Miracle-dz/UniFAR-FTUs huggingface dataset:
The starburst galaxy NGC 253 revisited by H.E.S.S. and Fermi-LAT

Context. NGC 253 is one of only two starburst galaxies found to emit γ-rays from hundreds of MeV to multi-TeV energies. Accurate measurements of the very-high-energy (VHE; E > 100 GeV) and high-energy (HE; E > 60 MeV) spectra are crucial to study the underlying particle accelerators, probe the dominant emission mechanism(s) and to study cosmic-ray interaction and transport. Aims. The measurement of the VHE γ-ray emission of NGC 253 published in 2012 by H.E. S.S. was limited by large systematic uncertainties. Here, the most up to date measurement of the γ-ray spectrum of NGC 253 is investigated in both HE and VHE γ-rays. Assuming a hadronic origin of the γ-ray emission, the measurement uncertainties are propagated into the interpretation of the accelerated particle population. Methods. The data of H.E. S.S. observations are reanalysed using an updated calibration and analysis chain. The improved Fermi–LAT analysis employs more than 8 yr of data processed using pass 8. The cosmic-ray particle population is evaluated from the combined HE–VHE γ-ray spectrum using NAIMA in the optically thin case. Results. The VHE γ-ray energy spectrum is best fit by a power-law distribution with a flux normalisation of (1.34 ± 0.14stat ± 0.27sys) × 10−13 cm−2 s−1 TeV1 at 1 TeV – about 40% above, but compatible with the value obtained in Abramowski et al. (2012). The spectral index Γ = 2.39 ± 0.14stat ± 0.25sys is slightly softer than but consistent with the previous measurement within systematic errors. In the Fermi energy range an integral flux of F(E > 60 MeV) = (1.56 ± 0.28stat ± 0.15sys) × 10−8 cm−2 s−1 is obtained. At energies above ∼3 GeV the HE spectrum is consistent with a power-law ranging into the VHE part of the spectrum measured by H.E. S.S. with an overall spectral index Γ = 2.22 ± 0.06stat. Conclusions. Two scenarios for the starburst nucleus are tested, in which the gas in the starburst nucleus acts as either a thin or a thick target for hadronic cosmic rays accelerated by the individual sources in the nucleus. In these two models, the level to which NGC 253 acts as a calorimeter is estimated to a range of fcal = 0.1 to 1 while accounting for the measurement uncertainties. The presented spectrum is likely to remain the most accurate measurements until the Cherenkov Telescope Array (CTA) has collected a substantial set of data towards NGC 253.
Dynamics of spatially localized states in transitional plane Couette flow

Unsteady spatially localized states such as puffs, slugs or spots play an important role in transition to turbulence. In plane Couette flow, steady versions of these states are found on two intertwined solution branches describing homoclinic snaking (Schneider et al., Phys. Rev. Lett., vol. 104, 2010, 104501). These branches can be used to generate a number of spatially localized initial conditions whose transition can be investigated. From the low Reynolds numbers where homoclinic snaking is first observed ( $Re<175$ ) to transitional ones ( $Re\approx 325$ ), these spatially localized states traverse various regimes where their relaminarization time and dynamics are affected by the dynamical structure of phase space. These regimes are reported and characterized in this paper for a $4\unicode[STIX]{x03C0}$ -periodic domain in the streamwise direction as a function of the two remaining variables: the Reynolds number and the width of the localized pattern. Close to the snaking, localized states are attracted by spatially localized periodic orbits before relaminarizing. At larger values of the Reynolds number, the flow enters a chaotic transient of variable duration before relaminarizing. Very long chaotic transients ( $t>10^{4}$ ) can be observed without difficulty for relatively low values of the Reynolds number ( $Re\approx 250$ ).
Analysis of the Amplitude of the Sunyaev–Zel’dovich Effect out to Redshift z = 0.8

The interaction of the cosmic microwave background (CMB) with the hot gas in clusters of galaxies, the so-called Sunyaev–Zel’dovich (SZ) effect, is a very useful tool that allows us to determine the physical conditions in such clusters and fundamental parameters of the cosmological models. In this work, we determine the dependence of the SZ surface brightness amplitude with redshift and mass of the clusters. We have used PLANCK+IRAS data in the microwave-far-infrared and a catalog with clusters of galaxies extracted from the SDSS by Wen et al. We estimate and subtract the dust emission from those clusters. From the residual flux, we extract its SZ flux densities. The absolute value of the SZ amplitude indicates that the gas mass is around 10% of the total mass for cluster masses of . This amplitude is compatible with no evolution with redshift and proportional to (using X-ray derived masses) or (using weak-lensing derived masses), with some tension regarding the expectations of the self-similar dependence (amplitude proportional to ). Other secondary products of our analysis include that clusters have a dust emission with emissivity index and temperature K; we confirm that the CMB temperature agrees with a dependence of with clusters of much lower mass than those explored previously; and we find that the cluster masses derived by Wen et al. from a richness-mass relationship are biased by a factor of with respect to the X-ray and weak-lensing measurements.
Low Temperature Ageing Behaviour of U-Nb $\gamma^{o}$ Phase Alloys

