publicationDate stringlengths 1 2.79k | title stringlengths 1 36.5k ⌀ | abstract stringlengths 1 37.3k ⌀ | id stringlengths 9 47 |
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2009-09-03 | Simulating the effect of AGN feedback on the metal enrichment of galaxy clusters | We present a study of the effect of AGN feedback on metal enrichment and
thermal properties of the intracluster medium (ICM) in hydrodynamical
simulations. The cosmological simulations are performed for a set of clusters
using a version of the TreePM-SPH Gadget code that follows chemo-dynamical
evolution by accounting ... | 0909.0664v1 |
2009-12-31 | Production of the p-Process Nuclei in the Carbon-Deflagration Model for Type Ia Supernovae | We calculate nucleosynthesis of proton-rich isotopes in the
carbon-deflagration model for Type Ia supernovae (SNe Ia). The seed abundances
are obtained by calculating the s-process nucleosynthesis that is expected to
occur in the repeating helium shell flashes on the carbon-oxygen (CO) white
dwarf (WD) during mass accr... | 1001.0145v3 |
2010-01-19 | Analyzing the prices of the most expensive sheet iron all over the world: Modeling, prediction and regime change | The private car license plates issued in Shanghai are bestowed the title of
"the most expensive sheet iron all over the world", more expensive than gold. A
citizen has to bid in an monthly auction to obtain a license plate for his new
private car. We perform statistical analysis to investigate the influence of
the mini... | 1001.3176v1 |
2010-02-12 | Abundances and physical parameters for stars in the open clusters NGC 5822 and IC 4756 | Classical chemical analyses may be affected by systematic errors that would
cause observed abundance differences between dwarfs and giants. For some
elements, however, the abundance difference could be real. We address the issue
by observing 2 solar--type dwarfs in NGC 5822 and 3 in IC 4756, and comparing
their composi... | 1002.2547v3 |
2010-03-18 | High magnetic field scales and critical currents in SmFeAs(O,F) crystals: promising for applications | Superconducting technology provides most sensitive field detectors, promising
implementations of qubits and high field magnets for medical imaging and for
most powerful particle accelerators. Thus, with the discovery of new
superconducting materials, such as the iron pnictides, exploring their
potential for application... | 1003.3612v2 |
2010-03-24 | Abundances of C, N, Sr and Ba on the red giant branch of omega Centauri | Abundances relative to iron for carbon, nitrogen, strontium and barium are
presented for 33 stars on the red giant branch of the globular cluster omega
Centauri. They are based on intermediate-resolution spectroscopic data covering
the blue spectral region analyzed using spectrum synthesis techniques. The data
reveal t... | 1003.4661v2 |
2010-04-12 | A self-consistent approach to the hard and soft states of 4U 1705-44 | We analyzed two XMM-Newton observations of the bright atoll source 4U
1705-44, which can be considered a prototype of the class of the persistent NS
LMXBs showing both hard and soft states. The first observation was performed
when the source was in a hard low flux state, the second during a soft,
high-flux state. Both ... | 1004.1963v2 |
2010-04-13 | Analysis of optical Fe II emission in a sample of AGN spectra | We present a study of optical Fe II emission in 302 AGNs selected from the
SDSS. We group the strongest Fe II multiplets into three groups according to
the lower term of the transition (b $^4$F, a $^6$S and a $^4$G terms). These
correspond approximately to the blue, central, and red part respectively of the
"iron shelf... | 1004.2212v2 |
2010-04-20 | Convective shifts of iron lines in the spectrum of the solar photosphere | The influence of the convective structure of the solar photosphere on the
shifts of spectral lines of iron was studied. Line profiles in the visible and
infrared spectrum were synthesized with the use of 2-D time-dependent
hydrodynamic solar model atmospheres. The dependence of line shifts on
excitation potential, wave... | 1004.3438v1 |
2010-04-21 | Nodes in the gap structure of the iron-arsenide superconductor Ba(Fe_{1-x}Co_x)_2As_2 from c-axis heat transport measurements | The thermal conductivity k of the iron-arsenide superconductor
Ba(Fe_{1-x}Co_x)_2As_2 was measured down to 50 mK for a heat current parallel
(k_c) and perpendicular (k_a) to the tetragonal c axis, for seven Co
concentrations from underdoped to overdoped regions of the phase diagram (0.038
< x < 0.127). A residual linea... | 1004.3804v1 |
2010-05-20 | Co-evolution of atmospheres, life, and climate | After Earth's origin, our host star, the Sun, was shining 20 to 25 percent
less brightly than today. Without greenhouse-like conditions to warm the
atmosphere, our early planet would have been an ice ball and life may never
have evolved. But life did evolve, which indicates that greenhouse gases must
have been present ... | 1005.3589v1 |
2010-06-04 | Spitzer spectral line mapping of the HH211 outflow | Aims: We employ archival Spitzer slit-scan observations of the HH211 outflow
in order to investigate its warm gas content, assess the jet mass flux in the
form of H2 and probe for the existence of an embedded atomic jet. Methods:
Detected molecular and atomic lines are interpreted by means of emission line
diagnostics ... | 1006.0821v1 |
2010-06-07 | Evidence for a Truncated Accretion Disc in the Low Luminosity Seyfert Galaxy, NGC 7213? | We present the broad-band 0.6-150 keV Suzaku and Swift BAT spectra of the low
luminosity Seyfert galaxy, NGC 7213. The time-averaged continuum emission is
well fitted by a single powerlaw of photon index Gamma = 1.75 and from
consideration of the Fermi flux limit we constrain the high energy cutoff to be
350 keV < E < ... | 1006.1318v1 |
2010-06-10 | Fe II Emission in AGN: The Role of Total and Gas-Phase Iron Abundance | Active galactic nuclei (AGN) have Fe II emission from the broad line region
(BLR) that differs greatly in strength from object to object. We examine the
role of the total and gas-phase iron abundance in determining Fe II strength.
