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Book from Project Gutenberg: Νόμοι και Επινομίς, Τόμος Γ
Topics: JC, Political science -- Early works to 1800, State, The -- Early works to 1800
Source: https://www.gutenberg.org/ebooks/36191
Project Gutenberg
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Book from Project Gutenberg: Νόμοι και Επινομίς, Τόμος Α
Topics: Political science -- Early works to 1800, JC, State, The -- Early works to 1800
Source: https://www.gutenberg.org/ebooks/36088
Project Gutenberg
- Plato; I. N. (Ioannes N.) Grypares
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Book from Project Gutenberg: Πολιτεία, Τόμος 1
Topics: Utopias -- Early works to 1800, Political science -- Early works to 1800, JC, Justice -- Early...
Source: https://www.gutenberg.org/ebooks/39476
Arxiv.org
- Maxim Lyutikov
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The direction of polarization produced by a moving source rotates with the respect to the rest frame. We show that this effect, induced by pulsar rotation, leads to an important correction to polarization swings within the framework of rotating vector model (RVM); this effect has been missed by previous works. We construct relativistic RVM taking into account finite heights of the emission region that lead to aberration, time-of-travel effects and relativistic rotation of polarization....
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1607.00777
Arxiv.org
- D. Nesvorny; D. Vokrouhlicky; R. Deienno
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The irregular satellites of outer planets are thought to have been captured from heliocentric orbits. The exact nature of the capture process, however, remains uncertain. We examine the possibility that irregular satellites were captured from the planetesimal disk during the early Solar System instability when encounters between the outer planets occurred (Nesvorny, Vokrouhlicky & Morbidelli 2007, AJ 133; hereafter NVM07). NVM07 already showed that the irregular satellites of Saturn, Uranus...
Topics: Earth and Planetary Astrophysics, Astrophysics
Source: http://arxiv.org/abs/1401.0253
Arxiv.org
- K. B. Schmidt; T. Treu; G. B. Brammer; M. Bradac; X. Wang; M. Dijkstra; A. Dressler; A. Fontana; R. Gavazzi; A. L. Henry; A. Hoag; T. A. Jones; P. L. Kelly; M. A. Malkan; C. Mason; L. Pentericci; B. Poggianti; M. Stiavelli; M. Trenti; A. von der Linden; B. Vulcani
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The Grism Lens-Amplified Survey from Space (GLASS) is a Hubble Space Telescope (HST) Large Program, which will obtain 140 orbits of grism spectroscopy of the core and infall regions of 10 galaxy clusters, selected to be among the very best cosmic telescopes. Extensive HST imaging is available from many sources including the CLASH and Frontier Fields programs. We introduce the survey by analyzing spectra of faint multiply-imaged galaxies and $z\gtrsim6$ galaxy candidates obtained from the first...
Topics: Astrophysics of Galaxies, Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1401.0532
Arxiv.org
- C. C. Cheung; S. Larsson; J. D. Scargle; M. A. Amin; R. D. Blandford; D. Bulmash; J. Chiang; S. Ciprini; R. H. D. Corbet; E. E. Falco; P. J. Marshall; D. L. Wood; M. Ajello; D. Bastieri; A. Chekhtman; F. D'Ammando; M. Giroletti; J. E. Grove; B. Lott; R. Ojha; M. Orienti; J. S. Perkins; M. Razzano; A. W. Smith; D. J. Thompson; K. S. Wood
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Using data from the Fermi Large Area Telescope (LAT), we report the first clear gamma-ray measurement of a delay between flares from the gravitationally lensed images of a blazar. The delay was detected in B0218+357, a known double-image lensed system, during a period of enhanced gamma-ray activity with peak fluxes consistently observed to reach >20-50 times its previous average flux. An auto-correlation function analysis identified a delay in the gamma-ray data of 11.46 +/- 0.16 days (1...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1401.0548
Arxiv.org
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We report on detection of the double pulsar system J0737-3039 in the far-UV with the ACS/SBC detector aboard HST. We measured the energy flux F = 4.5+/-1.0e-17 erg cm-2s-1 in the 1250-1550 AA band, which corresponds to the extinction-corrected luminosity L~1.5e28 erg s-1 for the distance d=1.1 kpc and a plausible reddening E(B-V)=0.1. If the detected emission comes from the entire surface of one of the neutron stars with a 13 km radius, the surface blackbody temperature is in the range T~2-5e5...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1401.0573
Arxiv.org
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We develop and test with cosmological simulations a physically motivated theory for how the interplay between gravity, pressure, cooling, and self-shielding set the redshift--dependent mass scale at which halos can accrete intergalactic gas. This theory provides a physical explanation for the halo mass scale that can accrete unshocked intergalactic gas, which has been explained with ad hoc criteria tuned to reproduce the results of a few simulations. Furthermore, it provides an intuitive...
Topics: Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1401.0737
Arxiv.org
- William C. Keel; Anna M. Manning; Benne W. Holwerda; Chris J. Lintott; Kevin Schawinski
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(Abridged) The effective extinction law (attenuation behavior) in galaxies in the emitted ultraviolet is well known only for actively star-forming objects and combines effects of the grain properties, fine structure in the dust distribution, and relative distributions of stars and dust. We use GALEX, XMM Optical Monitor, and HST data to explore the UV attenuation in the outer parts of spiral disks which are backlit by other UV-bright galaxies, starting with candidates provided by Galaxy Zoo...
Topics: Astrophysics of Galaxies, Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1401.0773
Arxiv.org
- Liton Majumdar; Ankan Das; Sandip K. Chakrabarti
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Main focus of this paper is to explore the possibility of findings two deuterated isotopomers of H2Cl+ (Chloronium) in and around the Interstellar Medium (ISM). Presence of Chloronium ion has recently been confirmed by Herschel Space Observatory's Heterodyne Instrument for the Far-Infrared (Neufeld et al., 2012). It observed para-chloronium towards six sources in the Galaxy. Existence of its deuterated isotopomers (HDCl+ & D2Cl+) are till date not discussed in the literature. We find that...
Topics: Astrophysics of Galaxies, Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1401.0890
The millisecond pulsar in a triple system (PSR J0337+1715, recently discovered by Ransom et al.) is an unusual neutron star with two orbiting white dwarfs. The existence of such a system in the Galactic field poses new challenges to stellar astrophysics for understanding evolution, interactions and mass-transfer in close multiple stellar systems. In addition, this system provides the first precise confirmation for a very wide-orbit system of the white dwarf mass-orbital period relation. Here we...
Topics: High Energy Astrophysical Phenomena, Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1401.0941
Arxiv.org
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Recent determination of the distance to HDE 226868/Cyg X-1 binary system (Reid et al., 2011) and more precise determination of the effective temperature of HDE 226868 (Caballero- Nieves et al., 2009) permit a more accurate estimate of the masses of both components. Using up to date evolutionary models, I obtain a mass range of between 25 to 35 Msun for the mass of the supergiant and between 13 to 23 Msun for the mass of the black hole. Accepting more liberal estimates of uncertainties in both...
