Miracle-dz/UniFAR-FTUs huggingface dataset:
Spectrophotometric redshifts. A new approach to the reduction of noisy spectra and its application to GRB 090423

Context. The measurement of redshifts for objects on the verge of instrumental observability is difficult and prone to error. This is especially true for almost featureless spectra, as is the case for GRB afterglows. They can be detected out to the farthest distances, and usually spectroscopy poses a serious problem because they fade quickly. Aims. We have developed a new method that is close in philosophy to the photometric redshift technique, which can be applied to spectral data with a very low signal-to-noise ratio. We intend to measure redshifts, while minimising the dangers posed by the usual extraction techniques. Methods. GRB afterglows have generally very simple optical spectra, which can be described well by a pure power law, over which the separate effects of absorption and reddening in the GRB host, the intergalactic medium, and our own Galaxy are superimposed. We model all these effects over a series of template afterglow spectra to produce a set of clean spectra that reproduce what would reach our telescope. We also carefully model the effects of the telescope-spectrograph combination and the properties of noise in the data, which are then applied to the template spectra. The final templates are compared to the two-dimensional spectral data, and the basic parameters (redshift, spectral index, hydrogen absorption column) are estimated with statistical tools. Results. We show how our method works by applying it to our data of the NIR afterglow of Swift GRB 090423. At z ≈ 8.2, this was the most distant object ever observed. Our team took a spectrum using the Telescopio Nazionale Galileo, which we use in this article to derive its redshift and its intrinsic neutral hydrogen column density. Our best fit yields z = 8.4 +0.05 −0.03 and N(HI) < 5 × 10 20 cm −2 ,b ut with a highly non-Gaussian uncertainty including the redshift range z ∈ [6.7,8.5] at the 2-sigma confidence level. Conclusions. Our method will be useful for maximising the recovered information from low-quality spectra, particularly when the set of possible spectra is limited or easily parameterisable (as is the case in GRB afterglows), while at the same time ensuring adequate confidence analysis.
The very low mass multiple system LHS 1070. A testbed for model atmospheres for the lower end of the main sequence

Context. LHS 1070 is a nearby multiple system of low mass stars. It is an important source of information for probing the low mass end of the main sequence, down to the hydrogen-burning limit. The primary of the system is a mid-M dwarf and two components are late-M to early L dwarfs, at the star-brown dwarf transition. Hence LHS 1070 is a valuable object to understand the onset of dust formation in cool stellar atmospheres. Aims. This work aims at determining the fundamental stellar parameters of LHS 1070 and to test recent model atmospheres: BT-Dusty, BT-Settl, DRIFT, and MARCS models. Methods. Unlike in previous studies, we have performed a chi(2)-minimization comparing well calibrated optical and infrared (IR) spectra with recent cool star synthetic spectra leading to the determination of the physical stellar parameters T-eff, radius, and log g for each of the three components of LHS 1070. Results. With exception of the MARCS models which do not include dust formation, the models are able to reproduce the observations and describe the main features of the visible to IR spectra. This is consistent with the fact that dust formation prevails in the B and C component atmospheres. The parameters obtained with the DRIFT models confirm the values determined in earlier studies. But important differences between models are observed, where the MARCS model is too bright in the H and K bands, and the BT-Settl and BT-Dusty models systematically yield up to 100 K higher T-eff in the case of the B and C components. This confirms a trend for models without, or with less efficient cloud formation, to predict higher T-eff than models richer in dust (DRIFT). Even models including cloud physics however still produce slightly too bright J band flux, showing as too blue J - K colors. The onset of dust formation remains therefore a particularly challenging regime to understand.
Polynomial Form of the Matrix Exponential