Using AGN spectra from the Sloan Digital Sky Survey (SDSS) in the redshift
range of 0.2 <... | 1006.2043v2 |
2010-07-22 | Neutron-rich chromium isotope anomalies in supernova nanoparticles | Neutron-rich isotopes with masses near that of iron are produced in type Ia
and II supernovae. Traces of such nucleosynthesis are found in primitive
meteorites in the form of variations in the isotopic abundance of 54Cr, the
most neutron-rich stable isotope of chromium. The hosts of these isotopic
anomalies must be pre... | 1007.4016v1 |
2010-07-29 | The Mouse that Roared: A Superflare from the dMe Flare Star EV Lac detected by Swift and Konus-Wind | We report on a large stellar flare from the nearby dMe flare star EV Lac
observed by the Swift and Konus-Wind satellites and the Liverpool Telescope. It
is the first large stellar flare from a dMe flare star to result in a Swift
trigger based on its hard X-ray intensity. Its peak f_X from 0.3--100 keV of
5.3x10^-8 erg/... | 1007.5300v1 |
2010-08-18 | Optical properties of the iron-arsenic superconductor BaFe1.85Co0.15As2 | The transport and complex optical properties of the electron-doped
iron-arsenic superconductor BaFe1.85Co0.15As2 with Tc = 25 K have been examined
in the Fe-As planes above and below Tc. A Bloch-Gruneisen analysis of the
resistivity yields a weak electron-phonon coupling constant lambda_ph ~ 0.2.
The low-frequency opti... | 1008.3098v2 |
2010-08-18 | Cold fronts and multi-temperature structures in the core of Abell 2052 | The physics of the coolest phases in the hot Intra-Cluster Medium (ICM) of
clusters of galaxies is yet to be fully unveiled. X-ray cavities blown by the
central Active Galactic Nucleus (AGN) contain enough energy to heat the
surrounding gas and stop cooling, but locally blobs or filaments of gas appear
to be able to co... | 1008.3109v2 |
2010-08-18 | Open clusters towards the Galactic center: chemistry and dynamics. A VLT spectroscopic study of NGC6192, NGC6404, NGC6583 | In the framework of the study of the Galactic metallicity gradient and its
time evolution, we present new high-resolution spectroscopic observations
obtained with FLAMES and the fiber link to UVES at VLT of three open clusters
(OCs) located within $\sim$7~kpc from the Galactic Center (GC): NGC~6192,
NGC~6404, NGC~6583.... | 1008.3158v1 |
2010-10-01 | Absorption Features in Spectra of Magnetized Neutron Stars | The X-ray spectra of some magnetized isolated neutron stars (NSs) show
absorption features with equivalent widths (EWs) of 50 - 200 eV, whose nature
is not yet well known. To explain the prominent absorption features in the soft
X-ray spectra of the highly magnetized (B ~ 10^{14} G) X-ray dim isolated NSs
(XDINSs), we ... | 1010.0125v1 |
2010-10-21 | The RAVE Survey: Rich in Very Metal-Poor Stars | Very metal-poor stars are of obvious importance for many problems in chemical
evolution, star formation, and galaxy evolution. Finding complete samples of
such stars which are also bright enough to allow high-precision individual
analyses is of considerable interest. We demonstrate here that stars with iron
abundances ... | 1010.4491v1 |
2010-10-30 | Symmetry breaking orbital anisotropy on detwinned Ba(Fe1-xCox)2As2 above the spin density wave transition | Nematicity, defined as broken rotational symmetry, has recently been observed
in competing phases proximate to the superconducting phase in the cuprate high
temperature superconductors. Similarly, the new iron-based high temperature
superconductors exhibit a tetragonal to orthorhombic structural transition
(i.e. a brok... | 1011.0050v2 |
2010-11-07 | On the multi-orbital band structure and itinerant magnetism of iron-based superconductors | This paper explains the multi-orbital band structures and itinerant magnetism
of the iron-pnictide and chalcogenides. We first describe the generic band
structure of an isolated FeAs layer. Use of its Abelian glide-mirror group
allows us to reduce the primitive cell to one FeAs unit. From
density-functional theory, we ... | 1011.1658v3 |
2010-12-02 | Tracing the evolution of NGC6397 through the chemical composition of its stellar populations | With the aim to constrain multiple populations in the metal-poor globular
cluster NGC6397, we analyse and discuss the chemical compositions of a large
number of elements in 21 red giant branch stars. High-resolution spectra were
obtained with the FLAMES/UVES spectrograph on VLT. We have determined non-LTE
abundances of... | 1012.0477v2 |
2011-01-24 | A non-LTE study of neutral and singly-ionized iron line spectra in 1D models of the Sun and selected late-type stars | A comprehensive model atom for Fe with more than 3000 energy levels is
presented. As a test and first application of this model atom, Fe abundances
are determined for the Sun and five stars with well determined stellar
parameters and high-quality observed spectra. Non-LTE leads to systematically
depleted total absorpti... | 1101.4570v1 |
2011-01-25 | On the Structure of Vacancy Ordered Superconducting Alkali Metal Iron Selenide | With single crystal X-ray diffraction studies, we compare the structures of
three sample showing optimal superconductivity, K0.774(4)Fe1.613(2)Se2,
K0.738(6)Fe1.631(3)Se2 and Cs0.748(2)Fe1.626(1)Se2. All have an almost
identical ordered vacancy structure with a ({\sqrt}5 x {\sqrt}5 x 1) super
cell. The tetragonal unit ... | 1101.4882v2 |
2011-01-25 | A possible solution to the [alpha/Fe]-sigma problem in early type galaxies within a hierarchical galaxy formation model | The most massive elliptical galaxies apparently formed the fastest, because
