ShantanuT01/DACTYL-Pretraining huggingface dataset:
To find X-ray bursts from sources within the field of view of the IBIS/INTEGRAL telescope, we have analysed all the archival data of the telescope available at the time of writing the paper (the observations from January 2003 to April 2009). We have detected 834 hard (15-25 keV) X-ray bursts, 239 of which were simultaneously recorded by the JEM-X/INTEGRAL telescope in the standard X-ray energy range. More than 70% of all bursts (587 events) have been recorded from the well-known X-ray burster GX 354-0. We have found upper limits on the distances to their sources by assuming that the Eddington luminosity limit was reached at the brightness maximum of the brightest bursts.
A review is given on the various aspects of gamma-ray burst afterglow observations, and the inferences derived from the data. After a short history of optical transient search and the BeppoSAX discoveries, the main topics included are prompt multiwavelength emission, dark bursts, spectral lines line and continuum variability, the early light curve behaviour, jet breaks, X-ray flares, late afterglow features, polarization, and orphan afterglows.
We introduce a non-linear paracontrolled calculus and use it to renormalise a class of singular SPDEs including certain quasilinear variants of the periodic two dimensional parabolic Anderson model.
We aim to obtain new insights into the internal dynamics of the cluster Abell 1240, showing the presence of two roughly symmetric radio relics, separated by ~2 h_70^-1 Mpc. Our analysis is mainly based on redshift data for 145 galaxies and on new photometric data. We also use X-ray data from the Chandra archive and photometric data from the SDSS (DR7). We combine galaxy velocities and positions to select 89 cluster galaxies and analyze the internal dynamics of the Abell 1237 + Abell 1240 cluster complex. We estimate similar redshifts for Abell 1237 and Abell 1240, <z>=0.1935 and <z>=0.1948, respectively. For Abell 1237 we estimate velocity dispersion sigma_v~740 km/s and a mass M~6 10^14 h_70^-1 M_sun. For Abell 1240 we estimate a LOS sigma_v~870 km/s and a mass range M~0.9-1.9 10^15 h_70^-1 M_sun, which takes into account its complex dynamics. Abell 1240 is shown to have a bimodal structure with two galaxy clumps roughly defining the N-S direction, the same one defined by the elongation of its X-ray surface brightness and by the axis of symmetry of the relics. The two--body model agrees with the hypothesis that we are looking at a cluster merger occurred largely in the plane of the sky, with the two galaxy clumps separated by a rest-frame velocity difference V_rf~2000 km/s at a time of 0.3 Gyrs after the crossing core, while Abell 1237 is still infalling onto Abell 1240. Chandra archive data confirm the complex structure of Abell 1240 and allow us to estimate a global X-ray temperature T_X=6.0+-0.5 keV. In agreement with the findings from radio data, our results for Abell 1240 strongly support the "outgoing merger shocks" model to explain the presence of the relics.
The VIMOS Public Extragalactic Redshift Survey (VIPERS) is an ongoing ESO Large Programme to map in detail the large-scale distribution of galaxies at 0.5 < z <1.2. With a combination of volume and sampling density that is unique for these redshifts, it focuses on measuring galaxy clustering and related cosmological quantities as part of the grand challenge of understanding the origin of cosmic acceleration. VIPERS has also been designed to guarantee a broader legacy, allowing detailed investigations of the properties and evolutionary trends of z~1 galaxies. The survey strategy exploits the specific advantages of the VIMOS spectrograph at the VLT, aiming at a final sample of nearly 100,000 galaxy redshifts to iAB = 22.5 mag, which represents the largest redshift survey ever performed with ESO telescopes. In this introductory article we describe the survey construction, together with early results based on a first sample of ~55,000 galaxies.
Let $\mathcal{A}$ be a finite set of $d\times d$ matrices with integer entries and let $m_n(\mathcal{A})$ be the maximum norm of a product of $n$ elements of $\mathcal{A}$. In this paper, we classify gaps in the growth of $m_n(\mathcal{A})$; specifically, we prove that $\lim_{n\to\infty} \log m_n(\mathcal{A})/\log n\in\mathbb{Z}_{\geqslant 0}\cup\{\infty\}.$ This has applications to the growth of regular sequences as defined by Allouche and Shallit.