An algorithm for numerically computing the exponential of a matrix is presented. We have derived a polynomial expansion of $e^x$ by computing it as an initial value problem using a symbolic programming language. This algorithm is shown to be comparable in operation count and convergence with the state--of--the--art method which is based on a Pade approximation of the exponential matrix function. The present polynomial form, however, is more reliable because the evaluation requires only linear combinations of the input matrix. We also show that the technique used to solve the differential equation, when implemented symbolically, leads to a rational as well as a polynomial form of the solution function. The rational form is the well-known diagonal Pade approximation of $e^x$. The polynomial form, after some rearranging to minimize operation count, will be used to evaluate the exponential of a matrix so as to illustrate its advantages as compared with the Pade form.
CHANDRA OBSERVATIONS OF THE HIGH-MAGNETIC-FIELD RADIO PULSAR J1718−3718

High-magnetic-field pulsars represent an important class of objects for studying the relationship between magnetars and radio pulsars. Here we report on four Chandra observations of the high-magnetic-field pulsar J1718−3718 (B = 7.4 × 1013 G) taken in 2009 as well as a reanalysis of 2002 Chandra observations of the region. We also report an improved radio position for this pulsar based on ATCA observations. We detect X-ray pulsations at the pulsar's period in the 2009 data, with a pulsed fraction of 52% ± 13% in the 0.8–2.0 keV band. We find that the X-ray pulse is aligned with the radio pulse. The data from 2002 and 2009 show consistent spectra and fluxes: a merged overall spectrum is well fit by a blackbody of temperature 186+19 − 18 eV, slightly higher than predicted by standard cooling models; however, the best-fit neutron star atmosphere model is consistent with standard cooling. We find the bolometric luminosity L∞bb = 4+5 − 2 × 1032 erg s−1 for a distance of 4.5 kpc. We compile measurements of the temperatures of all X-ray-detected high-B pulsars as well as those of low-B radio pulsars and find evidence for the former being hotter on average than the latter.
Explicit equations of a fake projective plane

Fake projective planes are smooth complex surfaces of general type with Betti numbers equal to those of the usual projective plane. They come in complex conjugate pairs and have been classified as quotients of the two-dimensional ball by explicitly written arithmetic subgroups. In this paper we find equations of a projective model of a conjugate pair of fake projective planes by studying the geometry of the quotient of such surface by an order seven automorphism.
Scatter and bias in weak lensing selected clusters

We examine scatter and bias in weak lensing selected clusters, employing both an analytic model of dark matter haloes and numerical mock data of weak lensing cluster surveys. We pay special attention to effects of the diversity of dark matter distributions within clusters. We find that peak heights of the lensing convergence map correlate rather poorly with the virial mass of haloes. The correlation is tighter for the spherical overdensity mass with a higher mean interior density (e.g. M1000). We examine the dependence of the halo shape on the peak heights, and find that the root mean square scatter caused by the halo diversity scales linearly with the peak heights with the proportionality factor of 0.1–0.2. The noise originated from the halo shape is found to be comparable to the source galaxy shape noise and the cosmic shear noise. We find the significant halo orientation bias, i.e. weak lensing selected clusters on average have their major axes aligned with the line-of-sight direction, and that the orientation bias is stronger for higher signal-to-noise ratio (S/N) peaks. We compute the orientation bias using an analytic triaxial halo model and obtain results quite consistent with the ray-tracing results. We develop a prescription to analytically compute the number count of weak lensing peaks taking into account all the main sources of scatters in the peak heights. We find that the improved analytic predictions agree well with the simulation results for high-S/N peaks of . We also compare the expected number count with our weak lensing analysis results for 4 deg2 of Subaru/Suprime-Cam observations and find a good agreement.
Minimal Lipschitz and ∞-harmonic extensions of vector-valued functions on finite graphs

This paper deals with extensions of vector-valued functions on finite graphs fulfilling distinguished minimality properties. We show that so-called $\mathrm{lex}$ and $L\mbox{-}\mathrm{lex}$ minimal extensions are actually the same and call them minimal Lipschitz extensions. Then, we prove that the solution of the graph $p$-Laplacians converge to these extensions as $p\to \infty$. Furthermore, we examine the relation between minimal Lipschitz extensions and iterated weighted midrange filters and address their connection to $\infty$-Laplacians for scalar-valued functions. A convergence proof for an iterative algorithm proposed by Elmoataz et al. (2014) for finding the zero of the $\infty$-Laplacian is given. Finally, we present applications in image inpainting.
On integrals associated with the free particle wave packet

