ShantanuT01/DACTYL-Pretraining huggingface dataset:
HDE228766 is a very massive binary system hosting a secondary component, which is probably in an intermediate evolutionary stage between an Of supergiant and an WN star. The wind of this star collides with the wind of its O8 II companion, leading to relatively strong X-ray emission. Measuring the orbital variations of the line-of-sight absorption toward the X-ray emission from the wind-wind interaction zone yields information on the wind densities of both stars. X-ray spectra have been collected at three key orbital phases to probe the winds of both stars. Optical photometry has been gathered to set constraints on the orbital inclination of the system. The X-ray spectra reveal prominent variations of the intervening column density toward the X-ray emission zone, which are in line with the expectations for a wind-wind collision. We use a toy model to set constraints on the stellar wind parameters by attempting to reproduce the observed variations of the relative fluxes and wind optical depths at 1 keV. The lack of strong optical eclipses sets an upper limit of about 68 degrees on the orbital inclination. The analysis of the variations of the X-ray spectra suggests an inclination in the range 54 - 61 degrees and indicates that the secondary wind momentum ratio exceeds that of the primary by at least a factor 5. Our models further suggest that the bulk of the X-ray emission arises from the innermost region of the wind interaction zone, which is from a region whose outer radius, as measured from the secondary star, lies between 0.5 and 1.5 times the orbital separation.
Upcoming radio telescopes will allow to study the radio sky at low frequencies with unprecedent sensitivity and resolution. New surveys are expected to discover a large number of new radio sources. Here we investigate the abundance of radio relics, i.e. steep-spectrum diffuse radio emission coming from the periphery of galaxy clusters, which are believed to trace shock waves induced by cluster mergers. With the advent of comprehensive relic samples a framework is needed to analyze statistically the relic abundance. To this end, we introduce the probability to find a relic located in a galaxy cluster with given mass and redshift allowing us to relate the halo mass function of the Universe with the radio relic number counts. Up to date about 45 relics have been reported and we compile the resulting counts, N(>S_1.4). In principle, the parameters of the distribution could be determined using a sufficiently large relic sample. However, since the number of known relics is still small for that purpose we use the MareNostrum Universe simulation to determine the relic radio power scaling with cluster mass and redshift. Our model is able to reproduce the recently found tentative evidence for an increase in the fraction of clusters hosting relics, both with X-ray luminosity and redshift, using an X-ray flux limited cluster sample. Moreover, we find that a considerable fraction of faint relics (S_1.4 < ~10 mJy) reside in clusters with an X-ray flux below ~3e-12 erg/s/cm^2. Finally, we estimate the number of radio relics which await discovery by future low frequency surveys proposed for LOFAR and WSRT. We estimate that the WODAN survey proposed for WSRT may discover 900 relics and that the LOFAR-Tier 1-120 MHz survey may discover about 2500 relics. However, the actual number of newly discovered relics will crucially depend on the existence of sufficiently complete galaxy cluster catalogues.
The Bogoliubov model for weakly interacting Bose gas is extended to Bose-Einstein condensation (BEC) of spin-S atoms in a magnetic field. Equation for the vectorial order parameter valid at temperature $T\to 0$ is derived and its particular solution is found. This solution corresponds to the formation of BEC of atoms with a definite spin projection onto direction of a magnetic field. We study the thermodynamic stability of the found solution and obtain the expressions for low-lying collective modes.
The large, so-called colossal, magnetoresistivity of doped manganese oxides based on LaMnO3 has attracted considerable attention, but only one unusual feature of the ferromagnetic transition in these compounds. We examine in this paper the progression of magnetic and thermodynamic behavior as the transition temperature is made to vary from 360 K to 218 K by changing the divalent dopant. Single crystals of La_{0.7}Sr_{0.3}MnO3, as is well known, show modest magnetoresistivity and conventional critical behavior. La$_{0.7}$Pb$_{0.3}$ Mn$O_3$, and to an even greater extent, La$_{0.7}$Ca$_{0.3}$MnO$_3$, have unusual magnetic properties extending more than 100 K above the transition. We treat the properties of the latter samples in the context of a Griffiths phase in which the transition temperature is depressed from its maximum value T_{G} by random bond-angle bending.