Topics: Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1401.1035
Arxiv.org
- P. Ventura; F. Dell'Agli; R. Schneider; M. Di Criscienzo; C. Rossi; F. La Franca; S. Gallerani; R. Valiante
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The dust formation process in the winds of Asymptotic Giant Branch stars is discussed, based on full evolutionary models of stars with mass in the range $1$M$_{\odot} \leq$M$\leq 8$M$_{\odot}$, and metallicities $0.001 < Z
Topics: Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1401.1332
Arxiv.org
- Gregory Maurice Green; Edward F. Schlafly; Douglas P. Finkbeiner; Mario Jurić; Hans Walter Rix; Will Burgett; Kenneth C. Chambers; Peter W. Draper; Heather Flewelling; Rolf Peter Kudritzki; Eugene Magnier; Nicolas Martin; Nigel Metcalfe; John Tonry; Richard Wainscoat; Christopher Waters
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We present a method to infer reddenings and distances to stars, based only on their broad-band photometry, and show how this method can be used to produce a three-dimensional dust map of the Galaxy. Our method samples from the full probability density function of distance, reddening and stellar type for individual stars, as well as the full uncertainty in reddening as a function of distance in the 3D dust map. We incorporate prior knowledge of the distribution of stars in the Galaxy and the...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1401.1508
Arxiv.org
- Dario Colombo; Annie Hughes; Eva Schinnerer; Sharon E. Meidt; Adam K. Leroy; Jerome Pety; Clare L. Dobbs; Santiago Garcia-Burillo; Gaelle Dumas; Todd A. Thompson; Karl F. Schuster; Carsten Kramer
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Using data from the PdBI Arcsecond Whirlpool Survey (PAWS), we have generated the largest extragalactic Giant Molecular Cloud (GMC) catalog to date, containing 1,507 individual objects. GMCs in the inner M51 disk account for only 54% of the total 12CO(1-0) luminosity of the survey, but on average they exhibit physical properties similar to Galactic GMCs. We do not find a strong correlation between the GMC size and velocity dispersion, and a simple virial analysis suggests that 30% of GMCs in...
Topics: Astrophysics of Galaxies, Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1401.1505
Arxiv.org
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We re-evaluate the roles of different dust sources in dust production as a function of metallicity in late-type dwarf galaxies, with the goal of understanding the relation between dust content and metallicity. The dust content of late-type dwarf galaxies with episodic star formation is studied with a multicomponent model of dust evolution, which includes dust input from AGB stars, type II SNe and dust mass growth by accretion of gas species in the ISM. Dust growth in the ISM becomes an...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1401.1675
Radiation of supersoft X-ray sources (SSS) dominates both the supersof X-ray and the far-UV domain. A fraction of their radiation can be reprocessed into the thermal nebular emission, seen in the spectrum from the near-UV to longer wavelengths. In the case of symbiotic X-ray binaries (SyXBs) a strong contribution from their cool giants is indicated in the optical/near-IR. In this paper I introduce a method of multiwavelength modelling the spectral energy distribution (SED) of SSSs from the...
Topics: Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1401.1848
Arxiv.org
- Nicolas Lehner; John M. O'Meara; Andrew J. Fox; J. Christopher Howk; J. Xavier Prochaska; Vincent Burns; Ashley A. Armstrong
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We present the first results from our NASA Keck Observatory Database of Ionized Absorbers toward Quasars (KODIAQ) survey which aims to characterize the properties of the highly ionized gas of high redshift galaxies and their circumgalactic medium (CGM) at 2 1, log N(HI) > 17.3) as probes of these galaxies and their CGM where both transitions of the O VI doublet have little contamination from the Ly {\alpha}, {\beta} forests. We found 20 absorbers that satisfy these rules: 7 Lyman limit...
Topics: Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1401.1811
Arxiv.org
- Akito Kusaka; Edward J. Wollack; Thomas R. Stevenson
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High sensitivity receiver systems with near ideal polarization sensitivity are highly desirable for development of millimeter and sub-millimeter radio astronomy. Multimoded bolometers provide a unique solution to achieve such sensitivity, for which hundreds of single-mode sensors would otherwise be required. The primary concern in employing such multimoded sensors for polarimetery is the control of the polarization systematics. In this paper, we examine the angular- and polarization- dependent...
Topics: Physics, Astrophysics, Optics, Cosmology and Nongalactic Astrophysics, Instrumentation and...
Source: http://arxiv.org/abs/1401.1859
Arxiv.org
- C. Ducourant; R. Teixeira; P. A. B. Galli; J. F. Le Campion; A. Krone-Martins; B. Zuckerman; G. Chauvin; I. Song
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The nearby TW Hydrae Association (TWA) is currently a benchmark for the study of formation and evolution of young low-mass stars, circumstellar disks and the imaging detection of planetary companions. For such studies, it is crucial to evaluate the distance to group members in order to access their physical properties. Membership of several stars is strongly debated and age estimates vary from one author to another with doubts about coevality. We revisit the kinematic properties of the TWA in...
Topics: Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1401.1935
Arxiv.org
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We review the plasma phenomenology in the astrophysical sources which show appreciable radio emissions, namely Radio-Jets from Pulsars, Microquasars, Quasars and Radio-Active Galaxies. A description of their basic features is presented, then we discuss in some details the links between their morphology and the mechanisms that lead to the different radio-emissions, investigating especially the role played by the plasma configurations surrounding compact objects (Neutron Stars, Black Holes). For...
Topics: Physics, High Energy Astrophysical Phenomena, Astrophysics, Plasma Physics
Source: http://arxiv.org/abs/1401.1995
Arxiv.org
- P. Chmielewski; A. K. Srivastava; K. Murawski; Z. E. Musielak
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We present simulation results of the impulsively generated linear and non-linear Alfv\'en waves in the weakly curved coronal magnetic flux-tubes (coronal funnels) and discuss their implications for the coronal heating and solar wind acceleration. We solve numerically the time-dependent magnetohydrodynamic (MHD) equations to obtain the temporal signatures of the small (linear) and large-amplitude (non-linear) Alfv\'en waves in the model atmosphere of expanding open magnetic field configuration...
Topics: Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1401.2329
Arxiv.org
- I. Jimenez-Serra; P. Caselli; F. Fontani; J. C. Tan; J. D. Henshaw; J. Kainulainen; A. K. Hernandez
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Some theories of dense molecular cloud formation involve dynamical environments driven by converging atomic flows or collisions between preexisting molecular clouds. The determination of the dynamics and physical conditions of the gas in clouds at the early stages of their evolution is essential to establish the dynamical imprints of such collisions, and to infer the processes involved in their formation. We present multi-transition 13CO and C18O maps toward the IRDC G035.39-00.33, believed to...
Topics: Astrophysics of Galaxies, Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1401.2347
Arxiv.org
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We show that space-based microlensing experiments can recover lens masses and distances for a large fraction of all events (those with individual photometric errors
Topics: Earth and Planetary Astrophysics, Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1401.2463
Arxiv.org
- Andrew Lobban; Simon Vaughan
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IRAS 18325-5926 is an X-ray bright, Compton-thin, type-2 Seyfert galaxy and it was the first Seyfert 2 in which the presence of a broad Fe K-alpha emission line was claimed. However, although the structure of the Fe line appears broad, there is tentative evidence that it may comprise multiple lines. Nevertheless, previous analyses have only consisted of fitting standalone broad components to the Fe K band. Here, we have analyzed all available X-ray CCD data from Suzaku, XMM-Newton and ASCA to...
Topics: Astrophysics of Galaxies, High Energy Astrophysical Phenomena, Astrophysics, Cosmology and...
Source: http://arxiv.org/abs/1401.2420
Arxiv.org
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During their evolution, short-period exoplanets may lose envelope mass through atmospheric escape owing to intense XUV (X-ray and extreme ultraviolet) radiation from their host stars. Roche-lobe overflow induced by orbital evolution or intense atmospheric escape can also contribute to mass loss. To study the effects of mass loss on inner planet populations, we calculate the evolution of hot Jupiters considering mass loss of their envelopes and thermal contraction. Mass loss is assumed to occur...