Abstract We discuss some properties of integrals associated with the free particle wave packet, ψ ⁢ ( x , t ) {\psi(x,t)} , which are solutions to the time-dependent Schrödinger equation for a free particle. Some noteworthy discussion is made in relation to integrals which have appeared in the literature. We also obtain formulas for half-integer arguments of the Riemann zeta function.
DIA-TTS: Deep-Inherited Attention-Based Text-to-Speech Synthesizer

Text-to-speech (TTS) synthesizers have been widely used as a vital assistive tool in various fields. Traditional sequence-to-sequence (seq2seq) TTS such as Tacotron2 uses a single soft attention mechanism for encoder and decoder alignment tasks, which is the biggest shortcoming that incorrectly or repeatedly generates words when dealing with long sentences. It may also generate sentences with run-on and wrong breaks regardless of punctuation marks, which causes the synthesized waveform to lack emotion and sound unnatural. In this paper, we propose an end-to-end neural generative TTS model that is based on the deep-inherited attention (DIA) mechanism along with an adjustable local-sensitive factor (LSF). The inheritance mechanism allows multiple iterations of the DIA by sharing the same training parameter, which tightens the token–frame correlation, as well as fastens the alignment process. In addition, LSF is adopted to enhance the context connection by expanding the DIA concentration region. In addition, a multi-RNN block is used in the decoder for better acoustic feature extraction and generation. Hidden-state information driven from the multi-RNN layers is utilized for attention alignment. The collaborative work of the DIA and multi-RNN layers contributes to outperformance in the high-quality prediction of the phrase breaks of the synthesized speech. We used WaveGlow as a vocoder for real-time, human-like audio synthesis. Human subjective experiments show that the DIA-TTS achieved a mean opinion score (MOS) of 4.48 in terms of naturalness. Ablation studies further prove the superiority of the DIA mechanism for the enhancement of phrase breaks and attention robustness.
Quantum-state tomography using a single apparatus

The density matrix of a two-level system (spin, atom) is usually determined by measuring the three noncommuting components of the Pauli vector. This density matrix can also be obtained via the measurement data of two commuting variables, using a single apparatus. This is done by coupling the two-level system to a mode of radiation field, where the atom-field interaction is described with the Jaynes-Cummings model. The mode starts its evolution from a known coherent state. The unknown initial state of the atom is found by measuring two commuting observables: the population difference of the atom and the photon number of the field. We discuss the advantages of this setup and its possible applications.
Neutrino Physics

These lectures aim at providing a pedagogical overview of neutrino physics. We will mostly deal with standard neutrinos, the ones that are part of the Standard Model of particle physics, and with their standard dynamics, which is enough to understand in a coherent picture most of the rich data available. After introducing the basic theoretical framework, we will illustrate the experimental determination of the neutrino parameters and their theoretical implications, in particular for the origin of neutrino masses.
AGN feedback and iron enrichment in the powerful radio galaxy, 4C+55.16

We present a detailed X-ray analysis of 4C+55.16, an unusual and interesting radio galaxy, located at the centre of a cool core cluster of galaxies. 4C+55.16 is X-ray bright (LX(cluster)∼ 1045 erg s−1), radio powerful, and shows clear signs of interaction with the surrounding intracluster medium (ICM). By combining deep Chandra (100 ks) with 1.4 GHz Very Large Array observations, we find evidence of multiple outbursts from the central active galactic nucleus (AGN), providing enough energy to offset cooling of the ICM (Pbubbles= 6.7 × 1044 erg s−1). Furthermore, 4C+55.16 has an unusual intracluster iron distribution showing a plume-like feature rich in Fe L emission that runs along one of the X-ray cavities. The excess of iron associated with the plume is around 107 M⊙. The metal abundances are consistent with being solar-like, indicating that both Type Ia supernova and Type II supernova contribute to the enrichment. The plume and southern cavity form a region of cool metal-rich gas, and at the edge of this region, there is a clear discontinuity in temperature (from kT∼ 2.5 to ∼5.0 keV), metallicity (from ∼0.4 to ∼0.8 Z⊙), and surface brightness distribution, consistent with it being caused by a cold front. However, we also suggest that this discontinuity could be caused by cool metal-rich gas being uplifted from the central AGN along one of its X-ray cavities.
Extension the Noether's theorem to Lagrangian formulation with nonlocality

