11,656 research outputs found

    An alternative attractor in gauged NJL inflation

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    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 α\alpha-attractor model. It is found that the attractor inflation in the gauged NJL model corresponds to the α=2\alpha = 2 case.Comment: 7 pages, 2 figure

    Microwave radiometric studies and ground truth measurements of the NASA/USGS Southern California test site

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    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

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    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 ∼−100\sim -100 km/s accords with a recently discovered, large radial velocity stream at ∼300\sim 300 km/s towards the Galactic longitude of ∼270∘\sim 270^\circ. 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

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    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

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    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

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    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

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    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

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    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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