Topics: Earth and Planetary Astrophysics, Astrophysics
Source: http://arxiv.org/abs/1401.2511
Arxiv.org
- O. Chesneau; A. Meilland; E. Chapellier; F. Millour; A. M. Van Genderen; Y. Nazé; N. Smith; A. Spang; J. V. Smoker; L. Dessart; S. Kanaan; Ph. Bendjoya; M. W. Feast; J. H. Groh; A. Lobel; N. Nardetto; S. Otero; R. D. Oudmaijer; A. G. Tekola; P. A. Whitelock; C. Arcos; M. Curé; L. Vanzi
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We initiated long-term optical interferometry monitoring of the diameters of unstable yellow hypergiants (YHG) with the goal of detecting both the long-term evolution of their radius and shorter term formation related to large mass-loss events. We observed HR5171 A with AMBER/VLTI. We also examined archival photometric data in the visual and near-IR spanning more than 60 years, as well as sparse spectroscopic data. HR5171A exhibits a complex appearance. Our AMBER data reveal a surprisingly...
Topics: Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1401.2628
Millisecond pulsars (MSPs) and normal non-recycled pulsars are both detected in $\gamma$-rays. However, it appears that a much larger fraction of known energetic and nearby MSPs are detected in $\gamma$-rays, in comparison with normal pulsars, thereby making undetected $\gamma$-ray MSPs exceptions. In this paper, we demonstrate that the viewing angles (i.e. between the pulsar spin axis and the line of sight) are well described by the orbital inclination angles which, for binary MSPs with helium...
Topics: Astrophysics of Galaxies, High Energy Astrophysical Phenomena, Astrophysics, Solar and Stellar...
Source: http://arxiv.org/abs/1401.2773
Arxiv.org
- Jean-Marc Huré; Audrey Trova; Franck Hersant
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The local character of self-gravity along with the number of spatial dimensions are critical issues when computing the potential and forces inside massive systems like stars and disks. This appears from the discretisation scale where each cell of the numerical grid is a self-interacting body in itself. There is apparently no closed-form expression yet giving the potential of a three-dimensional homogeneous cylindrical or spherical cell, in contrast with the Cartesian case. By using Green's...
Topics: Instrumentation and Methods for Astrophysics, Astrophysics
Source: http://arxiv.org/abs/1401.2758
Arxiv.org
- M. Gillon; D. R. Anderson; A. Collier-Cameron; L. Delrez; C. Hellier; E. Jehin; M. Lendl; P. F. L. Maxted; F. Pepe; D. Pollacco; D. Queloz; D. Segransan; A. M. S. Smith; B. Smalley; J. Southworth; A. H. M. J. Triaud; S. Udry; V. Van Grootel; R. G. West
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We report the discovery of WASP-103b, a new ultra-short-period planet (P=22.2 hr) transiting a 12.1 V-magnitude F8-type main-sequence star (1.22+-0.04 Msun, 1.44-0.03+0.05 Rsun, Teff = 6110+-160 K). WASP-103b is significantly more massive (1.49+-0.09 Mjup) and larger (1.53-0.07+0.05 Rjup) than Jupiter. Its large size and extreme irradiation (around 9 10^9 erg/s/cm^2) make it an exquisite target for a thorough atmospheric characterization with existing facilities. Furthermore, its orbital...
Topics: Earth and Planetary Astrophysics, Astrophysics
Source: http://arxiv.org/abs/1401.2784
Arxiv.org
- A. S. Rajpurohit; C. Reyle; F. Allard; R. -D. Scholz; D. Homeier; M. Schultheis; A. Bayo
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Context. M subdwarfs are metal poor and cool stars. They are important probes of the old galactic populations. However, they remain elusive due to their low luminosity. Observational and modeling efforts are required to fully understand their physics and to investigate the effects of metallicity in their cool atmospheres. Aims. We perform a detailed study of a sample of subdwarfs to determine their stellar parameters and constrain the stat-of-the art atmospheric models. Methods. We present...
Topics: Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1401.2901
Arxiv.org
- Silvia Martínez-Núñez; José Miguel Torrejón; Matthias Kühnel; Peter Kretschmar; Martin Stuhlinger; José Joaquín Rodes-Roca; Feliz Fürst; Ingo Kreykenbohm; Antonio Martin-Carrillo; Andy M. T. Pollock; Joern Wilms
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We present analysis of 100 ks contiguous XMM-Newton data of the prototypical wind accretor Vela X-1. The observation covered eclipse egress between orbital phases 0.134 and 0.265, during which a giant flare took place, enabling us to study the spectral properties both outside and during the flare. This giant flare with a peak luminosity of $3.92^{+0.42}_{-0.09} \times 10^{37}$ erg s$^{-1}$ allows estimates of the physical parameters of the accreted structure with a mass of $\sim$ $10^{21}$ g....
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1401.2848
Arxiv.org
- Sebastian Haan; Robert Braun
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We consider the most commonly occurring circumstances which apply to galaxies, namely membership in galaxy groups of about $10^{13}h^{-1} M_\odot$ total mass, and estimate the accompanying physical conditions of intergalactic medium (IGM) density and the relative galaxy-IGM space velocity. We then investigate the dynamical consequences of such a typical galaxy-IGM interaction on a rotating gaseous disk within the galaxy potential. We find that the rotating outer disk is systematically distorted...
Topics: Astrophysics of Galaxies, Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1401.2988
The time lag between optical and near-infrared (IR) flux variability can be taken as a means to determine the sublimation radius of the dusty "torus" around supermassive black holes in active galactic nuclei (AGN). I will show that data from big optical survey telescopes, e.g. the Large Synoptic Survey Telescope (LSST), can be used to measure dust sublimation radii as well. The method makes use of the fact that the Wien tail of the hot dust emission reaches into the optical and can be...
Topics: Astrophysics of Galaxies, Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1401.2999
Arxiv.org
- M. James Jee; Henk Hoekstra; Andisheh Mahdavi; Arif Babul
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We present the results from a weak gravitational lensing study of the merging cluster A520 based on the analysis of Hubble Space Telescope/Advanced Camera for Surveys (ACS) data. The excellent data quality allows us to reach a mean number density of source galaxies of ~109 per sq. arcmin, which improves both resolution and significance of the mass reconstruction compared to a previous study based on Wide Field Planetary Camera 2 (WFPC2) images. We take care in removing instrumental effects such...
Topics: Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1401.3356
Arxiv.org
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We analyze the HI absorption profile for TeV Supernova Remnant (SNR) G349.7+0.2 based on updated knowledge of the inner Galaxy's structure. We significantly revise its kinematic distance from the previous ~ 22 kpc to ~11.5 kpc, indicating it is in the far 3 kpc arm of the Galactic center. We give a revised age of ~ 1800 year for G349.7+0.2 which has a low explosion energy of ~ 2.5 x 10^50 ergs. This removes G349.7+0.2 from the set of brightest SNRs in radio, X-ray to gamma-ray wavebands and...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1401.3354
Arxiv.org
- Mark B. Peacock; Stephen E. Zepf; Thomas J. Maccarone; Arunav Kundu; Anthony H. Gonzalez; Bret D. Lehmer; Claudia Maraston
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A number of recent studies have proposed that the stellar initial mass function (IMF) of early type galaxies varies systematically as a function of galaxy mass, with higher mass galaxies having bottom heavy IMFs. These bottom heavy IMFs have more low-mass stars relative to the number of high mass stars, and therefore naturally result in proportionally fewer neutron stars and black holes. In this paper, we specifically predict the variation in the number of black holes and neutron stars based on...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1401.3405
Arxiv.org
- F. Murgas; E. Palle; M. R. Zapatero Osorio; L. Nortmann; S. Hoyer; A. Cabrera-Lavers
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We used GTC instrument OSIRIS to obtain long-slit spectra in the optical range (520-1040 nm) of the planetary host star WASP-43 (and a reference star) during a full primary transit event and four partial transit observations. We integrated the stellar flux of both stars in different wavelength regions producing several light curves. We fitted transit models to these curves to measure the star-to-planet radius ratio, Rp/Rs, across wavelength among other physical parameters. We measure a Rp/Rs in...
