29
29
Jul 20, 2013
07/13
by
M. Kowalski
texts
eye 29
favorite 0
comment 0
Accumulation and annihilation of weakly interacting massive particles (WIMPs) in the earth and the sun may be observed by the resulting neutrino signal. We demonstrate that, for certain parts of the SUSY parameter space, present and future neutrino telescopes can expect a higher rate of events due to tau-neutrinos than of events due to muon-neutrinos. We show how $\nu_{\tau}\leftrightarrow\nu_{\mu}$ oscillations, and in the case of the sun also scattering, absorption and regeneration, modify...
Source: http://arxiv.org/abs/hep-ph/0009183v2
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30
Sep 20, 2013
09/13
by
Piotr M. Kowalski
texts
eye 30
favorite 0
comment 0
We investigate the importance of the pseudo-continuum bound-free opacity from hydrogen atoms in the atmospheres of cool white dwarfs. This source of absorption, when calculated by the occupation probability formalism applied in the modeling of white dwarf atmospheres with $T_{\rm eff}\rm
Source: http://arxiv.org/abs/astro-ph/0607606v1
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17
Feb 10, 2012
02/12
by
Kathiann M. Kowalski
texts
eye 17
favorite 0
comment 0
Topics: Affirmative action programs -- United States -- History -- Juvenile literature., Discrimination in...
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46
Feb 13, 2012
02/12
by
Kathiann M. Kowalski
texts
eye 46
favorite 3
comment 0
Topics: Alternative medicine -- Juvenile literature., Alternative medicine.
0
0.0
Jun 30, 2018
06/18
by
Piotr M. Kowalski
texts
eye 0
favorite 0
comment 0
Aims: Hydrogen deficient white dwarfs are characterized by very dense, fluid-like atmospheres of complex physics and chemistry that are still poorly understood. The incomplete description of these atmospheres by the models results in serious problems with the description of spectra of these stars and subsequent difficulties in derivation of their surface parameters. Here, we address the problem of infrared (IR) opacities in the atmospheres of cool white dwarfs by direct $ab$ $initio$...
Topics: Physics, Astrophysics, Atomic Physics, Computational Physics, Materials Science, Solar and Stellar...
Source: http://arxiv.org/abs/1406.4591
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37
Sep 21, 2013
09/13
by
Piotr M. Kowalski
texts
eye 37
favorite 0
comment 0
The DQ white dwarfs are stars whose atmosphere is enriched with carbon, which for cool stars ($T_{\rm eff}
Source: http://arxiv.org/abs/1008.4542v1
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51
Sep 19, 2013
09/13
by
Piotr M. Kowalski
texts
eye 51
favorite 0
comment 0
We discuss the importance of pure hydrogen white dwarf atmosphere models with Ly-$\rm \alpha$ far red wing opacity in the analysis of the white dwarf cooling sequence of the globular cluster NGC 6397. Our recently improved atmosphere models account for the previously missing opacity from the Ly-$\rm \alpha$ hydrogen line broadened by collisions of the absorbing hydrogen atoms with molecular and atomic hydrogen. These models are the first that well reproduce the UV colors and spectral energy...
Source: http://arxiv.org/abs/0708.3795v1
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33
Sep 19, 2013
09/13
by
Piotr M. Kowalski
texts
eye 33
favorite 0
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Reliable modeling of the atmospheres of cool white dwarfs is crucial for understanding the atmospheric evolution of these stars and for accurate white dwarfs cosmochronology. Over the last decade {\it ab initio} modeling entered many research fields and has been successful in predicting properties of various materials under extreme conditions. In many cases the investigated physical regimes are difficult or even impossible to access by experimental methods, and first principles quantum...
Source: http://arxiv.org/abs/1010.1603v1
2
2.0
Feb 22, 2020
02/20
by
M Kowalski; G Lesinski
texts
eye 2
favorite 0
comment 0
46
46
Jul 20, 2013
07/13
by
Piotr M. Kowalski; Sandro Jahn
texts
eye 46
favorite 0
comment 0
The mass-dependent equilibrium stable isotope fractionation between different materials is an important geochemical process. Here we present an efficient method to compute the isotope fractionation between complex minerals and fluids at high pressure, P, and temperature, T, representative for the Earth's crust and mantle. The method is tested by computation of the equilibrium fractionation of lithium isotopes between aqueous fluids and various Li bearing minerals such as staurolite, spodumene...
