ShantanuT01/DACTYL-Pretraining huggingface dataset:
We present the AGILE-GRID monitoring of Cygnus X-3, during the period between November 2007 and July 2009. We report here the whole AGILE-GRID monitoring of Cygnus X-3 in the AGILE "pointing" mode data-taking, to confirm that the gamma-ray activity coincides with the same repetitive pattern of multiwavelength emission and to analyze in depth the overall gamma-ray spectrum by assuming both leptonic and hadronic scenarios. Seven intense gamma-ray events were detected in this period, with a typical event lasting one or two days. These durations are longer than the likely cooling times of the gamma-ray emitting particles, implying we see continuous acceleration rather than the result of an impulsive event such as the ejection of a single plasmoid which then cools as it propagates outwards. Cross-correlating the AGILE-GRID light curve with X-ray and radio monitoring data, we find that the main events of gamma-ray activity have been detected while the system was in soft spectral X-ray states (RXTE/ASM count rate > 3 counts/s), that coincide with local and often sharp minima of the hard X-ray flux (Swift/BAT count rate < 0.02 counts/cm^2/s), a few days before intense radio outbursts. [...] These gamma-ray events may thus reflect a sharp transition in the structure of the accretion disk and its corona, which leads to a rebirth of the microquasar jet and subsequent enhanced radio activity. [...] Finally, we examine leptonic and hadronic emission models for the gamma-ray events and find that both scenarios are valid. In the leptonic model - based on inverse Compton scatterings of mildly relativistic electrons on soft photons from the Wolf-Rayet companion star and from the accretion disk - the emitting particles may also contribute to the overall hard X-ray spectrum, possibly explaining the hard non-thermal power-law tail sometimes seen during special soft X-ray states in Cygnus X-3.
This study is based on the use of the new ExoMol TiO rovibronic line lists to identify and model TiO isotopologue features in spectra of M-dwarfs.   We aim to investigate problems involving the computation of electronic bands for different isotopologues of TiO by modelling optical spectra of late-type stars and to determine their Ti isotopic abundances, to compare the TiO isotopologues spectra computed using line lists by different authors.   We fit theoretical synthetic spectra to the observed stellar molecular bands of TiO. We model spectra of two M-dwarfs: GJ 15A (M1V) and GJ 15B (M3 V) to determine Ti isotopic ratios in their atmospheres.   We demonstrate the accuracy of the ExoMol {\sc Toto} line list for differentisotopologues of TiO and the possibility of determining accurate Ti isotope abundances in a numberof spectral ranges. The 7580--7594 \AA\ spectral range seems particularly useful, with two atomic linesof Fe I and molecular band heads of $^{50}Ti$O, $^{49}Ti$O, $^{48}Ti$O, $^{47}Ti$O clearly observable in our two M-dwarf spectra. We determine non-solar Ti isotopic ratios of $^{46}Ti$ : $^{47}Ti$ : $^{48}Ti$ : $^{49}Ti$ : $^{50}Ti$ = 7.9 : 5.2 : 72.8 : 7.9 :6.2 for GJ 15A and 7.4 : 4.2 : 76.6 : 5.8 : 6.0 for GJ 15B with accuracy of order $\pm$ 0.2. [Ti] = 0.040 and 0.199 within accuracy $\pm$ 0.10 were also determined for GJ 15A and GJ 15B, respectively.   We find that the ExoMol {\sc Toto} TiO line list: a) describes the fine details in line position and intensities of the M-dwarf spectra better than other available TiO line lists; b) correctly reproduces the positions and intensities of the TiO isotopologue band heads observed in M-dwarf spectra; c) can be used to determine Ti isotope abundances in atmospheres of M-stars.
Cosmic rays physics is currently being studied with rather sophisticated detectors running in a variety of experimental conditions and atmospheric depths around the world. In this paper we describe the reasons why cosmic ray physics experiments at high altitudes like Chacaltaya are so important for resolving some of the open problems in cosmic physics. A discussion on the future prospects of the high altitude mountain laboratories such as Chacaltaya for cosmic ray physics is presented.
