ShantanuT01/DACTYL-Pretraining huggingface dataset:
Between the launch of the \textit{GGS Wind} spacecraft in 1994 November and the end of 2010, the Konus-\textit{Wind} experiment detected 296 short-duration gamma-ray bursts (including 23 bursts which can be classified as short bursts with extended emission). During this period, the IPN consisted of up to eleven spacecraft, and using triangulation, the localizations of 271 bursts were obtained. We present the most comprehensive IPN localization data on these events. The short burst detection rate, $\sim$18 per year, exceeds that of many individual experiments.
We propose a novel scenario for possible electromagnetic (EM) emission by compact binary mergers in the accretion disks of active galactic nuclei (AGNs). Nuclear star clusters in AGNs are a plausible formation site of compact-stellar binaries (CSBs) whose coalescences can be detected through gravitational waves (GWs). We investigate the accretion onto and outflows from CSBs embedded in AGN disks. We show that these outflows are likely to create outflow "cavities" in the AGN disks before the binaries merge, which makes EM or neutrino counterparts much less common than would otherwise be expected. We discuss the necessary conditions for detectable EM counterparts to mergers inside the outflow cavities. If the merger remnant black hole experiences a high recoil velocity and can enter the AGN disk, it can accrete gas with a super-Eddington rate, newly forming a cavity-like structure. This bubble can break out of the disk within a day to a week after the merger. Such breakout emission can be bright enough to be detectable by current soft X-ray instruments, such as Swift-XRT and Chandra.
We present the next-to-leading-order QCD corrections of O(alpha_s^2 G_F M_t^2) to the low-M_H effective l^+l^-H, ZZH, and W^+W^-H interaction Lagrangians in the high-M_t limit. In the on-shell scheme formulated with G_F, the O(alpha_s^2 G_F M_t^2) corrections support the O(alpha_s G_F M_t^2) ones and further increase the screening of the O(G_F M_t^2) terms. The coefficients of (alpha_s/pi)^2 range from -6.847 to -16.201, being in line with the value -14.594 recently found for Delta rho. All four QCD expansions converge considerably more rapidly, if they are written with mu_t=m_t(mu_t), where m_t(mu) is the MS-bar mass, rather than the pole mass, M_t.
Over two decades ago, a prominent, mysterious emission band peaking at ~20.1 micrometer was serendipitously detected in four preplanetary nebulae (PPNe; also known as "protoplanetary nebulae"). So far, this spectral feature, designated as the "21 micrometer" feature, has been seen in 18 carbon-rich PPNe. The nature of the carriers of this feature remains unknown although many candidate materials have been proposed. The 21 micrometer sources also exhibit an equally mysterious, unidentified emission feature peaking at 30 micrometer. While the 21 micrometer feature is exclusively seen in PPNe, a short-lived evolutionary stage between the end of the asymptotic giant branch (AGB) and planetary nebula (PN) phases, the 30 micrometer feature is commonly observed in all stages of stellar evolution from the AGB through PPN to PNe phases. We derive the stellar mass loss rates (M_{loss}) of these 21 micrometer sources from their dust infrared (IR) emission, using the "2-DUST" radiative transfer code for axisymmetric dusty systems which allows one to distinguish the mass loss rates of the AGB phase (\dot{M_{AGB}}) from that of the superwind (\dot_{M_{SW}}) phase. We examine the correlation between \dot{M_{AGB}} or \dot_{M_{SW}} and the fluxes emitted from the 21 and 30 micrometer features. We find that both features tend to correlate with \dot{M_{AGB}}, suggesting that their carriers are probably formed in the AGB phase. The nondetection of the 21 micrometer feature in AGB stars suggests that, unlike the 30 micrometer feature, the excitation of the carriers of the 21 micrometer feature may require ultraviolet photons which are available in PPNe but not in AGB stars.
