ShantanuT01/DACTYL-Pretraining huggingface dataset:
During the first two years of observation, AGILE detected several blazars at high significance: 3C 279, 3C 454.3, PKS 1510-089, S5 0716+714, 3C 273, W Comae, Mrk 421 and PKS 0537-441. We obtained long-term coverage of 3C 454.3, for a total of more than three months at energies above 100 MeV. 3C 273 was the first blazar detected simultaneously by the AGILE gamma-ray detector and by its hard X-ray monitor. S5 0716+714, an intermediate BL Lac object, exhibited a very fast and intense gamma-ray transient during an optical high-state phase, challenging the current theoretical models for energy extraction from a rotating black hole, while W Comae and Mkn 421 were detected during an AGILE Target of Opportunity (ToO) repointing, and were simultaneously detected by Cherenkov telescopes. Thanks to the rapid dissemination of our alerts, we were able to obtain multi-wavelength ToO data from other observatories such as Spitzer, Swift, RXTE, Suzaku, INTEGRAL, MAGIC, VERITAS, as well as radio-to-optical coverage by means of the WEBT Consortium and REM, allowing us to study truly simultaneous spectral energy distributions from the radio to the TeV energy band.
Novel ground states might be realized in honeycomb lattices with strong spin-orbit coupling. Here we study the electronic structure of ${\alpha}$-RuCl$_3$, in which the Ru ions are in a d5 configuration and form a honeycomb lattice, by angle-resolved photoemission, x-ray photoemission and electron energy loss spectroscopy supported by density functional theory and multiplet calculations. We find that ${\alpha}$-RuCl$_3$ is a Mott insulator with significant spin-orbit coupling, whose low energy electronic structure is naturally mapped onto Jeff states. This makes ${\alpha}$-RuCl$_3$ a promising candidate for the realization of Kitaev physics. Relevant electronic parameters such as the Hubbard energy U, the crystal field splitting 10Dq and the charge transfer energy are evaluated. Furthermore, we observe significant Cl photodesorption with time, which must be taken into account when interpreting photoemission and other surface sensitive experiments.
The study of quasi-periodic oscillations (QPOs) of X-ray flux observed in the stellar-mass black hole binaries can provide a powerful tool for testing of the phenomena occurring in strong gravity regime. The high frequency (HF) QPOs usually come in pairs of double peaks which have a frequency ratio close to $3:2$. In addition to HF QPOs, some sources display simultaneous existence of the low frequency (LF) QPOs in Fourier power spectra. We demonstrate that the explanation of these phenomena can be well related to the epicyclic oscillations of charged particles in accretion disks orbiting Kerr black holes immersed in external large-scale magnetic fields. Magnetized versions of the standard geodesic models of QPOs can explain the observationally fixed data from the three microquasars. We perform a successful fitting of the HF QPOs observed in three microquasars, GRS 1915+105, XTE 1550-564 and GRO 1655-40, containing black holes, for magnetised versions of both epicyclic rezonance and relativistic precession models and discuss the corresponding constraints of parameters of the model, which are the mass and spin of black hole and the parameter related to the external magnetic field. Assuming the main source of synchrotron radiation producing X-rays are the relativistic electrons, we estimate the magnetic field in the vicinity of the black hole in the three sources to be of order $10^{-5}$ Gs which can serve as possible signature of the Galactic magnetic field magnitude. For heavier particles (protons, ions) larger magnetic fields are necessary for fitting the data.
We present the analysis of RXTE monitoring data obtained during the January 2009 outburst of the hard X-ray transient 1A 1118-61. Using these observations the broadband (3.5-120 keV) spectrum of the source was measured for the first time ever. We have found that the broadband continuum spectrum of the source is similar to other accreting pulsars and is well described by several conventionally used phenomenological models. We have discovered that regardless of the applied continuum model, a prominent broad absorption feature at ~55 keV is observed. We interpret this feature as a cyclotron resonance scattering feature (CRSF). The observed CRSF energy is one of the highest known and corresponds to a magnetic field of B~4.8 x 10^12 G in the scattering region. Our data also indicate the presence of an iron emission line presence that has not been previously reported for 1A 1118-61. Timing properties of the source, including a strong spin-up, were found to be similar to those observed by CGRO/BATSE during the previous outburst, but the broadband capabilities of RXTE reveal a more complicated energy dependency of the pulse-profile.