In the manuscript, the properties of the proposed intermediate BLR are checked for the mapped AGN PG 0052+251. With the considerations of the apparent effects of the broad He {\sc ii} line on the observed broad H$\beta$ profile, the line parameters (especially the line width and the line flux) of the observed broad H$\alpha$ and the broad H$\beta$ are carefully determined. Based on the measured line parameters, the model with two broad components applied for each observed broad balmer line is preferred, and then confirmed by the calculated much different time lags for the inner/intermediate broad components and the corresponding virial BH masses ratio determined by the properties of the inner and the intermediate broad components. Then, the correlation between the broad line width and the broad line flux is checked for the two broad components: one clearly strong negative correlation for the inner broad component, but one positive correlation for the intermediate broad component. The different correlations for the two broad components strongly support the intermediate BLR of PG0052+251.
A semi-microscopic approach, based on the continuum-random-phase Approximation (CRPA) method, is applied to describe the main properties (strength function, transition density, direct-nucleon-decay branching ratios) of the overtone of the isoscalar giant monopole resonance. Results of the calculation are presented for 208Pb in comparison with those obtained for the isoscalar monopole and dipole giant resonances within the same approach.
We present an exact diagonalization study of the half-filled Hubbard model on bipartite quasi-one-dimensional lattices. In particular, we emphasize the dependence of the ferrimagnetic ground state properties, and its associated magnetic excitations, on the Coulomb repulsion U.
Recently a {\it local} true (completely gauge fixed) Hamiltonian for spherically symmetric collapse was derived in terms of Ashtekar variables. We show that such a local Hamiltonian follows directly from the geometrodynamics of gravity theories that obey a Birkhoff theorem and possess a mass function that is constant on the constraint surface in vacuum. In addition to clarifying the geometrical content, our approach has the advantage that it can be directly applied to a large class of spherically symmetric and 2D gravity theories, including $p$-th order Lovelock gravity in D dimensions. The resulting expression for the true local Hamiltonian is universal and remarkably simple in form.
Engineering a strongly interacting uniform qubit cluster would be a major step towards realizing a scalable quantum system for quantum sensing, and a node-based qubit register. For a solid-state system that uses a defect as a qubit, various methods to precisely position defects have been developed, yet the large-scale fabrication of qubits within the strong coupling regime at room temperature continues to be a challenge. In this work, we generate nitrogen vacancy (NV) color centers in diamond with sub-10 nm scale precision by using a combination of nanoscale aperture arrays (NAAs) with a high aspect ratio of 10 and a secondary E-beam hole pattern used as an ion-blocking mask. We perform optical and spin measurements on a small cluster of NV spins and statistically investigate the effect of the NAAs during an ion-implantation process. We discuss how this technique is effective for constructing a scalable system.
A graph is called normal if its vertex set can be covered by cliques and also by stable sets, such that every such clique and stable set have non-empty intersection. This notion is due to Korner, who introduced the class of normal graphs as an extension of the class of perfect graphs. Normality has also relevance in information theory. Here we prove, that the line graphs of cubic graphs are normal.
We generalize the surface growth model of Gates and Westcott to arbitrary inclination. The exact steady growth velocity is of saddle type with principal curvatures of opposite sign. According to Wolf this implies logarithmic height correlations, which we prove by mapping the steady state of the surface to world lines of free fermions with chiral boundary conditions.
Our goal in this paper is to investigate properties of 3D shape that can be determined from a single image. We define 3D shape attributes -- generic properties of the shape that capture curvature, contact and occupied space. Our first objective is to infer these 3D shape attributes from a single image. A second objective is to infer a 3D shape embedding -- a low dimensional vector representing the 3D shape.   We study how the 3D shape attributes and embedding can be obtained from a single image by training a Convolutional Neural Network (CNN) for this task. We start with synthetic images so that the contribution of various cues and nuisance parameters can be controlled. We then turn to real images and introduce a large scale image dataset of sculptures containing 143K images covering 2197 works from 242 artists.   For the CNN trained on the sculpture dataset we show the following: (i) which regions of the imaged sculpture are used by the CNN to infer the 3D shape attributes; (ii) that the shape embedding can be used to match previously unseen sculptures largely independent of viewpoint; and (iii) that the 3D attributes generalize to images of other (non-sculpture) object classes.