A Lagrangian formulation with nonlocality is investigated in this paper. The nonlocality of the Lagrangian is introduced by a new nonlocal argument that is defined as a no nlocal residual satisfying the zero mean condition. The nonlocal Euler-Lagrangian equation is derived fr om the Hamilton’s principle. The Noether’s theorem is extended to this Lagrangian formulation with nonlocalit y. With the help of the extended Noether’s theorem, the conservation laws relevant to energy, linear momentum, angular momentum and the Eshelby tensor are determined in the nonlocal elasticity associated with the mec hanically based constitutive model. The results show that the conservation laws exist only in the form of the integ ral over the whole domain occupied by body. The localization of the conservation laws is discussed in detai l. We demonstrate that not every conservation law corresponds to a local equilibrium equation. Only when the nonl ocal residual of conservation current exists, can a conservation law be transformed into a local equilibrium eq uation by localization.
Improving student understanding of addition of angular momentum in quantum mechanics

We describe the difficulties advanced undergraduate and graduate students have with concepts related to addition of angular momentum in quantum mechanics. We also describe the development and implementation of a research-based learning tool, a Quantum Interactive Learning Tutorial (QuILT), to reduce these difficulties. The preliminary evaluation shows that the QuILT related to the basics of the addition of angular momentum is helpful in improving students' understanding of these concepts.
A solution to two party typicality using representation theory of the symmetric group

We show that, given a state on a bipartite system AB, the product of the tensor product of the typical projections for the marginal states on A and B and the typical projection for AB can be used to describe the correct asymptotics of the bipartite state itself, its square, marginals and sqares of the marginals. Typicality is defined using the representation theory of the symmetric group. This result has already been proven, but with a different notion of typicality.
Gap Localization of TE-Modes by arbitrarily weak defects - multiband case

This paper considers the propagation of TE-modes in photonic crystal waveguides. The waveguide is created by introducing a linear defect into a periodic background medium. Both the periodic background problem and the perturbed problem are modelled by a divergence type equation. A feature of our analysis is that we allow discontinuities in the coefficients of the operator, which is required to model many photonic crystals. Using the Floquet-Bloch theory in negative order Sobolev spaces, we characterize the precise number of eigenvalues created by the line defect in terms of the band functions of the original periodic background medium for arbitrarily weak defects.
Large jets from small-scale magnetic fields

We consider the conditions under which a rotating magnetic object can produce a magnetically powered outflow in an initially unmagnetized medium stratified under gravity. 3D MHD simulations are presented in which the footpoints of localized, arcade-shaped magnetic fields are placed in rotation. We show how the effectiveness of producing a collimated magnetically powered outflow depends on the rotation rate, and both the strength and the geometry of the field. The flows produced by uniformly rotating, non-axisymmetric fields are found to consist mainly of buoyant plumes heated by the dissipation of rotational energy. Collimated magnetically powered flows are formed if the field and the rotating surface are arranged such that a toroidal magnetic field is produced. This requires that the arcades’ footpoints are differentially rotating. These jets are well-collimated and we follow their propagation through the stratified atmosphere over a distance 100 times the source size. The magnetic field is tightly wound and its propagation is dominated by the development of non-axisymmetric instabilities. We observe a Poynting flux conversion efficiency of over 75% in the longest simulations. Applications to the collapsar model and protostellar jets are discussed.
LABOR USE EFFICIENCY OF ETHIOPIAN AIRPORTS

