Miracle-dz/UniFAR-FTUs huggingface dataset:
Structural Condition Assessment from White Noise Excitation and Covariance of Covariance Matrix

The sensitivity of covariance of covariancematrix with respect to a local stiffness change in the structural system is derived analytically based on the auto/cross-correlation function of the acceleration response, and the original covariance of covariance formula is improved for use with any number of selected structure modes. This paper presents the approach using the improved covariance of covariance matrix of acceleration response for structural condition assessment under white noise support excitation. A simply supported 31 bar plane truss with and without 10% measurement noise is studied numerically. Results show that the sensitivity approach with the covariance of covariance matrix is accurate, and when including the finite impulse response forward and backward filtering technique, themethod would be suitable for industrial application. The covariance of covariancemethod is shown to be insensitive to measurement noise when the measurement time duration is sufficiently long.
Elasticity in certain block monoids via the Euclidean table

AbstractThis paper continues the study begun in [GEROLDINGER, A. : On non-unique factorizations into irreducible elements II, Colloq. Math. Soc. János Bolyai 51 (1987), 723–757] concerning factorization properties of block monoids of the form ℬ(ℤn, S) where S = $$\{ \bar 1,\bar a\} $$ (hereafter denoted ℬa(n)). We introduce in Section 2 the notion of a Euclidean table and show in Theorem 2.8 how it can be used to identify the irreducible elements of ℬa(n). In Section 3 we use the Euclidean table to compute the elasticity of ℬa(n) (Theorem 3.4). Section 4 considers the problem, for a fixed value of n, of computing the complete set of elasticities of the ℬa(n) monoids. When n = p is a prime integer, Proposition 4.12 computes the three smallest possible elasticities of the ℬa(p).
GRB 170817A Associated with GW170817: Multi-frequency Observations and Modeling of Prompt Gamma-Ray Emission

We present our observations of electromagnetic transients associated with GW170817/GRB 170817A using optical telescopes of Chilescope observatory and Big Scanning Antenna (BSA) of Pushchino Radio Astronomy Observatory at 110 MHz. The Chilescope observatory detected an optical transient of ∼19m on the third day in the outskirts of the galaxy NGC 4993; we continued observations following its rapid decrease. We put an upper limit of 1.5 × 104 Jy on any radio source with a duration of 10–60 s, which may be associated with GW170817/GRB 170817A. The prompt gamma-ray emission consists of two distinctive components—a hard short pulse delayed by ∼2 s with respect to the LIGO signal and softer thermal pulse with T ∼ 10 keV lasting for another ∼2 s. The appearance of a thermal component at the end of the burst is unusual for short GRBs. Both the hard and the soft components do not satisfy the Amati relation, making GRB 170817A distinctively different from other short GRBs. Based on gamma-ray and optical observations, we develop a model for the prompt high-energy emission associated with GRB 170817A. The merger of two neutron stars creates an accretion torus of ∼10−2 M⊙, which supplies the black hole with magnetic flux and confines the Blandford–Znajek-powered jet. We associate the hard prompt spike with the quasispherical breakout of the jet from the disk wind. As the jet plows through the wind with subrelativistic velocity, it creates a radiation-dominated shock that heats the wind material to tens of kiloelectron volts, producing the soft thermal component.
The Rest-Frame Optical Properties of SCUBA Galaxies