Source: http://arxiv.org/abs/1107.5132v1
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30
Jul 20, 2013
07/13
by
P. M. Kowalski; D. Saumon
texts
eye 30
favorite 0
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We investigate the importance of the far red wing of the Lyman $ \alpha$ line of hydrogen in the atmospheres of cool white dwarfs of pure hydrogen composition. We find that this absorption process dominates all important sources of opacity in the blue part of the optical spectrum of these stars. Our successful fits to the spectra of cool DA/DC white dwarfs indicate that the far red wing of the $\rm Ly \alpha$ line is the source of opacity that had been missing in the models. The observed...
Source: http://arxiv.org/abs/astro-ph/0609720v1
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40
Sep 19, 2013
09/13
by
Piotr M. Kowalski; Mukremin Kilic
texts
eye 40
favorite 0
comment 0
Over the last decade {\it ab initio} modeling of material properties has become widespread in diverse fields of research. It has proved to be a powerful tool for predicting various properties of matter under extreme conditions. We apply modern computational chemistry and materials science methods, including density functional theory (DFT), to solve lingering problems in the modeling of the dense atmospheres of cool white dwarfs ($T_{\rm eff}\rm
Source: http://arxiv.org/abs/1010.1614v1
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0.0
Jun 30, 2018
06/18
by
R. Rossignoli; A. M. Kowalski
texts
eye 0
favorite 0
comment 0
We discuss the necessity of using non-standard boson operators for diagonalizing quadratic bosonic forms which are not positive definite and its convenience for describing the temporal evolution of the system. Such operators correspond to non-hermitian coordinates and momenta and are associated with complex frequencies. As application, we examine a bosonic version of a BCS-like pairing Hamiltonian, which, in contrast with the fermionic case, is stable just for limited values of the gap...
Topic: Quantum Physics
Source: http://arxiv.org/abs/1404.4603
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26
Sep 24, 2013
09/13
by
R. Rossignoli; A. M. Kowalski
texts
eye 26
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We examine the dynamics of a particle in a general rotating quadratic potential, not necessarily stable or isotropic, using a general complex mode formalism. The problem is equivalent to that of a charged particle in a quadratic potential in the presence of a uniform magnetic field. It is shown that the unstable system exhibits a rich structure, with complex normal modes as well as non-standard modes of evolution characterized by equations of motion which cannot be decoupled (non-separable...
Source: http://arxiv.org/abs/1112.1311v1
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36
Sep 21, 2013
09/13
by
P. M. Kowalski; D. Saumon
texts
eye 36
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We consider the problem of radiative transfer in stellar atmospheres where the index of refraction departs from unity and is a function of density and temperature. We present modified Feautrier and Lambda-iteration methods to solve the equation of radiative transfer with refraction in a plane parallel atmosphere. These methods are general and can be used in any problem with 1-D geometry where the index of refraction is a monotonically varying function of vertical optical depth. We present an...
Source: http://arxiv.org/abs/astro-ph/0402419v1
555
555
May 10, 2009
05/09
by
Marion Alʹbertovich Kovalʹskiĭ, M. Kowalski
texts
eye 555
favorite 0
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Book digitized by Google from the library of Oxford University and uploaded to the Internet Archive by user tpb.
Source: http://books.google.com/books?id=ozoDAAAAQAAJ&oe=UTF-8
0
0.0
Jun 29, 2018
06/18
by
Simon Blouin; Patrick Dufour; Piotr M. Kowalski
texts
eye 0
favorite 0
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Due to their high photospheric density, cool helium-rich white dwarfs (particularly DZ, DQpec and ultracool) are often poorly described by current atmosphere models. As part of our ongoing efforts to design atmosphere models suitable for all cool white dwarfs, we investigate how the ionization ratio of heavy elements and the H$_2$-He collision-induced absorption (CIA) spectrum are altered under fluid-like densities. For the conditions encountered at the photosphere of cool helium-rich white...
Topics: Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1610.01009
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29
Sep 21, 2013
09/13
by
Piotr M. Kowalski; Bernd Meyer; Dominik Marx
texts
eye 29
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A comprehensive phase diagram of lowest-energy structures and compositions of the rutile TiO_2(110) surface in equilibrium with a surrounding gas phase at finite temperatures and pressures has been determined using density functional theory in combination with a thermodynamic formalism. The exchange of oxygen, hydrogen, and water molecules with the gas phase is considered. Particular attention is given to the convergence of all calculations with respect to lateral system size and slab...
