publicationDate stringlengths 1 2.79k | title stringlengths 1 36.5k ⌀ | abstract stringlengths 1 37.3k ⌀ | id stringlengths 9 47 |
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2022-07-10 | Semimetallic spin-density wave state in iron pnictides | We examine the existence of semimetallic spin-density wave states in iron
pnictides. In the experimentally observed metallic spin-density wave state, the
symmetry-protected Dirac cones are located away from the Fermi surface giving
rise to tiny pockets and there are also additional Fermi pockets such as one
around $\Ga... | 2207.04365v1 |
2022-07-22 | Orbital and magnetic ordering in single-layer FePS3: A DFT+U study | Among the numerous 2D system that can be prepared via exfoliation, iron
phosphorus trisulfide (FePS3) attracts a lot of attention recently due to its
broad-range photoresponse, its unusual Ising-type magnetic order and possible
applications in spintronic nano-devices. Despite various experimental and
theoretical-comput... | 2207.11283v2 |
2022-07-25 | Anomalous Shiba states in topological iron-based superconductors | We demonstrate the formation of robust zero energy modes close to magnetic
impurities in the iron-based superconductor FeSe$_{1-x}$Te$_x$. We find that
the Zeeman field generated by the impurity favors a spin-triplet inter-orbital
pairing as opposed to the spin-singlet intra-orbital pairing prevalent in the
bulk. The p... | 2207.12425v2 |
2022-08-16 | Core-shell enhanced single particle model for lithium iron phosphate batteries: model formulation and analysis of numerical solutions | In this paper, a core-shell enhanced single particle model for iron-phosphate
battery cells is formulated, implemented, and verified. Starting from the
description of the positive and negative electrodes charge and mass transport
dynamics, the positive electrode intercalation and deintercalation phenomena
and associate... | 2208.07485v1 |
2022-08-26 | Pure nematic state in iron-based superconductor | Lattice and electronic states of thin FeSe films on LaAlO$_3$ substrates are
investigated in the vicinity of the nematic phase transition. No evidence of
structural phase transition is found by x-ray diffraction below $T^\ast \sim
90$ K, while results obtained from resistivity measurement and angle-resolved
photoemissi... | 2208.12384v4 |
2022-08-27 | Magnetic bond-order potential for iron-cobalt alloys | For large-scale atomistic simulations of magnetic materials, the interplay of
atomic and magnetic degrees of freedom needs to be described with high
computational efficiency. Here we present an analytic bond-order potential
(BOP) for iron-cobalt, an interatomic potential based on a coarse-grained
description of the ele... | 2208.12973v2 |
2022-08-31 | The giants that were born swiftly -- Implications of the top-heavy stellar initial mass function on the birth conditions of globular clusters | Recent results suggest that the initial mass function (IMF) of globular
clusters (GCs) is metallicity and density dependent. Here it is studied how
this variation affects the initial masses and the numbers of core collapse
supernovae (CCSNe) required to reproduce the observed iron spreads in GCs. The
IMFs of all of the... | 2209.00045v1 |
2022-09-05 | Increased muon field at surface and substrate interface of palladium thin films | We performed depth-dependent low-energy muon spin spectroscopy ($\mu$SR)
studies on three palladium 100 nm thin films, both undoped and doped with 170
ppm of iron. Muons implanted in the surface and substrate interface region
probe an increased local magnetic field compared to the inner part of the
sample. The field in... | 2209.02002v1 |
2022-09-17 | Onset Temperatures for Superconducting Fluctuations in Te-annealed FeTe$_{1-x}$Se$_x$ Single Crystals: Evidence for the BCS-BEC Crossover | Recently, the superconductors' community has witnessed an unsettled debate
regarding whether iron-based superconductors, in particular FeSe and
FeSe$_{1-x}$S$_x$, are in the Bardeen-Cooper-Shrieffer (BCS) - Bose-Einstein
condensation (BEC) crossover regime. Nonetheless, one particular system,
FeTe$_{1-x}$Se$_x$, has be... | 2209.08238v1 |
2022-09-19 | Anisotropic gap structure and sign reversal symmetry in monolayer Fe(Se,Te) | The iron-based superconductors are an ideal platform to reveal the enigma of
the unconventional superconductivity and potential topological
superconductivity. Among them, the monolayer Fe(Se,Te)/SrTiO3(001), which is
proposed to be topological nontrivial, shows interface-enhanced
high-temperature superconductivity in t... | 2209.08683v2 |
2022-10-03 | Energetics, electronic states, and magnetism of iron phthalocyanine on pristine and defected graphene layers | Transition metal phthalocyanines (TMPc's) are under intense scrutiny in the
field of spintronics, as they may be promising storage devices. The simplicity
and cheapness of such molecules increase their commercial potential. There is
an active study of how the magnetic moment of the metal centre of such
molecules can be... | 2210.01025v1 |
2022-10-19 | Competing ferromagnetic superconducting states in europium-based iron pnictides | In europium-based iron pnictides superconducting Fe-planes can be influenced
by a Zeeman field originated from the neighboring Eu-planes. The field tends to
induce spin-density waves with a ferromagnetic average which coexists with the
superconducting order by forming complementary patterns of the superconducting
and m... | 2210.10312v1 |
2022-11-14 | Rapid Formation of Exoplanetesimals Revealed by White Dwarfs | The timing of formation for the first planetesimals determines the mode of
planetary accretion and their geophysical and compositional evolution.