Topics: Earth and Planetary Astrophysics, Astrophysics
Source: http://arxiv.org/abs/1401.3692
Arxiv.org
- Can Güngör; Tolga Güver; K. Yavuz Ekşi
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We present a broad classification of all outbursts detected with the All-Sky Monitor (ASM) on the Rossi X-Ray Timing Explorer (RXTE) and the Monitor of All Sky X-Ray Image (MAXI) of Aql X-1. We identify three types of outbursts; long-high, medium-low, and short-low, based on the duration and maximum flux. We analyse the trends in the "phase-space" of flux-derivative versus flux to demonstrate the differences in the three identified outburst types. We present a spectral analysis of the...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1401.4054
Arxiv.org
- K. B. Ramesh; N Vasantharaju
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Temporal offsets between the time series of solar activity indicators provide important clues regarding the physical processes responsible for the cyclic variability in the solar atmosphere. Hysteresis patterns generated between any two indicators were popularly used to study their morphological features and further to understand their inter relationships. We use time series of different solar indicators to understand the possible cause-and-effect criteria between their respective source...
Topics: Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1401.3990
Arxiv.org
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Class I protostars in three high-mass star-forming regions are found to have correlations among the local projected density of other Class I protostars, the summed flux from these other protostars, and the protostellar luminosity in the WISE 22 micron band. Brighter Class I sources form in higher-density and higher-flux regions, while low luminosity sources form anywhere. These correlations depend slightly on the number of neighbors considered (from 2 to 20) and could include a size-of-sample...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1401.4016
Arxiv.org
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Hydrogen molecules (H2) come in two forms in the interstellar medium, ortho- and para-hydrogen, corresponding to the two different spin configurations of the two hydrogen atoms. The relative abundances of the two flavours in the interstellar medium are still very uncertain, and this abundance ratio has a significant impact on the thermal properties of the gas. In the context of star formation, theoretical studies have recently adopted two different strategies when considering the ortho:para...
Topics: Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1401.4299
Arxiv.org
- James Overduin; Francis Everitt; Paul Worden; John Mester
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The Satellite Test of the Equivalence Principle (STEP) will advance experimental limits on violations of Einstein's Equivalence Principle from their present sensitivity of 2 parts in $10^{13}$ to 1 part in $10^{18}$ through multiple comparison of the motions of four pairs of test masses of different compositions in a drag-free earth-orbiting satellite. We describe the experiment, its current status, and its potential implications for fundamental physics. Equivalence is at the heart of general...
Topics: Instrumentation and Methods for Astrophysics, Astrophysics, General Relativity and Quantum Cosmology
Source: http://arxiv.org/abs/1401.4784
This thesis reports on the application of new wide-field Very Long Baseline Interferometry (VLBI) imaging techniques using real data for the first time. These techniques are used to target three specific science areas: (i) a sub-parsec-scale study of compact radio sources in nearby starburst galaxies, (ii) a study of jet interactions in active radio galaxies, and (iii) an unbiased study of the sub-arcsecond, 90 cm sky.
Topics: Astrophysics of Galaxies, Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1401.4791
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- E. M. Sion; J. B. Holberg; T. D. Oswalt; G. P. McCook; R. Wasatonic; J. Myszka
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We present the fractional distribution of spectroscopic subtypes, range and distribution of surface temperatures, and kinematical properties of the white dwarfs within 25pc of the sun. There is no convincing evidence of halo white dwarfs in the total 25 pc sample of 224 white dwarfs. There is also little to suggest the presence of genuine thick disk subcomponent members within 25 parsecs. It appears that the entire 25 pc sample likely belong to the thin disk. We also find no significant...
Topics: Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1401.4989
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A wide range of large scale observations hint towards possible modifications on the standard cosmological model which is based on a homogeneous and isotropic universe with a small cosmological constant and matter. These observations, also known as "cosmic anomalies" include unexpected Cosmic Microwave Background perturbations on large angular scales, large dipolar peculiar velocity flows of galaxies ("bulk flows"), the measurement of inhomogenous values of the fine structure...
Topics: Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1401.5044
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- Andrea Mehner; Kazunori Ishibashi; Patricia Whitelock; Takahiro Nagayama; Michael Feast; Francois van Wyk; Willem-Jan de Wit
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Aims. Eta Car's ultra-violet, optical, and X-ray light curves and its spectrum suggest a physical change in its stellar wind over the last decade. It was proposed that the mass-loss rate decreased by a factor of about 2 in the last 15 years. We complement these recent results by investigating the past evolution and the current state of eta Car in the near-infrared (IR). Methods. We present JHKL photometry of eta Car obtained at SAAO Sutherland from 2004-2013 with the Mk II photometer at the...
Topics: Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1401.4999
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- Gen Chiaki; Raffaella Schneider; Takaya Nozawa; Kazuyuki Omukai; Marco Limongi; Naoki Yoshida; Alessandro Chieffi
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Dust grains in low-metallicity star-forming regions may be responsible for the formation of the first low-mass stars. The minimal conditions to activate dust-induced fragmentation require the gas to be pre-enriched above a critical dust-to-gas mass ratio Dcr=[2.6--6.3]x10^-9 with the spread reflecting the dependence on the grain properties. The recently discovered Galactic halo star SDSS J102915+172927 has a stellar mass of 0.8 Msun and a metallicity of Z=4.5x10^-5 Zsun and represents an...
Topics: Astrophysics of Galaxies, Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1401.5057
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- Mitsuru Kokubo; Tomoki Morokuma; Takeo Minezaki; Mamoru Doi; Toshihiro Kawaguchi; Hiroaki Sameshima; Shintaro Koshida
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We investigate the UV-optical (longward of Ly$\alpha$ 1216\AA) spectral variability of nearly 9000 quasars ($0
Topics: Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1401.5074
Arxiv.org
- Zheng Zheng; Jeffrey L. Carlin; Timothy C. Beers; Licai Deng; Carl J. Grillmair; Puragra Guhathakurta; Sebastien Lepine; Heidi Jo Newberg; Brian Yanny; Haotong Zhang; Chao Liu; Ge Jin; Yong Zhang
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We report the first hypervelocity star (HVS) discovered from the LAMOST spectroscopic survey. It is a B-type star with a heliocentric radial velocity about 620 km/s, which projects to a Galactocentric radial velocity component of ~477 km/s. With a heliocentric distance of ~13 kpc and an apparent magnitude of ~13 mag, it is the nearest bright HVS currently known. With a mass of ~9Msun, it is one of the three most massive HVSs discovered so far. The star is clustered on the sky with many other...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1401.5063
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We give precise details to support that observations of gravitational lensing at scales of individual, groups and clusters of galaxies can be understood in terms of non-Newtonian gravitational interactions with a relativistic structure compatible with the Einstein Equivalence Principle. This result is derived on very general grounds without knowing the underlying structure of the gravitational field equations. As such, any developed gravitational theory built to deal with these astrophysical...