The status of the evaluation of the MSSM Higgs sector is reviewed. The phenomenological impact of recently obtained corrections is discussed. In particular it is shown that the upper bound on m_h within the MSSM is shifted upwards. Consequently, lower limits on tan beta obtained by confronting the upper bound as function of tan beta with the lower bound on m_h from Higgs searches are significantly weakened. Furthermore, the region in the M_A-tan beta-plane where the coupling of the lightest Higgs boson to down-type fermions is suppressed is modified. The presently not calculated higher-order corrections to the Higgs-boson mass matrix are estimated to shift the mass of the lightest Higgs boson by up to 3 GeV.
The two-dimensional Epstein zeta function formulated on a rectangular lattice with spacings $a_x=1$ and $a_y=\Delta$, $\zeta^{(2)}(s,\Delta) = \frac{1}{2} \sum_{j,k} (j^2+\Delta^2 k^2)^{-s}$ $(\Re(s)>1)$ where the sum goes over all integers except of the origin $(j,k)=(0,0)$, is studied. It can be analytically continued to the whole complex $s$-plane except for the point $s=1$. The nontrivial zeros $\{ \rho=\rho_x+{\rm i}\rho_y \}$ of the Epstein zeta function, defined by $\zeta^{(2)} (\rho,\Delta)=0$, split into ``critical'' zeros (on the critical line $\rho_x=\frac{1}{2}$) and ``off-critical'' zeros ($\rho_x\ne\frac{1}{2}$). According to the present numerical calculation, the critical zeros form open or closed curves $\rho_y(\Delta)$ in the plane $(\Delta,\rho_y)$. Two nearest critical zeros merge at special points, referred to as left/right edge zeros, which are defined by a divergent tangent ${\rm d}\rho_y/{\rm d}\Delta\vert_{\Delta^*}$. Each of these edge zeros gives rise to a continuous curve of off-critical zeros which can thus be generated systematically. As a rule, each curve of off-critical zeros joins a pair of left and right edge zeros. It is shown that in the regions of small/large values of the anisotropy parameter $\Delta$ the Epstein zeta function can be approximated adequately by a function which reveals an equidistant distribution of critical zeros along the imaginary axis in the limits $\Delta\to 0$ and $\Delta\to\infty$. It is also found that for each $\Delta\in (0,\Delta_c^*]\cup [1/\Delta_c^*,\infty)$ with $\Delta_c^*\approx 0.141733$ there exists a pair of \emph{real} off-critical zeros, their $\rho_x$ components go to the borders $0$ and $1$ of the critical region in the limits $\Delta\to 0,\infty$. As a rule, each curve of off-critical zeros joins a pair of left and right edge zeros.
As shown by the development of Special Relativity the simultaneity concept should be related to that of reference frame. Poincare' proposed to define the simultaneity of two events by means of light signals following what is nowadays known as the Einstein simultaneity convention. The need of a simultaneity definition is present also in general relativity and in curved spacetimes in order to provide the observers with a coordinate time.   It is recognized that the old Einstein simultaneity convention is nothing but a connection on a suitable trivial bundle that defines the reference frame. Unfortunately, it has a non vanishing holonomy in curved and even in flat spacetimes a fact that makes it almost useless. We point out the advantage of local simultaneity conventions showing that they are represented by local simultaneity connections. Among them there is one, uniquely determined by the reference frame, which is particularly well-behaved globally.
We calculate the surface critical exponents of the ordinary transition occuring in semi-infinite, quenched dilute Ising-like systems. This is done by applying the field theoretic approach directly in d=3 dimensions up to the two-loop approximation, as well as in $d=4-\epsilon$ dimensions. At $d=4-\epsilon$ we extend, up to the next-to-leading order, the previous first-order results of the $\sqrt{\epsilon}$ expansion by Ohno and Okabe [Phys.Rev.B 46, 5917 (1992)]. In both cases the numerical estimates for surface exponents are computed using Pade approximants extrapolating the perturbation theory expansions. The obtained results indicate that the critical behavior of semi-infinite systems with quenched bulk disorder is characterized by the new set of surface critical exponents.
