2,674 research outputs found
Spitzer/IRS investigation of MIPSGAL 24 microns compact bubbles
The MIPSGAL 24 m Galactic Plane Survey has revealed more than 400
compact-extended objects. Less than 15% of these MIPSGAL bubbles (MBs) are
known and identified as evolved stars. We present Spitzer observations of 4 MBs
obtained with the InfraRed Spectrograph to determine the origin of the mid-IR
emission. We model the mid-IR gas lines and the dust emission to infer physical
conditions within the MBs and consequently their nature. Two MBs show a
dust-poor spectrum dominated by highly ionized gas lines of [\ion{O}{4}],
[\ion{Ne}{3}], [\ion{Ne}{5}], [\ion{S}{3}] and [\ion{S}{4}]. We identify them
as planetary nebulae with a density of a few 10 and a central
white dwarf of K. The mid-IR emission of the two other MBs is
dominated by a dust continuum and lower-excitation lines. Both of them show a
central source in the near-IR (2MASS and IRAC) broadband images. The first
dust-rich MB matches a Wolf-Rayet star of K at 7.5 kpc with dust
components of and K. Its mass is about $10^{-3}\
\rm{M_\odot}10^{-6}\ \rm{M_\odot/yr}. The second
dust-rich MB has recently been suggested as a Be/B[e]/LBV candidate. The gas
lines of [\ion{Fe}{2}] as well as hot continuum components (\sim300\sim1250\sim7510^{-3}\ \rm{M_\odot}10^{-5}\ \rm{M_\odot/yr}$.Comment: accepted for publication in Ap
The Balloon-Borne Large Aperture Submillimeter Telescope (BLAST) 2005: A 10 deg^2 Survey of Star Formation in Cygnus X
We present Cygnus X in a new multi-wavelength perspective based on an unbiased BLAST survey at 250, 350, and 500 μm, combined with rich data sets for this well-studied region. Our primary goal is to investigate the early stages of high-mass star formation. We have detected 184 compact sources in various stages of evolution across all three BLAST bands. From their well-constrained spectral energy distributions, we obtain the physical properties mass, surface density, bolometric luminosity, and dust temperature. Some of the bright sources reaching 40 K contain well-known compact H_(II) regions. We relate these to other sources at earlier stages of evolution via the energetics as deduced from their position in the luminosity-mass (L-M) diagram. The BLAST spectral coverage, near the peak of the spectral energy distribution of the dust, reveals fainter sources too cool (~10 K) to be seen by earlier shorter-wavelength surveys like IRAS. We detect thermal emission from infrared dark clouds and investigate the phenomenon of cold "starless cores" more generally. Spitzer images of these cold sources often show stellar nurseries, but these potential sites for massive star formation are "starless" in the sense that to date there is no massive protostar in a vigorous accretion phase. We discuss evolution in the context of the L-M diagram. Theory raises some interesting possibilities: some cold massive compact sources might never form a cluster containing massive stars, and clusters with massive stars might not have an identifiable compact cold massive precursor
Proper Motions of Young Stellar Outflows in the Mid-Infrared with Spitzer. II. HH 377/Cep E
We have used multiple mid-infrared observations at 4.5 micron obtained with
the Infrared Array Camera, of the compact (~1.4 arcmin) young stellar bipolar
outflow Cep E to measure the proper motion of its brightest condensations. The
images span a period of ~6 yr and have been reprocessed to achieve a higher
angular resolution (~0.8 arcsec) than their normal beam (2 arcsec).