Topics: Astrophysics of Galaxies, Astrophysics, General Relativity and Quantum Cosmology, Cosmology and...
Source: http://arxiv.org/abs/1401.5104
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- Aurélie Guilbert-Lepoutre
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Jupiter Trojans appear to be a key population of small bodies to study and test the models of the Solar System formation and evolution. Because understanding the evolution of Trojans can bring strong and unique constraints on the origins of our planetary system, a significant observational effort has been undertaken to unveil their physical characteristics. The data gathered so far are consistent with Trojans having volatile-rich interiors (possibly water ice) and volatile-poor surfaces (fine...
Topics: Earth and Planetary Astrophysics, Astrophysics
Source: http://arxiv.org/abs/1401.5196
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Magnetic fields represent a crucial aspect of the physics and astrophysics of neutron stars. Despite its great relevance, the internal magnetic field configuration of neutron stars is very poorly constrained by the observations, and understanding its properties is a long-standing theoretical challenge. The investigation on the subject is focused on the search for those magnetic field geometries which are stable on several Alfv\`en timescales, thus constituting a viable description of neutron...
Topics: High Energy Astrophysical Phenomena, Astrophysics, Solar and Stellar Astrophysics, General...
Source: http://arxiv.org/abs/1401.5276
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- H. Siejkowski; K. Otmianowska-Mazur; M. Soida; D. J. Bomans; M. Hanasz
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Star-forming dwarf galaxies can be seen as the local proxies of the high-redshift building blocks of more massive galaxies according to the current paradigm of the hierarchical galaxy formation. They are low-mass objects, and therefore their rotation speed is very low. Several galaxies are observed to show quite strong magnetic fields. These cases of strong ordered magnetic fields seem to correlate with a high, but not extremely high, star formation rate. We investigate whether these magnetic...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1401.5293
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- C. Wetterich
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We confront the big bang for the beginning of the universe with an equivalent picture of a slow freeze - a very cold and slowly evolving universe. In the freeze picture the masses of elementary particles increase and the gravitational constant decreases with cosmic time, while the Newtonian attraction remains unchanged. The freeze and big bang pictures both describe the same observations or physical reality. We present a simple "crossover model" without a big bang singularity. In the...
Topics: High Energy Physics - Theory, Astrophysics, General Relativity and Quantum Cosmology, Cosmology and...
Source: http://arxiv.org/abs/1401.5313
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- Mitchell C. Begelman; Philip J. Armitage
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We suggest that the hysteretic cycle of black hole state transitions arises from two established properties of accretion disks: the increase in turbulent stress in disks threaded by a net magnetic field and the ability of thick (but not thin) disks to advect such a field radially. During quiescence, magnetic field loops are generated by the magnetorotational instability at the interface between the inner hot flow and outer thin disk. Vertical flux is advected into and accumulates stochastically...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1401.5475
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We describe the Dragonfly Telephoto Array, a robotic imaging system optimized for the detection of extended ultra low surface brightness structures. The array consists of eight Canon 400mm f/2.8 telephoto lenses coupled to eight science-grade commercial CCD cameras. The lenses are mounted on a common framework and are co-aligned to image simultaneously the same position on the sky. The system provides an imaging capability equivalent to a 0.4m aperture f/1.0 refractor with a 2.6 deg X 1.9 deg...
Topics: Instrumentation and Methods for Astrophysics, Astrophysics of Galaxies, Astrophysics, Solar and...
Source: http://arxiv.org/abs/1401.5473
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We calculate radiatively driven wind models of main-sequence B stars and provide the wind mass-loss rates and terminal velocities. The main-sequence mass-loss rate strongly depends on the stellar effective temperature. For the hottest B stars the mass-loss rate amounts to $10^{-9}\,\text{M}_\odot\,\text{year}^{-1}$, while for the cooler ones themass-loss rate is lower by more than three orders of magnitude. Main-sequence B stars with solar abundance and effective temperatures lower than...
Topics: Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1401.5511
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- P. Saracco; A. Casati; A. Gargiulo; M. Longhetti; I. Lonoce; S. Tamburri; D. Bettoni; M. D'Onofrio; G. Fasano; B. M. Poggianti; K. Boutsia; M. Fumana; E. Sani
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[Abridged] We studied the size-surface brightness and the size-mass relations of a sample of 16 cluster elliptical galaxies in the mass range 10^{10}-2x10^{11} M_sun which were morphologically selected in the cluster RDCS J0848+4453 at z=1.27. Our aim is to assess whether they have completed their mass growth at their redshift or significant mass and/or size growth can or must take place until z=0 in order to understand whether elliptical galaxies of clusters follow the observed size evolution...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1401.5600
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The Planck mission has conclusively detected lensing of the Cosmic Microwave Background (CMB) radiation from foreground sources to an overall significance of greater than $25\sigma$. The high precision of this measurement motivates the development of a more complete formulation of the calculation of this effect. While most effects on the CMB anisotropies are widely studied through direct solutions of the Boltzmann equation, the non-linear effect of CMB lensing is formulated through the...
Topics: Astrophysics, General Relativity and Quantum Cosmology, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1401.5737
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- V. Lorenzi; N. Pinilla-Alonso; J. Licandro; C. M. Dalle Ore; J. P. Emery
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Models of the escape and retention of volatiles by minor icy objects exclude any presence of volatile ices on the surface of TNOs smaller than ~1000km in diameter at the typical temperature in this region of the solar system, whereas the same models show that water ice is stable on the surface of objects over a wide range of diameters. Collisions and cometary activity have been used to explain the process of surface refreshing of TNOs and Centaurs. These processes can produce surface...
Topics: Earth and Planetary Astrophysics, Astrophysics
Source: http://arxiv.org/abs/1401.5962
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- J. L. Hewett; H. Weerts; K. S. Babu; J. Butler; B. Casey; A. de Gouvea; R. Essig; Y. Grossman; D. Hitlin; J. Jaros; E. Kearns; K. Kumar; Z. Ligeti; Z. -T. Lu; K. Pitts; M. Ramsey-Musolf; J. Ritchie; K. Scholberg; W. Wester; G. P. Zeller
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These reports present the results of the 2013 Community Summer Study of the APS Division of Particles and Fields ("Snowmass 2013") on the future program of particle physics in the U.S. Chapter 2, on the Intensity Frontier, discusses the program of research with high-intensity beams and rare processes. This area includes experiments on neutrinos, proton decay, charged-lepton and quark weak interactions, atomic and nuclear probes of fundamental symmetries, and searches for new, light,...
Topics: Cosmology and Nongalactic Astrophysics, High Energy Physics - Theory, High Energy Physics -...
Source: http://arxiv.org/abs/1401.6077
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- L. Slavcheva-Mihova; B. Mihov; I. Iliev
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We have presented an optical monitoring of 3C 273, the first quasar discovered fifty years ago. It does not show variability both on intra-night and long-term time scales. To facilitate the further monitoring of 3C 273, we compiled the available calibrations of the comparison stars in its field into a mean sequence.
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1401.5987
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- Seth A. Cohen; Ryan C. Hickox; Gary A. Wegner; Maret Einasto; Jaan Vennik
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We investigate the relationship between star formation (SF) and substructure in a sample of 107 nearby galaxy clusters using data from the Sloan Digital Sky Survey (SDSS). Several past studies of individual galaxy clusters have suggested that cluster mergers enhance cluster SF, while others find no such relationship. The SF fraction in multi-component clusters (0.228 +/- 0.007) is higher than that in single-component clusters (0.175 +/- 0.016) for galaxies with M^0.1_r < -20.5. In both...