Astronomical observations of circumstellar discs and Solar System geochronology
provide evidence for planetesimal formation during molecular cloud collapse,
much earlier than... | 2211.07244v1 |
2022-12-06 | Transient gap generation in BaFe$_2$As$_2$ driven by coherent lattice vibrations | The electronic structure and the magnetic properties of iron-based
superconductors are highly sensitive to the pnictogen height. Coherent
excitation of the $A_{1g}$ phonon by femtosecond laser directly modulates the
pnictogen height, which has been used to control the physical properties of
iron-based superconductors. ... | 2212.03337v1 |
2022-12-28 | ISAI: Investigating Solar Axion by Iron-57 | The existence of the axion is a unique solution for the strong CP problem,
and the axion is one of the most promising candidates of the dark matter.
Investigating Solar Axion by Iron-57 (ISAI) is being prepared as a complemented
table-top experiment to confirm the solar axion scenario. Probing an X-ray
emission from th... | 2212.13708v1 |
2023-02-27 | Predicting elastic and plastic properties of small iron polycrystals by machine learning | Deformation of crystalline materials is an interesting example of complex
system behaviour. Small samples typically exhibit a stochastic-like, irregular
response to externally applied stresses, manifested as significant
sample-to-sample variation in their mechanical properties. In this work we
study the predictability ... | 2302.13745v3 |
2023-04-13 | Aromatic molecules as sustainable lubricants explored by ab initio simulations | In the pursuit of sustainable lubricant materials, the conversion of common
organic molecules into graphitic material has been recently shown to
effectively reduce friction of metallic interfaces. Aromatic molecules are
perfect candidates due to their inertness and possibility to form carbon-based
tribofilms. Among man... | 2304.06501v2 |
2023-04-17 | Ultrafast Relaxation Dynamics of Spin-Density Wave Order in BaFe$_2$As$_2$ under High Pressures | BaFe$_2$As$_2$ is the parent compound for a family of iron-based
high-temperature superconductors as well as a prototypical example of the
spin-density wave (SDW) system. In this study, we perform an optical pump-probe
study of this compound to systematically investigate the SDW order across the
pressure-temperature ph... | 2304.08080v1 |
2023-04-18 | Electron correlation effects in paramagnetic cobalt | We study the influence of Coulomb correlations on spectral and magnetic
properties of fcc cobalt using a combination of density functional theory and
dynamical mean-field theory. The computed uniform and local magnetic
susceptibilities obey the Curie-Weiss law, which, as we demonstrate, occurs due
to the partial format... | 2304.08980v1 |
2023-04-27 | Influence of oxygen on electronic correlation and transport in iron in the outer Earth's core | Knowing the transport properties of iron under realistic conditions present
in the Earth's core is essential for the geophysical modeling of Earth's
magnetic field generation. Besides by extreme pressures and temperatures,
transport may be influenced importantly also by the presence of light elements.
Using a combinati... | 2304.13962v1 |
2023-05-08 | Uniaxial-Strain Tuning of the Intertwined Orders in BaFe$_2$(As$_{1-x}$P$_{x}$)$_2$ | An experimental determination of electronic phase diagrams of high-transition
temperature (high-$T_c$) superconductors forms the basis for a microscopic
understanding of unconventional superconductivity. For most high-$T_c$
superconductors, the electronic phase diagrams are established through partial
chemical substitu... | 2305.04424v1 |
2023-06-19 | Kinetics of hydrogen and vacancy diffusion in iron: A Kinetic Activation Relaxation technique (k-ART) study | We investigate hydrogen (H) and mono and divacancy-hydrogen complexes (VH$_x$
and V$_2$H$_x$) diffusion in body-centered-cubic (BCC) iron using the kinetic
Activation-Relaxation Technique (k-ART), an off-lattice kinetic Monte Carlo
approach with on-the-fly event catalog building, to explore diffusion barriers
and assoc... | 2306.11176v1 |
2023-06-30 | Orbital-selective correlations for topology in FeSe$_{x}$Te$_{1-x}$ | Strong correlations lead to emergent excitations at low energies. When
combined with symmetry constraints, they may produce topological electronic
states near the Fermi energy. Within this general framework, here we address
the topological features in iron-based superconductors. We examine the effects
of orbital-select... | 2306.17739v1 |
2023-07-02 | Thermochemical Stability of Low-Iron, Manganese-Enriched Olivine in Astrophysical Environments | Low-iron, manganese-enriched (LIME) olivine grains are found in cometary
samples returned by the Stardust mission to comet 81P/Wild 2. Similar grains
are found in primitive meteoritic clasts and unequilibrated meteorite matrix.