We report our discovery of orbitally modulated $\gamma$-ray emission from the black widow system PSR J1311-3430. We analyze the \textit{Fermi} Large Area Telescope data during the offpulse phase interval of the pulsar, and find the orbital modulation signal at a $\sim$3$\sigma$ confidence level. Further spectral analysis shows no significant differences for the spectra obtained during the bright and faint orbital phase ranges. A simple sinusoid-like function can describe the modulation. Given these properties, we suggest that the intrabinary $\gamma$-ray emission arises from the region close to the companion and the modulation is caused by the occultation of the emitting region by the companion, similar to that is seen in the transitional millisecond pulsar binary (MSP) PSR J1023+0038. Considering the X-ray detection of intrabinary shock emission from eclipsing MSP binaries recently reported, this discovery further suggests the general existence of intrabinary $\gamma$-ray emission from them.
Given a stability condition on a smooth projective variety $X$, we construct a family of stability conditions on $X\times C$, where $C$ is a smooth projective curve. In particular, this gives the existence of stability conditions on arbitrary products of curves. The proof uses, by following an idea of Toda, the positivity lemma established by Bayer and Macr\`i and weak stability conditions on the Abramovich-Polishchuk heart of a bounded t-structure in $D(X\times C)$.
In this work we analyze the incidence of the plates' thickness on the Casimir force and radiative heat transfer for a configuration of parallel plates in a non-equilibrium scenario, relating to Lifshitz's and Landauer's formulas. From a first-principles canonical quantization scheme for the study of the matter-field interaction, we give closed-form expressions for the non-equilibrium Casimir force and the heat transfer between plates of thickness $d_{\rm L},d_{\rm R}$. We distinguish three different contributions to the Casimir force and to the heat transfer in the general non-equilibrium situation: two associated to each of the plates, and one to the initial state of the field. We analyze the dependence of the Casimir force and heat transfer with the plate thickness (setting $d_{\rm L}=d_{\rm R}\equiv d$), showing the scale at which each magnitude converges to the value of infinite thickness ($d\rightarrow+\infty$) and how to correctly reproduce the non-equilibrium Lifshitz's formula. For the heat transfer, we show that Landauer's formula does not apply to every case (where the three contributions are present), but it is correct for some specific situations. We also analyze the interplay of the different contributions for realistic experimental and nanotechnological conditions, showing the impact of the thickness in the measurements. For small thickness (compared to the separation distance), the plates act to decrease the background blackbody flux, while for large thickness the heat is given by the baths' contribution only. The combination of these behaviors allows for the possibility of having a tunable minimum in the heat transfer that is experimentally attainable and observable for metals, and also of having vanishing heat flux in the gap when those difference are of opposite signs (thermal shielding). These features turns out to be relevant for nanotechnological applications.
We discuss a new exact solution for self-dual Abelian gauge fields living on the space of the Kerr-Taub-bolt instanton, which is a generalized example of asymptotically flat instantons with non-self-dual curvature.
In this paper, we adopt the maximizing mutual information (MI) approach to tackle the problem of unsupervised learning of binary hash codes for efficient cross-modal retrieval. We proposed a novel method, dubbed Cross-Modal Info-Max Hashing (CMIMH). First, to learn informative representations that can preserve both intra- and inter-modal similarities, we leverage the recent advances in estimating variational lower-bound of MI to maximize the MI between the binary representations and input features and between binary representations of different modalities. By jointly maximizing these MIs under the assumption that the binary representations are modelled by multivariate Bernoulli distributions, we can learn binary representations, which can preserve both intra- and inter-modal similarities, effectively in a mini-batch manner with gradient descent. Furthermore, we find out that trying to minimize the modality gap by learning similar binary representations for the same instance from different modalities could result in less informative representations. Hence, balancing between reducing the modality gap and losing modality-private information is important for the cross-modal retrieval tasks. Quantitative evaluations on standard benchmark datasets demonstrate that the proposed method consistently outperforms other state-of-the-art cross-modal retrieval methods.