Source: http://arxiv.org/abs/0902.0854v1
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22
Sep 22, 2013
09/13
by
Piotr M. Kowalski; Bernd Wunder; Sandro Jahn
texts
eye 22
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Over the last decade experimental studies have shown a large B isotope fractionation between materials carrying boron incorporated in trigonally and tetrahedrally coordinated sites, but the mechanisms responsible for producing the observed isotopic signatures are poorly known. In order to understand the boron isotope fractionation processes and to obtain a better interpretation of the experimental data and isotopic signatures observed in natural samples, we use first principles calculations...
Source: http://arxiv.org/abs/1210.1674v1
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32
Sep 20, 2013
09/13
by
P. M. Kowalski; D. Saumon; S. Mazevet
texts
eye 32
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The atmospheres of cool, helium-rich white dwarfs constitute an exotic and poorly explored physical regime of stellar atmospheres. Under physical conditions where the temperature varies from $\rm 1000K$ to $\rm 10000K$, the density can reach values as large as $\rm 2 g/cm^{3}$, and the pressure is as high as $\rm 1 Mbar$, the atmosphere is no longer an ideal gas and must be treated as a dense fluid. Helium atoms become strongly correlated and refraction effects are present. Opacity sources such...
Source: http://arxiv.org/abs/astro-ph/0410358v1
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33
Sep 21, 2013
09/13
by
D. F. Cowen; A. Franckowiak; M. Kowalski
texts
eye 33
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Core-collapse supernovae are among the prime candidate sources of high energy neutrinos. Accordingly, the IceCube collaboration has started a program to search for such a signal. IceCube operates an online search for neutrino bursts, forwarding the directions of candidate events to a network of optical telescopes for immediate follow-up observations. If a supernova is identified from the optical observations, in addition to a directional coincidence a temporal photon-neutrino coincidence also...
Source: http://arxiv.org/abs/0901.4877v2
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41
Sep 23, 2013
09/13
by
P. M. Kowalski; S. Mazevet; D. Saumon
texts
eye 41
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We investigate the ionization and the opacity of warm, dense helium under conditions found in the atmospheres of cool white dwarf stars. Our particular interest is in densities up to $\rm 3 g/cm^{3}$ and temperatures from 1000K to 10000K. For these physical conditions various approaches for modeling the ionization equilibrium predict ionization fractions that differ by orders of magnitudes. Furthermore, estimates of the density at which helium pressure-ionizes vary from $\rm 0.3$ to $\rm 14...
Source: http://arxiv.org/abs/cond-mat/0511400v1
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38
Sep 22, 2013
09/13
by
M. Kowalski; A. Ringwald; H. Tu
texts
eye 38
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comment 0
In scenarios with extra dimensions and TeV-scale quantum gravity, black holes are expected to be produced in the collision of light particles at center-of-mass energies above the fundamental Planck scale with small impact parameters. Black hole production and evaporation may thus be studied in detail at the Large Hadron Collider (LHC). But even before the LHC starts operating, neutrino telescopes such as AMANDA/IceCube, ANTARES, Baikal, and RICE have an opportunity to search for black hole...
Source: http://arxiv.org/abs/hep-ph/0201139v1
0
0.0
Jun 29, 2018
06/18
by
Piotr M. Kowalski; Simon Blouin; Patrick Dufour
texts
eye 0
favorite 0
comment 0
Dense, He-rich atmospheres of cool white dwarfs represent a challenge to the modeling. This is because these atmospheres are constituted of a dense fluid in which strong multi-atomic interactions determine their physics and chemistry. Therefore, the ideal-gas-based description of absorption is no longer adequate, which makes the opacities of these atmospheres difficult to model. This is illustrated with severe problems in fitting the spectra of cool, He-rich stars. Good description of the...
Topics: Computational Physics, Atomic Physics, Space Physics, Solar and Stellar Astrophysics, Condensed...