the ratio of alpha elements (such as oxygen) to iron is the smallest. In fact,
iron is mainly produced from type Ia supernovae on a timescale of ~ 0.1-1
billion years, while the alpha elements come from massive stars on timescales
of a few tens... | 1101.4938v1 |
2011-04-26 | On the driver of relativistic effects strength in Seyfert galaxies | Spectroscopy of X-ray emission lines emitted in accretion discs around
supermassive black holes is one of the most powerful probes of the accretion
flow physics and geometry, while also providing in principle observational
constraints on the black hole spin.[...] We aim at determining the ultimate
physical driver of th... | 1104.4918v1 |
2011-04-27 | Spitzer spectra of evolved stars in omega Centauri and their low-metallicity dust production | Dust production is explored around 14 metal-poor ([Fe/H] = -1.91 to -0.98)
giant stars in the Galactic globular cluster omega Centauri using new Spitzer
IRS spectra. This sample includes the cluster's post-AGB and carbon stars and
is thus the first representative spectral study of dust production in a
metal-poor ([Fe/H... | 1104.5155v1 |
2011-05-16 | The influence of non-isotropic scattering of thermal radiation on spectra of brown dwarfs and hot exoplanets | (abridged) We calculate near-infrared thermal emission spectra using a
doubling-adding radiative transfer code, which includes scattering by clouds
and haze. Initial temperature profiles and cloud optical depths are taken from
the drift-phoenix brown dwarf model. As is well known, cloud particles change
the spectrum co... | 1105.3062v2 |
2011-07-05 | GRAVITAS : General Relativistic Astrophysics VIa Timing And Spectroscopy: An ESA M3 mission proposal | GRAVITAS is an X-ray observatory, designed and optimised to address the ESA
Cosmic Vision theme of "Matter under extreme conditions". It was submitted as a
response to the call for M3 mission proposals. The concept centres around an
X-ray telescope of unprecedented effective area, which will focus radiation
emitted fro... | 1107.0955v1 |
2011-08-04 | Identifying a new intermediate-polar using XMM-Newton and INTEGRAL | The bright X-ray source, 2XMMi J180438.7-145647 is fortunate to have long
baseline observations in INTEGRAL that compliment observations taken by other
missions. Optical spectroscopy of this object has suggested a distance of ~7
kpc and an identification with a low mass X-ray binary. We instead use the
X-ray data from ... | 1108.1105v1 |
2011-08-12 | The High Energy view of the Broad Line Radio Galaxy 3C 111 | We present the analysis of Suzaku and XMM-Newton observations of the
broad-line radio galaxy (BLRG) 3C 111. Its high energy emission shows
variability, a harder continuum with respect to the radio quiet AGN population,
and weak reflection features. Suzaku found the source in a minimum flux level;
a comparison with the ... | 1108.2609v1 |
2011-08-30 | The Bulge Radial Velocity/Abundance Assay | The Bulge Radial Velocity/Abundance Assay (BRAVA) has accomplished a survey
of 10,000 red giants in the Southern Galactic bulge, approximately spanning -8
deg. < l < +8 deg. and -3 deg. <b < -8 deg., a region within roughly 1 kpc from
the nucleus. We find that the Galactic bulge at b=-4 deg. displays a clear
departure ... | 1108.6044v1 |
2011-09-01 | Suzaku Observations of Iron K-lines from the Intracluster Medium of the Coma Cluster | The Coma cluster was observed with an X-ray Imaging Spectrometer (XIS)
onboard Suzaku in six pointings, including the central X-ray peak region, the
14'west offset region, 30'and 34'north-west offset regions, and 44'and
60'south-west offset regions. Owing to its lower background level, Suzaku has
better sensitivity to ... | 1109.0154v2 |
2011-09-09 | The Chemical Evolution of Globular Clusters - II. Metals and Fluorine | In the first paper in this series, we proposed a new framework in which to
model the chemical evolution of globular clusters. This model, is predicated
upon the assumption that clusters form within an interstellar medium enriched
locally by the ejecta of a single Type Ia supernova and varying numbers of
asymptotic gian... | 1109.1938v1 |
2011-09-21 | NGC 5548: Lack of a Broad Fe K Line and Constraints on the Location of the Hard X-ray Source | We present an analysis of the co-added and individual 0.7-40 keV spectra from
seven Suzaku observations of the Sy 1.5 galaxy NGC 5548 taken over a period of
eight weeks. We conclude that the source has a moderately ionized, three-zone
warm absorber, a power-law continuum, and exhibits contributions from cold,
distant r... | 1109.4651v1 |
2011-10-20 | High Resolution XMM-Newton Spectroscopy of the Cooling Flow Cluster A3112 | We examine high signal to noise XMM-Newton European Photon Imaging Camera
(EPIC) and Reflection Grating Spectrometer (RGS) observations to determine the
physical characteristics of the gas in the cool core and outskirts of the
nearby rich cluster A3112. The XMM-Newton Extended Source Analysis Software
data reduction an... | 1110.4422v2 |
2011-11-11 | Modelling of the ultraviolet and visual SED variability in the hot magnetic Ap star CU Vir | The spectral energy distribution (SED) in chemically peculiar stars may be
significantly affected by their abundance anomalies. The observed SED
variations are usually assumed to be a result of inhomogeneous surface
distribution of chemical elements, flux redistribution and stellar rotation.