LIME olivine is thermodynamically stable in a vapor of solar composition at
high temperature... | 2307.00652v1 |
2023-08-10 | Absence of superconductivity in electron-doped chromium pnictides ThCrAsN$_{1-x}$O$_x$ | Theoretical studies predicted possible superconductivity in electron-doped
chromium pnictides isostructural to their iron counterparts. Here, we report
the synthesis and characterization of a new ZrCuSiAs-type Cr-based compound
ThCrAsN, as well as its oxygen-doped variants. All samples of
ThCrAsN$_{1-x}$O$_x$ show meta... | 2308.05267v1 |
2023-08-16 | Phase separation and phase transitions in undoped and Rh3+ doped iron pnictide CaFe2As2: a Raman scattering study | Iron-pnictides Ca(Fe1-xRhx)2As2 (x = 0, 0.035, and 0.19) were studied across
the tetragonal-orthorhombic and uncollapsed to collapsed tetragonal phase
transitions using Raman spectroscopy. The effect of the phase separation was
observed in the high-temperature phase for the first time. Two phases with the
low-spin and ... | 2308.08633v1 |
2023-08-23 | Oxygen-Terminated (1x1) Reconstruction of Reduced Magnetite Fe$_3$O$_4$(111) | The (111) facet of magnetite (Fe$_3$O$_4$) has been studied extensively by
experimental and theoretical methods, but controversy remains regarding the
structure of its low-energy surface terminations. Using density functional
theory (DFT) computations, we demonstrate three reconstructions that are more
favorable than t... | 2308.12023v1 |
2023-08-25 | Causally Sound Priors for Binary Experiments | We introduce the BREASE framework for the Bayesian analysis of randomized
controlled trials with a binary treatment and a binary outcome. Approaching the
problem from a causal inference perspective, we propose parameterizing the
likelihood in terms of the baseline risk, efficacy, and adverse side effects of
the treatme... | 2308.13713v2 |
2023-08-30 | Mechanism of cathodic protection of iron and steel in porous media | Cathodic protection (CP) was introduced two centuries ago and since has found
widespread application in protecting structures such as pipelines, offshore
installations, and bridges from corrosion. Despite its extensive use, the
fundamental working mechanism of CP remains debated, particularly for metals in
porous media... | 2308.15953v1 |
2023-09-08 | Interband scattering- and nematicity-induced quantum oscillation frequency in FeSe | Understanding the nematic phase observed in the iron-chalcogenide materials
is crucial for describing their superconducting pairing. Experiments on
FeSe$_{1-x}$S$_x$ showed that one of the slow Shubnikov--de Haas quantum
oscillation frequencies disappears when tuning the material out of the nematic
phase via chemical s... | 2309.04237v1 |
2023-09-21 | Spectral study of neutron star low mass X-ray binary source 1A 1744-361 | We present X-ray observations of the recent outburst of 2022 from the neutron
star low mass X-ray binary (LMXB) source 1A 1744-361. Spectral properties of
the source have been analyzed using joint NuSTAR and NICER observations. During
our observations, the source happens to be in the banana state (soft state) of
the ha... | 2309.11817v1 |
2023-09-21 | Interface of Equation-of-State, Atomic Data and Opacities in the Solar Problem | Convergence of the Rosseland Mean Opacity (RMO) is investigated with respect
to the equation-of-state (EOS) and the number of atomic levels of iron ions
prevalent at the solar radiative/convection boundary. The "chemical picture"
Mihalas-Hummer-D\"{a}ppen MHD-EOS, and its variant QMHD-EOS, are studied at two
representa... | 2309.12073v1 |
2023-09-26 | Polymer amide as a source of the cosmic 6.2 micron emission and absorption | Cosmic infrared emission and absorption spectra often carry a well-defined
and invariant 6.2 micron band that has been proposed to emanate from very small
dust grains that may carry polyaromatic hydrocarbons. Hemoglycin, a
well-defined polymer of glycine that also contains iron, has been found in
meteorites of the prim... | 2309.14914v1 |
2023-10-10 | Improved iron-tolerance in recycled aluminum alloys via direct strip casting process | Recycled aluminum alloys are pivotal for sustainable manufacturing, offering
strength, durability, and environmental advantages. However, the presence of
iron (Fe) impurities poses a major challenge, undermining their properties and
recyclability. Conventional manufacturing processes result in coarse Fe-rich
intermetal... | 2310.06327v1 |
2023-10-16 | Spectral Properties of GX~339--4 in the Intermediate State Using AstroSat Observation | We present the results obtained from the spectral studies of black hole X-ray
binary GX~339--4 using \astrosat~ observations during its 2021 outburst.
