58 research outputs found
A Super Bubble Candidate in the Galactic Center and a Local Enhancement G359.77-0.09
A 20' \times 16' elliptical ring-like structure has been found near the
Galactic center in the narrow energy band corresponding to the K line
from He-like sulfur. In the ring, two diffuse sources are found, a supernova
remnant candidate G359.79-0.26 and an unidentified source G359.77-0.09. The
X-ray spectrum of G359.77-0.09 is similar to that of G359.79-0.26, which can be
explained by an absorbed thin thermal plasma model with temperatures of 0.7 and
1.0 keV. The absorption column densities of these two sources are large (N_H =
6.9 \times 10^{22} and 4.5 \times 10^{22} cm^{-2}) and are consistent with that
of the Galactic center distance. The X-ray spectrum extracted from the
ring-like structure is also represented by an absorbed thin thermal plasma
model (kT_e \sim 0.9 keV). The thermal energy of the plasma filling the
ring-like structure is estimated to be 1.0 \times 10^{51} erg. We therefore
propose that the two sources comprise a single ring-like object, which is
possibly a super bubble with a size of 49 pc \times 40 pc in the Galactic
center region.Comment: 9 pages, 7 figures, accepted for publication in PAS
Through the Looking-Glass: reflection of ant-diversity in ant-mimics
Trabalho final de mestrado integrado em Medicina, apresentado à Faculdade de Medicina da Universidade de Coimbra.Todos os anos nascem cerca de 15 milhões de crianças prematuras em todo o mundo e
mais de 1 milhão morre no primeiro mês devido a várias complicações.
A sobrevivência de um prematuro é cada vez maior devido aos avanços nos cuidados
perinatais, contudo estas crianças sofrem frequentemente de morbilidade respiratória crónica.
Os recém-nascidos prematuros têm um risco aumentado de possuírem alterações na função
pulmonar durante a infância, adolescência e idade adulta, bem como um risco aumentado de
infeções respiratórias, asma e doença pulmonar obstrutiva crónica. Estes problemas
respiratórios são particularmente evidentes quando estas crianças prematuras desenvolvem
displasia broncopulmonar.
O objetivo deste trabalho passa deste modo por destacar quais as principais
complicações a nível do sistema respiratório dos nascimentos pré-termo, salientando a
importância de um correto desenvolvimento do aparelho respiratório na fase pré-natal e pósnatal.An estimated 15 million of babies are born too early every year around the world and
over 1 million die in the first month due to various complications.
Recent advances in perinatal care have increased the survival rates of preterm birth
however, this improved survival has led to an increase in significant chronic respiratory
morbidity.
The children born preterm have an increased risk of abnormal lung function during
childhood, adolescence and adulthood, as well as respiratory infections, asthma and chronic
obstructive pulmonary disease. These respiratory problems are particularly evident when
these preterm birth develop bronchopulmonary dysplasia (BDP).
The purpose of this work is thus to highlight what are the main complications in the
respiratory system due to preterm birth emphasizing the importance of a correct development
of the respiratory system in prenatal and postnatal phase
Suzaku Spectroscopy of an X-Ray Reflection Nebula and a New Supernova Remnant Candidate in the Sgr B1 Region
We made a 100 ks observation of the Sagittarius (Sgr) B1 region at (l, b) =
(0.5, -0.1) near to the Galactic center (GC) with the Suzaku/XIS. Emission
lines of S XV, Fe I, Fe XXV, and Fe XXVI were clearly detected in the spectrum.
We found that the Fe XXV and Fe XXVI line emissions smoothly distribute over
the Sgr B1 and B2 regions connecting from the GC. This result suggests that the
GC hot plasma extends at least up to the Sgr B region with a constant
temperature. There are two diffuse X-ray sources in the observed region. One of
the two (G0.42-0.04) is newly discovered, and exhibits a strong S XV Ka
emission line, suggesting a candidate for a supernova remnant located in the GC
region. The other one (M0.51-0.10), having a prominent Fe I Ka emission line
and a strongly absorbed continuum, is likely to be an X-ray reflection nebula.
There is no near source bright enough to irradiate M0.51-0.10. However, the Fe
I Ka emission can be explained if Sgr A* was ~ 10^6 times brighter 300 years
ago, the light travel time for 100 pc to M0.51-0.10, than it is at present.Comment: 10 pages, 10 figure
Suzaku X-Ray Spectroscopy of a Peculiar Hot Star in the Galactic Center Region
We present the results of a Suzaku study of a bright point-like source in the
6.7 keV intensity map of the Galactic center region. We detected an intense
FeXXV 6.7 keV line with an equivalent width of ~1 keV as well as emission lines
of highly ionized Ar and Ca from a spectrum obtained by the X-ray Imaging
Spectrometer. The overall spectrum is described very well by a heavily absorbed
(~2x10^{23}cm^{-2}) thin thermal plasma model with a temperature of 3.8+/-0.6
keV and a luminosity of ~3x10^{34} erg s^{-1} (2.0--8.0 keV) at 8 kpc. The
absorption, temperature, luminosity, and the 6.7 keV line intensity were
confirmed with the archived XMM-Newton data. The source has a very red
(J-Ks=8.2 mag) infrared spectral energy distribution (SED), which was fitted by
a blackbody emission of ~1000 K attenuated by a visual extinction of ~31 mag.
The high plasma temperature and the large X-ray luminosity are consistent with
a wind-wind colliding Wolf-Rayet binary. The similarity of the SED to those of
the eponymous Quintuplet cluster members suggests that the source is a WC-type
source.Comment: Accepted for publication on PASJ Vol.60, SP-1, 200
A new species of the genus Castoponera (Araneae, Corinnidae) from Sarawak, Borneo, with comparison to a related species
A new species of the genus Castoponera Deeleman-Reinhold, 2001, Castoponera christae sp. n., is described here. The species is closely related to C. lecythus Deeleman-Reinhold, 2001, but can be distinguished by the structures of the male palp and the female genitalia
Suzaku Detection of Extended/Diffuse Hard X-Ray Emission from the Galactic Center
Five on-plane regions within +/- 0.8deg of the Galactic center were observed
with the Hard X-ray Detector (HXD) and the X-ray Imaging Spectrometer (XIS)
onboard Suzaku. From all regions, significant hard X-ray emission was detected
with HXD-PIN up to 40 keV, in addition to the extended plasma emission which is
dominant in the XIS band. The hard X-ray signals are inferred to come primarily
from a spatially extended source, rather than from a small number of bright
discrete objects. Contributions to the HXD data from catalogued X-ray sources,
typically brighter than 1 mCrab, were estimated and removed using information
from Suzaku and other satellites. Even after this removal, the hard X-ray
signals remained significant, exhibiting a typical 12--40 keV surface
brightness of 4E-10 erg cm-2 s-1 deg-2 and power-law-like spectra with a photon
index of 1.8. Combined fittings to the XIS and HXD-PIN spectra confirm that a
separate hard tail component is superposed onto the hot thermal emission,
confirming a previous report based on the XIS data. Over the 5--40 keV band,
the hard tail is spectrally approximated by a power law of photon index ~2, but
better by those with somewhat convex shapes. Possible origins of the extended
hard X-ray emission are discussed.Comment: 13 pages, 18 figure
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