We found that for a distance of 730 pc, the tangential velocities of the
North and South outflow lobes are 62+/-29 and 94+/-6 km/s respectively, and
moving away from the central source roughly along the major axis of the flow. A
simple 3D hydrodynamical simulation of the H2 gas in a precessing outflow
supports this idea. Observations and model confirm that the molecular Hydrogen
gas, traced by the pure rotational transitions, moves at highly supersonic
velocities without being dissociated. This suggests either a very efficient
mechanism to reform H2 molecules along these shocks or the presence of some
other mechanism (e.g. strong magnetic field) that shields the H2 gas.Comment: Accepted for publication in New Journal of Physics (Special Issue
article
The ultraviolet spectrum of HH 24A and its relation to optical spectra
The spectrum of the brightest part (HH 24A) of the complex Herbig-Haro object HH 24 in the short wavelength UV range was studied. The object is of special interest since it is known that in the optical range the continuum is due to dust scattered light originating in a young stellar object while the shock excited emission lines are formed in HH 24A itself. The spectrum shows only a continuum or a quasi-continuum and is not comparable to that of the typical high excitation object like HH1 or HH2 nor to that of a low excitation object like HH3 or HH47
The MIPSGAL View of Supernova Remnants in the Galactic Plane
We report the detection of Galactic supernova remnants (SNRs) in the mid-infrared (at 24 and 70 μm), in the coordinate ranges 10° < l < 65° and 285° < l < 350°, |b| < 1°, using MIPS aboard the Spitzer Space Telescope. We search for infrared counterparts to SNRs in Green's catalog and identify 39 out of 121, i.e., a detection rate of about 32%. Such a relatively low detection fraction is mainly due to confusion with nearby foreground/background sources and diffuse emission. The SNRs in our sample show a linear trend in [F_8/F_(24)] versus [F_(70)/F_(24)]. We compare their infrared fluxes with their corresponding radio flux at 1.4 GHz and find that most remnants have a ratio of 70 μm to 1.4 GHz which is similar to those found in previous studies of SNRs (with the exception of a few that have ratios closer to those of H II regions). Furthermore, we retrieve a slope close to unity when correlating infrared (24 and 70 μm) with 1.4 GHz emission. Our survey is more successful in detecting remnants with bright X-ray emission, which we find is well correlated with the 24 μm morphology. Moreover, by comparing the power emitted in the X-ray, infrared, and radio, we conclude that the energy released in the infrared is comparable to the cooling in the X-ray range
Analysis of the quark sector in the 2HDM-III with a four-zero Yukawa texture using the most recent data on the CKM matrix
In this letter we analyse, in the context of the general 2-Higgs Doublet
Model, the structure of the Yukawa matrices, , by assuming a four-zero texture ansatz for their definition. In this
framework, we obtain compact expressions for , which are reduced to the Cheng and Sher ansatz with the difference that
they are obtained naturally as a direct consequence of the invariants of the
fermion mass matrices. Furthermore, in order to avoid large flavour violating
effects coming from charged Higgs exchange, we consider the main flavour
constraints on the off-diagonal terms of Yukawa texture {{}} (). We perform a -fit
based on current experimental data on the quark masses and the
Cabibbo-Kobayashi-Maskawa mixing matrix . Hence, we obtain
the allowed ranges for the parameters at
1 for several values of . The results are in complete
agreement with the bounds obtained taking into account constraints on Flavour
Changing Neutral Currents reported in the literature.Comment: 12 pages, 1 figure. Version accepted in Phys. Lett.
Weight and levels of physical activity influences on quality of life of university students
Este estudio persigue dilucidar si hay relación existente entre la cantidad de actividad física realizada, la composición corporal y la Calidad de Vida Relacionada con la Salud (CVRS) en estudiantes de primer curso de Grado en Educación Infantil (n=88). Los sujetos realizaron el cuestionario SF-36 sobre CVRS y el cuestionario Internacional de Actividad Física (IPAQ). Los sujetos fueron divididos en tres grupos de acuerdo a su Índice de Masa Corporal (IMC).
Los resultados obtenidos muestran que no existe relación existente entre la cantidad de actividad física, la composición corporal y la CVRS en esta muestra
Crecimiento postraumático en padres de niños y adolescentes con cáncer.
El cáncer puede provocar reacciones psicológicas
negativas. No obstante, la lucha al abordar los problemas
oncológicos también puede dar lugar a cambios
psicológicos positivos que demuestran la fortaleza del
ser humano, siendo una de ellas el crecimiento postraumático
(CPT). El objetivo de esta revisión narrativa fue
revisar y analizar los artículos, publicados durante los
años 2000 a 2018 y disponibles en distintas bases de
datos, sobre el CPT en padres y madres de niños y adolescentes
con cáncer en el ámbito pediátrico.
Se identificaron 20 estudios que incluían 2.422 sujetos,
mayoritariamente madres (n=1.788), y que analizaban
el CPT en función del parentesco, evolución y tipo
de enfermedad del hijo, así como factores predictores
del mismo. Tanto padres como madres, son capaces de
desarrollar CPT como consecuencia de la experiencia
del cáncer de sus hijos, siendo ellas quienes experimentan
mayores niveles. En comparación con otras muestras
como progenitores de niños con diabetes tipo I o
de niños sanos, o pacientes adultos con osteosarcoma,
los padres y madres de niños con cáncer refieren mayor
CPT. Asimismo, se observan factores que influyen en el
desarrollo del CPT, como el contexto cultural, el procesamiento
cognitivo, el ajuste a la enfermedad y ciertos
rasgos de personalidad.
La evidencia científica publicada avala la existencia
de CPT en madres y padres de hijos con cáncer. No
obstante, sería necesario realizar estudios objetivos,
longitudinales, con muestras homogéneas de mayor
tamaño, para diseñar intervenciones dirigidas a promocionar
ese CPT y no centrarse solo en los aspectos
negativos de la enfermedad.post-print213 K
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