However, the direct evidenc... | 1111.2746v1 |
2011-11-28 | Dust in Historical Galactic Type Ia Supernova Remnants with Herschel | The origin of interstellar dust in galaxies is poorly understood,
particularly the relative contributions from supernovae and the cool stellar
winds of low-intermediate mass stars. Here, we present Herschel PACS and SPIRE
photometry at 70-500um of the historical young supernova remnants: Kepler and
Tycho; both thought ... | 1111.6627v2 |
2011-12-23 | Non-standard s process in low metallicity massive rotating stars | Context. Rotation is known to affect the nucleosynthesis of light elements in
massive stars, mainly by rotation-induced mixing. In particular, rotation
boosts the primary nitrogen production. Models of rotating stars are able to
reproduce the nitrogen observed in low-Z halo stars. Aims. Here we present the
first grid o... | 1112.5548v1 |
2012-01-24 | Effective temperatures, rotational velocities, microturbulent velocities and abundances in the atmospheres of the Sun,. HD1835 and HD10700 | We describe our procedure to determine effective temperatures, rotational
velocities, microturbulent velocities, and chemical abundances in the
atmospheres of Sun-like stars. We use independent determinations of iron
abundances using the fits to the observed Fe I and Fe II atomic absorption
lines. We choose the best so... | 1201.5099v2 |
2012-02-14 | On The Effect of Giant Planets on the Scattering of Parent Bodies of Iron Meteorite from the Terrestrial Planet Region into the Asteroid Belt: A Concept Study | In their model for the origin of the parent bodies of iron meteorites, Bottke
et al proposed differentiated planetesimals that were formed in the region of
1-2 AU during the first 1.5 Myr, as the parent bodies, and suggested that these
objects and their fragments were scattered into the asteroid belt as a result
of int... | 1202.2975v1 |
2012-03-08 | Suzaku observations of the Hydra A cluster out to the virial radius | We report Suzaku observations of the northern half of the Hydra A cluster out
to ~1.4 Mpc, reaching the virial radius. This is the first Suzaku observations
of a medium-size (kT ~3 keV) cluster out to the virial radius. Two observations
were conducted, north-west and north-east offsets, which continue in a filament
dir... | 1203.1700v4 |
2012-03-14 | Barium abundance in red giants of NGC 6752. Non-local thermodynamic equilibrium and three-dimensional effects | (Abridged) Aims: We study the effects related to departures from non-local
thermodynamic equilibrium (NLTE) and homogeneity in the atmospheres of red
giant stars in Galactic globular cluster NGC 6752, to assess their influence on
the formation of Ba II lines. Methods: One-dimensional (1D) local thermodynamic
equilibriu... | 1203.3124v2 |
2012-03-20 | Manganese in dwarf spheroidal galaxies | We provide manganese abundances (corrected for the effect of the hyperfine
structure) for a large number of stars in the dwarf spheroidal galaxies
Sculptor and Fornax, and for a smaller number in the Carina and Sextans dSph
galaxies. Abundances had already been determined for a number of other elements
in these galaxie... | 1203.4491v2 |
2012-04-02 | Correlated Gravitational Wave and Neutrino Signals from General-Relativistic Rapidly Rotating Iron Core Collapse | We present results from a new set of 3D general-relativistic hydrodynamic
simulations of rotating iron core collapse. We assume octant symmetry and focus
on axisymmetric collapse, bounce, the early postbounce evolution, and the
associated gravitational wave (GW) and neutrino signals. We employ a
finite-temperature nucl... | 1204.0512v2 |
2012-04-04 | The Suzaku X-ray spectrum of NGC 3147. Further insights on the best "true" Seyfert 2 galaxy candidate | NGC 3147 is so far the most convincing case of a "true" Seyfert 2 galaxy,
i.e. a source genuinely lacking the Broad Line Regions. We obtained a Suzaku
observation with the double aim to study in more detail the iron line complex,
and to check the Compton-thick hypothesis for the lack of observed optical
broad lines.