This study analyses labor use efficiency of Ethiopian airports using an input requirement function approach. The study considers panel data for 13 international and domestic airports covering the period 2002-2017. The fixed effects, a multi-step model of separating persistent and transitory inefficiency, and maximum likelihood estimation techniques are used for estimating the airports’ labor use efficiency. The study concluded that labor use and airport output were complementary hence expansion of airport facilities is recommended. Capital, energy, and maintenance and repair inputs substitute labor use. The efficiency results vary according to the models’ underlying assumptions. The average labor use efficiency of the fixed-effects, multi-step and maximum likelihood methods are 47.52, 49.60 and 50.59% respectively. Despite these minor differences, many domestic airports performed relatively better compared to international airports. Thus, deployment of resources above the minimum requirements should be reconsidered as a source of cost reduction. The airports with high persistent inefficiency will continue to remain inefficient which may necessitate structural changes and revision of employment and labor use policies so as to increase their labor productivity.
BURST TAILS FROM SGR J1550–5418 OBSERVED WITH THE ROSSI X-RAY TIMING EXPLORER

We present the results of our extensive search using the Bayesian block method for long tails following short bursts from a magnetar, SGR J1550–5418, over all RXTE observations of the source. We identified four bursts with extended tails, most of which occurred during its 2009 burst active episode. The durations of tails range between ∼13 s and over 3 ks, which are much longer than the typical duration of bursts. We performed detailed spectral and temporal analyses of the burst tails. We find that the spectra of three tails show a thermal nature with a trend of cooling throughout the tail. We compare the results of our investigations with the properties of four other extended tails detected from SGR 1900+14 and SGR 1806–20 and suggest a scenario for the origin of the tail in the framework of the magnetar model.
Transverse and longitudinal gradients of the spin magnetization in spin-density-functional theory

We derive the gradient expansion for the exchange energy of a spin-polarized electron gas by perturbing the uniformly spin polarized state and thus inducing a small non-collinearity that is slowly varying in space. We show that the exchange-energy contribution due to the induced longitudinal gradient of the spin polarization to the exchange energy differs from the contribution due to the transverse gradient. The difference is present at any non-vanishing spin polarization and becomes larger with increasing spin polarization. We argue that improved generalized gradient approximations of Spin-Density-Functional Theory must account for the difference between the longitudinal and transverse spin stiffness.
Global ocean dimethylsulfide photolysis rates quantified with a 2 spectrally and vertically resolved model 3

31 Photochemical reactions initiated by ultraviolet (UV) radiation remove the climate-active gas dimethylsulfide (DMS) from the ocean’s surface layer. Here we quantified DMS 33 photolysis using a satellite-based model that accounts for spectral irradiance attenuation in the water column, its absorption by chromophoric dissolved organic matter (CDOM), 35 and the apparent quantum yields (AQYs) with which absorbed photons photodegrade 36 DMS. Models with two alternative parameterizations for AQY estimate global DMS 37 photolysis at between 17 and 20 Tg S yr -1 , equivalent to 13–15 Tg C yr -1 , of which ~73% 38 occurs in the Southern hemisphere. This asymmetry results mostly from the high AQYs 39 found south of 40°S, which more than counteract the prevailing low irradiance and deep 40 mixing in that region. Simplified schemes currently used in biogeochemical models, 41 whereby photolysis is proportional to visible radiation, likely overestimate DMS 42 photolysis by around 150% globally. We propose relevant corrections and simple 43 adjustments to those models.
Planetary nebulae in the VISTA Magellanic Cloud (VMC) Survey

Abstract The multi-epoch YJK s sub-arcsecond photometry of the VMC survey provides a long anticipated deep near-infrared (NIR) window into further understanding the stellar populations of the Magellanic Clouds. The first year of observations consisted of six tiles covering ~9% of the Large Magellanic Cloud (LMC) survey region and contains 102 objects previously classified as planetary nebulae (PNe). A large proportion of the sample were found to be contaminated by non-PNe. These initial results underline the importance of establishing a clean catalogue of LMC PNe before they are applied in areas such as the planetary nebula luminosity function (PNLF) and searches for binary central stars. As the VMC survey progresses it will play a fundamental role in cleaning extant PN catalogues and a complementary role in the discovery of new PNe.