spatial and kinematic offsets. These observations and modeling of [CII] add
further to the evidence that IRDC G035.39-00.33 has been formed by a process of
GMC-GMC collision, which may thus be an important mechanism for initiating star
cluster formation.Comment: 5 pages, 4 figures, submitted to MNRAS Letter
Kinematics of Galactic Centre clouds shaped by shear-seeded solenoidal turbulence
The Central Molecular Zone (CMZ; the central ~ 500 pc of the Galaxy) is a
kinematically unusual environment relative to the Galactic disc, with high
velocity dispersions and a steep size-linewidth relation of the molecular
clouds. In addition, the CMZ region has a significantly lower star formation
rate (SFR) than expected by its large amount of dense gas. An important factor
in explaining the low SFR is the turbulent state of the star-forming gas, which
seems to be dominated by rotational modes. However, the turbulence driving
mechanism remains unclear. In this work, we investigate how the Galactic
gravitational potential affects the turbulence in CMZ clouds. We focus on the
CMZ cloud G0.253+0.016 (`the Brick'), which is very quiescent and unlikely to
be kinematically dominated by stellar feedback. We demonstrate that several
kinematic properties of the Brick arise naturally in a cloud-scale
hydrodynamics simulation that takes into account the Galactic gravitational
potential. These properties include the line-of-sight velocity distribution,
the steepened size-linewidth relation, and the predominantly solenoidal nature
of the turbulence. Within the simulation, these properties result from the
Galactic shear in combination with the cloud's gravitational collapse. This is
a strong indication that the Galactic gravitational potential plays a crucial
role in shaping the CMZ gas kinematics, and is a major contributor to
suppressing the SFR by inducing predominantly solenoidal turbulent modes.Comment: 7 pages, 8 figures; accepted to MNRAS (July 24th 2023
CICATRIZAÇÃO DE LESÕES CUTÂNEAS A PARTIR DA MENSURAÇÃO COMO PARÂMETRO DE EVOLUÇÃO
Introdução: Entre as formas de avaliação do processo cicatricial a mais usual é a mensuração da área lesional, que pode ser realizada a partir de técnicas manuais e software. Objetivo: Descrever a cicatrização de lesões cutâneas, a partir da mensuração como parâmetro de evolução. Método: Estudo observacional descritivo, prospectivo, com abordagem quantitativa, desenvolvido em um ambulatório de feridas de referência entre novembro de 2021 a fevereiro de 2022. Realizada com pacientes portadores de lesão cutânea maiores de 18 anos e de ambos os sexos. Resultados: A amostra totalizou 23 pacientes, com média de idade de 58,8 anos. A maioria homens, com etnia autodeclarada parda, naturalidade Pernambucana e ocupação aposentada. Em relação às médias de redução percentual, os pacientes que tinham entre 20 e 39 anos, que não eram hipertensos, nem tabagistas, e que não faziam uso de anti-hipertensivo apresentaram melhor cicatrização. Assim como, os que apresentavam lesões traumáticas, com tempo de existência menor ou igual a um mês, localizada na mão, pouco exsudativas, com presença de tecido de granulação no leito, sem infecção, necrose, exposição óssea e hipergranulação. Na mesma perspectiva também evoluíram, as que na conduta terapêutica não foi utilizada cobertura antimicrobiana e que a frequência de troca dos curativos era realizada duas vezes por semana. Conclusão: A aplicação de instrumentos preditivos de cicatrização de forma sistematizada contribui positivamente para avaliação e manejo do processo cicatricial pela equipe de Enfermagem
Long-term outcomes of the global tuberculosis and COVID-19 co-infection cohort
Background: Longitudinal cohort data of patients with tuberculosis (TB) and coronavirus disease 2019 (COVID-19) are lacking. In our global study, we describe long-term outcomes of patients affected by TB and COVID-19. Methods: We collected data from 174 centres in 31 countries on all patients affected by COVID-19 and TB between 1 March 2020 and 30 September 2022. Patients were followed-up until cure, death or end of cohort time. All patients had TB and COVID-19; for analysis purposes, deaths were attributed to TB, COVID-19 or both. Survival analysis was performed using Cox proportional risk-regression models, and the log-rank test was used to compare survival and mortality attributed to TB, COVID-19 or both. Results: Overall, 788 patients with COVID-19 and TB (active or sequelae) were recruited from 31 countries, and 10.8% (n=85) died during the observation period. Survival was significantly lower among patients whose death was attributed to TB and COVID-19 versus those dying because of either TB or COVID-19 alone (p<0.001). Significant adjusted risk factors for TB mortality were higher age (hazard ratio (HR) 1.05, 95% CI 1.03-1.07), HIV infection (HR 2.29, 95% CI 1.02-5.16) and invasive ventilation (HR 4.28, 95% CI 2.34-7.83). For COVID-19 mortality, the adjusted risks were higher age (HR 1.03, 95% CI 1.02-1.04), male sex (HR 2.21, 95% CI 1.24-3.91), oxygen requirement (HR 7.93, 95% CI 3.44-18.26) and invasive ventilation (HR 2.19, 95% CI 1.36-3.53). Conclusions: In our global cohort, death was the outcome in >10% of patients with TB and COVID-19. A range of demographic and clinical predictors are associated with adverse outcomes