Equilibration times for nuclear matter configurations -- modelling intermediate and high energy nucleus-nucleus collisions -- are evaluated within the semiclassical off-shell transport approach developed recently. The transport equations are solved for a finite box in coordinate space employing periodic boundary conditions. The off-shell transport model is shown to give proper off-shell equilibrium distributions in the limit $t \to \infty$ for the nucleon and $\Delta$-resonance spectral functions. We find that equilibration times within the off-shell approach are only slightly enhanced as compared to the on-shell limit for the momentum configurations considered.
We construct linearized solutions to Vasiliev's four-dimensional higher spin gravity on warped $AdS_3 \times_\xi S^1$ which is an $Sp(2)\times U(1)$ invariant non-rotating BTZ-like black hole with $\mathbb{R}^2\times T^2$ topology. The background can be obtained from $AdS_4$ by means of identifications along a Killing boost $K$ in the region where $\xi^2\equiv K^2\geqslant 0$, or, equivalently, by gluing together two Ba\~nados--Gomberoff--Martinez eternal black holes along their past and future space-like singularities (where $\xi$ vanishes) as to create a periodic (non-Killing) time. The fluctuations are constructed from gauge functions and initial data obtained by quantizing inverted harmonic oscillators providing an oscillator realization of $K$ and of a commuting Killing boost $\widetilde K$. The resulting solution space has two main branches in which $K$ star commutes and anti-commutes, respectively, to Vasiliev's twisted-central closed two-form $J$. Each branch decomposes further into two subsectors generated from ground states with zero momentum on $S^1$. We examine the subsector in which $K$ anti-commutes to $J$ and the ground state is $U(1)_K\times U(1)_{\widetilde K}$-invariant of which $U(1)_K$ is broken by momenta on $S^1$ and $U(1)_{\widetilde K}$ by quasi-normal modes. We show that a set of $U(1)_{\widetilde K}$-invariant modes (with $n$ units of $S^1$ momenta) are singularity-free as master fields living on a total bundle space, although the individual Fronsdal fields have membrane-like singularities at $\widetilde K^2=1$. We interpret our findings as an example where Vasiliev's theory completes singular classical Lorentzian geometries into smooth higher spin geometries.
A new stochastic cellular automaton (CA) model of traffic flow, which includes slow-to-start effects and a driver's perspective, is proposed by extending the Burgers CA and the Nagel-Schreckenberg CA model. The flow-density relation of this model shows multiple metastable branches near the transition density from free to congested traffic, which form a wide scattering area in the fundamental diagram. The stability of these branches and their velocity distributions are explicitly studied by numerical simulations.
A systematic investigation of dust emission associated with the ionized gas has so far been performed only in our Galaxy and for wavelengths longer than 60 {\mu}m. Newly available Spitzer data now offer the opportunity to carry out a similar analysis in the Large Magellanic Cloud (LMC). By cross-correlating Spitzer SAGE (Surveying the Agents of a Galaxy's Evolution) data with the ATCA/Parkes HI 21-cm data, the NANTEN 12CO (J=1-0) data, and both the SHASSA H{\alpha} and the Parkes 6-cm data, we investigate the physical properties of dust associated with the different phases of the gas (atomic, molecular and ionized). In particular, we study the presence and nature of dust from 3.6 to 160 {\mu}m and for various regimes of the ionized gas, spanning emission measures (EM) from \sim 1 pc cm-6 (diffuse component) to \sim 10^3 pc cm-6 (HII regions). Using a dust emission model, and testing our results with several radiation field spectra, we show that dust in the ionized gas is warmer than dust associated with other phases (atomic and molecular). We also find a decrease of the polycyclic aromatic hydrocarbons (PAH) relative abundance with respect to big grains (BGs), as well as an increase of the near infrared (NIR) continuum. These three results (e.g. warmer temperature, decrease of PAH abundance and increase of the NIR continuum) are found consistently for all regimes of the ionized gas. On the contrary, the molecular phase appears to provide favorable conditions for the survival of PAHs. Furthermore, the very small grain (VSG) relative abundance tends to increase in the ionized phase, especially in bright HII regions. Last but not least, our analysis shows that the emissivity of dust associated with the ionized gas is lower in the LMC than in our Galaxy, and that this difference is not accounted for by the lower metallicity of the LMC.