We discuss a sampling algorithm which generates flat histogram in energy. In combination with transition matrix Monte Carlo, the density of states and derived quantities such as entropy and free energy as a function of temperature can be computed in a single simulation.
An isoradial graph is a planar graph in which each face is inscribable into a circle of common radius. We study the 2-dimensional perfect matchings on a bipartite isoradial graph, obtained from the union of an isoradial graph and its interior dual graph. Using the isoradial graph to approximate a simply-connected domain bounded by a simple closed curve, by letting the mesh size go to zero, we prove that in the scaling limit, the distribution of height is conformally invariant and converges to a Gaussian free field.
The popular JF12 analytic model by Jansson & Farrar provides a quantitative description of the Galaxy's large-scale magnetic field, which is widely used in various astrophysical applications. However, both the poloidal X-type component and the spiral disk component of JF12 exhibit regions in which the magnetic divergence constraint is violated. We first propose a cure for this problem, resulting in a truly solenoidal large-scale spiral field. Second, the otherwise straight field lines of the X-type component exhibit kinks in the Galactic plane that, in addition to implying the presence of a singular current sheet, may pose difficulties for e.g., numerical tracing of cosmic-ray particles. We propose and discuss two possible strategies to mitigate this problem. Although all corrections are kept as minimal as possible, the extended set of model parameters will have to be carefully readjusted in order to fully restore the agreement to observational data that the unmodified JF12 field is based on. Furthermore, the performance of our improved version of the field model is quantitatively assessed by test simulations using the CRPropa Galactic cosmic-ray propagation code.
Recent results on production of $J/\psi$ pairs in LHCb initiated discussion on double parton scattering (DPS) contribution to this process, which is not yet elaborated well. In this short report $J/\psi \chi_c$ and $J/\psi \Upsilon$ modes are proposed for DPS studies. Estimations for $\Upsilon \Upsilon$ and $J/\psi \Upsilon$ production in LHCb are presented.
We reconsider the classical problem of representing a finite number of forms of degree d in n+1 variables as sums of powers of linear forms. We define a geometric construct called a `grove', which, in a number of cases allows us to determine the dimension of the space of forms which can be so represented. We also present two new `exceptional' examples, where this dimension is less than what a naive parameter count would predict.
Contamination by polarized foregrounds is one of the biggest challenges for future polarized cosmic microwave background (CMB) surveys and the potential detection of primordial $B$-modes. Future experiments, such as Simons Observatory (SO) and CMB-S4, will aim at very deep observations in relatively small ($f_{\rm sky} \sim 0.1$) areas of the sky. In this work, we investigate the forecasted performance, as a function of the survey field location on the sky, for regions over the full sky, balancing between polarized foreground avoidance and foreground component separation modeling needs. To do this, we simulate observations by an SO-like experiment and measure the error bar on the detection of the tensor-to-scalar ratio, $\sigma(r)$, with a pipeline that includes a parametric component separation method, the Correlated Component Analysis, and the use of the Fisher information matrix. We forecast the performance over 192 survey areas covering the full sky and also for optimized low-foreground regions. We find that modeling the spectral energy distribution of foregrounds is the most important factor, and any mismatch will result in residuals and bias in the primordial $B$-modes. At these noise levels, $\sigma(r)$ is not especially sensitive to the level of foreground contamination, provided the survey targets the least-contaminated regions of the sky close to the Galactic poles.
The structural and elastic properties of orthorhombic black phosphorus have been investigated using first-principles calculations based on density functional theory. The structural parameters have been calculated using the local density approximation (LDA), the generalized gradient approximation (GGA), and with several dispersion corrections to include van der Waals interactions. It is found that the dispersion corrections improve the lattice parameters over LDA and GGA in comparison with experimental results. The calculations reproduce well the experimental trends under pressure and show that van der Waals interactions are most important for the crystallographic b-axis, in the sense that they have the largest effect on the bonding between the phosphorus layers. The elastic constants are calculated and are found to be in good agreement with experimental values. The calculated C$_{22}$ elastic constant is significantly larger than the C$_{11}$ and C$_{33}$ parameters, implying that black phosphorus is stiffer against strain along the a-axis than along the b- and c-axes. From the calculated elastic constants,the mechanical properties such as bulk modulus, shear modulus, Young's modulus and Poisson's ratio are obtained. The calculated Raman active optical phonon frequencies and their pressure variations are in excellent agreement with available experimental results.