We present optical and near-infrared photometry for a sample of 96 dusty, far-infrared-luminous galaxies. We have precise spectroscopic redshifts for all these galaxies, yielding a median redshift of = 2.2. The majority, 78, are submillimeter-detected galaxies lying at z = 0.2-3.6, while the remaining 18 are optically faint μJy radio galaxies at z = 0.9-3.4 that are proposed to be similarly luminous, dusty galaxies whose dust emission is too hot to be detected in the submillimeter waveband. We compare the photometric and morphological properties of these distant, ultraluminous galaxies with local samples of dusty, luminous galaxies. We confirm that spectroscopically identified far-infrared-luminous galaxies at z > 1 display a wide variety in their optical-near-infrared and near-infrared colors, with only a modest proportion red enough to classify as unusually red. We show that, on average, luminous, high-redshift dusty galaxies are both brighter and redder in rest-frame optical passbands than comparable samples of UV-selected star-forming galaxies at similar redshifts. Archival Hubble Space Telescope ACS imaging of 20 of our galaxies demonstrates both morphological indications of mergers and interactions, which may have triggered their luminous far-infrared activity, and structured dust distributions within these galaxies. We derive a near-infrared Hubble diagram for far-infrared-luminous galaxies. This shows that this population is typically fainter than high-luminosity radio galaxies at similar redshifts and exhibits significantly more scatter in their K-band magnitudes. The rest-frame optical luminosities of the far-infrared-luminous population are comparable to those of local ultraluminous infrared galaxies, although their far-infrared luminosities are several times higher. The typical extinction-corrected optical luminosity of the high-redshift population, assuming passive evolution, provides a good fit to the bright end of the luminosity function of luminous spheroidal galaxies seen in rich clusters at intermediate redshifts. This adds to the growing body of evidence showing that these high-redshift, far-infrared-luminous sources identify star formation and active galactic nucleus-fueling events in the early life of massive galaxies in the universe.
Image-Subtraction Photometry of the Globular Cluster M3: Identification of New Double-Mode RR Lyrae Stars

We have applied the image subtraction method of Alard and Lupton to the extensive M3 data set previously analyzed by Corwin and Carney using DAOPHOT and ALLSTAR. This new analysis has produced light curves and periods for 15 variables not found in the previous study but already known to be variables, and it has also resulted in improved periods for several other variables. The additional variables recovered with the image subtraction analysis are in the very central region of M3, where crowding is severe and the photometry was not of sufficient quality that it could be put on the standard system. The present study brings to 222 the total number of RR Lyrae variables in Corwin and Carney's M3 data set for which light curves and periods are available. Among them we have identified three new candidate double-mode pulsating variables (V13, V200, and V251), reported here for the first time. This brings to eight the total number of double-mode RR Lyrae (RRd's) identified in M3. Of the newly discovered RRd's V13 is unusual in that it has the fundamental as the dominant pulsation mode. M3 is unique among the globular clusters in having RRd variables with a dominant fundamental mode. Two of the new candidate RRd's (V13 and V200) have period ratios as low as 0.738–0.739. They lie well separated from all previously known double-mode variable stars in the Petersen diagram in positions implying a large spread in mass and/or, less likely, in heavy element mass fraction, among the M3 horizontal-branch (HB) stars. We explore mass transfer and helium enhancement as possible explanations for the apparent spread in HB masses. We also note that the masses derived from the double-mode analyses now favor little mass loss on the red giant branch. We find that V200 has changed its dominant pulsation mode from fundamental to first overtone, while V251 has changed its dominant mode from first overtone to fundamental in the interval 1992 to 1993. Together with M3-V166 this is the first time that double-mode variables are observed to switch their dominant pulsation modes while remaining RRd's. The phenomenon is found to occur in a 1 yr time span, thus suggesting that these stars are undergoing a rapid evolutionary phase and that both redward and blueward evolution may take place among the HB stars in the Oosterhoff type I cluster M3. The unusual behavior of the M3 RRd's is discussed in detail and compared with that of the double-mode RR Lyrae identified so far in globular clusters and in the field of our and other Local Group galaxies. We find a lack of correlation between the presence of RRd variables and any of the cluster structural parameters.
Clues to detect the Pilot Wave in a photon double-slit interference experiment