It has been suggested that wormholes and other non-trivial geometrical structures might have been formed during the quantum cosmological era ($t\sim 10^{-43}$s). Subsequent inflation of the universe might have enlarged these structures to macroscopic sizes. In this paper, spherical geometrical structures in an inflationary RW background are derived from the Einstein equations, using a constraint on the energy-momentum tensor which is an extension of the one expected for inflation. The possibility of dynamical wormholes and other spherical structures are explored in the framework of the solutions.
Parameters of a special kind of \alpha-effect known in dynamo theory as the Babcock-Leighton mechanism are estimated using the data of sunspot catalogs. The estimates evidence the presence of the Babcock-Leighton \alpha-effect on the Sun. Fluctuations of the \alpha-effect are also estimated. The fluctuation amplitude appreciably exceeds the mean value, and the characteristic time for the fluctuations is comparable to the period of the solar rotation. Fluctuations with the parameters found are included in a numerical model for the solar dynamo. Computations show irregular changes in the amplitudes of the magnetic cycles on time scales of centuries and millennia. The calculated statistical characteristics of the grand solar minima and maxima agree with the data on solar activity over the Holocene.
Fermion compositness, and other new physics which can be described by an exchange of very massive particles ($Z^\prime$ boson, leptoquarks, sparticles with R-parity violating couplings), can be manifest itself as the presence of a strong four-fermion contact interaction. For the processes $e^+e^-\to \mu^+\mu^-$, $\tau^+\tau^-$, $\bar{b}b$ and $\bar{c}c$ at a future $e^+e^-$ linear collider (LC) with $\sqrt{s}=0.5$ TeV, we examine the sensitivity of the helicity cross sections to four-fermion contact interactions. If longitudinal polarization of the electron beam were available, two polarized integrated cross sections would offer the opportunity to separate the helicity cross sections and, in this way, to derive model-independent bounds on the relevant parameters. The measurement of these polarized cross sections with optimal kinematical cuts could significantly increase the sensitivity of helicity cross sections to contact interaction parameters and could give crucial information on the chiral structure of such new interactions. In addition, we consider the application of the proposed approach to the search for manifestations of a $Z^\prime$ for typical extended model examples.
In this paper we propose two numerical algorithms to derive the extremal principal eigenvalue of the bi-Laplacian operator under Navier boundary conditions or Dirichlet boundary conditions. Consider a non-homogeneous hinged or clamped plate $\Omega$, the algorithms converge to the density functions on $\Omega$ which they yield the maximum or minimum basic frequency of the plate.
Here we describe how certain classes of two dimensional topological insulators, including the CdTe$/$HgTe quantum wells, display a new type of optical activity in two dimensions similar to the magneto-optical Kerr effect in the quantum Hall effect. This optical activity is characterized by a genuine Kerr angle and it is compatible with time reversal symmetry, being thus fundamentally different to other known types of time reversal invariant optical activity. The term responsible of such optical activity, having the form of $(\mathbf{E}\cdot\partial\mathbf{B}/\partial t-\mathbf{B}\cdot\partial\mathbf{E}/\partial t)$, can be considered a time reversal invariant counterpart of the magneto-electric term $\mathbf{E}\cdot\mathbf{B}$. The microscopical origin of this response is a chiral non-minimal coupling between electrons and the external electromagnetic field. This optical activity constitutes a proof of principle that there is possible to find systems that are time reversal invariant displaying a genuine Kerr effect.