Topics: Astrophysics of Galaxies, Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1401.6171
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- O. Ivy Wong; Jeffrey D. P. Kenney; Eric J. Murphy; George Helou
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We investigate the presence of shock-excited H2 in four Virgo cluster galaxies that show clear evidence of ongoing ram pressure stripping. Mid-infrared (MIR) spectral mapping of the rotational H2 emission lines were performed using the Infrared Spectrograph (IRS) on board the Spitzer space telescope. We target four regions along the leading side of galaxies where the intracluster medium (ICM) appears to be pushing back the individual galaxy's interstellar medium (ISM). For comparison purposes,...
Topics: Astrophysics of Galaxies, Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1401.6223
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- Kfir Blum; Raffaele Tito D'Agnolo; Mariangela Lisanti; Benjamin R. Safdi
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We show that Big Bang Nucleosynthesis (BBN) significantly constrains axion-like dark matter. The axion acts like an oscillating QCD $\theta$ angle that redshifts in the early universe, increasing the neutron-proton mass difference at neutron freeze-out. An axion-like particle that couples too strongly to QCD results in the underproduction of 4He during BBN and is thus excluded. The BBN bound overlaps with much of the parameter space that would be covered by proposed searches for time-varying...
Topics: High Energy Physics - Phenomenology, Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1401.6460
In the present paper we show how obtain the energy distribution f(E) in our vicinity starting from WIMP density profiles in a self consistent way by employing the Eddington approach and adding reasonable angular momentum dependent terms in the expression of the energy. We then show how we can obtain the velocity dispersion and the asymmetry parameter {\beta} in terms of the parameters describing the angular momentum dependence. From this expression for f(E) we proceed to construct an axially...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1401.6510
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- Griffin Foster; Jack Hickish; Alessio Magro; Danny C. Price; Kristian Zarb Adami
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A new digital backend has been developed for the BEST-2 array at Radiotelescopi di Medicina, INAF-IRA, Italy which allows concurrent operation of an FX correlator, and a direct-imaging correlator and beamformer. This backend serves as a platform for testing some of the spatial Fourier transform concepts which have been proposed for use in computing correlations on regularly gridded arrays. While spatial Fourier transform-based beamformers have been implemented previously, this is to our...
Topics: Instrumentation and Methods for Astrophysics, Astrophysics
Source: http://arxiv.org/abs/1401.6753
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- T. D. Kitching; A. F. Heavens; J. Alsing; T. Erben; C. Heymans; H. Hildebrandt; H. Hoekstra; A. Jaffe; A. Kiessling; Y. Mellier; L. Miller; L. van Waerbeke; J. Benjamin; J. Coupon; L. Fu; M. J. Hudson; M. Kilbinger; K. Kuijken; B. T. P. Rowe; T. Schrabback; E. Semboloni; M. Velander
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This paper presents the first application of 3D cosmic shear to a wide-field weak lensing survey. 3D cosmic shear is a technique that analyses weak lensing in three dimensions using a spherical harmonic approach, and does not bin data in the redshift direction. This is applied to CFHTLenS, a 154 square degree imaging survey with a median redshift of 0.7 and an effective number density of 11 galaxies per square arcminute usable for weak lensing. To account for survey masks we apply a 3D...
Topics: Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1401.6842
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- MAGIC Collaboration; J. Aleksić; S. Ansoldi; L. A. Antonelli; P. Antoranz; A. Babic; P. Bangale; U. Barres de Almeida; J. A. Barrio; J. Becerra González; W. Bednarek; N. Nowak; E. de Oña Wilhelmi; R. Orito; A. Overkemping; S. Paiano; M. Palatiello; D. Paneque; R. Paoletti; J. M. Paredes; X. Paredes-Fortuny; E. Bernardini; S. Partini; M. Persic; F. Prada; P. G. Prada Moroni; E. Prandini; S. Preziuso; I. Puljak; R. Reinthal; W. Rhode; M. Ribó; A. Biland; J. Rico; J. Rodriguez Garcia; S....
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HESS J1857+026 is an extended TeV gamma-ray source that was discovered by H.E.S.S. as part of its Galactic plane survey. Given its broadband spectral energy distribution and its spatial coincidence with the young energetic pulsar PSR J1856+0245, the source has been put forward as a pulsar wind nebula (PWN) candidate. MAGIC has performed follow-up observations aimed at mapping the source down to energies approaching 100 GeV in order to better understand its complex morphology. HESS J1857+026 was...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1401.7154
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- N. Laporte; A. Streblyanska; B. Clement; I. Perez-Fournon; D. Schaerer; H. Atek; F. Boone; J. -P. Kneib; E. Egami; P. Martinez-Navajas; R. Marques-Chaves; R. Pello; J. Richard
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We present in this letter the first analysis of a z~8 galaxy candidate found in the Hubble and Spitzer imaging data of Abell 2744, as part of the Hubble Frontier Fields legacy program. We applied the most commonly-used methods to select exceptionally high-z galaxies by combining non-detection and color-criteria using seven HST bands. We used GALFIT on IRAC images for fitting and subtracting contamination of bright nearby sources. The physical properties have been inferred from SED-fitting using...
Topics: Astrophysics of Galaxies, Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1401.8263
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- James F. Steiner; Jeffrey E. McClintock; Jerome A. Orosz; Ronald A. Remillard; Charles D. Bailyn; Mari Kolehmainen; Odele Straub
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Building upon a new dynamical model for the X-ray binary LMC X-3, we measure the spin of its black hole primary via the continuum-fitting method. We consider over one thousand thermal-state RXTE X-ray spectra of LMC X-3. Using a large subset of these spectra, we constrain the spin parameter of the black hole to be spin = 0.21(+0.18,-0.22), 90% confidence. Our estimate of the uncertainty in spin takes into account a wide range of systematic errors. We discuss evidence for a correlation between a...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1402.0148
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- Joyce A. Guzik; Catherine C. Lovekin
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The Luminous Blue Variable stars exhibit behavior ranging from light curve `microvariations' on timescales of tens of days, to `outbursts' accompanied by mass loss of up to 10e-03 solar masses per year, occurring decades apart, to `giant eruptions' such as seen in Eta Carinae ejecting one or more solar masses and recurring on timescales of centuries. Here we review the work of the Los Alamos group since 1993 to investigate pulsations and instabilities in massive stars using linear pulsation...
Topics: Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1402.0257
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- A. Boselli; L. Cortese; M. Boquien; S. Boissier; B. Catinella; G. Gavazzi; C. Lagos; A. Saintonge
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The HRS is a complete volume-limited sample of nearby objects including Virgo cluster and isolated objects. Using a recent compilation of HI and CO data we study the effects of the cluster on the molecular gas content of spiral galaxies. We first identify M* as the scaling variable that traces the total H2 mass of galaxies better. We show that, on average, HI-deficient galaxies are significantly offset from the M(H2) vs. M* relation for HI-normal galaxies. We use the M(H2) vs. M* scaling...
Topics: Astrophysics of Galaxies, Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1402.0326
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Neutron stars (NSs) are thought to be excellent laboratories for determining the equation of state (EoS) of cold dense matter. Their strong gravity suggests that they can also be used to constrain gravity models. The mass and radius (M-R) of a NS both depend on the choice of EoS and gravity, meaning that NSs cannot be simultaneously good laboratories for both of these questions. A measurement of M-R would constrain the less well known physics input. The assumption that M-R measurements can be...