\astrosat~ observed the source in the intermediate state for $\sim600$ ks. The
combined spectra of SXT and LAXPC in the $0.7-25$ keV energy range are studied
with phenom... | 2310.10444v1 |
2023-10-16 | Quantum hardware calculations of the activation and dissociation of nitrogen on iron clusters and surfaces | Catalytic processes are vital in the chemical industry, with
nitrogen-to-ammonia conversion being a major industrial process. Designing
catalysts relies on computational chemistry methods like Density Functional
Theory (DFT), which have limitations in accuracy, especially for complex
materials. Quantum computing advanc... | 2310.10478v1 |
2023-10-31 | The Larmor frequency shift of a white matter magnetic microstructure model with multiple sources | Magnetic susceptibility imaging may provide valuable information about
chemical composition and microstructural organization of tissue. However, its
estimation from the MRI signal phase is particularly difficult as it is
sensitive to magnetic tissue properties ranging from the molecular to
macroscopic scale. The MRI La... | 2311.00086v3 |
2023-11-19 | Diverse features of dust particles and their aggregates inferred from experimental nanoparticles | Nanometre- to micrometre-sized solid dust particles play a vital role in star
and planet formations. Despite of their importance, however, our understanding
of physical and chemical properties of dust particles is still provisional. We
have conducted a condensation experiment of the vapour generated from a solid
starti... | 2311.11213v1 |
2023-12-14 | Confinement of electron holes via the peroxo group formation in the negative charge-transfer materials on the example of SrFeO3: plane-wave density functional theory predictions | The present work puts forward a concept that the thermostable O1s XPS peaks
with energy of about 531 eV in negative charge-transfer SrFeO_{3-\delta}
perovskite are determined by the peroxo-like oxygen species. The peroxo group
forms via coupling two oxygen anions coordinated to iron cations with
d^5\bar-under{L} (\bar-... | 2312.08665v1 |
2023-12-18 | Quantum criticality in quasi-binary compounds of iron-based superconductors | In this work, we present the studies of structural phase transitions in
Fe(Se,Te) crystals in the range of about 30% selenium substitution by
tellurium. We found a significant change in the properties of the ordered state
of these compositions compared to the case of pure FeSe. The resistivity at low
temperatures for t... | 2312.10901v1 |
2024-01-05 | Comparison of Two Detector Magnetic Systems for the Future Circular Hadron-Hadron Collider | The conceptual design study of a Future Circular hadron-hadron Collider
(FCC-hh) to be con-structed at CERN with a center-of-mass energy of the order
of 100 TeV requires superconducting magnetic systems with a central magnetic
flux density of an order of 4 T for the experimental detectors. The developed
concept of the ... | 2401.02835v1 |
2024-01-08 | Harvesting nucleating structures in nanoparticle crystallization: The example of gold, silver and iron | The thermodynamics and kinetics of crystallization of nanoparticles, as
opposed to bulk phases, may be influenced by surface and size effects. We
investigate the importance of such factors in the crystallization process of
gold, silver, and iron nanodroplets using numerical simulations in the form of
molecular dynamics... | 2401.03969v1 |
2024-01-16 | Influence of temperature, doping, and amorphization on the electronic structure and magnetic damping of iron | Hybrid magnonic quantum systems have drawn increased attention in recent
years for coherent quantum information processing, but too large magnetic
damping is a persistent concern when metallic magnets are used. Their intrinsic
damping is largely determined by electron-magnon scattering induced by
spin-orbit interaction... | 2401.08076v1 |
2024-01-23 | Understanding atom probe's analytical performance for iron oxides using correlation histograms and ab initio calculations | Field evaporation from ionic or covalently bonded materials often leads to
the emission of molecular ions. The metastability of these molecular ions,
particularly under the influence of the intense electrostatic field (1010
Vm-1), makes them prone to dissociation with or without an exchange of energy
amongst them. Thes... | 2401.12784v1 |
2024-01-29 | HEQuant: Marrying Homomorphic Encryption and Quantization for Communication-Efficient Private Inference | Secure two-party computation with homomorphic encryption (HE) protects data
privacy with a formal security guarantee but suffers from high communication
overhead. While previous works, e.g., Cheetah, Iron, etc, have proposed
efficient HE-based protocols for different neural network (NN) operations, they
still assume hi... | 2401.15970v2 |
2024-01-30 | A New Database of Giant Impacts over a Wide Range of Masses and with Material Strength: A First Analysis of Outcomes | In the late stage of terrestrial planet formation, planets are predicted to
undergo pairwise collisions known as giant impacts. Here we present a
high-resolution database of giant impacts for differentiated colliding bodies
of iron-silicate composition, with target masses ranging from 10^-4 M_Earth up
to super-Earths (... | 2401.17356v1 |
2024-02-09 | Copper phosphate micro-flowers coated with indocyanine green and iron oxide nanoparticles for in vivo localization optoacoustic tomography and magnetic actuation | Efficient drug delivery is a major challenge in modern medicine and
pharmaceutical research. Micrometer-scale robots have recently been proposed as
a promising venue to amplify precision of drug administration. Remotely