While in the past spheroidicity was assumed, and still is used in modeling of most nebulae, we know now that only a small number of planetary nebulae (PNe) are really spherical or at least nearly round. Round planetary nebulae are the minority of objects. In case of those objects that underwent a very late helium flash (called VLTP or "born-again" PNe) it seems to be different. The first, hydrogen rich PN, is more or less round. The ejecta from the VLTP event is extremely asymmetrically. Angular momentum is mostly assumed to be the main reason for the asymmetry in PNe. Thus we have to find processes either changing their behavior within a few hundred to a few thousands of years or change their properties dramatically due to the variation of the abundance. They most likely have a strong link or dependency with the abundance of the ejecta.
Radial velocity surveys such as the Radial Velocity Experiment (RAVE) provide us with measurements of hundreds of thousands of nearby stars most of which belong to the Galactic thin, thick disk or halo. Ideally, to study the Galactic disks (both thin and thick) one should make use of the multi-dimensional phase-space and the whole pattern of chemical abundances of their stellar populations. In this paper, with the aid of the RAVE Survey, we study the thin and thick disks of the Milky Way, focusing on the latter. We present a technique to disentangle the stellar content of the two disks based on the kinematics and other stellar parameters such as the surface gravity of the stars. Using the Padova Galaxy Model, we checked the ability of our method to correctly isolate the thick disk component from the Galaxy mixture of stellar populations. We introduce selection criteria in order to clean the observed radial velocities from the Galactic differential rotation and to take into account the partial sky coverage of RAVE. We developed a numerical technique to statistically disentangle thin and thick disks from their mixture. We deduce the components of the solar motion relative to the Local Standard of Rest (LSR) in the radial and vertical direction, the rotational lag of the thick disk component relative to the LSR, and the square root of the absolute value of the velocity dispersion tensor for the thick disk alone. The analysis of the thin disk is presented in another paper. We find good agreement with previous independent parameter determinations. In our analysis we used photometrically determined distances. In the Appendix we show that similar values can be found for the thick disk alone as derived in the main sections of our paper even without the knowledge of photometric distances.
In the paper we show that the real gravitational waves which have $R_{iklm}\not= 0$ always carry energy-momentum and angular momentum. Our proof uses canonical superenergy and supermomentum tensors for gravitational field.
Mg0.29Zn0.71O/ZnO (MZO/ZnO) bilayers were grown on sapphire substrates by pulsed laser deposition at ~ 400 C and were subsequently annealed at different temperatures ranging from ~ 500 to 900 C to allow diffusion of Mg across the interface. The diffusion of Mg was confirmed from secondary ion mass spectroscopy (SIMS) and Photo-absorption measurements on the samples. As a result of Mg diffusion the photoluminescence (PL) spectra of the bilayers got significantly modified. Whereas the as grown structure had two distinct near band edge UV luminescence peaks corresponding to the ZnO and MZO layer, the one annealed at ~ 900 C had a single near band edge PL peak corresponding to a complete intermixed layer. At the intermediate annealing temperature of ~800 C the PL peak position corresponding to the MZO layer red-shifted while that corresponding to the ZnO layer blue-shifted, implying a diffused interface and partial intermixing. A theoretical model has been developed and numerically simulated to correlate the PL spectra of the bilayers with the Mg diffusion profile across the interface, as measured by SIMS.
Three hundred fifty three radio sources from the NRAO VLA Sky Survey (NVSS) (Condon et al. 1998) and the FIRST Survey (White et al. 1997}, are detected in the areas of 179 Shakhbazian Compact Groups (ShCGs) of galaxies. Ninety three of them are identified with galaxies in 74 ShCGs. Six radio sources have complex structure. The radio spectra of 22 sources are determined. Radio luminosities of galaxies in ShCGs are in general higher than that of galaxies in Hickson Compact Groups (HCGs). The comparison of radio (at 1.4 GHz) and FIR (at 60 $\mu$m) fluxes of ShCG galaxies with that of HCG galaxies shows that galaxies in ShCGs are relatively stronger emitters at radio wavelengths, while galaxies in HCGs have relatively stronger FIR emission. The reasons of such difference is discussed.