Source: http://arxiv.org/abs/1610.07357
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36
Jul 20, 2013
07/13
by
Matteo Farnesi Camellone; Piotr M. Kowalski; Dominik Marx
texts
eye 36
favorite 0
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Extensive first principles calculations are carried out to investigate gold-promoted TiO2(110) surfaces in terms of structure optimizations, electronic structure analyses, ab initio thermodynamics calculations of surface phase diagrams, and ab initio molecular dynamics simulations. All computations rely on density functional theory in the generalized gradient approximation (PBE) and account for on-site Coulomb interactions via inclusion of a Hubbard correction, PBE+U, where U is computed from...
Source: http://arxiv.org/abs/1107.0840v1
1
1.0
Jun 30, 2018
06/18
by
D. Saumon; J. B. Holberg; P. M. Kowalski
texts
eye 1
favorite 0
comment 0
The atmospheres of very cool, hydrogen-rich white dwarfs (Teff
Topics: Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1406.4171
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39
Sep 22, 2013
09/13
by
A. M. Kowalski; M. T. Martin; A. Plastino; L. Zunino
texts
eye 39
favorite 0
comment 0
We investigate the classical limit of a type of semiclassical evolution, the pertinent system representing the interaction between matter and a given field. On using as a quantifier of the ensuing dynamics Tsallis q-entropy, we encounter that it not only appropriately describes the quantum-classical transition, but that the associated deformation-parameter q itself characterizes the different regimes involved in the process, detecting the most salient fine details of the changeover.
Source: http://arxiv.org/abs/0812.4221v1
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43
Sep 21, 2013
09/13
by
Mukremin Kilic; John R. Thorstensen; P. M. Kowalski; J. Andrews
texts
eye 43
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We present a detailed model atmosphere analysis of two of the oldest stars known in the solar neighborhood, the high proper motion white dwarfs SDSS J110217.48+411315.4 (hereafter J1102) and WD 0346+246 (hereafter WD0346). We present trigonometric parallax observations of J1102, which places it at a distance of only 33.7 +- 2.0 pc. Based on the state of the art model atmospheres, optical, near-, mid-infrared photometry, and distances, we constrain the temperatures, atmospheric compositions,...
Source: http://arxiv.org/abs/1204.2570v1
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43
Sep 22, 2013
09/13
by
Piotr M. Kowalski; Didier Saumon; Jay Holberg; Sandy Leggett
texts
eye 43
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Cool white dwarfs with Teff < 6000 K are the remnants of the oldest stars that existed in our Galaxy. Their atmospheres, when properly characterized, can provide valuable information on white dwarf evolution and ultimately star formation through the history of the Milky Way. Understanding the atmospheres of these stars requires joined observational effort and reliable atmosphere modeling. We discuss and analyze recent observations of the near-ultraviolet (UV) and near-infrared (IR) spectrum...
Source: http://arxiv.org/abs/1210.3192v1
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37
Sep 21, 2013
09/13
by
Mukremin Kilic; Piotr M. Kowalski; Fergal Mullally; William T. Reach; Ted von Hippel
texts
eye 37
favorite 0
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We present the first mid-infrared spectra of two cool white dwarfs obtained with the Spitzer Space Telescope. We also present 3.5-8 micron photometry for 19 cool white dwarfs with 5000K < Teff < 9000K. We perform a detailed model atmosphere analysis of these white dwarfs by fitting their UBVRIJHK and Spitzer photometry with state-of-the-art model atmospheres, and demonstrate that the optical and infrared spectral energy distributions of cool white dwarfs are well reproduced by our grid of...
Source: http://arxiv.org/abs/0712.2461v1
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29
Jul 19, 2013
07/13
by
M. Salaris; S. Cassisi; A. Pietrinferni; P. M. Kowalski; J. Isern
texts
eye 29
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We present a new set of cooling models and isochrones for both H- and He-atmosphere white dwarfs, incorporating accurate boundary conditions from detailed model atmosphere calculations, and carbon-oxygen chemical abundance profiles based on updated stellar evolution calculations from the BaSTI stellar evolution archive - a theoretical data center for the Virtual Observatory. We discuss and quantify the uncertainties in the cooling times predicted by the models, arising from the treatment of...