... | 1204.0946v1 |
2012-04-24 | Intrinsic crystal phase separation in antiferromagnetic superconductor RbyFe2-xSe2: a diffraction study | The crystal and magnetic structures of the superconducting iron based
chalcogenides RbyFe2-xSe2 have been studied by means of single crystal
synchrotron x-ray and high resolution neutron powder diffraction in the
temperature range 2-570 K. The ground state of the crystal is an intrinsically
phase separated state with t... | 1204.5449v3 |
2012-04-26 | XMM-Newton observations of GX 13+1: correlation between photoionised absorption and broad line emission | We analysed data from five XMM-Newton observations of GX 13+1 to investigate
the variability of the photo-ionised absorber present in this source. We fitted
EPIC and RGS spectra obtained from the "least-variable" intervals with a model
consisting of disc-blackbody and blackbody components together with a Gaussian
emiss... | 1204.5904v1 |
2012-05-30 | Overabundance of alpha-elements in exoplanet host stars | We present the results for a chemical abundance analysis between
planet-hosting and stars without planets for 12 refractory elements for a total
of 1111 nearby FGK dwarf stars observed within the context of the HARPS GTO
programs. Of these stars, 109 are known to harbour high-mass planetary
companions and 26 stars are ... | 1205.6670v2 |
2012-07-07 | An upper limit on the sulphur abundance in HE 1327-2326 | Context: Star HE 1327-2326 is a unique object, with the lowest measured iron
abundance ([Fe/H] ~ -6) and a peculiar chemical composition that includes large
overabundances of C, N, and O with respect to iron. One important question is
whether the chemical abundances in this star reflect the chemical composition
of the ... | 1207.1806v3 |
2012-07-25 | Rapid-response mode VLT/UVES spectroscopy of super iron-rich gas exposed to GRB 080310. Evidence of ionization in action and episodic star formation in the host | We analyse high-resolution near-UV and optical spectra of the afterglow of
GRB 080310, obtained with the Very Large Telescope Ultraviolet and Visual
Echelle Spectrograph (VLT/UVES), to investigate the circumburst environment and
the interstellar medium of the gamma-ray burst (GRB) host galaxy. The VLT
rapid-response mo... | 1207.6102v1 |
2012-08-14 | The Golden Channel at a Neutrino Factory revisited: improved sensitivities from a Magnetised Iron Neutrino Detector | This paper describes the performance and sensitivity to neutrino mixing
parameters of a Magnetised Iron Neutrino Detector (MIND) at a Neutrino Factory
with a neutrino beam created from the decay of 10 GeV muons. Specifically, it
is concerned with the ability of such a detector to detect muons of the
opposite sign to th... | 1208.2735v2 |
2012-09-13 | Solar Fe abundance and magnetic fields - Towards a consistent reference metallicity | We investigate the impact on Fe abundance determination of including magnetic
flux in series of 3D radiation-MHD simulations of solar convection which we
used to synthesize spectral intensity profiles corresponding to disc centre. A
differential approach is used to quantify the changes in theoretical equivalent
width o... | 1209.2771v1 |
2012-10-02 | X-ray spectroscopy of the ADC source X1822-371 with Chandra and XMM-Newton | The eclipsing low-mass X-ray binary X1822-371 is the prototype of the
accretion disc corona (ADC) sources. We analyse two Chandra observations and
one XMM-Newton observation to study the discrete features and their variation
as a function of the orbital phase, deriving constraints on the temperature,
density, and locat... | 1210.0874v1 |
2012-10-25 | XMM-Newton observations of the Galactic Centre Region - I: The distribution of low-luminosity X-ray sources | We exploit XMM-Newton archival data in a study of the extended X-ray emission
emanating from the Galactic Centre (GC) region. EPIC-pn and EPIC-MOS
observations, with a total exposure approaching 0.5 and 1 Ms respectively, were
used to create mosaiced images of a 100 pc x 100 pc region centred on Sgr A* in
four bands co... | 1210.6808v1 |
2012-11-12 | Theory of Quantum Phase Transition in Iron-based Superconductors with Half-Dirac Nodal Electron Fermi Surface | The quantum phase transition in iron-based superconductors with 'half-Dirac'
node at the electron Fermi surface as a $T=0$ structural phase transition
described in terms of nematic order is discussed. An effective low energy
theory that describes half-Dirac nodal Fermions and their coupling to Ising
nematic order that ... | 1211.2790v4 |
2012-12-04 | An Examination of the Spectral Variability in NGC 1365 with Suzaku | We present jointly analyzed data from three deep Suzaku observations of NGC
1365. These high signal-to-noise spectra enable us to examine the nature of
this variable, obscured AGN in unprecedented detail on timescales ranging from
hours to years. We find that, in addition to the power-law continuum and
absorption from ... | 1212.0772v1 |
2012-12-06 | Radiative cooling in collisionally and photo ionized plasmas | We discuss recent improvements in the calculation of the radiative cooling in
both collisionally and photo ionized plasmas. We are extending the spectral
simulation code Cloudy so that as much as possible of the underlying atomic
data is taken from external databases, some created by others, some developed
by the Cloud... | 1212.1233v1 |
2013-01-04 | Optical properties of iron-based superconductor LiFeAs single crystal | We have measured the reflectivity spectra of the iron based superconductor
LiFeAs (Tc = 17.6 K) in the temperature range from 4 to 300 K. In the
superconducting state (T < Tc), the clear opening of the optical absorption gap
was observed below 25 cm-1, indicating an isotropic full gap formation. In the
normal state (T ... | 1301.0694v2 |
2013-02-06 | Octant sensitivity for large theta(13) in atmospheric and long baseline neutrino experiments | One of the unknown parameters in neutrino oscillations is the octant of the