An experiment in Low Earth Orbit (LEO) is proposed to measure components of the Riemann curvature tensor using atom interferometry. We show that the difference in the quantum phase $\Delta\phi$ of an atom that can travel along two intersecting geodesics is given by $mR_{0i0j}/\hbar$ times the spacetime volume contained within the geodesics. Our expression for $\Delta\phi$ also holds for gravitational waves in the long wavelength limit.
In this paper we give quantitative local test vectors for Waldspurger's period integral (i.e., a toric period on $\text{GL}_2$) in new cases with joint ramifications. The construction involves minimal vectors, rather than newforms and their variants. This paper gives a uniform treatment for the matrix algebra and division algebra cases under mild assumptions, and establishes an explicit relation between the size of the local integral and the finite conductor $C(\pi\times\pi_{\chi^{-1}})$. As an application, we combine the test vector results with the relative trace formula, and prove a hybrid type subconvexity bound which can be as strong as the Weyl bound in proper range.
A novel effect of population transfer in a five-level system is analyzed. This population transfer effect is found to be a version of a Raman process, which is facilitated and assisted by coherence effects, acting to close other available decay channels.
A systematic method to fabricate porous silicon one dimensional photonic crystals has been engineered to have a photonic bandwidth up to 2000nm. The observation of the tailorability of the photonic bandgap (PBG) underscores the requirement of the large refractive index contrast for making broad PBG structures. In this letter, we present the fabrication and characteristics of such structures that may be promising structures for a large variety of applications.
We present results from deep HI and optical imaging of AGC 229101, an unusual HI source detected at v$_{\rm helio}$ = 7116 km/s in the ALFALFA survey. Initially classified as a candidate "dark" source because it lacks a clear optical counterpart in SDSS or DSS2 imaging, AGC 229101 has $10^{9.31\pm0.05}$ solar masses of HI, but an HI line width of only 43$\pm$9 km/s. Low resolution WSRT imaging and higher resolution VLA B-array imaging show that the source is significantly elongated, stretching over a projected length of ~80 kpc. The HI imaging resolves the source into two parts of roughly equal mass. WIYN pODI optical imaging reveals a faint, blue optical counterpart coincident with the northern portion of the HI. The peak surface brightness of the optical source is only $\mu_{g}$ = 26.6 mag arcsec$^{-2}$, well below the typical cutoff that defines the isophotal edge of a galaxy, and its estimated stellar mass is only $10^{7.32\pm0.33}$ solar masses, yielding an overall neutral gas-to-stellar mass ratio of M$_{\rm HI}$/M$_*=$~98$_{+111}\atop^{-52}$. We demonstrate the extreme nature of this object by comparing its properties to those of other HI-rich sources in ALFALFA and the literature. We also explore potential scenarios that might explain the existence of AGC~229101, including a tidal encounter with neighboring objects and a merger of two dark HI clouds.
A family of congruences interpolating between those of Wilson and Giuga is constructed. Several elementary results are established, in order to present a possible approach to establishing Giuga's conjecture.
We discuss some computational problems associated to matched filtering of experimental signals from gravitational wave interferometric detectors in a parallel-processing environment. We then specialize our discussion to the use of the APEmille and apeNEXT processors for this task. Finally, we accurately estimate the performance of an APEmille system on a computational load appropriate for the LIGO and VIRGO experiments, and extrapolate our results to apeNEXT.
We theoretically investigate interactions between non-degenerate mechanical oscillators mediated by a time-dependent cavity field. We obtain a reduced master equation valid for all optomechanical systems operating in the weak coupling regime. This master equation includes all forms of decoherence and back-action due to the dissipation of the field mediating the interaction. We apply the master equation to study two resonant coupling schemes within a rotating-wave approximation: the beam splitter Hamiltonian and the two-mode parametric amplifier. In both cases, the effective unitary interaction can be made arbitrarily strong compared to the decoherence due to dissipation of the mediating field by choosing appropriate detunings.