Source: http://arxiv.org/abs/1005.1791v1
0
0.0
Jun 29, 2018
06/18
by
A. Gazizov; M. Kowalski; K. S. Kuzmin; V. A. Naumov; Ch. Spiering
texts
eye 0
favorite 0
comment 0
An updated set of (anti)neutrino-nucleon charged and neutral current cross sections at $3~{\rm GeV} \lesssim E_\nu \lesssim 100~{\rm GeV}$ is presented. These cross sections are of particular interest for the detector optimization and data processing and interpretation in the future Megaton-scale experiments like PINGU, ORCA, and Hyper-Kamiokande. Finite masses of charged leptons and target mass corrections in exclusive and deep inelastic $(\bar\nu)\nu N$ interactions are taken into account. A...
Topic: High Energy Physics - Phenomenology
Source: http://arxiv.org/abs/1604.02092
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43
Sep 21, 2013
09/13
by
Mukremin Kilic; Piotr M. Kowalski; William T. Reach; Ted von Hippel
texts
eye 43
favorite 0
comment 0
We present Spitzer 5-15 micron spectroscopy of one cool white dwarf and 3.6-8 micron photometry of 51 cool white dwarfs with T_eff < 6000 K. The majority of our targets have accurate BVRIJHK photometry and trigonometric parallax measurements available, which enables us to perform a detailed model atmosphere analysis using their optical, near- and mid-infrared photometry with state- of-the-art model atmospheres. We demonstrate that the optical and infrared spectral energy distributions of...
Source: http://arxiv.org/abs/0902.4004v1
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40
Sep 21, 2013
09/13
by
Piotr M. Kowalski; Matteo Farnesi Camellone; Nisanth N. Nair; Bernd Meyer; Dominik Marx
texts
eye 40
favorite 0
comment 0
The dynamics of an F--center created by an oxygen vacancy on the $\mathrm{TiO_{2}(110)}$ rutile surface has been investigated using {\it ab initio} molecular dynamics. These simulations uncover a truly complex, time-dependent behavior of fluctuating electron localization topologies in the vicinity of the oxygen vacancy. Although the two excess electrons are found to populate preferentially the second subsurface layer, they occasionally visit surface sites and also the third subsurface layer....
Source: http://arxiv.org/abs/1008.4652v1
1
1.0
Jun 30, 2018
06/18
by
J. M. Carrasco; S. Catalán; C. Jordi; P. E. Tremblay; R. Napiwotzki; X. Luri; A. C. Robin; P. M Kowalski
texts
eye 1
favorite 0
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Context. White dwarfs can be used to study the structure and evolution of the Galaxy by analysing their luminosity function and initial mass function. Among them, the very cool white dwarfs provide the information for the early ages of each population. Because white dwarfs are intrinsically faint only the nearby (about 20 pc) sample is reasonably complete. The Gaia space mission will drastically increase the sample of known white dwarfs through its 5-6 years survey of the whole sky up to...
Topics: Instrumentation and Methods for Astrophysics, Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1403.6045
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26
Sep 23, 2013
09/13
by
M. Durant; O. Kargaltsev; G. G. Pavlov; P. M. Kowalski; B. Posselt; M. H. van Kerkwijk; D. L. Kaplan
texts
eye 26
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We present extensive spectral and photometric observations of the recycled pulsar/white-dwarf binary containing PSR J0437-4715, which we analyzed together with archival X-ray and gamma-ray data, to obtain the complete mid-infrared to gamma-ray spectrum. We first fit each part of the spectrum separately, and then the whole multi-wavelength spectrum. We find that the optical-infrared part of the spectrum is well fit by a cool white dwarf atmosphere model with pure hydrogen composition. The model...
Source: http://arxiv.org/abs/1111.2346v1
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76
Sep 20, 2013
09/13
by
G. Hunter; P. Ecimovic; I. Schlifer; I. M. Walker; D. Beamish; S. Donev; M. Kowalski; S. Arslan; S. Heck
texts
eye 76
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Spherical Harmonics, $Y_\ell^m(\theta,\phi)$, are derived and presented (in a Table) for half-odd-integer values of $\ell$ and $m$. These functions are eigenfunctions of $L^2$ and $L_z$ written as differential operators in the spherical-polar angles, $\theta$ and $\phi$. The Fermion Spherical Harmonics are a new, scalar and angular-coordinate-dependent representation of fermion spin angular momentum. They have $4\pi$ symmetry in the angle $\phi$, and hence are not single-valued functions on the...