controlled microrobots sufficiently small to navigate through microvascular
networks can reach any p... | 2402.06749v1 |
2024-03-24 | Rigorous ESR spectroscopy of $Fe^{3+}$ impurity ion with oxygen vacancy in ferroelectric $SrTiO_3$ crystal at 20 mK | Impurity $Fe^{3+}$ ion electron spin resonance (ESR) spectroscopy using
multiple dielectric modes in a $SrTiO_3$ dielectric resonator has been
performed with a tuneable DC magnetic field of up to $1.6~T$. The
$Ti^{4+}(d^0)$ ion is substituted by $Fe^{3+}$ ion forming $FeO_6$ octahedral
complex with an iron-oxygen-vacan... | 2403.16299v1 |
2024-03-29 | Synthesis and Characterization of Superparamagnetic Iron Oxide Nanoparticles: A Series of Laboratory Experiments | The following laboratory procedure provides students with a hands-on
experience in nanomaterials chemistry and characterization. This three-day
protocol is easy to follow for undergraduates with basic chemistry or materials
science backgrounds and is suitable for inclusion in upper division courses in
inorganic chemist... | 2403.19970v1 |
2024-04-10 | Microbial iron reduction under oxic conditions: implications for subsurface biogeochemistry | Iron (Fe) reduction is one of Earth's most ancient microbial metabolisms, but
after atmosphere-ocean oxygenation, this anaerobic process was relegated to
niche anoxic environments below the water and soil surface. However, new
technologies to monitor redox processes at the microscale relevant to microbial
cells have re... | 2404.07137v1 |
2021-06-15 | Measurement of the Iron Spectrum in Cosmic Rays from 10 GeV$/n$ to 2.0 TeV$/n$ with the Calorimetric Electron Telescope on the International Space Station | The Calorimetric Electron Telescope (CALET), in operation on the
International Space Station since 2015, collected a large sample of cosmic-ray
iron over a wide energy interval. In this Letter a measurement of the iron
spectrum is presented in the range of kinetic energy per nucleon from 10
GeV$/n$ to 2.0 TeV$/n$ allow... | 2106.08036v1 |
2023-04-13 | Probing magnetic ordering in air stable iron-rich van der Waals minerals | In the rapidly expanding field of two-dimensional materials, magnetic
monolayers show great promise for the future applications in nanoelectronics,
data storage, and sensing. The research in intrinsically magnetic
two-dimensional materials mainly focuses on synthetic iodide and telluride
based compounds, which inherent... | 2304.06533v1 |
2023-11-08 | A human brain atlas of chi-separation for normative iron and myelin distributions | Iron and myelin are primary susceptibility sources in the human brain. These
substances are essential for healthy brain, and their abnormalities are often
related to various neurological disorders. Recently, an advanced susceptibility
mapping technique, which is referred to as chi-separation, has been proposed,
success... | 2311.04468v3 |
1997-12-18 | ASCA detection of the FeK edge in the spectrum of the Seyfert 2 galaxy IRAS 04575-7537: a sign of a complex absorber | ASCA X-ray spectral analysis of the Seyfert 2 galaxy IRAS 04575-7537 is
presented. The main result is the presence of a significant iron edge at a rest
energy of 7.13^+0.21_-0.16 keV. The spectrum is flat (Gamma = 1.5) with a
substantial absorption Nh = 10^22 cm^-2 and does not require any reflection
component. There i... | 9712250v1 |
1999-07-13 | A Consistency Test of Spectroscopic Gravities for Late-Type Stars | Chemical analyses of late-type stars are usually carried out following the
classical recipe: LTE line formation and homogeneous, plane-parallel,
flux-constant, and LTE model atmospheres. We review different results in the
literature that have suggested significant inconsistencies in the spectroscopic
analyses, pointing... | 9907155v1 |
2000-01-07 | The variability of the Seyfert galaxy NGC 2992: the case for a revived AGN | We report the transition to an active state of the nucleus in the Seyfert 1.9
galaxy NGC 2992, discovered by means of new hard X-ray data. While the 2-10 keV
flux declined by a factor of ~ 20 from 1978 to 1994, two recent BeppoSAX
observations in 1997 and in 1998 caught the nuclear emission raising back to
the same lev... | 0001107v1 |
2000-08-31 | Variable Iron K-alpha Lines in Seyfert 1 Galaxies | We find that variability of the iron K-alpha line is common in Seyfert 1
galaxies. Using data from the ASCA archive for objects that have been observed
more than once during the mission, we study the time-averaged spectra from
individual observations, thereby probing variability on timescales that range
from days to ye... | 0008522v1 |
2000-09-13 | First Stellar Abundances in NGC 6822 from VLT-UVES and Keck-HIRES Spectroscopy | We have obtained the first high resolution spectra of individual stars in the
dwarf irregular galaxy, NGC 6822. The spectra of the two A-type supergiants
were obtained at the VLT and Keck Observatories, using UVES and HIRES,
respectively. A detailed model atmospheres analysis has been used to determine
their atmospheri... | 0009213v1 |
2000-10-17 | Estimation of relativistic accretion disk parameters from iron line emission | The observed iron K-alpha fluorescence lines in Seyfert-1 galaxies provide
strong evidence for an accretion disk near a supermassive black hole as a
source of the emission. Here we present an analysis of the geometrical and
kinematic properties of the disk based on the extreme frequency shifts of a
line profile as dete... | 0010318v1 |
2001-03-07 | Chandra observtaion of A2256 - a cluster at the early stage of merging | We present here \chandra observations of the rich cluster of galaxies A2256.