The importance of the spectral density of the Dirac operator in studying spontaneous chiral symmetry breaking and anomalous U(1) axial symmetry breaking are reviewed. It is shown that both types of symmetry breaking can be traced to effects of modes near zero virtuality. Above T_c, where chiral symmetry is restored, it is shown on general grounds that (in the massless quark limit), the density of states vanishes at zero virtuality faster than $\lambda$, where $\lambda$ is the virtuality-- $\rho(\lambda) \sim |\lambda|^\alpha$ is not possible for $\alpha \le 1$. Isospin invariance is used to show that $\rho(\lambda) \sim m_q^{1-\alpha} |\lambda|^\alpha$ is also not possible for $\alpha \le 1$. State-of-the-art lattice calculations are reviewed in light of these constraints. In particular, it is argued that violations of these constraints by lattice calculations indicate possible large systematic errors; this raises questions about $U(1)_A$ violating effects seen on the lattice.It is also shown that above $T_c$, the Dirac spectrum has a gap near zero (in the $m_q \to 0$ limit) unless contributions from quark-line-connected and disconnected contributions conspire to cancel.
Let $p$ be a sufficiently large prime number, $n$ be a positive odd integer with $n|\,p-1$ and $n>p^\varepsilon $, where $\varepsilon$ is a sufficiently small constant. Let $k(p,\,n)$ denote the least positive integer $k$ such that for $x=-k,\,\dots,\,-1,\,1,\,2,\,\dots,\,k$, the numbers $x^n\pmod p$ yield all the non-zero $n$-th power residues modulo $p$. In this paper, we shall prove $$ k(p,\,n)=O(p^{1-\delta}), $$ which improves a result of S. Chowla and H. London in the case of large $n$.
The strength of the (Rashba-type) spin-orbit coupling in mesoscopic semiconductor rings can be tuned with external gate voltages. Here we consider the case of a periodically changing spin-orbit interaction strength as induced by sinusoidal voltages. In a closed one dimensional quantum ring with weak spin-orbit coupling, Rabi oscillations are shown to appear. We find that the time evolution of initially localized wave packets exhibits a series of collapse and revival phenomena. Partial revivals -- that are typical in nonlinear systems -- are shown to correspond to superpositions of states localized at different spatial positions along the ring. These "spintronic Schrodinger-cat sates" appear periodically, and similarly to their counterparts in other physical systems, they are found to be sensitive to environment induced disturbances. The time dependent spin transport problem, when leads are attached to the ring, is also solved. We show that the "sideband currents" induced by the oscillating spin-orbit interaction strength can become the dominant output channel, even in the presence of moderate thermal fluctuations and random scattering events.
We present new imaging and spectral analysis of the recently discovered extended X-ray emission around the high magnetic field rotating radio transient RRAT J1819-1458. We used two Chandra observations performed for this object in 2008 May 31 and 2011 May 28, respectively. The diffuse X-ray emission was detected with a significance of \sim19 sigma in the image obtained by combining the two observations. Neither long-term spectral nor timing variability have been observed from the source or the nebula. RRAT J1819-1458 shows an unusual high X-ray efficiency of L_x(0.3-5 keV)/Edot_{rot} \sim 0.15 at converting spin-down power into X-ray luminosity. The most favourable scenario for the origin of this extended X-ray emission is either a pulsar-wind nebula (PWN) or a scattering halo. A magnetically powered scenario for the extended emission is viable only in the case of a Compton nebula, while can be tentatively disfavoured in the case of synchrotron emission.
The {\em instability of vacuum energy} in de Sitter space as discussed recently by Polyakov is argued to be a generic feature when external gravitational fields are present. It is related to the existence of {\em forbidden} (by momentum conservation) decays derived in some detail by Bros, Epstein and Moschella. Some calculations are discussed in a conformally invariant setting, and a flat space model is presented.
