5
5.0

Jun 30, 2018
06/18

by
A. Skopal; H. Drechsel; T. N. Tarasova; T. Kato; M. Fujii; F. Teyssier; O. Garde; J. Guarro; J. Edlin; C. Buil; D. Antao; J. N. Terry; T. Lemoult; S. Charbonnel; T. Bohlsen; A. Favaro; K. Graham

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We determine the temporal evolution of the luminosity L(WD), radius R(WD) and effective temperature Teff of the white dwarf (WD) pseudophotosphere of V339 Del from its discovery to around day 40. Another main objective was studying the ionization structure of the ejecta. These aims were achieved by modelling the optical/near-IR spectral energy distribution (SED) using low-resolution spectroscopy (3500 - 9200 A), UBVRcIc and JHKLM photometry. During the fireball stage (Aug. 14.8 - 19.9, 2013),...

Topics: Astrophysics, Solar and Stellar Astrophysics

Source: http://arxiv.org/abs/1407.8212

4
4.0

Jun 30, 2018
06/18

by
Chia-Yu Hsieh; YunKyong Hyon; Hijin Lee; Tai-Chia Lin; Chun Liu

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In order to describe the dynamics of crowded ions (charged particles), we use an energetic variation approach to derive a modified Poisson-Nernst-Planck (PNP) system which includes an extra dissipation due to the effective velocity differences between ion species. Such a system is more complicated than the original PNP system but with the same equilibrium states. Using Schauder's fixed-point theorem, we develop a local existence theorem of classical solutions for the modified PNP system....

Topics: Mathematics, Analysis of PDEs, Mathematical Physics

Source: http://arxiv.org/abs/1407.8245

7
7.0

Jun 30, 2018
06/18

by
Christopher B. Johnson; R. I. Hynes; T. Maccarone; C T. Britt; H. Davis; P. G. Jonker; M. A. P. Torres; D. Steeghs; S. Greiss; G. Nelemans

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We present the results of a spectroscopic and photometric analysis of HD314884, a slowly pulsating B star (SPB) in a binary system with detected soft X-ray emission. We spectrally classify the B star as a B5V-B6V star with T$_{eff}$ = 15,490 $\pm$ 310 K, log $g$ = 3.75 $\pm$ 0.25 dex, and a photometric period of P$_{0}$ = 0.889521(12) days. A spectroscopic period search reveals an orbital period for the system of P$_{orb}$ = 1.3654(11) days. The discrepancy in the two periods and the...

Topics: Astrophysics, Solar and Stellar Astrophysics

Source: http://arxiv.org/abs/1407.7938

4
4.0

Jun 30, 2018
06/18

by
Diogo A. Gomes; Hiroyoshi Mitake

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In this paper, we investigate the existence and uniqueness of solutions to a stationary mean field game model introduced by J.-M. Lasry and P.-L. Lions. This model features a quadratic Hamiltonian with possibly singular congestion effects. Thanks to a new class of a-priori bounds, combined with the continuation method, we prove the existence of smooth solutions in arbitrary dimensions.

Topics: Mathematics, Analysis of PDEs

Source: http://arxiv.org/abs/1407.8267

5
5.0

Jun 30, 2018
06/18

by
Friedrich Knop; Bernhard Krötz; Eitan Sayag; Henrik Schlichtkrull

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We apply the local structure theorem and the polar decomposition to a real spherical space Z=G/H and control the volume growth on Z. We define the Harish-Chandra Schwartz space on Z. We give a geometric criterion to ensure $L^p$-integrability of matrix coefficients on Z.

Topics: Mathematics, Representation Theory

Source: http://arxiv.org/abs/1407.8006

5
5.0

Jun 30, 2018
06/18

by
H. Zhu; W. W. Tian; P. Zuo

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We study Gamma-ray supernova remnant W49B and its environment using recent radio and infrared data. {\it Spitzer} IRS low resolution data of W49B shows shocked excitation lines of H$_{2}$ (0,0) S(0)-S(7) from the SNR-molecular cloud interaction. The H$_2$ gas is composed of two components with temperature of $\sim$260 K and $\sim$1060 K respectively. Various spectral lines from atomic and ionic particles are detected towards W49B. We suggest the ionic phase has an electron density of $\sim$500...