Source: http://arxiv.org/abs/math-ph/9810001v1
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47
Jul 20, 2013
07/13
by
Patrick B. Hall; Piotr M. Kowalski; Hugh C. Harris; Akshay Awal; S. K. Leggett; Mukremin Kilic; Scott F. Anderson; Evalyn Gates
texts
eye 47
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We report the discovery of a nearby, old, halo white dwarf candidate from the Sloan Digital Sky Survey. SDSS J110217.48+411315.4 has a proper motion of 1.75 arcsec/year and redder optical colors than all other known featureless (type DC) white dwarfs. We present SDSS imaging and spectroscopy of this object, along with near-infrared photometry obtained at the United Kingdom Infra-Red Telescope. Fitting its photometry with up-to-date model atmospheres, we find that its overall spectral energy...
Source: http://arxiv.org/abs/0804.1570v1
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39
Sep 19, 2013
09/13
by
A. Franckowiak; C. Akerlof; D. F. Cowen; M. Kowalski; R. Lehmann; T. Schmidt; F. Yuan; for the IceCube collaboration; for the ROTSE collaboration
texts
eye 39
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Three-quarters of the 1 cubic kilometer neutrino telescope IceCube is currently taking data. Current models predict high-energy neutrino emission from transient objects like supernovae (SNe) and gammaray bursts (GRBs). To increase the sensitivity to such transient objects we have set up an optical follow-up program that triggers optical observations on multiplets of high-energy muon-neutrinos. We define multiplets as a minimum of two muon-neutrinos from the same direction (within 4 deg) that...
Source: http://arxiv.org/abs/0909.0631v1
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34
Sep 20, 2013
09/13
by
L. Fossati; S. Bagnulo; C. A. Haswell; M. R. Patel; R. Busuttil; P. M. Kowalski; D. V. Shulyak; M. F. Sterzik
texts
eye 34
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comment 0
Since there are several ways planets can survive the giant phase of the host star, we examine the habitability and detection of planets orbiting white dwarfs. As a white dwarf cools from 6000 K to 4000 K, a planet orbiting at 0.01 AU would remain in the Continuous Habitable Zone (CHZ) for ~8 Gyr. We show that photosynthetic processes can be sustained on such planets. The DNA-weighted UV radiation dose for an Earth-like planet in the CHZ is less than the maxima encountered on Earth, hence...
Source: http://arxiv.org/abs/1207.6210v1
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36
Sep 22, 2013
09/13
by
Mukremin Kilic; Jeffrey A. Munn; Kurtis A. Williams; P. M. Kowalski; Ted von Hippel; Hugh C. Harris; Elizabeth J. Jeffery; Steven DeGennaro; Warren R. Brown; B. McLeod
texts
eye 36
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We report the discovery of three nearby old halo white dwarf candidates in the Sloan Digital Sky Survey (SDSS), including two stars in a common proper motion binary system. These candidates are selected from our 2800 square degree proper motion survey on the Bok and U.S. Naval Observatory Flagstaff Station 1.3m telescopes, and they display proper motions of 0.4-0.5 arcsec/yr. Follow-up MMT spectroscopy and near-infrared photometry demonstrate that all three objects are hydrogen-dominated...
Source: http://arxiv.org/abs/1004.0958v1
4
4.0
Jun 26, 2018
06/18
by
P. A. Evans; J. P. Osborne; J. A. Kennea; M. Smith; D. M. Palmer; N. Gehrels; J. M. Gelbord; A. Homeier; M. Voge; N. L. Strotjohann; D. F. Cowen; S. Boeser; M. Kowalski; A. Stasik
texts
eye 4
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Between 2011 March and 2014 August Swift responded to 20 triggers from the IceCube neutrino observatory, observing the IceCube 50% confidence error circle in X-rays, typically within 5 hours of the trigger. No confirmed counterpart has been detected. We describe the Swift follow up strategy and data analysis and present the results of the campaign. We discuss the challenges of distinguishing the X-ray counterpart to a neutrino trigger from serendipitous uncatalogued X-ray sources in the error...