mixing angle theta_{23}. In this paper, we discuss the possibility of
determining the octant of theta_{23} in the long baseline experiments T2K and
NOvA in conjunction with future atmospheric neutrino detectors, in light of
non-zero value of th... | 1302.1370v2 |
2013-02-13 | Measuring Black Hole Spin using X-ray Reflection Spectroscopy | I review the current status of X-ray reflection (a.k.a. broad iron line)
based black hole spin measurements. This is a powerful technique that allows us
to measure robust black hole spins across the mass range, from the stellar-mass
black holes in X-ray binaries to the supermassive black holes in active
galactic nuclei... | 1302.3260v2 |
2013-03-12 | Fast and Furious: Shock Heated Gas as the Origin of Spatially Resolved Hard X-ray Emission in the Central 5 kpc of the Galaxy Merger NGC 6240 | We have obtained a deep, sub-arcsecond resolution X-ray image of the nuclear
region of the luminous galaxy merger NGC 6240 with Chandra, which resolves the
X-ray emission from the pair of active nuclei and the diffuse hot gas in great
detail. We detect extended hard X-ray emission from kT~6 keV (~70 million K)
hot gas ... | 1303.2980v2 |
2013-03-12 | Lithium abundance in the metal-poor open cluster NGC 2243 | Lithium is a fundamental element for studying the mixing mechanisms acting in
the stellar interiors, for understanding the chemical evolution of the Galaxy
and the Big Bang nucleosynthesis. The study of Li in stars of open clusters
(hereafter OC) allows a detailed comparison with stellar evolutionary models
and permits... | 1303.3027v1 |
2013-04-27 | Environments of Strong / Ultrastrong, Ultraviolet Fe II Emitting Quasars | We have investigated the strength of ultraviolet Fe II emission from quasars
within the environments of Large Quasar Groups (LQGs) in comparison with
quasars elsewhere, for 1.1 <= <z_LQG> <= 1.7, using the DR7QSO catalogue of the
Sloan Digital Sky Survey. We use the Weymann et al. W2400 equivalent width,
defined betwee... | 1304.7396v2 |
2013-05-15 | Dust input from AGB stars in the Large Magellanic Cloud | The dust-forming population of AGB stars and their input to the interstellar
dust budget of the Large Magellanic Cloud (LMC) are studied with evolutionary
dust models with the main goals (1) to investigate how the amount and
composition of dust from AGB stars vary over galactic history; (2) to
characterise the mass and... | 1305.3521v1 |
2013-06-05 | Chemical abundances of the Milky Way thick disk and stellar halo II.: sodium, iron-peak and neutron-capture elements | We present chemical abundance analyses of sodium, iron-peak and
neutron-capture elements for 97 kinematically selected thick disk, inner halo
and outer halo stars with metallicities -3.3<[Fe/H]<-0.5. The main aim of this
study is to examine chemical similarities and differences among metal-poor
stars belonging to these... | 1306.0954v1 |
2013-06-09 | Advanced burning stages and fate of 8-10 Mo stars | The stellar mass range 8<M/Mo<12 corresponds to the most massive AGB stars
and the most numerous massive stars. It is host to a variety of supernova
progenitors and is therefore very important for galactic chemical evolution and
stellar population studies. In this paper, we study the transition from
super-AGB star to m... | 1306.2030v1 |
2013-06-10 | X-ray Outflows and Super-Eddington Accretion in the Ultraluminous X-ray Source Holmberg IX X-1 | Studies of X-ray continuum emission and flux variability have not
conclusively revealed the nature of ultra-luminous X-ray sources (ULXs) at the
high-luminosity end of the distribution (those with Lx > 1e40 erg/s). These are
of particular interest because the luminosity requires either super-Eddington
accretion onto a ... | 1306.2317v1 |
2013-06-11 | Thermal convection in Earth's inner core with phase change at its boundary | Inner core translation, with solidification on one hemisphere and melting on
the other, provides a promising basis for understanding the hemispherical
dichotomy of the inner core, as well as the anomalous stable layer observed at
the base of the outer core - the F-layer - which might be sustained by
continuous melting ... | 1306.2482v1 |
2013-06-25 | Superorbital Phase-Resolved Analysis of SMC X-1 | The high-mass X-ray binary SMC X-1 is an eclipsing binary with an orbital
period of 3.89 d. This system exhibits a superorbital modulation with a period
varying between ~40 d and ~65 d. The instantaneous frequency and the
corresponding phase of the superorbital modulation can be obtained by a
recently developed time-fr... | 1306.5819v1 |
2013-07-30 | New and updated stellar parameters for 71 evolved planet hosts. On the metallicity - giant planet connection | It is still being debated whether the well-known metallicity - giant planet
correlation for dwarf stars is also valid for giant stars. For this reason,
having precise metallicities is very important. Different methods can provide
different results that lead to discrepancies in the analysis of planet hosts.
To study the... | 1307.7870v1 |
2013-08-07 | Abundance gradients in spiral disks: is the gradient inversion at high redshift real? | We compute the abundance gradients along the disk of the Milky Way by means
of the two-infall model: in particular, the gradients of oxygen and iron and
their temporal evolution. First, we explore the effects of several physical
processes which influence the formation and evolution of abundance gradients.
They are: i) ... | 1308.1549v1 |
2013-08-09 | KASCADE-Grande measurements of energy spectra for elemental groups of cosmic rays | The KASCADE-Grande experiment, located at KIT-Karlsruhe, Germany, consists of
a large scintillator array for measurements of charged particles, N_ch, and of
an array of shielded scintillation counters used for muon counting, N_mu.