The Young double-slit interference pattern produced by quantum objects, like photons, that move through a double-slit is regarded, by the conventional Copenhagen interpretation of Quantum Mechanics, as the evidence of the wave-like behaviour potentially contained in the wave function. On the contrary, a more realistic view of this phenomenon considers the quantum object a particle accompanied by a pilot wave which would be the cause of the interference fringes. This paper proposes a feasible experiment, based on an easy variation of the nowadays common double-slit experimental set-ups, aimed at detecting the effects of the pilot wave once 'detached' from the particles that it steers. Besides, a further realistic idea, based on the geometrical violation of Local Lorentz Invariance (LLI), is put forward as to the intrinsic nature of the photon. This new idea along with the possibly positive results of the experiment would allow us to shed new light on the real nature of quantum objects in term of the geometrical violation of LLI.
Optical gain in InGaN∕GaN quantum well structures with embedded AlGaN δ layer

Optical gain characteristics of InGaN∕GaN double quantum well (QW) structures with embedded AlGaN δ layer are investigated using the multiband effective mass theory. These results are compared with those of single QW structure without a δ layer. The theoretical energies show very good agreement with the experimental results for both single and double QW structures. The inclusion effect of a δ layer is found to be dominant at a relatively low carrier density. A double QW structure has larger optical gain than the single QW structure, in particular, at higher carrier density.
Quantizing polaritons in inhomogeneous dissipative systems

In this article we provide a a general analysis of canonical quantization for polaritons in dispersive and dissipative electromagnetic media. We compare several approaches based either on the Huttner Barnett model [B. Huttner, S. M. Barnett, Phys. Rev. A \textbf{46}, 4306 (1992)] or the Green function, Langevin noise method [T. Gruner, D. -G. Welsch, Phys. Rev. A \textbf{53}, 1818 (1996)] which includes only material oscillators as fundamental variables. We show in order to preserve unitarity, causality and time symmetry one must necessarily include with an equal footing both electromagnetic modes and material fluctuations on the evolution equations. This becomes particularly relevant for all nanophotonics and plasmonics problems involving spatially localized antennas or devices.
Twist of a stationary black hole or ring in five dimensions

It is unlikely that uniqueness theorem holds for stationary black holes in higher dimensional spacetimes. However, we will examine the possibility that the higher multipole moments classify vacuum solutions uniquely. Especially, we compute the potentials associated with rotational Killing vectors and look at the dependence on the total mass M and angular momentum J. Consequently, there is a potential {sigma} which we cannot write down in terms of integer power of M and J explicitly. This may be regarded as an evidence for the uniqueness using multipole moments generated by {sigma}.
Measurement of the blackbody radiation shift of the {sup 133}Cs hyperfine transition in an atomic fountain

We used a Cs fountain to measure the Stark shift of the ground-state hyperfine transition frequency in cesium (9.2 GHz) due to the electric field of the blackbody radiation. The relative shift at 300 K deduced from our measurements, including the leading and the second-order term in temperature, is (-1.45{+-}0.09)x10{sup -14} and agrees with our recent theoretical evaluation (-1.51{+-}0.07)x10{sup -14} [Micalizio et al. Phys. Rev. A 69, 053401 (2004)]. These values differ from that currently used (-1.735{+-}0.003)x10{sup -14}, with significant implications on frequency standards accuracy, on clocks comparison and on a variety of high-precision physics tests, such as the time stability of fundamental constants.
A fast spinning magnetic white dwarf in the double degenerate, super-Chandrasekhar system NLTT 12758

We present an analysis of the close double degenerate NLTT 12758, which is comprised of a magnetic white dwarf with a field of about 3.1 MG and an apparently non-magnetic white dwarf. We measured an orbital period of 1.154 d and found that the magnetic white dwarf is spinning around its axis with a period of 23 min. An analysis of the atmospheric parameters has revealed that the cooling ages of the two white dwarfs are comparable, suggesting that they formed within a short period of time from each other. Our modelling indicates that the non-magnetic white dwarf is more massive (M = 0.83M(circle dot)) than its magnetic companion (M = 0.69M(circle dot)) and that the total mass of the system is higher than the Chandrasekhar mass. Although the stars will not come into contact over a Hubble time, when they do come into contact, dynamically unstable mass transfer will take place leading to either an accretion induced collapse into a rapidly spinning neutron star or a Type Ia supernova.
Predicting pulsar scintillation from refractive plasma sheets