Person re-identification is indeed a challenging visual recognition task due to the critical issues of human pose variation, human body occlusion, camera view variation, etc. To address this, most of the state-of-the-art approaches are proposed based on deep convolutional neural network (CNN), being leveraged by its strong feature learning power and classification boundary fitting capacity. Although the vital role towards person re-identification, how to build effective CNN baseline model has not been well studied yet. To answer this open question, we propose 3 good practices in this paper from the perspectives of adjusting CNN architecture and training procedure. In particular, they are adding batch normalization after the global pooling layer, executing identity categorization directly using only one fully-connected, and using Adam as optimizer. The extensive experiments on 3 widely-used benchmark datasets demonstrate that, our propositions essentially facilitate the CNN baseline model to achieve the state-of-the-art performance without any other high-level domain knowledge or low-level technical trick.
The problem to estimate the background due to accidental coincidences in the search for coincidences in gravitational wave experiments is discussed. The use of delayed coincidences obtained by orderly shifting the event times of one of the two detectors is shown to be the most correct
We present a general description of electromagnetic RR interactions between pairs of magnetically dual D-branes, focusing on the interaction of a magnetically charged brane with an electrically charged one. In the boundary state formalism, it turns out that while the electric-electric and/or magnetic-magnetic interaction corresponds to the usual RR even spin structure, the magnetic-electric interaction is described by the RR odd spin structure. As representative of the generic case of a dual pair of p and 6-p branes, we discuss in detail the case of the self-dual 3-brane wrapped on a T_6/Z_3, which looks like an extremal dyonic black hole in 4 dimensions.
We present multi-wavelength imagery of the merger remnant galaxy NGC 1316 with an objective to study the content of dust and its association with the other phases of the ISM. Color-index maps as well as extinction maps derived for this galaxy reveal an intricate and complex dust morphology in NGC 1316, i.e., in the inner part it exists in the form of a prominent lane while at about 6--7\,kpc it apparently takes an arc-like pattern extended along the North-East direction. In addition to this, several other dust clumps and knots are also evident in this galaxy. Dust emission mapped using \textit{Spitzer} data at 8 $\mu$m indicates even more complex morphological structures of the dust in NGC1316. The extinction curve derived over the optical to near-IR bands closely follows the standard Galactic curve suggesting similar properties of the dust grains. The dust content of NGC 1316 estimated from optical extinction is $\sim$ 2.13$\times\, 10^5$ \Msun. This is a lower limit compared to that estimated using the IRAS flux densities $\sim$ 5.17$\times\, 10^6$ \Msun\, and flux densities at 24$\mu$m, 70$\mu$m and 160 $\mu$m from MIPS $\sim$ 3.2$\times\, 10^7$ \Msun. High resolution \textit{Chandra} observations of this merger remnant system have provided with an unprecedented view of the complex nature of hot gas distribution in NGC 1316 which closely matches the morphology of ionized gas and to some extent with the dust also. X-ray color-color plot for the resolved sources within optical D$_{25}$ extent of NGC 1316 has enabled us to separate them in different classes.
Total solar irradiance variations, about 0.1% between solar activity maximum and minimum, are available from accurate satellite measurements since 1978 and thus do not provide useful information on longer-term secular trends. Recently, Krivova et al., 2007 reconstructed, using suitable models, the total solar irradiance from the end of the Maunder minimum to the present, based on variations of the surface distribution of the solar magnetic field. The latter is calculated from the long historical record of the sunspot numbers using a simple but consistent physical model. There are many classes of proposed prediction methods for solar cycles behavior, based on different direct solar activity indices or on various valuable proxies. In particular, the precursor based methods, utilize a given proxy index to predict the future evolution of solar activity. Long-term time series of sunspot numbers, allow us to reliably predict the behavior of the next solar cycle, few years in advance. In previous papers we predicted the full-shape curve of future solar cycles, using a proper non-linear dynamics method applied to monthly smoothed sunspot numbers. In particular, we proved that a sufficiently reliable phase-amplitude prediction of the current solar cycle 24, requires the knowledge of the initial increasing phase of the cycle spanning at least two years. The aim of the present paper is to give a robust long-term prediction of solar cycle activity, many years in advance and for at least three successive solar cycles using the same nonlinear method and, as solar activity proxy index, the reconstructed total solar irrandiance.