The diffuse ionized gas (DIG) is an important component of the interstellar medium that can provide insights into the different physical processes affecting the gas in galaxies. We utilise optical IFU observations of 71 gas-stripped and control galaxies from the Gas Stripping Phenomena in galaxies (GASP) survey, to analyze the gas properties of the dense ionized gas and the DIG, such as metallicity, ionization parameter log(q), and the difference between the measured $\log[OI]/H\alpha$ and the value predicted by star-forming models, given the measured log[OIII]/H$\beta$ ($\Delta log[OI]/H\alpha$). We compare these properties at different spatial scales, among galaxies at different gas-stripping stages, and between disks and tails of the stripped galaxies. The metallicity is similar between the dense gas and DIG at a given galactocentric radius. The log(q) is lower for DIG compared to dense gas. The median values of log(q) correlate best with stellar mass, and the most massive galaxies show an increase in log(q) toward their galactic centers. The DIG clearly shows higher $\Delta log[OI]/H\alpha$ values compared to the dense gas, with much of the spaxels having LIER/LINER like emission. The DIG regions in the tails of highly stripped galaxies show the highest $\Delta log[OI]/H\alpha$, exhibit high values of log(q) and extend to large projected distances from star-forming areas (up to 10 kpc). We conclude that the DIG in the tails is at least partly ionized by a process other than star-formation, probably by mixing, shocks and accretion of inter-cluster and interstellar medium gas.
Mildly relativistic, oblique shocks are frequently invoked as possible sites of relativistic particle acceleration and production of strongly variable, polarized multi-wavelength emission from relativistic jet sources such as blazars, via diffusive shock acceleration (DSA). In recent work, we had self-consistently coupled DSA and radiation transfer simulations in blazar jets. These one-zone models determined that the observed spectral energy distributions (SEDs) of blazars strongly constrain the nature of the hydromagnetic turbulence responsible for pitch-angle scattering. In this paper, we expand our previous work by including full time dependence and treating two emission zones, one being the site of acceleration. This modeling is applied to a multiwavelength flare of the flat spectrum radio quasar 3C~279, fitting snap-shot SEDs and light curves. We predict spectral hysteresis patterns in various energy bands as well as cross-band time lags with optical and GeV gamma-rays as well as radio and X-rays tracing each other closely with zero time lag, but radio and X-rays lagging behind the optical and gamma-ray variability by several hours.
We define a metric theory of gravity with preferred Newtonian frame (X^i(x),T(x)) by   L = L_{GR}   + \Xi g^{mn}\delta_{ij}X^i_{,m}X^j_{,n}   - \Upsilon g^{mn}T_{,m}T_{,n}   It allows a condensed matter interpretation which generalizes LET to gravity.   The \Xi-term influences the age of the universe. \Upsilon>0 allows to avoid big bang singularity and black hole horizon formation. This solves the horizon problem without inflation. An atomic hypothesis solves the ultraviolet problem by explicit regularization. We give a prediction about cutoff length.
In this paper, we investigate the Chinese calligraphy synthesis problem: synthesizing Chinese calligraphy images with specified style from standard font(eg. Hei font) images (Fig. 1(a)). Recent works mostly follow the stroke extraction and assemble pipeline which is complex in the process and limited by the effect of stroke extraction. We treat the calligraphy synthesis problem as an image-to-image translation problem and propose a deep neural network based model which can generate calligraphy images from standard font images directly. Besides, we also construct a large scale benchmark that contains various styles for Chinese calligraphy synthesis. We evaluate our method as well as some baseline methods on the proposed dataset, and the experimental results demonstrate the effectiveness of our proposed model.
We present a new algorithm for the reduction of one-loop tensor Feynman integrals within the framework of the XLOOPS project, covering both mathematical and programming aspects. The new algorithm supplies a clean way to reduce the one-loop one-, two- and three-point Feynman integrals with arbitrary tensor rank and powers of the propagators to a basis of simple integrals. We also present a new method of coding XLOOPS in C++ using the GiNaC library.