The dynamic and secondary spectra of many pulsars show evidence for long-lived, aligned images of the pulsar that are stationary on a thin scattering sheet. One explanation for this phenomenon considers the effects of wave crests along sheets in the ionized interstellar medium, such as those due to Alfven waves propagating along current sheets. If these sheets are closely aligned to our line-of-sight to the pulsar, high bending angles arise at the wave crests and a selection effect causes alignment of images produced at different crests, similar to grazing reflection off of a lake. Using geometric optics, we develop a simple parameterized model of these corrugated sheets that can be constrained with a single observation and that makes observable predictions for variations in the scintillation of the pulsar over time and frequency. This model reveals qualitative differences between lensing from overdense and underdense corrugated sheets: Only if the sheet is overdense compared to the surrounding interstellar medium can the lensed images be brighter than the line-of-sight image to the pulsar, and the faint lensed images are closer to the pulsar at higher frequencies if the sheet is underdense, but at lower frequencies if the sheet is overdense.
Exotic X-ray back-diffraction: a path toward a soft inelastic X-ray scattering spectrometer

In this work, soft X-ray back-diffraction (XBD; X-ray diffraction at angles near and exactly equal to 90°) is explored. The experiment was conducted at the SXS beamline at Laboratorio Nacional de Luz Sincrotron, Brazil, at ∼3.2 keV. A high-resolution Si(220) multi-bounce back-diffraction monochromator was designed and constructed for this experiment. An ultra-thin Si(220) crystal (5 µm thick) was used as the sample. This ultra-thin crystal was characterized by profilometry, rocking-curve measurements and X-ray topography prior to the XBD measurements. It is shown that the measured forward-diffracted beam (o-beam) profiles, taken at different temperatures, are in close agreement with profiles predicted by the extended dynamical theory of X-ray diffraction, with the absence of multiple-beam diffraction (MBD). This is an important result for future studies on the basic properties of back-diffracted X-ray beams at energies slightly above the exact XBD condition (extreme condition where XBD is almost extinguished). Also, the results presented here indicate that stressed crystals behave like ideal strain-free crystals when used for low-energy XBD. This is mainly due to the large widths of XBD profiles, which lead to a low strain sensitivity in the detection of defects. This result opens up new possibilities for mounting spherical analyzers without degrading the energy resolution, at least for low energies. This is a path that may be used to construct a soft inelastic X-ray scattering spectrometer where different applications such as element-specific magnetic imaging tools could be explored.
The Role of Chaos in the Circularization of Tidal Capture Binaries. I. The Chaos Boundary

A self-consistent model for binary evolution devised by Gingold \& Monaghan (1980) is used to show that two distinctly different types of behaviour are possible for close eccentric binaries. The model is based on a linear adiabatic normal mode analysis of the problem, which allows detailed examination of the transfer of energy from the orbit to the tides. We show that for most binaries, energy is exchanged quasi-periodically, with the system regulating itself so that the maximum tidal energy always remains small, and no circularization takes place. In contrast, for a range of eccentricities and periastron separations, {\it chaotic} behaviour prevails, with the eccentricity following a random walk and with the energy transferred to the tides during a single periastron passage being up to an order of magnitude larger than that transferred during the initial periastron passage. These results have important consequences for the study of tidal capture binaries. The standard model (see, for example, McMillan, McDermott \& Taam 1987) assumes that the energy transferred to the tides during a periastron encounter is independent of the oscillatory state of the stars, and that the amount of tidal energy present at any time can be calculated using a formula which (accurately) gives the amount deposited after the first encounter (Press \& Teukolsky 1977). The calculations presented here show that a self-consistent treatment is necessary in order to study the dynamical evolution of tidal capture binaries. We conclude that the tidal capture process would not be possible were it not for the existence of chaotic behaviour.
Vector meson production and nucleon resonance analysis in a coupled-channel approach for energies m N <(s)<2 GeV. I. Pion-induced results and hadronic parameters