Topics: High Energy Astrophysical Phenomena, Astrophysics, Solar and Stellar Astrophysics

Source: http://arxiv.org/abs/1407.8260

8
8.0

Jun 30, 2018
06/18

by
Hilding R. Neilson; Alexandra C. Bisol; Ed Guinan; Scott Engle

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Measurements of secular period change probe real-time stellar evolution of classical Cepheids making these measurements powerful constraints for stellar evolution models, especially when coupled with interferometric measurements. In this work, we present stellar evolution models and measured rates of period change for two Galactic Cepheids: Polaris and l Carinae, both important Cepheids for anchoring the Cepheid Leavitt law (period-luminosity relation). The combination of previously-measured...

Topics: Astrophysics, Solar and Stellar Astrophysics

Source: http://arxiv.org/abs/1407.8098

4
4.0

Jun 30, 2018
06/18

by
Hoai-Minh Nguyen

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This paper is devoted to the study of cloaking via anomalous localized resonance (CALR) in the two and three dimensional quasistatic regimes. CALR associated with negative index materials was discovered by Milton and Nicorovicci in [21] and attracted a lot attention in the scientific community. Two key figures of this phenomenon are the localized resonance, i.e., the fields blow up in some regions and remain bounded in some others, and the connection between the localized resonance and the blow...

Topics: Mathematics, Analysis of PDEs

Source: http://arxiv.org/abs/1407.7977

9
9.0

Jun 30, 2018
06/18

by
M. Guedel; R. Dvorak; N. Erkaev; J. Kasting; M. Khodachenko; H. Lammer; E. Pilat-Lohinger; H. Rauer; I. Ribas; B. E. Wood

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With the discovery of hundreds of exoplanets and a potentially huge number of Earth-like planets waiting to be discovered, the conditions for their habitability have become a focal point in exoplanetary research. The classical picture of habitable zones primarily relies on the stellar flux allowing liquid water to exist on the surface of an Earth-like planet with a suitable atmosphere. However, numerous further stellar and planetary properties constrain habitability. Apart from...

Topics: Earth and Planetary Astrophysics, Astrophysics, Solar and Stellar Astrophysics

Source: http://arxiv.org/abs/1407.8174

5
5.0

Jun 30, 2018
06/18

by
Meysam Alishahi; Hossein Hajiabolhassan

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For a graph $G$, the tree graph ${\cal T}_{G,t}$ has all tree subgraphs of $G$ with $t$ vertices as vertex set and two tree subgraphs are neighbors if they are edge-disjoint. Also, the $r^{th}$ cut number of $G$ is the minimum number of edges between parts of a partition of vertex set of $G$ into two parts such that each part has size at least $r$. We show that if $t=(1-o(1))n$ and $n$ is large enough, then for any dense graph $G$ with $n$ vertices, the chromatic number of the tree graph ${\cal...

Topics: Mathematics, Combinatorics

Source: http://arxiv.org/abs/1407.8035

3
3.0

Jun 30, 2018
06/18

by
S. C. C. Barros; J. M. Almenara; M. Deleuil; R. F. Diaz; Sz Csizmadia; J. Cabrera; S. Chaintreuil; A. Collier Cameron; A. Hatzes; R. Haywood; A. F. Lanza; S. Aigrain; R. Alonso; R. Bordé; F. Bouchy; H. J. Deeg; A. Erikson; M. Fridlund; S. Grziwa; D. Gandolfi; T. Guillot; E. Guenther; A. Leger; C. Moutou; M. Ollivier; T. Pasternacki; M. Patzold; H. Rauer; D. Rouan; A. Santerne; J. Schneider; G. Wuchterl

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CoRoT-7b, the first super-Earth with measured radius discovered, has opened the new field of rocky exoplanets characterisation. To better understand this interesting system, new observations were taken with the CoRoT satellite. During this run 90 new transits were obtained in the imagette mode. These were analysed together with the previous 151 transits obtained in the discovery run and HARPS radial velocity observations to derive accurate system parameters. A difference is found in the...

Topics: Earth and Planetary Astrophysics, Astrophysics, Solar and Stellar Astrophysics

Source: http://arxiv.org/abs/1407.8099

3
3.0

Jun 30, 2018
06/18

by
Yun-Fei Yang; Hui-Xue Qu; Kai-Fan Ji; Song Feng; Hui Deng; Jia-Ben Lin; Feng Wang

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We study the motions of G band bright points (GBPs) in the quiet Sun to obtain the characteristics of different motion types. A high resolution image sequence taken with the Hinode/Solar Optical Telescope (SOT) is used, and GBPs are automatically tracked by segmenting 3D evolutional structures in a space time cube. After putting the GBPs that do not move during their lifetimes aside, the non stationary GBPs are categorized into three types based on an index of motion type. Most GBPs that move...

Topics: Astrophysics, Solar and Stellar Astrophysics

Source: http://arxiv.org/abs/1407.7958