11,656 research outputs found
An alternative attractor in gauged NJL inflation
We have investigated the attractor structure for the CMB fluctuations in
composite inflation scenario within the gauged Nambu-Jona-Lasinio (NJL) model.
Such composite inflation represents an attractor which can not be found in a
fundamental scalar model. As is known, the number of inflationary models
contains the attractor classified by the -attractor model. It is found
that the attractor inflation in the gauged NJL model corresponds to the case.Comment: 7 pages, 2 figure
Microwave radiometric studies and ground truth measurements of the NASA/USGS Southern California test site
The field measurement program conducted at the NASA/USGS Southern California Test Site is discussed. Ground truth data and multifrequency microwave brightness data were acquired by a mobile field laboratory operating in conjunction with airborne instruments. The ground based investigations were performed at a number of locales representing a variety of terrains including open desert, cultivated fields, barren fields, portions of the San Andreas Fault Zone, and the Salton Sea. The measurements acquired ground truth data and microwave brightness data at wavelengths of 0.8 cm, 2.2 cm, and 21 cm
Kinematics of Tidal Debris from Omega Centauri's Progenitor Galaxy
We present the kinematic properties of a tidally disrupted dwarf galaxy in
the Milky Way, based on the hypothesis that its central part once contained the
most massive Galactic globular cluster, omega Cen. Dynamical evolution of a
self-gravitating progenitor galaxy that follows the present-day and likely past
orbits of omega Cen is calculated numerically and the kinematic nature of their
tidal debris is analyzed, combined with randomly generated stars comprising
spheroidal halo and flat disk components. We show that the retrograde rotation
of the debris stars at km/s accords with a recently discovered,
large radial velocity stream at km/s towards the Galactic longitude
of . These stars also contribute, only in part, to a reported
retrograde motion of the outer halo at the North Galactic Pole. The prospects
for future debris searches and the implications for the early evolution of the
Galaxy are briefly presented.Comment: 14 pages, 3 figures, accepted for publication in ApJ Letter
Epeak estimator for Gamma-Ray Bursts Observed by the Swift Burst Alert Telescope
We report a correlation based on a spectral simulation study of the prompt
emission spectra of gamma-ray bursts (GRBs) detected by the Swift Burst Alert
Telescope (BAT). The correlation is between the Epeak energy, which is the peak
energy in the \nu F_\nu spectrum, and the photon index (\Gamma) derived from a
simple power-law model. The Epeak - \Gamma relation, assuming the typical
smoothly broken power-law spectrum of GRBs, is \log Epeak = 3.258 - 0.829\Gamma
(1.3 < \Gamma < 2.3). We take into account not only a range of Epeak energies
and fluences, but also distributions for both the low-energy photon index and
the high-energy photon index in the smoothly broken power-law model. The
distribution of burst durations in the BAT GRB sample is also included in the
simulation. Our correlation is consistent with the index observed by BAT and
Epeak measured by the BAT, and by other GRB instruments. Since about 85% of
GRBs observed by the BAT are acceptably fit with the simple power-law model
because of the relatively narrow energy range of the BAT, this relationship can
be used to estimate Epeak when it is located within the BAT energy range.Comment: 27 pages, 31 figures, accepted for publication in Ap
The Arp 220 merger on kpc scales
For the first time we study the Eastern nucleus in greater detail and search
for the more extended emission in the molecular gas in different CO line
transitions of the famous ULIRG Arp 220. Furthermore we present a model of the
merger in Arp 220 on large scales with the help of the CO data and an optical
and near-infrared composite HST image of the prototypical ULIRG. Using the
Plateau de Bure Interferometer (PdBI) we obtained CO(2-1) and (1-0) data at
wavelengths of 1 and 3 mm in 1994, 1996, 1997 and 2006 at different beam sizes
and spatial resolutions. The simulations of the merger in Arp 220 were
performed with the Identikit modeling tool. The model parameters that describe
the galaxy merger best give a mass ratio of 1:2 and result in a merger of
~6x10^8 yrs. The low resolution CO(1-0) PdBI observations suggest that there
are indications for emission ~10" towards the south, as well as to the north
and to the west of the two nuclei.Comment: accepted for publication in ApJ, 14 pages 10 figure
Recent States and Prevention for Chronic Periodontitis and Diabetes in Actual Practice
Chronic periodontitis and type 2 diabetes mellitus (T2DM) have been recently prevalent and crucial diseases. Both diseases show mutual vicious cycle as influencing each other. A systematic review revealed that T2DM cases with periodontitis have elevated odds ratio for retinopathy (2.8-8.7), neuropathy (3.2-6.6), nephropathy (1.9-8.5), cardiovascular complications (1.3-17.7) and mortality (2.3-8.5) compared to those without periodontitis. Adequate therapy for chronic periodontitis a few months would bring 0.27-0.48% decrease in HbA1c by meta-analyses. For patients with both diseases, low carbohydrate diet (LCD) seems to be effective associated with reduced HbA1c, body weight, Advanced Glycation End Products (AGEs) and inflammatory process
Rotating Boson Star with Large Self-interaction in (2+1) dimensions
Solutions for rotating boson stars in (2+1) dimensional gravity with a
negative cosmological constant are obtained numerically. The mass, particle
number, and radius of the (2+1) dimensional rotating boson star are shown.
Consequently we find the region where the stable boson star can exist.Comment: 14 pages, 6 figures, RevTe
The Second Swift BAT Gamma-Ray Burst Catalog
We present the second Swift Burst Alert Telescope (BAT) catalog of gamma-ray
bursts (GRBs), which contains 476 bursts detected by the BAT between 2004
December 19 and 2009 December 21. This catalog (hereafter the BAT2 catalog)
presents burst trigger time, location, 90% error radius, duration, fluence,
peak flux, time-averaged spectral parameters and time-resolved spectral
parameters measured by the BAT. In the correlation study of various observed
parameters extracted from the BAT prompt emission data, we distinguish among
long-duration GRBs (L-GRBs), short-duration GRBs (S-GRBs), and short-duration
GRBs with extended emission (S-GRBs with E.E.) to investigate differences in
the prompt emission properties. The fraction of L-GRBs, S-GRBs and S-GRBs with
E.E. in the catalog are 89%, 8% and 2% respectively. We compare the BAT prompt
emission properties with the BATSE, BeppoSAX and HETE-2 GRB samples. We also
correlate the observed prompt emission properties with the redshifts for the
GRBs with known redshift. The BAT T90 and T50 durations peak at 70 s and 30 s,
respectively. We confirm that the spectra of the BAT S-GRBs are generally
harder than those of the L-GRBs. The time-averaged spectra of the BAT S-GRBs
with E.E. are similar to those of the L-GRBs. Whereas, the spectra of the
initial short spikes of the S-GRBs with E.E. are similar to those of the
S-GRBs. We show that the BAT GRB samples are significantly softer than the
BATSE bright GRBs, and that the time-averaged Epeak of the BAT GRBs peaks at 80
keV which is significantly lower energy than those of the BATSE sample which
peak at 320 keV. The time-averaged spectral properties of the BAT GRB sample
are similar to those of the HETE-2 GRB samples. By time-resolved spectral
analysis, we find that only 10% of the BAT observed photon indices are outside
the allowed region of the synchrotron shock model.Comment: 65 pages, 33 figures, 13 tables, Accepted in ApJS, Nine
machine-readable tables are available at
http://swift.gsfc.nasa.gov/docs/swift/results/bat2_catalog
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