Linear instability of two equilibrium configurations with either poloidal (I) or toroidal (II) dominant magnetic field components are studied in thin vertically-isothermal Keplerian discs. Solutions of the stability problem are found explicitly by asymptotic expansions in the small aspect ratio of the disc. In both equilibrium configurations the perturbations are decoupled into in-plane and vertical modes. For equilibria of type I those two modes are the Alfv\'en-Coriolis and sound waves, while for equilibria of type II they are the inertia-Coriolis and magnetosonic waves. Exact expressions for the growth rates as well as the number of unstable modes for type I equilibria are derived. Those are the discrete counterpart of the continuous infinite homogeneous cylinder magnetorotational (MRI) spectrum. It is further shown that the axisymmetric MRI is completely suppressed by dominant toroidal magnetic fields (i.e. equilibria of type II). This renders the system prone to either non-axisymmetric MRI or non-modal algebraic growth mechanisms. The algebraic growth mechanism investigated in the present study occurs exclusively due to the rotation shear, generates the inertia-Coriolis driven magnetosonic modes due to non-resonant or resonant coupling that induces, respectively, linear or quadratic temporal growth of the perturbations.
We constructe the $\mathcal{N}=1$ SYM lagrangian in light-cone gauge using chiral superfields instead of the standard vector superfield approach and derive the MHV lagrangian. The canonical transformations of the gauge field and gaugino fields are summarised by the transformation condition of chiral superfields. We show that $\mathcal{N}=1$ MHV super-vertices can be described by a formula similar to that of the $\mathcal{N}=4$ MHV super-amplitude. In the discussions we briefly remark on how to derive Nair's formula for $\mathcal{N}=4$ SYM theory directly from light-cone lagrangian.
This work studies stability and robustness of a nonlinear system given as an interconnection of an ODE and a parabolic PDE subjected to external disturbances entering through the boundary conditions of the parabolic equation. To this end we develop an approach for a construction of a suitable coercive Lyapunov function as one of the main results. Based on this Lyapunov function we establish the well-posedness of the considered system and establish conditions that guarantee the ISS property. ISS estimates are derived explicitly for the particular case of globally Lipschitz nonlinearities.
We numerically study two conservative two-dimensional maps, namely the baker map (whose Lyapunov exponent is known to be positive), and a typical one (exhibiting a vanishing Lyapunov exponent) chosen from the generalized shift family of maps introduced by C. Moore [Phys Rev Lett {\bf 64}, 2354 (1990)] in the context of undecidability. We calculated the time evolution of the entropy $S_q \equiv \frac{1-\sum_{i=1}^Wp_i^q}{q-1}$ ($S_1=S_{BG}\equiv -\sum_{i=1}^Wp_i \ln p_i$), and exhibited the dramatic effect introduced by numerical precision. Indeed, in spite of being area-preserving maps, they present, {\it well after} the initially concentrated ensemble has spread virtually all over the phase space, unexpected {\it pseudo-attractors} (fixed-point like for the baker map, and more complex structures for the Moore map). These pseudo-attractors, and the apparent time (partial) reversibility they provoke, gradually disappear for increasingly large precision. In the case of the Moore map, they are related to zero Lebesgue-measure effects associated with the frontiers existing in the definition of the map. In addition to the above, and consistently with the results by V. Latora and M. Baranger [Phys. Rev. Lett. {\bf 82}, 520 (1999)], we find that the rate of the far-from-equilibrium entropy production of baker map, numerically coincides with the standard Kolmogorov-Sinai entropy of this strongly chaotic system.
We describe the possible scenarios for the evolution of a thin spherically symmetric self-gravitating phantom shell around the Schwarzschild black hole. The general equations describing the motion of the shell with a general form of equation of state are derived and analyzed. The different types of space-time R- and T-regions and shell motion are classified depending on the parameters of the problem. It is shown that in the case of a positive shell mass there exist three scenarios for the shell evolution with an infinite motion and two distinctive types of collapse. Analogous scenarios were classified for the case of a negative shell mass. In particular this classification shows that it is impossible for the physical observer to detect the fantom energy flow. We shortly discuss the importance of our results for astrophysical applications.
A survey of algebraic approaches to various problems in nuclear physics is given. Examples are chosen from pairing of many-nucleon systems, nuclear structure, fusion reactions below the Coulomb barrier, and supernova neutrino physics to illustrate the utility of group-theoretical and related algebraic methods in nuclear physics.