We present a microscopic index formula for the degeneracy of dyons in four-dimensional N=4 string theory. This counting formula is manifestly symmetric under the duality group, and its asymptotic growth reproduces the macroscopic Bekenstein-Hawking entropy. We give a derivation of this result in terms of the type II five-brane compactified on K3, by assuming that its fluctuations are described by a closed string theory on its world-volume. We find that the degeneracies are given in terms of the denominator of a generalized super Kac-Moody algebra. We also discuss the correspondence of this result with the counting of D-brane states.
Ideal Sharvin contact in a multimode regime shows the conductance $G\approx{}G_{\rm Sharvin}=g_0k_F{}W/\pi$ (with $g_0$ the conductance quantum, $k_F$ the Fermi momentum, and $W$ the contact width) accompanied by strongly suppressed shot-noise quantified by small Fano factor $F\approx{}0$. For ballistic graphene away from the charge-neutrality point the sub-Sharvin transport occurs, characterised by suppressed conductance $G\approx{}(\pi/4)\,G_{\rm Sharvin}$ and enhanced shot noise $F\approx{}1/8$. All these results can be derived from a basic model of quantum scattering, involving assumptions of infinite height and perfectly rectangular shape of the potential barrier in the sample. Here we have carried out the numerical analysis of the scattering on a family of smooth barriers of finite height interpolating between parabollic and rectangular shapes. We find that tuning the barrier shape one can modify the asymmetry between electron- and hole-doped systems. For electronic dopings, the system crosses from Sharvin to sub-Sharvin transport regime (indicated by both the conductance and the Fano factor) as the potential becomes closer to the rectangular shape. In contrast, for hole dopings, the conductivity is strongly suppressed when the barrier is parabolic and slowly converges to $G\approx{}(\pi/4)\,G_{\rm Sharvin}$ as the potential evolves towards rectangular shape. In such a case the Sharvin transport regime is inaccessible, shot noise is generically enhanced (with much slower convergence to $F\approx{}1/8$) comparing to the electron-doped case, and aperiodic oscillations of both $G$ and $F$ are prominent due to the formation of quasibound states.
Mixed moving average processes appear in the ergodic decomposition of stationary symmetric \alpha-stable (S\alpha S) processes. They correspond to the dissipative part of "deterministic" flows generating S\alpha S processes (Rosinski, 1995). Along these lines we study stationary increment and self-similar S\alpha S processes. Since the classes of stationary increment and self-similar processes can be embedded into the class of stationary processes by the Masani and Lamperti transformations, respectively, we characterize these classes of S\alpha S processes in terms of nonsingular flows and the related cocycles. We illustrate this approach considering various examples of self-similar mixed moving average S\alpha S processes introduced in (Surgailis, Rosinski, Mandrekar and Cambanis, 1992).
We present the VST Optical Imaging of the CDFS and ES1 Fields (VOICE) Survey, a VST INAF Guaranteed Time program designed to provide optical coverage of two 4 deg$^2$ cosmic windows in the Southern hemisphere. VOICE provides the first, multi-band deep optical imaging of these sky regions, thus complementing and enhancing the rich legacy of longer-wavelength surveys with VISTA, Spitzer, Herschel and ATCA available in these areas and paving the way for upcoming observations with facilities such as the LSST, MeerKAT and the SKA. VOICE exploits VST's OmegaCAM optical imaging capabilities and completes the reduction of WFI data available within the ES1 fields as part of the ESO-Spitzer Imaging Extragalactic Survey (ESIS) program providing $ugri$ and $uBVR$ coverage of 4 and 4 deg$^2$ areas within the CDFS and ES1 field respectively. We present the survey's science rationale and observing strategy, the data reduction and multi-wavelength data fusion pipeline. Survey data products and their future updates will be released at http://www.mattiavaccari.net/voice/ and on CDS/VizieR.