In addition to the known cool subcluster, a new structure was resolved 2$'$
east of the peak of the main cluster. Its position is roughtly at the center of
a low-brightness radio halo. Spectral analysis shows that the "shoulder" has
high iron ... | 0103103v2 |
2001-03-15 | Nucleosynthesis of Zinc and Iron-Peak Elements in Pop III Type II Supernovae : Comparison with abundances of Very Metal-Poor Halo Stars | We calculate nucleosynthesis in core-collapse explosions of massive Pop III
stars, and compare the results with abundances of metal-poor halo stars to
constrain the parameters of Pop III supernovae. We focus on iron-peak elements
and, in particular, we try to reproduce the large [Zn/Fe] observed in extremely
metal-poor... | 0103241v4 |
2001-04-10 | Partially Absorbed Comptonization Spectrum from the Nearly Edge-on Source X 1822-371 | We report the results of a spectral analysis over the range 0.1-200 keV
performed on the dipping source X 1822-371 observed by BeppoSAX. We find the
best fit to the continuum using a partially covered Comptonization model, due
to scattering off soft seed photons by electrons at a temperature of ~4.8 keV,
without the pr... | 0104171v2 |
2001-09-21 | A Chandra HETG Observation of the Quasar H 1821+643 and Its Surrounding Cluster | We present the high-resolution X-ray spectrum of the low-redshift quasar H
1821+643 and its surrounding hot cluster observed with the Chandra High Energy
Transmission Grating Spectrometer (HETGS). An iron emission line attributed to
the quasar at ~6.43 keV (rest frame) is clearly resolved, with an equivalent
width of ~... | 0109389v1 |
2003-02-21 | The iron $K_α$-line diagnostics of a rotational black hole metric | The original idea to show the spacetime geometry using few geodesics was
developed by Johnson and Ruffini (1974). We used this idea to interpret the
observational data for rotating BH's. We developed the imitation approach to
simulate a propagation of radiation near BH's. An important problem for this
approach is the d... | 0302454v1 |
2003-09-22 | The Effects of Binary Evolution on the Dynamics of Core Collapse and Neutron-Star Kicks | We systematically examine how the presence in a binary affects the final core
structure of a massive star and its consequences for the subsequent supernova
explosion. Interactions with a companion star may change the final rate of
rotation, the size of the helium core, the strength of carbon burning and the
final iron ... | 0309588v2 |
2003-09-25 | Close and distant reprocessing media in Mkn509 studied with BeppoSAX | We present the broad band analysis of two BeppoSAX observations of the Sy 1
Mkn509. In 2000 the source was in a typical flux state,
F{2-10keV}=2.7x10^{-11}erg cm^{-2} s^{-1}, while in 1998 it was found in a high
flux state, F{2-10keV}=5.7x10^{-11} erg cm^{-2} s^{-1}. A comparison between
the two states shows a energy-d... | 0309699v1 |
2003-10-20 | Chandra X-ray Observations of NGC 4258: Iron Absorption Lines from the Nucleus | We report sub-arcsecond resolution X-ray imaging spectroscopy of the low
luminosity active galactic nucleus of NGC 4258 and its immediate surroundings
with the Chandra X-ray Observatory. NGC 4258 was observed four times, with the
first two observations separated by one month, followed over a year later by
two consecuti... | 0310553v1 |
2004-07-22 | XMM-Newton observation of the Seyfert 1.8 ESO 113-G010: discovery of a highly redshifted iron line at 5.4 keV | We present a spectral analysis of the Seyfert 1.8 ESO 113-G010 observed with
XMM-Newton for 4 ks. The spectrum shows a soft excess below 0.7 keV and more
interestingly a narrow emission Gaussian line at 5.4 keV (in its rest-frame),
most probably originating from a redshifted iron Kalpha line. No significant
line at or ... | 0407472v2 |
2004-08-12 | The Li Overabundance of J37: Diffusion or Accretion? | In September 2002 the discovery of a super Li-rich F-dwarf (J37) in NGC 6633,
an iron poor analogue of the better studied Hyades and Praecepe open clusters,
was announced. This unique star was thought to be the smoking gun for the
action of diffusion, models of which predict a narrow "Li-peak" at
approximately the corr... | 0408223v1 |
2004-09-29 | Chemical Abundances for Seven Giant Stars in M68 (NGC 4590) : A Globular Cluster with Abnormal Silicon and Titanium Abundances | We present a detailed chemical abundance study of seven giant stars in M68
including six red giants and one post-AGB star. We find significant differences
in the gravities determined using photometry and those obtained from ionization
balance, which suggests that non-LTE effects are important for these
low-gravity, met... | 0409706v1 |
2005-04-14 | Three-dimensional modeling of Type Ia supernovae - The power of late time spectra | Late time synthetic spectra of Type Ia supernovae, based on three-dimensional
deflagration models, are presented. We mainly focus on one
model,"c3_3d_256_10s", for which the hydrodynamics (Roepke 2005) and
nucleosynthesis (Travaglio et al. 2004) was calculated up to the homologous
phase of the explosion. Other models w... | 0504317v1 |
2006-02-25 | Probing Multiple Sight Lines through the SN 1006 Remnant by UV Absorption Spectroscopy | Absorption-line spectroscopy is an effective probe for cold ejecta within an
SNR, provided that suitable background UV sources can be identified. For the SN
1006 remnant we have identified four such sources, in addition to the
much-studied Schweitzer-Middleditch (SM) star. We have used STIS on HST to
obtain UV spectra ... | 0602555v1 |
2006-05-15 | Accretion processes in AGN: The X-ray View | We discuss constraints on the physics of the inner accretion disk, as well as
the properties of the black hole itself, that can be derived by a detailed
examination of the relativistically broadened spectral features (especially the
fluorescent iron line) in the Seyfert galaxy MCG-6-30-15. To begin with, we
show that s... | 0605368v1 |
2006-11-09 | Medium resolution spectroscopy in Omega Centauri: abundances of 400 subgiant and turn-off region | Medium resolution spectra of more than 400 subgiant and turn-off region stars
in Omega Centauri were analysed. The observations were performed at the
VLT/Paranal with FORS2/MXU. In order to determine the metallicities of the
sample stars, we defined a set of line indices (mostly iron) adjusted to the
resolution of our ... | 0611286v1 |
2006-12-28 | Probing the Disk-jet Connection of the Radio Galaxy 3C120 Observed with Suzaku | Broad line radio galaxies (BLRGs) are a rare type of radio-loud AGN, in which
the broad optical permitted emission lines have been detected in addition to
the extended jet emission. Here we report on deep (40ksec x4) observations of
the bright BLRG 3C~120 using Suzaku. The observations were spaced a week apart,
and sam... | 0612754v1 |
2007-02-16 | Accretion of chemically fractionated material on a wide binary with a blue straggler | The components of the wide binary HIP64030=HD 113984 show a large (about 0.25
dex) iron content difference (Desidera et al.~2006 A&A 454, 581). The positions
of the components on the color magnitude diagram suggest that the primary is a
blue straggler. We studied the abundance difference of several elements besides
iro... | 0702439v1 |
2007-07-17 | Wide-band spectroscopy of the Compton thick Seyfert 2 galaxy Mrk 3 with Suzaku | We obtained a wide-band spectrum of the Compton-thick Seyfert 2 galaxy Mrk 3
with Suzaku. The observed spectrum was clearly resolved into weak, soft
power-law emission, a heavily absorbed power-law component, cold reflection,
and many emission lines. The heavily absorbed component, absorbed by gas with a
column density... | 0707.2425v1 |
2007-07-19 | Relativistic Iron K Emission and absorption in the Seyfert 1.9 galaxy MCG-5-23-16 | We present the results of the simultaneous deep XMM and Chandra observations
of the bright Seyfert 1.9 galaxy MCG-5-23-16, which is thought to have one of
the best known examples of a relativistically broadened iron K-alpha line. The
time averaged spectral analysis shows that the iron K-shell complex is best
modeled wi... | 0707.2950v1 |
2007-07-26 | Different Methods of Forming Cold Fronts in Non-Merging Clusters | Sharp edges in X-ray surface brightness with continuous gas pressure called
cold fronts have been often found in relaxed galaxy clusters such as Abell 496.