Topics: High Energy Astrophysical Phenomena, Astrophysics, General Relativity and Quantum Cosmology
Source: http://arxiv.org/abs/1402.0488
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We present a framework for discussing the cosmology of dark energy and dark matter based on two scalar degrees of freedom. An effective field theory of cosmological perturbations is employed. A unitary gauge choice renders the dark energy field into the gravitational sector, for which we adopt a generic Lagrangian depending on three-dimensional geometrical scalar quantities arising in the ADM decomposition. We add to this dark-energy associated gravitational sector a scalar field $\phi$ and its...
Topics: High Energy Physics - Theory, High Energy Physics - Phenomenology, Astrophysics, General Relativity...
Source: http://arxiv.org/abs/1402.0553
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Self-gravitating Bose-Einstein condensates (BEC) have been proposed in various astrophysical contexts, including Bose-stars and BEC dark matter halos. These systems are described by a combination of the Gross-Pitaevskii and Poisson equations (the GPP system). In the analysis of these hypothetical objects, the Thomas-Fermi (TF) approximation is widely used. This approximation is based on the assumption that in the presence of a large number of particles, the kinetic term in the Gross-Pitaevskii...
Topics: Quantum Gases, Astrophysics of Galaxies, Astrophysics, General Relativity and Quantum Cosmology,...
Source: http://arxiv.org/abs/1402.0600
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- Tomohiro Fujita; Shuichiro Yokoyama
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Recently, there are several reports that the cosmic magnetic fields on Mpc scale in void region is larger than $\sim 10^{-15}$G with an uncertainty of a few orders from the current blazar observations. On the other hand, in inflationary magnetogenesis models, additional primordial curvature perturbations are inevitably produced from iso-curvature perturbations due to generated electromagnetic fields. We explore such induced curvature perturbations in a model independent way and obtained a...
Topics: High Energy Physics - Theory, High Energy Physics - Phenomenology, Astrophysics, General Relativity...
Source: http://arxiv.org/abs/1402.0596
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- Laura M. Pérez; Andrea Isella; John M. Carpenter; Claire J. Chandler
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We present Atacama Large Millimeter/submillimeter Array (ALMA) observations in the dust continuum (690 GHz, 0.45 mm) and 12CO J=6-5 spectral line emission, of the transitional disks surrounding the stars SAO 206462 and SR 21. These ALMA observations resolve the dust-depleted disk cavities and extended gaseous disks, revealing large-scale asymmetries in the dust emission of both disks. We modeled these disks structures with a ring and an azimuthal gaussian, where the azimuthal gaussian is...
Topics: Earth and Planetary Astrophysics, Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1402.0832
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- Patrick Stengel
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We consider a class of leptogenesis models in which the lepton asymmetry arises from dark matter annihilation processes which violate CP and lepton number. Importantly, a necessary one-loop contribution to the annihilation matrix element arises from absorptive final state interactions. We elucidate the relationship between this one-loop contribution and the CP-violating phase. As we show, the branching fraction for dark matter annihilation to leptons may be small in these models, while still...
Topics: High Energy Physics - Phenomenology, Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1402.0930
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- Harpreet Dhanoa; Jonathan Mackey; Jeremy Yates
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The discovery of a hyper metal-poor star with total metallicity of $\le 10^{-5}$ Z$_\odot$, has motivated new investigations of how such objects can form from primordial gas polluted by a single supernova. In this paper we present a shock-cloud model which simulates a supernova remnant interacting with a cloud in a metal-free environment at redshift $z=10$. Pre-supernova conditions are considered, which include a multiphase neutral medium and H II region. A small dense clump ($n=100$...
Topics: Astrophysics of Galaxies, Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1402.1103
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- Natalia Zywucka; Arti Goyal; Marek Jamrozy; Michal Ostrowski; Lukasz Stawarz
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In the framework of the unification scheme of radio-loud active galactic nuclei, BL Lac objects and quasars are the beamed end-on counterparts of low-power (FRI) and high-power (FRII) radio galaxies, respectively. Some BL Lacs have been found to possess the FRII-type large-scale radio morphology, suggesting that the parent population of BL Lacs is a mixture of low- and high-power radio galaxies. This seems to apply only to `low frequency-peaked' BL Lacs, since all the `high frequency-peaked' BL...
Topics: Astrophysics of Galaxies, Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1402.1320
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- Kyle B. Westfall; David R. Andersen; Matthew A. Bershady; Thomas P. K. Martinsson; Robert A. Swaters; Marc A. W. Verheijen
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We study the relationship between the stability level of late-type galaxy disks and their star-formation activity using integral-field gaseous and stellar kinematic data. Specifically, we compare the two-component (gas+stars) stability parameter from Romeo & Wiegert (Q_RW), incorporating stellar kinematic data for the first time, and the star-formation rate estimated from 21cm continuum emission. We determine the stability level of each disk probabilistically using a Bayesian analysis of...
Topics: Astrophysics of Galaxies, Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1402.1499
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Disk accretion onto magnetic stars occurs in a variety of systems, including accreting neutron stars (with both high and low magnetic fields), white dwarfs, and protostars. We review some of the key physical processes in magnetosphere-disk interaction, highlighting the theoretical uncertainties. We also discuss some applications to the observations of accreting neutron stars and protostellar systems, as well as possible connections to protoplanetary disks and exoplanets.
Topics: High Energy Astrophysical Phenomena, Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1402.1903
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In 2012, physicists and astronomers celebrated the hundredth anniversary of the detection of cosmic rays by Viktor Hess. One year later, in 2013, there was first evidence for extraterrestrial high-energy neutrinos, i.e. for signal which may contain key information on the origin of cosmic rays. That evidence is provided by data taken with the IceCube neutrino telescope at the South Pole. First concepts to build a detector of this kind have been discussed at the 1973 International Cosmic Ray...
Topics: Instrumentation and Methods for Astrophysics, High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1402.2096
Arxiv.org
- S. Torres; E. García-Berro; J. Krzesinski; S. J. Kleinman
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We present a coherent and detailed Monte Carlo simulation of the population of hot white dwarfs. We assess the statistical significance of the hot end of the white dwarf luminosity function and the role played by the bolometric corrections of hydrogen-rich white dwarfs at high effective temperatures. We use the most up-to-date stellar evolutionary models and implement a full description of the observational selection biases to obtain realistic simulations of the observed white dwarf population....
Topics: Astrophysics of Galaxies, Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1402.2104
Arxiv.org
- Santiago Avila; Alexander Knebe; Frazer R. Pearce; Aurel Schneider; Chaichalit Srisawat; Peter A. Thomas; Peter Behroozi; Pascal J. Elahi; Jiaxin Han; Yao-Yuan Mao; Julian Onions; Vicente Rodriguez-Gomez
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Merger tree codes are routinely used to follow the growth and merger of dark matter haloes in simulations of cosmic structure formation. Whereas in Srisawat et. al. we compared the trees built using a wide variety of such codes here we study the influence of the underlying halo catalogue upon the resulting trees. We observe that the specifics of halo finding itself greatly influences the constructed merger trees. We find that the choices made to define the halo mass are of prime importance. For...