We study the meromorphy of various Euler products of degree two attached to cusp forms including Ramanujan's $\Delta$-function.
The branching fraction of the decay $\tau \to K^{-} K^{0} \nu_{\tau}$ is calculated in the framework of the extended Nambu--Jona-Lasinio model. The contact and vector channels are considered. The contributions to this process of the $\rho$ meson in the ground and first radially excited states are taken into account in the vector channel. The obtained results are in satisfactory agreement with the experimental data. Taking into account the kaon interaction in the final state results in insignificant corrections, which are not beyond the scope of the model uncertainties.
We investigate the relationship between ground-state (zero-temperature) quantum phase transitions in systems with variable Hamiltonian parameters and classical (temperature-driven) phase transitions in standard thermodynamics. An analogy is found between (i) phase-transitional distributions of the ground-state related branch points of quantum Hamiltonians in the complex parameter plane and (ii) distributions of zeros of classical partition functions in complex temperatures. Our approach properly describes the first- and second-order quantum phase transitions in the interacting boson model and can be generalized to finite temperatures.
In this paper, we show that the permeability of a porous {material} and that of a bubbly fluid are limiting cases of the complexified version of the two-fluid models posed in {Lipton_Avellaneda_1990}. We assume the viscosity of the inclusion fluid is $z\mu_1$ and the viscosity of the hosting fluid is $\mu_1\in \mathbb{R}^+$, $z\in\mathbb{C}$. The proof is carried out by the construction of solutions for large $|z|$ and small $|z|$ with an iteration process and the analytic continuation. Moreover, we also show that for a fixed microstructure, the permeabilities of these three cases share the same integral representation formula (IRF) in Equation (99) with different values of contrast parameter $s:=1/(z-1)$, as long as $s$ is outside the interval $[-\frac{2E_2^2}{1+2E_2^2},-\frac{1}{1+2E_1^2}]$, where the positive constants $E_1$ and $E_2$ are the extension constants that depend only on the geometry of the periodic pore space of the material.
We present a systematic analytical approach to the trapping of a random walk by a finite density rho of diffusing traps in arbitrary dimension d. We confirm the phenomenologically predicted e^{-c_d rho t^{d/2}} time decay of the survival probability, and compute the dimension dependent constant c_d to leading order within an eps=2-d expansion.
We consider renormalisable models extended in the scalar sector by a generic scalar field in addition to the standard model Higgs boson field, and work out the effective theory for the latter in the decoupling limit. We match the full theory onto the effective theory at tree and one-loop levels, and concentrate on dimension-6 operators of the Higgs and electroweak gauge fields induced from such matching. The Wilson coefficients of these dimension-6 operators from tree-level matching are further improved by renormalisation group running. For specific $SU(2)_L$ representations of the scalar field, some "accidental" couplings with the Higgs field are allowed and can lead to dimension-6 operators at tree and/or one-loop level. Otherwise, two types of interaction terms are identified to have only one-loop contributions, for the Wilson coefficients of which we have obtained a general formula. Using the obtained results, we analyse constraints from electroweak oblique parameters and the Higgs data on several phenomenological models.
Background: The calculation of the hyperon binding energy in hypernuclei is crucial to understanding the interaction between hyperons and nucleons.   Purpose: We assess the relative importance of two- and three-body hyperon-nucleon force by studying the effect of the hyperon-nucleon-nucleon interaction in closed shell \Lambda-hypernuclei from A=5 to 91.   Methods: The \Lambda-binding energy has been calculated using the auxiliary field diffusion Monte Carlo method for the first time, to study light and heavy hypernuclei within the same model.   Results: Our results show that including a three-body component in the hyperon-nucleon interaction leads to a saturation of the \Lambda-binding energy remarkably close to the experimental data. In contrast, the two-body force alone gives an unphysical limit for the binding energy.   Conclusions: The repulsive contribution of the three-body hyperon-nucleon-nucleon force is essential to reproduce, even qualitatively, the binding energy of the hypernuclei in the mass range considered.