Models that explain cold fronts as surviving cores of head-on subcluster
mergers do not work well for these clusters and competing models involving gas
sloshing hav... | 0707.4001v1 |
2007-08-25 | Modeling the chemical evolution of Omega Centauri using three-dimensional hydrodynamical simulations | We present a hydrodynamical and chemical model for the globular cluster Omega
Cen, under the assumption that it is the remnant of an ancient dwarf spheroidal
galaxy (dSph), the bulk of which was disrupted and accreted by our Galaxy ~10
Gyr ago. We highlight the very different roles played by Type II and Type Ia
superno... | 0708.3445v1 |
2007-09-10 | Iron lines from transient and persisting hot spots on AGN accretion disks | [abridged] We model the X-ray reprocessing from a strong co-rotating flare
above an accretion disk in active galactic nuclei. We explore the horizontal
structure and evolution of the underlying hot spot. To obtain the spectral
evolution seen by a distant observer, we apply a general relativity ray-tracing
technique. We... | 0709.1356v1 |
2007-10-31 | The Proto-neutron Star Phase of the Collapsar Model and the Route to Long-soft Gamma-ray Bursts and Hypernovae | Recent stellar evolutionary calculations of low-metallicity massive
fast-rotating main-sequence stars yield iron cores at collapse endowed with
high angular momentum. It is thought that high angular momentum and black hole
formation are critical ingredients of the collapsar model of long-soft
gamma-ray bursts (GRBs). H... | 0710.5789v2 |
2008-02-14 | Complexity on Small Scales III: Iron and alpha Element Abundances in the Carina Dwarf Spheroidal Galaxy | We have obtained high-resolution spectroscopy of ten red giants in the Carina
dwarf spheroidal (dSph) with UVES at the ESO/VLT. Here we present the
abundances of O,Na,Mg,Si,Ca,Ti and Fe. By comparing the iron abundances [Fe/H]
with calcium triplet (CaT) metallicities we show that the empirical CaT
technique yields good... | 0802.2104v1 |
2008-03-04 | A large population of recently-quenched red-sequence dwarf galaxies in the outskirts of the Coma Cluster | We analyse the stellar populations of 75 red-sequence dwarf galaxies in the
Coma cluster, based on high signal-to-noise spectroscopy from the 6.5m MMT. The
sample covers a luminosity range 3-4 magnitudes below M*, in the cluster core
and in a field centred 1 deg to the south-west. We find a strong dependence of
the abs... | 0803.0327v1 |
2008-09-01 | Abundance profiles in cooling-core clusters: a fossil record of past AGN-driven convection? | Central peaks in the iron abundance of intracluster plasma are a common
feature of cooling-core galaxy clusters. These abundance peaks have a much
broader profile than the stars of the central brightest cluster galaxy (BCG),
which produce the excess iron, indicating that metal-enriched plasma is
transported out of the ... | 0809.0238v1 |
2008-11-04 | Influence of the rare-earth element on the effects of the structural and magnetic phase transitions in CeFeAsO, PrFeAsO, and NdFeAsO | We present results of transport and magnetic properties and heat capacity
measurements on polycrystalline CeFeAsO, PrFeAsO, and NdFeAsO. These materials
undergo structural phase transitions, spin density wave-like magnetic ordering
of small moments on iron, and antiferromagnetic ordering of rare earth moments.