We present a nucleon resonance analysis by simultaneously considering all pion- and photon-induced experimental data on the final states $\ensuremath{\gamma}N,$ $\ensuremath{\pi}N,$ $2\ensuremath{\pi}N,$ $\ensuremath{\eta}N,$ $K\ensuremath{\Lambda},$ $K\ensuremath{\Sigma},$ and $\ensuremath{\omega}N$ for energies from the nucleon mass up to $\sqrt{s}=2$ GeV. In this analysis we find strong evidence for the resonances ${P}_{31}(1750),$ ${P}_{13}(1900),$ ${P}_{33}(1920),$ and ${D}_{13}(1950). $ The $\ensuremath{\omega}N$ production mechanism is dominated by large ${P}_{11}(1710)$ and ${P}_{13}(1900)$ contributions. In this first part, we present the results of the pion-induced reactions and the extracted resonance and background properties with emphasis on the difference between global and purely hadronic fits.
Brane in 6D with an increasing gravitational trapping potential

A new solution to the Einstein equations in $1+5$ spacetime with an embedded $1+3$ brane is given. This solution localizes the zero modes of all kinds of matter fields and four-gravity on the (1+3) brane by an increasing, transverse gravitational potential. This localization occurs despite the fact that the gravitational potential is not a decreasing exponential, and asymptotically approaches a finite value rather than zero.
Relativistic X-ray jets at high redshift

Powerful radio sources and quasars emit relativistic jets of plasma and magnetic fields that travel hundreds of kilo-parsecs, ultimately depositing energy into the intra- or inter-cluster medium. In the rest frame of the jet, the energy density of the cosmic microwave background is enhanced by the bulk Lorentz factor squared, and when this exceeds the magnetic energy density the primary loss mechanism of the relativistic electrons is via inverse Compton scattering. The microwave energy density is also enhanced by a factor (1+z)^4, which becomes important at large redshifts. We are using Chandra to survey a z>3 sub-sample of radio sources selected with 21 cm wavelength flux density > 70 mJy, and with a spectroscopic redshift. Out of the first 12 objects observed, there are two clear cases of the X-rays extending beyond the detectable radio jet.
The optical and X-ray flickering of XTE J1118+480

We use both time-domain and Fourier techniques to study the correlated optical/X-rays variability in the black hole X-ray nova XTE J1118+480. Its X-ray timing properties such as the shape of the X-ray power spectrum and cross-correlation functions (CCFs) between X-ray energy bands, the slight decrease of rms variability from 30% in the 2-5.9 ke V to 19% in the 15.5-44.4 ke V band, as well as the X-ray hardness/flux anti-correlation are very similar to what is found in other black hole binaries in the hard state. The optical/X-ray CCF is virtually independent of the X-ray energies. The optical flux appears to be correlated not only with the X-ray flux but also with the X-ray spectral variability. Both the coherence function and the lags between optical and the X-rays are Fourier frequency dependent. The optical/X-ray coherence function reaches its maximum (∼0.3) in the 0.1-1 Hz range and the time-lags decrease with frequency approximatively like f - 0 . 8 . The correlation between X-ray and optical light curves appears to have time-scale-invariant properties. The X-ray/optical CCF maintains a similar but resealed shape on time-scales ranging at least from 0.1 s to few 10 s. Using the event superposition method we show that the correlation is not triggered by a single type of event (dip or flare) in the light curves Instead, optical and X-ray fluctuations of very different shapes, amplitudes and time-scales are correlated in a similar mode where the optical light curve is seemingly related to the time derivative of the X-rays.