Topics: Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1402.2381
Arxiv.org
- Chang-Shuo Yan; Youjun Lu; Qingjuan Yu; Shude Mao; Joachim Wambsganss
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Sub-parsec binary massive black holes (BBHs) are long anticipated to exist in many QSOs but remain observationally elusive. In this paper, we propose a novel method to probe sub-parsec BBHs through microlensing of lensed QSOs. If a QSO hosts a sub-parsec BBH in its center, it is expected that the BBH is surrounded by a circum-binary disk, each component of the BBH is surrounded by a small accretion disk, and a gap is opened by the secondary component in between the circum-binary disk and the...
Topics: High Energy Astrophysical Phenomena, Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1402.2504
Arxiv.org
- Peter Vereš; Davide Farnocchia; Robert Jedicke; Federica Spoto
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We study the time evolution of the impact probability for synthetic but realistic impacting and close approaching asteroids detected in a simulated all-sky survey. We use the impact probability to calculate the impact warning time as the time interval between when an object reaches a Palermo Scale value of -2 and when it impacts Earth. A simple argument shows that warning time ~ D^x with the exponent in the range [1.0,1.5] and our derived value was $x=1.3\pm0.1$. The low-precision astrometry...
Topics: Earth and Planetary Astrophysics, Astrophysics
Source: http://arxiv.org/abs/1402.2466
Arxiv.org
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The analyses of Titan's gravity field obtained by Cassini space mission suggest the presence of an internal ocean beneath its icy surface. The characterization of the geophysical parameters of the icy shell and the ocean is important to constrain the evolution models of Titan. The knowledge of the librations, that are periodic oscillations around a uniform rotational motion, can bring piece of information on the interior parameters. The objective of this paper is to study the librational...
Topics: Earth and Planetary Astrophysics, Astrophysics
Source: http://arxiv.org/abs/1402.2493
Arxiv.org
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The classical picture of a star-forming filament is a near-equilibrium structure, with collapse dependent on its gravitational criticality. Recent observations have complicated this picture, revealing filaments as a mess of apparently interacting subfilaments, with transsonic internal velocity dispersions and mildly supersonic intra-subfilament dispersions. How structures like this form is unresolved. Here we study the velocity structure of filamentary regions in a simulation of a turbulent...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1402.2614
Arxiv.org
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Spider is a balloon-borne array of six telescopes that will observe the Cosmic Microwave Background. The 2400 antenna-coupled bolometers in the instrument will make a polarization map of the CMB with ~degree resolution at 150 GHz and 95 GHz. Polarization modulation is achieved via a cryogenic sapphire half-wave plate (HWP) skyward of the primary optic. In this thesis, the design, construction, and lab testing of the HWP system are discussed. The polarization modulation of these optical stacks...
Topics: Instrumentation and Methods for Astrophysics, Astrophysics
Source: http://arxiv.org/abs/1402.2591
Arxiv.org
- Imogen H. Whittam; Julia M. Riley; David A. Green
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We have used recent Very Long Baseline Interferometry (VLBI) observations by Middelberg et al. with a resolution of $\approx 10$ mas to investigate the properties of faint sources selected from the Tenth Cambridge (10C) survey in the Lockman Hole. The 10C survey is complete to 0.5 mJy at 15.7 GHz and has a resolution of 30 arcsec. We have previously shown that this population is dominated by flat-spectrum sources below $\approx 1$ mJy, in disagreement with several models of the faint,...
Topics: Astrophysics of Galaxies, Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1402.2553
Arxiv.org
- Yujin Yang; Fabian Walter; Roberto Decarli; Frank Bertoldi; Axel Weiss; Arjun Dey; Moire K. M. Prescott; Toma Badescu
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We present IRAM PdBI observations of the CO(3-2) and CO(5-4) line transitions from a Ly-alpha blob at z~2.7 in order to investigate the gas kinematics, determine the location of the dominant energy source, and study the physical conditions of the molecular gas. CO line and dust continuum emission are detected at the location of a strong MIPS source that is offset by ~1.5" from the Ly-alpha peak. Neither of these emission components is resolved with the 1.7" beam, showing that the gas...
Topics: Astrophysics of Galaxies, Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1402.2686
Arxiv.org
- Anja von der Linden; Adam Mantz; Steven W. Allen; Douglas E. Applegate; Patrick L. Kelly; R. Glenn Morris; Adam Wright; Mark T. Allen; Patricia R. Burchat; David L. Burke; David Donovan; Harald Ebeling
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In light of the tension in cosmological constraints reported by the Planck team between their SZ-selected cluster counts and Cosmic Microwave Background (CMB) temperature anisotropies, we compare the Planck cluster mass estimates with robust, weak-lensing mass measurements from the Weighing the Giants (WtG) project. For the 22 clusters in common between the Planck cosmology sample and WtG, we find an overall mass ratio of $\left < M_{Planck}/M_{\rm WtG} \right> = 0.688 \pm 0.072$....
Topics: Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1402.2670
Arxiv.org
- S. Adrián-Martínez; A. Albert; M. André; G. Anton; M. Ardid; J. -J. Aubert; B. Baret; J. Barrios-Martí; S. Basa; V. Bertin; S. Biagi; T. Pradier; C. Racca; G. Riccobene; R. Richter; K. Roensch; A. Rostovtsev; M. Saldaña; D. F. E. Samtleben; A. Sánchez-Losa; M. Sanguineti; C. Bogazzi; J. Schmid; J. Schnabel; S. Schulte; F. Schüssler; T. Seitz; C. Sieger; A. Spies; M. Spurio; J. J. M. Steijger; Th. Stolarczyk; R. Bormuth; M. Taiuti; C. Tamburini; Y. Tayalati; A. Trovato; B. Vallage; C....
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This paper reports a search for spatial clustering of the arrival directions of high energy muon neutrinos detected by the ANTARES neutrino telescope. An improved two-point correlation method is used to study the autocorrelation of 3058 neutrino candidate events as well as cross-correlations with other classes of astrophysical objects: sources of high energy gamma rays, massive black holes and nearby galaxies. No significant deviations from the isotropic distribution of arrival directions...
Topics: Instrumentation and Methods for Astrophysics, High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1402.2809
Arxiv.org
- Anna-Lea Lesage; Guenter Wiedemann
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Measuring the stellar position angle provides valuable information on binary stellar formation or stellar spin axis evolution. We aim to develop a method for determining the absolute stellar position angle using spectro-astrometric analysis of high resolution long-slit spectra. The method has been designed in particular for slowly rotating stars. We investigate its applicability to existing dispersive long-slit spectrographs, identified here by their plate scale, and the size of the resulting...
Topics: Instrumentation and Methods for Astrophysics, Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1402.3235
Arxiv.org
- Rose N. Lerner; Scott Melville
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We investigate the probability of obtaining an observable curvature perturbation, using as an example the minimal curvaton-higgs (MCH) model. We determine 'probably observable' and 'probably excluded' regions of parameter space assuming generic initial conditions and applying a stochastic approach for the curvaton's evolution during inflation. Inflation is assumed to last longer than the N_{obs} = 55 observable e-folds, and the total number of e-folds of inflation determines the particular...
Topics: High Energy Physics - Phenomenology, Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1402.3176
Arxiv.org
- C. Neiner; A. Tkachenko; the MiMeS collaboration
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The presence of a magnetic field can have a strong impact on the evolution of a binary star. However, only a dozen of magnetic OB binaries are known as of today and available to study this effect, including very few magnetic pulsating spectroscopic OB binaries. We aim at checking for the presence of a magnetic field in the B5IV hierarchical triple system HD 1976 with spectropolarimetric data obtained with Narval at the Bernard Lyot Telescope (TBL). We use orbital parameters of HD 1976 available...
Topics: Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1402.3245