The magnetic environment of the Orion-Eridanus superbubble as revealed by Planck

Using the 353-GHz polarization observations by the Planck satellite we characterize the magnetic field in the Orion-Eridanus superbubble, a nearby expanding structure that spans more than 1600 square degrees in the sky. We identify a region of both low dispersion of polarization orientations and high polarization fraction associated with the outer wall of the superbubble identified in the most recent models of the large-scale shape of the region. We use the Davis-Chandrasekhar-Fermi method to derive plane-of-the-sky magnetic field strengths of tens of microGauss toward the southern edge of the bubble. The comparison of these values with existing Zeeman splitting observations of HI in emission suggests that the large-scale magnetic field in the region was primarily shaped by the expanding superbubble.Comment: 7 pages, 8 figures. Accepted for publication as a Letter in A&A, section 1. Letters to the Editor (08/12/2017

Boundary layer separation in the surface quasi-geostrophic equations

Uniform potential vorticity flows are investigated. The evolution of surface potential temperature is studied in a two-dimensional oceanic model driven by a surface heating. The surface temperature plays the role of the vorticity, but the different relationship between the streamfunction and the advected scalar implies the formation of unidirectional free waves. Important distinctive features with respect to the standard homogeneous models are pointed out

Coupling constants of D∗DsKD^*D_sK and Ds∗DKD_s^*DK processes

We calculate the coupling constants of $D^*D_sK$ and $D_s^*DK$ vertices using the QCD sum rules technique. We compare results obtained in the limit of SU(4) symmetry and found that the symmetry is broken on the order of 40%.Comment: 4 pages, 3 ps figures. Talk presented in the 18 Workshop on Hadron Interactions, IFUSP, Sao Paulo, Brazil, may 22-24 of 200

Herschel-ATLAS: statistical properties of Galactic cirrus in the GAMA-9 Hour Science Demonstration Phase Field

We study the spectral energy distribution (SED) and the power spectrum of Galactic cirrus emission observed in the 14 deg^2 Science Demonstration Phase field of the Herschel-ATLAS using Herschel and IRAS data from 100 to 500 μm. We compare the Spectral and Photometric Imaging Receiver (SPIRE) 250, 350 and 500 μm maps with IRAS 100-μm emission, binned in 6-arcmin pixels. We assume a modified blackbody SED with dust emissivity parameter β (F∝λ^(−β)) and a single dust temperature T_d, and find that the dust temperature and emissivity index varies over the science demonstration field as 10 < T_d < 25K and 1 < β < 4. The latter values are somewhat higher than the range of β often quoted in the literature (1 < β < 2). We estimate the mean values of these parameters to be T_d= 19.0 ± 2.4 K and β= 1.4 ± 0.4. In regions of bright cirrus emission, we find that the dust has similar temperatures with T_d = 18.0 ± 2.5 K, and similar values of β, ranging from 1.4 ± 0.5 to 1.9 ± 0.5. We show that T_d and β associated with diffuse cirrus emission are anti-correlated and can be described by the relationship: β(T_d) =NT^α_d with [N= 116 ± 38, α=−1.4 ± 0.1]. The strong correlation found in this analysis is not just limited to high-density clumps of cirrus emission as seen in previous studies, but is also seen in diffuse cirrus in low-density regions. To provide an independent measure of T_d and β, we obtain the angular power spectrum of the cirrus emission in the IRAS and SPIRE maps, which is consistent with a power spectrum of the form P(k) =P_0(k/k_0)^γ, where γ= 2.6 ± 0.2 for scales of 50–200 arcmin in the SPIRE maps. The cirrus rms fluctuation amplitude at angular scales of 100 arcmin is consistent with a modified blackbody SED with T_d 20.1 ± 0.9 K and β= 1.3 ± 0.2, in agreement with the values obtained above

Applicability of shape parameterizations for giant dipole resonance in warm and rapidly rotating nuclei

We investigate how well the shape parameterizations are applicable for studying the giant dipole resonance (GDR) in nuclei, in the low temperature and/or high spin regime. The shape fluctuations due to thermal effects in the GDR observables are calculated using the actual free energies evaluated at fixed spin and temperature. The results obtained are compared with Landau theory calculations done by parameterizing the free energy. We exemplify that the Landau theory could be inadequate where shell effects are dominating. This discrepancy at low temperatures and high spins are well reflected in GDR observables and hence insists on exact calculations in such cases.Comment: 10 pages, 2 figure

A QCD sum rules calculation of the J/ψDs∗DsJ/\psi D_s^* D_s strong coupling constant

In this work, we calculate the form factors and the coupling constant of the strange-charmed vertex $J/\psi D_s^* D_s$ in the framework of the QCD sum rules by studying their three-point correlation functions. All the possible off-shell cases are considered, $D_s$, $D_s^*$ and $J/\psi$, resulting in three different form factors. These form factors are extrapolated to the pole of their respective off-shell mesons, giving the same coupling constant for the process. Our final result for the $J/\psi D_s^* D_s$ coupling constant is $g_{J/\psi D^*_s D_s} = 4.30^{+0.42}_{-0.37}\text{GeV}^{-1}$.Comment: 17 pages, 4 figure

Gamma decay of pygmy states from inelastic scattering of ions

An overview of relevant results on the study of 1− states focusing on their excitation with nuclear probes is given. Results obtained for the 90Zr , 124Sn , and 208Pb nuclei using the (17O,17O′γ) reaction are compared with available data obtained with the (γ, γ′, and (p, p′) reactions. These comparisons allow to learn on the nature of the populated states, particularly the E1 states, whose isospin character is presently poorly known. The DWBA description of the data is discussed in terms of different form factors, standard collective form factor and form factors obtained by folding microscopically calculated transition densities. The relevant aspects related to the used theoretical approach are also presented. The main objective of the analyses is the extraction of the values of the fraction of the energy weighted sum rule strength for the isoscalar dipole excitation. For completeness, in all cases, the DWBA analysis was made also for the excitations of 2+ and 3− states

Bs∗BKB_s^* B K vertex from QCD sum rules

The form factors and the coupling constant of the $B_s^* B K$ vertex are calculated using the QCD sum rules method. Three point correlation functions are computed considering both $K$ and $B$ mesons off-shell and, after an extrapolation of the QCDSR results, we obtain the coupling constant of the vertex. We study the uncertainties in our result by calculating a third form factor obtained when the $B^*_s$ is the off-shell meson, considering other acceptable structures and computing the variations of the sum rules' parameters. The form factors obtained have different behaviors but their simultaneous extrapolations reach to the same value of the coupling constant $g_{B_s^* B K}=10.6 \pm 1.7$. We compare our result with other theoretical estimates.Comment: 11 pages, 11 figure

Axiography and MRI in the diagnosis of temporomandibular joint pathology

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