The scaling laws which relate the peak temperature $T_M$ and volumetric heating rate $E_H$ to the pressure $P$ and length $L$ for static coronal loops were established over 40 years ago; they have proved to be of immense value in a wide range of studies. Here we extend these scaling laws to {\it dynamic} loops, where enthalpy flux becomes important to the energy balance, and study impulsive heating/filling characterized by upward enthalpy flows. We show that for collision-dominated thermal conduction, the functional dependencies of the scaling laws are the same as for the static case, when the radiative losses scale as $T^{-1/2}$, but with a different constant of proportionality that depends on the Mach number $M$ of the flow. The dependence on the Mach number is such that the scaling laws for low to moderate Mach number flows are almost indistinguishable from the static case. When thermal conduction is limited by turbulent processes, however, the much weaker dependence of the scattering mean free path (and hence thermal conduction coefficient) on temperature leads to a limiting Mach number for return enthalpy fluxes driven by thermal conduction between the corona and chromosphere.
Observations of the sun suggest that solar activities systematically create north-south hemispheric asymmetries. For instance, the hemisphere in which the sunspot activity is more active tends to switch after the early half of each solar cycle. Svalgaard & Kamide (2013) recently pointed out that the time gaps of polar field reversal between the north and south hemispheres are simply consequences of the asymmetry of sunspot activity. However, the mechanism underlying the asymmetric feature in solar cycle activities is not yet well understood. In this paper, in order to explain the cause of the asymmetry from the theoretical point of view, we investigate the relationship between the dipole- and quadrupole-type components of the magnetic field in the solar cycle using the mean-field theory based on the flux transport dynamo model. As a result, we found that there are two different attractors of the solar cycle, in which either the north or the south polar field is first reversed, and that the flux transport dynamo model well explains the phase-asymmetry of sunspot activity and the polar field reversal without any ad hoc source of asymmetry.
We present new Atacama Large Millimeter/submillimeter Array (ALMA) results obtained from spatially resolved CO $J$=2-1 line ($0.4''$ resolution) and 870 $\mu$m continuum ($0.2''$ resolution) observations of cluster galaxies in XMMXCS J2215.9-1738 at $z=1.46$. Our sample comprises 17 galaxies within $\sim0.5$ Mpc ($0.6R_{200}$) of the cluster center, all of which have previously been detected in the CO $J$=2-1 line at a lower resolution. The effective radii of both the CO $J$=2-1 line and 870 $\mu$m dust continuum emissions are robustly measured for nine galaxies by modeling the visibilities. We find that the CO $J$=2-1 line emission in all of the nine galaxies is more extended than the dust continuum emission by a factor of $2.8\pm1.4$. We investigate the spatially resolved Kennicutt-Schmidt (KS) relation in two regions within the interstellar medium of the galaxies. The relation for our sample reveals that the central region ($0<r<R_{e,{\rm 870\mu m}}$) of galaxies tends to have a shorter gas depletion timescale, i.e., a higher star formation efficiency, compared to the extended region ($R_{e,{\rm 870\mu m}}<r<R_{e,{\rm CO}}$). Overall, our result suggests that star formation activities are concentrated inside the extended gas reservoir, possibly resulting in the formation of a bulge structure. We find consistency between the ALMA 870 $\mu$m radii of star-forming members and the Hubble Space Telescope/1.6 $\mu$m radii of passive members in a mass-size distribution, which suggests a transition from star-forming to passive members within $\sim0.5$ Gyr. In addition, no clear differences in the KS relation nor in the sizes are found between galaxies with and without a close companion.
The entropy, the spectral radius and the drift are important numerical quantities associated to random walks on countable groups. We prove sharp inequalities relating those quantities for walks with a finite second moment, improving upon previous results of Avez, Varopoulos, Carne, Ledrappier. We also deduce inequalities between these quantities and the volume growth of the group. Finally, we show that the equality case in our inequality is rather rigid.
Compared to facial expression recognition, expression synthesis requires a very high-dimensional mapping. This problem exacerbates with increasing image sizes and limits existing expression synthesis approaches to relatively small images. We observe that facial expressions often constitute sparsely distributed and locally correlated changes from one expression to another. By exploiting this observation, the number of parameters in an expression synthesis model can be significantly reduced. Therefore, we propose a constrained version of ridge regression that exploits the local and sparse structure of facial expressions. We consider this model as masked regression for learning local receptive fields. In contrast to the existing approaches, our proposed model can be efficiently trained on larger image sizes. Experiments using three publicly available datasets demonstrate that our model is significantly better than $\ell_0, \ell_1$ and $\ell_2$-regression, SVD based approaches, and kernelized regression in terms of mean-squared-error, visual quality as well as computational and spatial complexities. The reduction in the number of parameters allows our method to generalize better even after training on smaller datasets. The proposed algorithm is also compared with state-of-the-art GANs including Pix2Pix, CycleGAN, StarGAN and GANimation. These GANs produce photo-realistic results as long as the testing and the training distributions are similar. In contrast, our results demonstrate significant generalization of the proposed algorithm over out-of-dataset human photographs, pencil sketches and even animal faces.