Topics: High Energy Astrophysical Phenomena, Astrophysics
Source: http://arxiv.org/abs/1501.04435
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51
Sep 20, 2013
09/13
by
D. Rubin; R. A. Knop; E. Rykoff; G. Aldering; R. Amanullah; K. Barbary; M. S. Burns; A. Conley; N. Connolly; S. Deustua; V. Fadeyev; H. K. Fakhouri; A. S. Fruchter; R. A. Gibbons; G. Goldhaber; A. Goobar; E. Y. Hsiao; X. Huang; M. Kowalski; C. Lidman; J. Meyers; J. Nordin; S. Perlmutter; C. Saunders; A. L. Spadafora; V. Stanishev; N. Suzuki; L. Wang
texts
eye 51
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We report the discovery of a redshift 1.71 supernova in the GOODS North field. The Hubble Space Telescope (HST) ACS spectrum has almost negligible contamination from the host or neighboring galaxies. Although the rest frame sampled range is too blue to include any Si ii line, a principal component analysis allows us to confirm it as a Type Ia supernova with 92% confidence. A recent serendipitous archival HST WFC3 grism spectrum contributed a key element of the confirmation by giving a...
Source: http://arxiv.org/abs/1205.3494v3
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42
Sep 20, 2013
09/13
by
The NA49 Collaboration; B. Baatar; G. Barr; J. Bartke; L. Betev; O. Chvala; J. Dolejsi; V. Eckardt; H. G. Fischer; Z. Fodor; A. Karev; V. Kolesnikov; M. Kowalski; M. Makariev; A. Malakhov; M. Mateev; G. Melkumov; A. Rybicki; N. Schmitz; P. Seyboth; R. Stock; G. Tinti; D. Varga; G. Vesztergombi; S. Wenig
texts
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The production of protons, anti-protons, neutrons, deuterons and tritons in minimum bias p+C interactions is studied using a sample of 385 734 inelastic events obtained with the NA49 detector at the CERN SPS at 158 GeV/c beam momentum. The data cover a phase space area ranging from 0 to 1.9 GeV/c in transverse momentum and in Feynman x from -0.80 to 0.95 for protons, from -0.2 to 0.4 for anti-protons and from 0.2 to 0.95 for neutrons. Existing data in the far backward hemisphere are used to...
Source: http://arxiv.org/abs/1207.6520v3
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78
Sep 17, 2013
09/13
by
D. Rubin; E. V. Linder; M. Kowalski; G. Aldering; R. Amanullah; K. Barbary; N. V. Connolly; K. S. Dawson; L. Faccioli; V. Fadeyev; G. Goldhaber; A. Goobar; I. Hook; C. Lidman; J. Meyers; S. Nobili; P. E. Nugent; R. Pain; S. Perlmutter; P. Ruiz-Lapuente; A. L. Spadafora; M. Strovink; N. Suzuki; H. Swift
texts
eye 78
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The recent robust and homogeneous analysis of the world's supernova distance-redshift data, together with cosmic microwave background and baryon acoustic oscillation data, provides a powerful tool for constraining cosmological models. Here we examine particular classes of scalar field, modified gravity, and phenomenological models to assess whether they are consistent with observations even when their behavior deviates from the cosmological constant Lambda. Some models have tension with the...
Source: http://arxiv.org/abs/0807.1108v1
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42
Sep 19, 2013
09/13
by
P. S. Ray; K. S. Wood; G. Fritz; P. Hertz; M. Kowalski; W. N. Johnson; M. N. Lovellette; M. T. Wolff; D. Yentis; R. M. Bandyopadhyay; E. D. Bloom; B. Giebels; G. Godfrey; K. Reilly; P. Saz Parkinson; G. Shabad; P. Michelson; M. Roberts; D. A. Leahy; L. Cominsky; J. Scargle; J. Beall; D. Chakrabarty; Y. Kim
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The USA Experiment is a new X-ray timing experiment with large collecting area and microsecond time resolution capable of conducting a broad program of studies of galactic X-ray binaries. USA is one of nine experiments aboard the Advanced Research and Global Observation Satellite which was launched February 23, 1999. USA is a collimated proportional counter X-ray telescope with about 1000 cm$^2$ of effective area per detector with two detectors sensitive to photons in the energy range 1-15 keV....