KASCADE-Grande is optimized for cosmic ray measurements in the energy range 10
PeV to 100... | 1308.2098v1 |
2013-08-09 | S-process in low-mass extremely metal-poor stars | Extremely metal-poor low-mass stars experience an ingestion of protons into
the helium-rich layer during the core He-flash, resulting in the production of
neutrons through the reactions
^{12}C(p,\gamma)^{13}N(\beta)^{13}C(\alpha,n)^{16}O. This is a potential site
for the production of s-process elements in extremely me... | 1308.2224v1 |
2013-08-12 | Distinguishing $s^{\pm}$ and $s^{++}$ electron pairing symmetries by neutron spin resonance in superconducting NaFe$_{0.935}$Co$_{0.045}$As | A determination of the superconducting (SC) electron pairing symmetry forms
the basis for establishing a microscopic mechansim for superconductivity. For
iron pnictide superconductors, the $s^\pm$-pairing symmetry theory predicts the
presence of a sharp neutron spin resonance at an energy below the sum of hole
and elec... | 1308.2453v1 |
2013-08-12 | 3-D non-LTE radiative transfer effects in Fe I lines: II. Line formation in 3-D radiation hydrodynamic simulations | We investigate the effects of horizontal radiative transfer (RT) a NLTE on
important diagnostic iron lines in a realistic 3-D HD simulation. Using a
multi-level atom we compute and compare widely used Fe I line profiles at 3
different levels of approximation (3-D NLTE, 1-D NLTE, LTE). We find that the
influence of hori... | 1308.2490v1 |
2013-08-21 | A High Resolution View of the Warm Absorber in the Quasar MR2251-178 | High resolution X-ray spectroscopy of the warm absorber in the nearby quasar,
MR2251-178 (z = 0.06398) is presented. The observations were carried out in
2011 using the Chandra High Energy Transmission Grating and the XMM-Newton
Reflection Grating Spectrometer, with net exposure times of approximately 400
ks each. A mu... | 1308.4550v1 |
2013-09-13 | The Stellar Abundances for Galactic Archaeology (SAGA) Database III - Analysis of Enrichment Histories for Elements and Two Modes of Star Formation during the Early Evolution of Milky Way | We study the enrichment histories for nine elements, C, four alpha-elements
of Mg, Si, Ca, and Ti, Sc, and three iron-peak elements of Co, Ni, and Zn, by
using a large number of stellar data, collected by the Stellar Abundances for
Galactic Archaeology (SAGA) database. We find statistically significant
changes, or brea... | 1309.3430v2 |
2013-09-17 | Chemical gradients in the Milky Way from the RAVE data. I. Dwarf stars | Aim: We aim at measuring the chemical gradients of the elements Mg, Al, Si,
and Fe along the Galactic radius to provide new constraints on the chemical
evolution models of the Galaxy and Galaxy models such as the Besancon model.
Methods: We analysed three different samples selected from three independent
datasets: a ... | 1309.4279v1 |
2013-09-24 | The magnetic and structural properties near the Lifshitz point in Fe1+xTe | We construct a phase diagram of the parent compound Fe1+xTe as a function of
interstitial iron x in terms of the electronic, structural, and magnetic
properties. For a concentration of x < 10%, Fe1+xTe undergoes a "semimetal" to
metal transition at approximately 70 K that is also first-order and coincident
with a struc... | 1309.6310v1 |
2013-10-09 | Four new X-ray-selected supernova remnants in the Large Magellanic Cloud | Aims: We present a detailed multi-wavelength study of four new supernova
remnants (SNRs) in the Large Magellanic Cloud (LMC). The objects were
identified as SNR candidates in X-ray observations performed during the survey
of the LMC with XMM-Newton.
Methods: Data obained with XMM-Newton are used to investigate the
mo... | 1310.2569v1 |
2013-10-14 | The Reflection Component from Cygnus X-1 in the Soft State Measured by NuSTAR and Suzaku | The black hole binary Cygnus X-1 was observed in late-2012 with the Nuclear
Spectroscopic Telescope Array (NuSTAR) and Suzaku, providing spectral coverage
over the ~1-300 keV range. The source was in the soft state with a
multi-temperature blackbody, power-law, and reflection components along with
absorption from highl... | 1310.3830v1 |
2013-10-16 | Identification of a Jet-Driven Supernova Remnant in the Small Magellanic Cloud: Possible Evidence for the Enhancement of Bipolar Explosions at Low Metallicity | Recent evidence has suggested that the supernova remnant (SNR) 0104-72.3 in
the Small Magellanic Cloud (SMC) may be the result of a prompt Type Ia SN based
on enhanced iron abundances and its association with a star-forming region. In
this paper, we present evidence that SNR 0104-72.3 arose from a jet-driven
bipolar co... | 1310.4498v2 |
2013-10-23 | Functional Renormalization Group for multi-orbital Fermi Surface Instabilities | Technological progress in material synthesis, as well as artificial
realization of condensed matter scenarios via ultra-cold atomic gases in
optical lattices or epitaxial growth of thin films, is opening the gate to
investigate a plethora of unprecedented strongly correlated electron systems.