The Lagrangian formulation of field theory does not provide any universal energy-momentum conservation law in order to analize that in gravitation theory. In Lagrangian field theory, we get different identities involving different stress energy-momentum tensors which however are not conserved, otherwise in the covariant multimomentum Hamiltonian formalism. In the framework of this formalism, we have the fundamental identity whose restriction to a constraint space can be treated the energy-momentum transformation law. This identity remains true also for gravity. Thus, the tools are at hand to investigate the energy-momentum conservation laws in gravitation theory. The key point consists in the feature of a metric gravitational field whose canonical momenta on the constraint space are equal to zero.
We establish a sufficient condition for the tightness of a sequence of stochastic processes. Our condition makes it possible to study processes with accumulations of fixed times of discontinuity. Our motivation comes from the study of processes in varying or random environment. We demonstrate the usefulness of our condition on two examples: Galton Watson branching processes in varying environment and logistic branching processes with catastrophes.
Let $K$ be a field and $f:\mathbb{P}^N \to \mathbb{P}^N$ a morphism. There is a natural conjugation action on the space of such morphisms by elements of the projective linear group $\text{PGL}_{N+1}$. The group of automorphisms, or stabilizer group, of a given $f$ for this action is known to be a finite group. In this article, we address two mainly computational problems concerning automorphism groups. Given a finite subgroup of $\text{PGL}_{N+1}$ determine endomorphisms of $\mathbb{P}^N$ with that group as subgroup of its automorphism group. In particular, we show that every finite subgroup occurs infinitely often and discuss some associated rationality problems. Inversely, given an endomorphism determine its automorphism group. In particular, we extended the Faber-Manes-Viray fixed-point algorithm for $\mathbb{P}^1$ to endomorphisms of $\mathbb{P}^2$. A key component is an explicit bound on the size of the automorphism group depending on the degree of the endomorphism.
We discuss the quark masses in a top condensate model where not only two quark but also four quark composite states may exist. We show that the presence of the top color group SU(3)_1\times SU(3)_2 with the correct non anomalous quark representations can justify even in the absence of additional technicolor interactions a hierarchy of the quark masses where the light quark masses have the same size, the charm and bottom masses are higher and similar and the top is the heaviest.
The properties of polycrystalline wurtzite Zn_{1-x}Mg_{x}O (0 <= x <= 0.15) have been studied, by powder X-ray diffraction, including an analysis of the X-ray line-broadening, and by luminescence, absorption, and Raman spectroscopies. We have previously established from synchrotron X-ray difffraction that with increasing Mg-concentration, the c-axis compresses, and the off-center cation displacement within each tetrahedral (Zn,Mg)O_{4} unit decreases. Here we perform a size-strain line-broadening analysis of the XRD peaks, which reveals that the Mg-substitution reduces the coherent crystallite size and also develops the lattice microstrain. The optical properties of the samples have been characterized by diffuse-reflectance spectroscopy and fluorimetry. Both the optical band gap and the band-edge emission energies gradually increase with the Mg-concentration in Zn_{1-x}Mg_{x}O. The Mg-substituted samples show broader band tails near the absorption edge, due to the increase of crystal imperfections. The peak broadening of the E_{2}{high} Raman mode, upon the Mg-substitution, is also ascribed to the phonon shortening lifetime mechanism via crystal defects.
Baryon asymmetry of the universe is generated in the supersymmetric standard model (SSM) through the charge transport mechanism mediated by top squarks. Necessary CP violation originates from a complex phase contained in mass-squared matrices of squarks and sleptons. This complex phase also gives contributions to the electric dipole moments (EDMs) of the neutron and the electron. The amount of induced baryon asymmetry is consistent with its observed value within reasonable ranges of SSM parameters. The EDMs are predicted to be slightly smaller than their experimental upper limits.