The analysis of quasiparticle spectra in heaviest $A\sim 250$ nuclei with spectroscopic data provides an additional constraint for the choice of effective interaction for the description of superheavy nuclei. It strongly suggest that only the parametrizations of the relativistic mean field Lagrangian which predict Z=120 and N=172 as shell closures are reliable for superheavy nuclei. The influence of the central depression in the density distribution of spherical superheavy nuclei on the shell structure is studied. Large central depression produces large shell gaps at Z=120 and N=172. The shell gaps at Z=126 and N=184 are favored by a flat density distribution in the central part of nucleus. It is shown that approximate particle number projection (PNP) by means of the Lipkin-Nogami method removes pairing collapse seen at these gaps in the calculations without PNP.
We derive the product law for the simplest multi-particle higher-spin algebra $M_2(A)$ and its factor-algebra $M^2(A)$ with rank-one fields factored out. Equations of motion for the systems resulting from these algebras are analysed. We conclude that the equations for $M_2(A)$ describe the conformal off-shell higher-spin system with the rank-two fields representing the off-shell degrees of freedom of the originally massless system. On the other hand the equations resulting from $M^2(A)$ describe the infinite system of conserved currents unrelated to massless fields.
For a perturbation of the state of a Conformal Field Theory (CFT), the response of the entanglement entropy is governed by the so-called "first law" of entanglement entropy, in which the change in entanglement entropy is proportional to the change in energy. Whether such a first law holds for other types of perturbations, such as a change to the CFT Lagrangian, remains an open question. We use holography to study the evolution in time $t$ of entanglement entropy for a CFT driven by a $t$-linear source for a conserved $U(1)$ current or marginal scalar operator. We find that although the usual first law of entanglement entropy may be violated, a first law for the rates of change of entanglement entropy and energy still holds. More generally, we prove that this first law for rates holds in holography for any asymptotically $(d+1)$-dimensional Anti-de Sitter metric perturbation whose $t$ dependence first appears at order $z^d$ in the Fefferman-Graham expansion about the boundary at $z=0$.
QSOs from SDSS, 2QZ and 2SLAQ covering an order of magnitude in luminosity at fixed redshift exhibit similar amplitudes of clustering. In addition, QSO clustering evolution at z>0.5 is well fitted by a model that assumes a fixed host halo mass, implying that QSOs may occur in a relatively narrow range of halo and BH mass. We argue that the slow evolution of early-type galaxies out to z~1-2 may also provide support for a slow evolution of QSO host BH masses. The result would mean that if high-z QSOs radiate at Eddington rates then low-z SyI must radiate at ~100x less than Eddington. We conclude that models where QSOs radiate at L_Edd require M_BH and M_halo to be decoupled to circumvent the clustering results. While single BH mass and flickering models fit the z>0.5 clustering results, they appear to be rejected by the z~0, M_BH-L relation from reverberation mapping. We find that the inclusion of z<0.5 QSO clustering data improves the fit of a long-lived QSO model and suggest that the predictions of a PLE model for QSO BH masses agree reasonably with UV-bump and reverberation estimates (abridged).
This paper gives a concise, mathematically rigorous description of phenomenological equilibrium thermodynamics for single-phase systems in the absence of chemical reactions and external forces.   The present approach is similar to that of Callen, who introduces in his well-known thermodynamics book the basic concepts by means of a few postulates from which everything else follows. His setting is modified to match the more fundamental approach based on statistical mechanics. Thermodynamic stability is derived from kinematical properties of states outside equilibrium by rigorous mathematical arguments, superseding Callen's informal arguments that depend on a dynamical assumption close to equilibrium.   From the formulas provided, it is an easy step to go to various examples and applications discussed in standard textbooks such as Callen or Reichl. A full discussion of global equilibrium would also involve the equilibrium treatment of multiple phases and chemical reactions. Since their discussion offers no new aspects compared with traditional textbook treatments, they are not treated here.