We use a set of high-resolution cosmological N-body simulations to investigate the inner mass profile of galaxy-sized cold dark matter (CDM) halos. These simulations extend the thorough numerical convergence study presented in Paper I of this series (Power et al. 2003), and demonstrate that the mass profile of CDM halos can be robustly estimated beyond a minimum converged radius of order r_conv ~ 1 kpc/h in our highest resolution runs. The density profiles of simulated halos become progressively shallow from the virial radius inwards, and show no sign of approaching a well-defined power-law behaviour near the centre. At r_conv, the logarithmic slope of the density profile is steeper than the asymptotic \rho \propto r^-1 expected from the formula proposed by Navarro, Frenk, and White (1996), but significantly shallower than the steeply divergent \rho \propto r^-1.5 cusp proposed by Moore et al. (1999). We perform a direct comparison of the spherically-averaged dark matter circular velocity (V_c) profiles with rotation curves of low surface brightness (LSB) galaxies from the samples of de Blok et al. (2001), de Blok and Bosma (2002), and Swaters et al. (2003). Most (about two-thirds) LSB galaxies in this dataset are roughly consistent with CDM halo V_c profiles. However, about one third of LSBs in these samples feature a sharp transition between the rising and flat part of the rotation curve that is not seen in the V_c profiles of CDM halos. This discrepancy has been interpreted as excluding the presence of cusps, but we argue that it might simply reflect the difference between circular velocity and gas rotation speed likely to arise in gaseous disks embedded within realistic, triaxial CDM halos.
We study non-uniform states and possible glassiness triggered by a competition between distinct local orders in disorder free systems. Both in Ginzburg-Landau theories and in simple field theories, such inhomogeneous states arise from negative gradient terms between the competing order parameters. We discuss applications of these ideas to a variety of strongly correlated systems.
Recent instrumentation has demonstrated that the solar atmosphere supports omnipresent transverse waves, which could play a key role in energizing the solar corona. Large-scale studies are required in order to build up an understanding of the general properties of these transverse waves. To help facilitate this, we present an automated algorithm for identifying and tracking features in solar images and extracting the wave properties of any observed transverse oscillations. We test and calibrate our algorithm using a set of synthetic data which includes noise and rotational effects. The results indicate an accuracy of 1-2% for displacement amplitudes and 4-10% for wave periods and velocity amplitudes. We also apply the algorithm to data from the Atmospheric Imaging Assembly (AIA) on board the $\textit{Solar Dynamics Observatory}$ (SDO) and find good agreement with previous studies. Of note, we find that 35-41% of the observed plumes exhibit multiple wave signatures, which indicates either the superposition of waves or multiple independent wave packets observed at different times within a single structure. The automated methods described in this paper represent a significant improvement on the speed and quality of direct measurements of transverse waves within the solar atmosphere. This algorithm unlocks a wide range of statistical studies that were previously impractical.
The observation of lepton flavor violation indicates new physics beyond the Standard Model. Lepton colliders are ideal facilities to probe charged lepton flavor violation (CLFV) signals induced by new physics at high energy. In this work we perform a comprehensive study of the sensitivity of future lepton colliders to charged lepton flavor violation. We consider the most general renormalizable Lagrangian coupling two leptons to new bosonic particles, involving both $\Delta L=0$ and $\Delta L=2$ interactions. The CLFV processes are introduced by the exchange of off-shell new particles at tree-level. We find that CEPC, ILC, FCC-ee, and CLIC each provide a complementary probe of CLFV couplings to low-energy precision experiments for $\tau$ lepton(s) in final states, while low-energy precision experiments are more sensitive in the absence of $\tau$ leptons.
Emerging of free (or quantum Boltzmann) statistics for a model of quantum particle interacting with quantum field is described in the stochastic limit without dipole approximation. The quantum field is considered in a Gaussian (for example temperature) state. Entangled operators which describe interaction of the field and the particle satisfy the q-deformed relations which in the stochastic limit generate free statistics.
Investigation on the object reported by SIMBAD database as V683 Cas shows that this variable star corresponds to the eclipsing binary system GSC 03699-00091 (also identified as NSVS 1850718). The results of the photometric observations of the stars nearby to the position indicated for V683 Cas are reported.
