613 research outputs found
Levels of Circulating MMCN-151, a Degradation Product of Mimecan, Reflect Pathological Extracellular Matrix Remodeling in Apolipoprotein E Knockout Mice
The Formation of Fossil Galaxy Groups in the hierarchical Universe
We use a set of twelve high-resolution N-body/hydrodynamical simulations in
the CDM cosmology to investigate the origin and formation rate of
fossil groups (FGs), which are X-ray bright galaxy groups dominated by a large
elliptical galaxy, with the second brightest galaxy being at least two
magnitudes fainter. The simulations invoke star formation, chemical evolution
with non-instantaneous recycling, metal dependent radiative cooling, strong
star burst driven galactic super winds, effects of a meta-galactic UV field and
full stellar population synthesis. We find an interesting correlation between
the magnitude gap between the first and second brightest galaxy and the
formation time of the group. It is found that FGs have assembled half of their
final dark matter mass already at z\ga1, and subsequently typically grow by
minor merging only, wheras non-FGs on average form later. The early assembly of
FGs leaves sufficient time for galaxies of to merge into the
central one by dynamical friction, resulting in the large magnitude gap at
. A fraction of 3316% of the groups simulated are found to be fossil,
whereas the observational estimate is 10-20%. The FGs are found to be
X-ray over-luminous relative to non-FGs of the same optical luminosity, in
qualitative agreement with observations. Finally, from a dynamical friction
analysis is found that only because infall of galaxies happens
along filaments with small impact parameters do FGs exist at all.Comment: 4 pages, 3 figures, one figure removed. Accepted for publication in
ApJ Lette
The Provision of Thromboprophylaxis and the Prediction of Renal Recovery in Critically Ill Patients with Acute Kidney Injury
Sociodemographic characteristics of nonparticipants in the Danish colorectal cancer screening program:a nationwide cross-sectional study
The Origin of the Hot Gas in the Galactic Halo: Confronting Models with XMM-Newton Observations
We compare the predictions of three physical models for the origin of the hot
halo gas with the observed halo X-ray emission, derived from 26 high-latitude
XMM-Newton observations of the soft X-ray background between l=120\degr and
l=240\degr. These observations were chosen from a much larger set of
observations as they are expected to be the least contaminated by solar wind
charge exchange emission. We characterize the halo emission in the XMM-Newton
band with a single-temperature plasma model. We find that the observed halo
temperature is fairly constant across the sky (~1.8e6-2.3e6 K), whereas the
halo emission measure varies by an order of magnitude (~0.0005-0.006 cm^-6 pc).
When we compare our observations with the model predictions, we find that most
of the hot gas observed with XMM-Newton does not reside in isolated extraplanar
supernova remnants -- this model predicts emission an order of magnitude too
faint. A model of a supernova-driven interstellar medium, including the flow of
hot gas from the disk into the halo in a galactic fountain, gives good
agreement with the observed 0.4-2.0 keV surface brightness. This model
overpredicts the halo X-ray temperature by a factor of ~2, but there are a
several possible explanations for this discrepancy. We therefore conclude that
a major (possibly dominant) contributor to the halo X-ray emission observed
with XMM-Newton is a fountain of hot gas driven into the halo by disk
supernovae. However, we cannot rule out the possibility that the extended hot
halo of accreted material predicted by disk galaxy formation models also
contributes to the emission.Comment: 20 pages, 14 figures. New version accepted for publication in ApJ.
Changes include new section discussing systematic errors (Section 3.2),
improved method for characterizing our model spectra (4.2.2), changes to
discussion of other observations (5.1). Note that we can no longer rule out
possibility that extended hot halo of accreted material contributes to
observed halo emission (see 5.2.1
DANMAP 2011:DANMAP 2011 - Use of antimicrobial agents and occurrence of antimicrobial resistance in bacteria from food animals, food and humans in Denmark
DANMAP 2010:DANMAP 2010 - Use of antimicrobial agents and occurrence of antimicrobial resistance in bacteria from food animals, food and humans in Denmark
High power microwave diagnostic for the fusion energy experiment ITER
Microwave diagnostics will play an increasingly important role in burning plasma fusion energy experiments like ITER and beyond. The Collective Thomson Scattering (CTS) diagnostic to be installed at ITER is an example of such a diagnostic with great potential in present and future experiments. The ITER CTS diagnostic will inject a 1 MW 60 GHz gyrotron beam into the ITER plasma and observe the scattering off fluctuations in the plasma - to monitor the dynamics of the fast ions generated in the fusion reactions
DANMAP 2012:DANMAP 2012 - Use of antimicrobial agents and occurrence of antimicrobial resistance in bacteria from food animals, food and humans in Denmark
Aspects of statin prescribing in Norwegian counties with high, average and low statin consumption â an individual-level prescription database study
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