The temp... | 0811.0589v3 |
2009-01-29 | A Galaxy Merger Scenario for the NGC 1550 Galaxy from Metal Distributions in the X-ray Emitting Plasma | The elliptical galaxy NGC 1550 at a redshift of $z=0.01239$, identified with
an extended X-ray source RX J0419+0225, was observed with {\it XMM-Newton} for
31 ks. From the X-ray data and archival near infra-red data of Two Micron All
Sky survay, we derive the profiles of components constituting the NGC 1550
system; the... | 0901.4626v1 |
2009-02-02 | Type-Ia Supernova-driven Galactic Bulge Wind | Stellar feedback in galactic bulges plays an essential role in shaping the
evolution of galaxies. To quantify this role and facilitate comparisons with
X-ray observations, we conduct 3D hydrodynamical simulations with the adaptive
mesh refinement code, FLASH, to investigate the physical properties of hot gas
inside a g... | 0902.0386v1 |
2009-02-10 | A Study of the Accuracy of Mass-Radius Relationships for Silicate-Rich and Ice-Rich Planets up to 100 Earth Masses | A mass-radius relationship is proposed for solid planets and solid cores
ranging from 1 to 100 Earth-mass planets. It relies on the assumption that
solid spheres are composed of iron and silicates, around which a variable
amount of water is added. The M-R law has been set up assuming that the
planetary composition is s... | 0902.1640v1 |
2009-02-20 | Frustrated Magnetic Interactions, Giant Magneto-Elastic Coupling, and Magnetic Phonons in Iron-Pnictides | We present a detailed first principles study of Fe-pnictides with particular
emphasis on competing magnetic interactions, structural phase transition, giant
magneto-elastic coupling and its effect on phonons. The exchange interactions
$J_{i,j}(R)$ are calculated up to $\approx 12 $\AA $. We find that $J_{i,j}(R)$
has a... | 0902.3462v1 |
2009-03-20 | Spectral Analysis of the Accretion Flow in NGC 1052 with Suzaku | We present an analysis of the 101 ks, 2007 Suzaku spectrum of the LINER
galaxy NGC 1052. The 0.5-10 keV continuum is well-modeled by a power-law
modified by Galactic and intrinsic absorption, and it exhibits a soft, thermal
emission component below 1 keV. Both a narrow core and a broader component of
Fe K emission cent... | 0903.3583v1 |
2009-04-06 | New insight into the physics of iron pnictides from optical and penetration depth data | We report theoretical values for the unscreened plasma frequencies Omega_p of
several Fe pnictides obtained from DFT based calculations within the LDA and
compare them with experimental plasma frequencies obtained from reflectivity
data. The sizable renormalization observed for all considered compounds points
to the pr... | 0904.0827v1 |
2009-04-07 | Search for associations containing young stars (SACY):II. Chemical abundances of stars in 11 young Associations in the Solar neighborhood | The recently discovered coeval, moving groups of young stellar objects in the
solar neighborhood represent invaluable laboratories to study recent star
formation and to search for high metallicity stars which can be included in
future exo-planet surveys. In this study we derived through an uniform and
homogeneous metho... | 0904.1221v1 |
2009-06-17 | On the metallicity gradient of the Galactic disk | Aims: The iron abundance gradient in the Galactic stellar disk provides
fundamental constraints on the chemical evolution of this important Galaxy
component. However the spread around the mean slope is, at fixed Galactocentric
distance, larger than estimated uncertainties. Methods: To provide quantitative
constraints o... | 0906.3140v1 |
2009-10-09 | Critical change in the Fermi surface of iron arsenic superconductors at the onset of superconductivity | The phase diagram of a correlated material is the result of a complex
interplay between several degrees of freedom, providing a map of the material's
behavior. One can understand (and ultimately control) the material's ground
state by associating features and regions of the phase diagram, with specific
physical events ... | 0910.1799v2 |
2009-11-06 | Accurate Fundamental Parameters or A, F, and G-type Supergiants in the Solar Neighbourhood | The following parameters are determined for 63 Galactic supergiants in the
solar neighbourhood: effective temperature Teff, surface gravity log g, iron
abundance log e(Fe), microturbulent parameter Vt, mass M/Msun, age t and
distance d. A significant improvement in the accuracy of the determination of
log g and, all pa... | 0911.1335v2 |
2009-12-09 | Empirically Derived Integrated Stellar Yields of Fe-Peak Elements | We present here the initial results of a new study of massive star yields of
Fe-peak elements. We have compiled from the literature a database of carefully
determined solar neighborhood stellar abundances of seven iron-peak elements,
Ti, V, Cr, Mn, Fe, Co, and Ni and then plotted [X/Fe] versus [Fe/H] to study
the trend... | 0912.1816v1 |
2010-01-03 | Suzaku Monitoring of the Iron K Emission Line in the Type 1 AGN NGC 5548 | We present 7 sequential weekly observations of NGC 5548 conducted in 2007
with the \textit{Suzaku} X-ray Imaging Spectrometer (XIS) in the 0.2-12 keV
band and Hard X-ray Detector (HXD) in 10-600 keV band. The iron K$\alpha$ line
is well detected in all seven observations and K$\beta$ line is also detected
in four obser... | 1001.0356v1 |
2010-01-07 | Supernova 2007bi as a pair-instability explosion | Stars with initial masses 10 M_{solar} < M_{initial} < 100 M_{solar} fuse
progressively heavier elements in their centres, up to inert iron. The core
then gravitationally collapses to a neutron star or a black hole, leading to an
explosion -- an iron-core-collapse supernova (SN). In contrast, extremely
massive stars (M... | 1001.1156v1 |
2010-03-29 | Ferromagnetism in defect-ridden oxides and related materials | The existence of high-temperature ferromagnetism in thin films and
nanoparticles of oxides containing small quantities of magnetic dopants remains
controversial. Some regard these materials as dilute magnetic semiconductors,
while others think they are ferromagnetic only because the magnetic dopants
form secondary ferr... | 1003.5558v1 |
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