Vertically oriented materials, such as van der Waals heterostructures, that have novel hybrid properties are crucial for fundamental scientific research and the design of new nano-devices. Currently, most available theoretical methods require applying a supercell approach with periodic boundary conditions to explore the electronic properties of such nanomaterials. Herein, we present supercell-core software, which provides a way to determine the supercell of non-commensurate lattices, in particular, van der Waals heterostructures. Although this approach is very common, most of the reported work still uses supercells that are constructed 'by hand' and on a temporary basis. The developed software is designed to facilitate finding and constructing optimised supercells (i.e., with small size and minimal strain accumulation in adjacent layers) of vertically stacked lattices.
The complex structure of gas, metals, and dust in the interstellar and circumgalactic medium (ISM and CGM, respectively) in star-forming galaxies can be probed by Ly$\alpha$ emission and absorption, low-ionization interstellar (LIS) metal absorption, and dust reddening E(B-V). We present a statistical analysis of the mutual correlations among Ly$\alpha$ equivalent width (EW$_{Ly\alpha}$), LIS equivalent width (EW$_{LIS}$), and E(B-V) in a sample of 157 star-forming galaxies at $z\sim2.3$. With measurements obtained from individual, deep rest-UV spectra and spectral-energy distribution (SED) modeling, we find that the tightest correlation exists between EW$_{LIS}$ and E(B-V), although correlations among all three parameters are statistically significant. These results signal a direct connection between dust and metal-enriched HI gas, and that they are likely co-spatial. By comparing our results with the predictions of different ISM/CGM models, we favor a dusty ISM/CGM model where dust resides in HI gas clumps and Ly$\alpha$ photons escape through the low HI covering fraction/column density intra-clump medium. Finally, we investigate the factors that potentially contribute to the intrinsic scatter in the correlations studied in this work, including metallicity, outflow kinematics, Ly$\alpha$ production efficiency, and slit loss. Specifically, we find evidence that scatter in the relationship between EW$_{Ly\alpha}$ and E(B-V) reflects the variation in metal-to-HI covering fraction ratio as a function of metallicity, and the effects of outflows on the porosity of the ISM/CGM. Future simulations incorporating star-formation feedback and the radiative transfer of Ly$\alpha$ photons will provide key constraints on the spatial distributions of neutral hydrogen gas and dust in the ISM/CGM structure.
Let $C$ be a genus 2 curve and $\su$ the moduli space of semi-stable rank 2 vector bundles on $C$ with trivial determinant. In \cite{bol:wed} we described the parameter space of non stable extension classes (invariant with respect to the hyperelliptic involution) of the canonical sheaf $\omega$ of $C$ with $\omega_C^{-1}$. In this paper we study the classifying rational map $\phi: \pr Ext^1(\omega,\omega^{-1})\cong \pr^4 \dashrightarrow \su\cong \pr^3$ that sends an extension class on the corresponding rank two vector bundle. Moreover we prove that, if we blow up $\pr^4$ along a certain cubic surface $S$ and $\su$ at the point $p$ corresponding to the bundle $\OO \oplus \OO$, then the induced morphism $\tilde{\phi}: Bl_S \ra Bl_p\su$ defines a conic bundle that degenerates on the blow up (at $p$) of the Kummer surface naturally contained in $\su$. Furthermore we construct the $\pr^2$-bundle that contains the conic bundle and we discuss the stability and deformations of one of its components.
In the framework of Anisotropic Chromo Dynamics, a non-perturbative model of QCD based on magnetic condensation in the vacuum, we develope a picture of the Pomeron. Within this model we are able to calculate the diffractive contribution to deep inelastic scattering in the small Bjorken x region, actually probed at Hera. We calculate the diffractive structure function of the proton and make the comparison with the experimental data of Zeus and H1 collaborations. Good agreement with the experimental data, both for the diffractive structure function $F_2^D$ and for the ''structure function'' of the Pomeron, is achieved.
We find an algorithm of numerical renormalization group for spin chain models. The essence of this algorithm is orthogonal transformation of basis states, which is useful for reducing the number of relevant basis states to create effective Hamiltonian. We define two types of rotations and combine them to create appropriate orthogonal transformation.