Source: http://arxiv.org/abs/astro-ph/9911236v1
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30
Sep 19, 2013
09/13
by
J. Melbourne; K. S. Dawson; D. C. Koo; C. Max; J. E. Larkin; S. A. Wright; E. Steinbring; M. Barczys; G. Aldering; K. Barbary; M. Doi; V. Fadeyev; G. Goldhaber; T. Hattori; Y. Ihara; N. Kashikawa; K. Konishi; M. Kowalski; N. Kuznetsova; C. Lidman; T. Morokuma; S. Perlmutter; D. Rubin; D. J. Schlegel; A. L. Spadafora; N. Takanashi; N. Yasuda
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We present Keck diffraction limited H-band photometry of a z~1.3 Type Ia supernova (SN) candidate, first identified in a Hubble Space Telescope (HST) search for SNe in massive high redshift galaxy clusters. The adaptive optics (AO) data were obtained with the Laser Guide Star facility during four observing runs from September to November 2005. In the analysis of data from the observing run nearest to maximum SN brightness, the SN was found to have a magnitude H=23.9 +/- 0.14 (Vega). We present...
Source: http://arxiv.org/abs/astro-ph/0703381v2
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0.0
Jun 30, 2018
06/18
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A. G. Kim; G. Aldering; P. Antilogus; C. Aragon; S. Bailey; C. Baltay; S. Bongard; C. Buton; A. Canto; F. Cellier-Holzem; M. Childress; N. Chotard; Y. Copin; H. K. Fakhouri; U. Feindt; M. Fleury; E. Gangler; P. Greskovic; J. Guy; M. Kowalski; S. Lombardo; J. Nordin; P. Nugent; R. Pain; E. Pecontal; R. Pereira; S. Perlmutter; D. Rabinowitz; M. Rigault; K. Runge; C. Saunders; R. Scalzo; G. Smadja; C. Tao; R. C. Thomas; B. A. Weaver
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Kim et al. (2013) [K13] introduced a new methodology for determining peak-brightness absolute magnitudes of type Ia supernovae from multi-band light curves. We examine the relation between their parameterization of light curves and Hubble residuals, based on photometry synthesized from the Nearby Supernova Factory spectrophotometric time series, with global host-galaxy properties. The K13 Hubble residual step with host mass is $0.013\pm 0.031$ mag for a supernova subsample with data coverage...
Topics: Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1401.3352
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30
Sep 22, 2013
09/13
by
A. G. Kim; R. C. Thomas; G. Aldering; P. Antilogus; C. Aragon; S. Bailey; C. Baltay; S. Bongard; C. Buton; A. Canto; F. Cellier-Holzem; M. Childress; N. Chotard; Y. Copin; H. K. Fakhouri; E. Gangler; J. Guy; M. Kerschhaggl; M. Kowalski; J. Nordin; P. Nugent; K. Paech; R. Pain; E. Pécontal; R. Pereira; S. Perlmutter; D. Rabinowitz; M. Rigault; K. Runge; C. Saunders; R. Scalzo; G. Smadja; C. Tao; B. A. Weaver; C. Wu
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We present a novel class of models for Type Ia supernova time-evolving spectral energy distributions (SED) and absolute magnitudes: they are each modeled as stochastic functions described by Gaussian processes. The values of the SED and absolute magnitudes are defined through well-defined regression prescriptions, so that data directly inform the models. As a proof of concept, we implement a model for synthetic photometry built from the spectrophotometric time series from the Nearby Supernova...
Source: http://arxiv.org/abs/1302.2925v1
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36
Sep 18, 2013
09/13
by
K. Barbary; K. S. Dawson; K. Tokita; G. Aldering; R. Amanullah; N. V. Connolly; M. Doi; L. Faccioli; V. Fadeyev; A. S. Fruchter; G. Goldhaber; A. Goobar; A. Gude; X. Huang; Y. Ihara; K. Konishi; M. Kowalski; C. Lidman; J. Meyers; T. Morokuma; P. Nugent; S. Perlmutter; D. Rubin; D. Schlegel; A. L. Spadafora; N. Suzuki; H. K. Swift; N. Takanashi; R. C. Thomas; N. Yasuda; for the Supernova Cosmology Project
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We present observations of SCP 06F6, an unusual optical transient discovered during the Hubble Space Telescope Cluster Supernova Survey. The transient brightened over a period of ~100 days, reached a peak magnitude of ~21.0 in both i_775 and z_850, and then declined over a similar timescale. There is no host galaxy or progenitor star detected at the location of the transient to a 3 sigma upper limit of i_775 = 26.4 and z_850 = 26.1, giving a corresponding lower limit on the flux increase of a...
Source: http://arxiv.org/abs/0809.1648v1