In a large subclass thereo... | 1310.6191v1 |
2013-11-20 | The curious time lags of PG 1244+026: Discovery of the iron K reverberation lag | High-frequency iron K reverberation lags, where the red wing of the line
responds before the line centroid, are a robust signature of relativistic
reflection off the inner accretion disc. In this letter, we report the
discovery of the Fe K lag in PG 1244+026 from ~120 ks of data (1 orbit of the
XMM-Newton telescope). T... | 1311.5164v1 |
2013-12-08 | On the kinematic separation of field and cluster stars across the Bulge globular NGC 6528 | We present deep and precise multi-band photometry of the Galactic Bulge
globular cluster NGC6528. The current dataset includes optical and
near-infrared images collected with ACS/WFC, WFC3/UVIS, and WFC3/IR on board
the Hubble Space Telescope. The images cover a time interval of almost ten
years and we have been able t... | 1312.2272v2 |
2013-12-16 | Magnetic structure map for face-centered tetragonal iron: appearance of a new collinear spin structure | For face-centered cubic (fcc) and tetragonal (fct) iron a large number of
magnetic configurations as a function of crystal structural parameters were
studied by means of density functional theory. The stability of magnetic
structures was defined by the magnetic re-orientation energy $\Delta
{E}^i_\text{reor}$ as the di... | 1312.4313v2 |
2014-01-07 | Superparamagnetic iron oxide polyacrylic acid coated γ-Fe2O3 nanoparticles does not affect kidney function but causes acute effect on the cardiovascular function in healthy mice | This study describes the distribution of intravenously injected polyacrylic
acid (PAA) coated {\gamma}-Fe2O3 NPs (10 mg kg-1) at the organ, cellular and
subcellular levels in healthy BALB/cJ mice and in parallel addresses the
effects of NP injection on kidney function, blood pressure and vascular
contractility. Magneti... | 1401.1847v1 |
2014-02-12 | Stokes $IQUV$ Magnetic Doppler Imaging of Ap stars II: Next Generation Magnetic Doppler Imaging of $α^2$ CVn | We present updated magnetic field maps of the chemically peculiar B9p star
$\alpha^2$ CVn created using a series of time resolved observations obtained
using the high resolution spectropolarimeters ESPaDOnS and Narval. We compare
these new magnetic field maps with the original magnetic Doppler imaging maps
based on spe... | 1402.2938v1 |
2014-02-15 | Revealing the location and structure of the accretion disk-wind in PDS456 | We present evidence for the rapid variability of the high velocity iron
K-shell absorption in the nearby ($z=0.184$) quasar PDS456. From a recent long
Suzaku observation in 2013 ($\sim1$Ms effective duration) we find that the the
equivalent width of iron K absorption increases by a factor of $\sim5$ during
the observat... | 1402.3700v2 |
2014-03-11 | Broad iron emission line and kilohertz quasi-periodic oscillations in the neutron star system 4U 1636-53 | Both the broad iron (Fe) line and the frequency of the kilohertz
quasi-periodic oscillations (kHz QPOs) in neutron star low-mass X-ray binaries
(LMXBs) can potentially provide independent measures of the inner radius of the
accretion disc. We use XMM-Newton and simultaneous Rossi X-ray Timing Explorer
observations of t... | 1403.2700v3 |
2014-04-14 | Interplane resistivity of underdoped single crystals (Ba$_{1-x}$K$_x$)Fe$_2$As$_2$, $0 \leq x<0.34$ | Temperature-dependent inter-plane resistivity, $\rho _c(T)$, was measured in
hole-doped iron-arsenide superconductor (Ba$_{1-x}$K$_x$)Fe$_2$As$_2$ over a
doping range from parent compound to optimal doping $T_c\approx 38~K$, $0\leq x
\leq 0.34$. Measurements were undertaken on high-quality single crystals grown
from Fe... | 1404.3664v1 |
2014-06-04 | New Fe I level energies and line identifications from stellar spectra | The spectrum of the Fe I atom is critical to many areas of astrophysics and
beyond. Measurements of the energies of its high-lying levels remain woefully
incomplete, however, despite extensive analysis of ultraviolet laboratory iron
absorption spectra, optical laboratory iron emission spectra, and the solar
infrared sp... | 1406.0933v3 |
2014-06-16 | Location and sizes of forsterite grains in protoplanetary disks: interpretation from the Herschel DIGIT programme | The spectra of protoplanetary disks contain mid- and far- infrared emission
features produced by forsterite dust grains. The spectral features contain
information about the forsterite temperature, chemical composition and grain
size. We aim to characterize how the 23 and 69 micron features can be used to
constrain the ... | 1406.3951v1 |
2014-06-17 | New Detections of Arsenic, Selenium, and Other Heavy Elements in Two Metal-Poor Stars | We use the Space Telescope Imaging Spectrograph on board the Hubble Space
Telescope to obtain new high-quality spectra covering the 1900 to 2360 Angstrom
wavelength range for two metal-poor stars, HD 108317 and HD 128279. We derive
abundances of Cu II, Zn II, As I, Se I, Mo II, and Cd II, which have not been
detected p... | 1406.4554v1 |
2014-06-20 | Suzaku Observation of the Black Hole Binary 4U 1630--47 in the Very High State | We report the results from an X-ray and near-infrared observation of the
Galactic black hole binary 4U 1630--47 in the very high state, performed with
{\it Suzaku} and IRSF around the peak of the 2012 September-October outburst.
The X-ray spectrum is approximated by a steep power law, with photon index of
3.2, identify... | 1406.5512v1 |
2014-06-27 | Chemical gradients in the Milky Way from the RAVE data. II. Giant stars | We provide new constraints on the chemo-dynamical models of the Milky Way by
measuring the radial and vertical chemical gradients for the elements Mg, Al,
Si, Ti, and Fe in the Galactic disc and the gradient variations as a function
of the distance from the Galactic plane ($Z$). We selected a sample of giant
stars from... | 1406.7244v1 |
2014-07-21 | Constraints on Core Collapse from the Black Hole Mass Function | We model the observed black hole mass function under the assumption that
black hole formation is controlled by the compactness of the stellar core at
the time of collapse. Low compactness stars are more likely to explode as
supernovae and produce neutron stars, while high compactness stars are more
likely to be failed ... | 1407.5622v1 |
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