Absorption spectra of closed-shell Na_2, Na_3+, Na_4, Na_5+, Na_6, Na_7+, and Na_8 clusters are calculated using a recently implemented conserving linear response method. In the framework of a quasiparticle approach, we determine electron-hole correlations in the presence of an external field. The calculated results are in excellent agreement with experimental spectra, and some possible cluster geometries that occur in experiments are analyzed. The position and the broadening of the resonances in the spectra arise from a consistent treatment of the scattering and dephasing contributions in the linear response calculation. Comparison between the experimental and the theoretical results yields information about the cluster geometry, which is not accessible experimentally.
Combining the latest Planck, Wilkinson Microwave Anisotropy Probe (WMAP), and baryon acoustic oscillation (BAO) data, we exploit the recent cosmic microwave background (CMB) B-mode power spectra data released by the BICEP2 collaboration to constrain the cosmological parameters of the $\Lambda$CDM model, esp. the primordial power spectra parameters of the scalar and the tensor modes, $n_s,\alpha_s, r, n_t$. We obtained constraints on the parameters for a lensed $\Lambda$CDM model using the Markov Chain Monte Carlo (MCMC) technique, the marginalized $68\%$ bounds are $r = 0.1043\pm_{0.0914}^{0.0307}$, $n_s = 0.9617\pm_{0.0061}^{ 0.0061}$, $\alpha_s = -0.0175\pm_{0.0097}^{0.0105}$, $n_t = 0.5198\pm_{0.4579}^{0.4515}$. We found that a blue tilt for $n_t$ is favored slightly, but it is still well consistent with flat or even red tilt. Our $r$ value is slightly smaller than the one obtained by the BICEP team, as we allow $n_t$ as a free parameter without imposing the single-field slow roll inflation consistency relation. If we impose this relation, $r=0.2130\pm_{0.0609}^{0.0446}$. For most other parameters, the best fit values and measurement errors are not altered much by the introduction of the BICEP2 data.
The propagating intensity disturbances (PIDs) in plumes are still poorly understood and their identity (magnetoacoustic waves or flows) remains an open question. We investigate PIDs in five plumes located in the northern polar coronal hole observed during the 2017 total solar eclipse. Three plumes are associated with coronal bright points, jets and macrospicules at their base (active plumes) and the other two plumes are not (quiet plumes). The electron temperature at the base of the plumes is obtained from the filter ratio of images taken with the X-ray Telescope on board Hinode and the passband ratio around 400 nm from an eclipse instrument, the Diagnostic Coronagraph Experiment (DICE). The phase speed (v_r), frequency (omega), and wavenumber (k) of the PIDs in the plumes are obtained by applying a Fourier transformation to the space-time (r-t plane) plots in images taken with the Atmospheric Imaging Assembly (AIA) in three different wavelength channels (171 A, 193 A, and 211 A). We found that the PIDs in the higher temperature AIA channels, 193 and 211 A, are faster than that of the cooler AIA 171 A channel. This tendency is more significant for the active plumes than the quiet ones. The observed speed ratio (~1.3) between the AIA 171 and 193 A channels is similar to the theoretical value (1.25) of a slow magnetoacoustic wave. Our results support the idea that PIDs in plumes represent a superposition of slow magnetoacoustic waves and plasma outflows that consist of dense cool flows and hot coronal jets.
We discuss the question of the relevance of perturbative QCD calculations for analyzing the properties of the dense medium produced in heavy ion collisions. Up to now leading order perturbative estimates have been worked out and confronted with data for quenched large $p_{\perp}$ hadron spectra. Some of them are giving paradoxical results, contradicting the perturbative framework and leading to speculations such as the formation of a strongly interacting quark-gluon plasma. Trying to bypass some drawbacks of these leading order analysis and without performing detailed numerical investigations, we collect evidence in favour of a consistent description of quenching and of the characteristics of the produced medium within the pQCD framework.
This note deals with existence and uniqueness of (variational) solutions to the following type of stochastic partial differential equations on a Hilbert space H dX(t) = A(t,X(t))dt + B(t,X(t))dW(t) + h(t) dG(t) where A and B are random nonlinear operators satisfying monotonicity conditions and G is an infinite dimensional Gaussian process adapted to the same filtration as the cylindrical Wiener pocess W(t), t >= 0.