Ageing mechanisms of the U-7\%wtNb alloy have been investigated on samples exposed to temperatures of 150$^{o}$C for up to 5000\,hours. A variety of surface and bulk analytic techniques have been used to investigate microstructural, chemical and crystallographic changes. Characterisation of the alloy's evolving behaviour was carried out through secondary electron microscopy, energy dispersive x-ray spectroscopy, electron backscatter diffraction, transmission electron microscopy and x-ray diffraction. Vickers hardness testing showed evidence of a strong thermal hardening relationship with ageing. The mechanism responsible for these changes is thought to be a stress-induced isothermal martensitic transformation; a displacive reaction, in which correlated shuffling of atoms creates a phase change from $\gamma^{o}$ to $\alpha''$ without chemical species redistribution.
The Dingle Dell meteorite: A Halloween treat from the Main Belt

We describe the fall of the Dingle Dell (L/LL 5) meteorite near Morawa in Western Australia on October 31, 2016. The fireball was observed by six observatories of the Desert Fireball Network (DFN), a continental‐scale facility optimized to recover meteorites and calculate their pre‐entry orbits. The 30 cm meteoroid entered at 15.44 km s−1, followed a moderately steep trajectory of 51° to the horizon from 81 km down to 19 km altitude, where the luminous flight ended at a speed of 3.2 km s−1. Deceleration data indicated one large fragment had made it to the ground. The four person search team recovered a 1.15 kg meteorite within 130 m of the predicted fall line, after 8 h of searching, 6 days after the fall. Dingle Dell is the fourth meteorite recovered by the DFN in Australia, but the first before any rain had contaminated the sample. By numerical integration over 1 Ma, we show that Dingle Dell was most likely ejected from the Main Belt by the 3:1 mean motion resonance with Jupiter, with only a marginal chance that it came from the ν6 resonance. This makes the connection of Dingle Dell to the Flora family (currently thought to be the origin of LL chondrites) unlikely.
A Climatology of Gravity Wave Motions in the Mesopause Region at Adelaide, Australia

Abstract A statistical study of gravity wave motions in the mesosphere and lower thermosphere measured with a MF partial reflection radar located at Buckland Park new Adelaide (35°S, 138°E) in the period November 1933 to December 1984 is presented. The analyses am confined to waves with ground based periods between 1 and 24 h. Time-height cross sections show that the mean square amplitudes u′2 and v′2, of the zonal and meridional perturbation velocities, respectively, vary in a predominantly semiannual manner such that the minima in wave activity coincide with the reversals in the zonal circulation in the middle atmosphere. In most instances, v′2 is greater than u′2 which, together with the small but nonzero u′v′ fluxes shows that the gravity wave field is partially polarized. A technique similar to that used to analyse partially polarized electromagnetic waves suggests that on a seasonal basis, the wave field is polarized by about 10% to 20% but for shorter periods the degree of polarization may be signi.
Splitting over nilpotent and hypercentral residuals

It is a well known theorem of Gaschütz (4) and Schenkman (12) that if G is a finite group whose nilpotent residual A is Abelian, then G splits over A and the complements to A in G are conjugate. Following Robinson (10) we describe this situation by saying that G splits conjugately over A. A number of generalizations of this result have since been obtained, some of them being in the context of the formation theory of finite or locally finite groups (see, for example, (1), (3)) and others, for example, the recent and far-reaching results of Robinson (10, 11) being concerned with groups which are not necessarily periodic. Our results here are of the latter type.
PHOTOCONDUCTOR GAIN MECHANISMS IN GAN ULTRAVIOLET DETECTORS

GaN photoconductive detectors have been fabricated on sapphire substrates by metal organic vapor phase epitaxy and gas-source molecular beam epitaxy on Si (111) substrates. The photodetectors showed high photoconductor gains, a very nonlinear response with illuminating power, and an intrinsic nonexponential photoconductance recovery process. A novel photoconductor gain mechanism is proposed to explain such results, based on a modulation of the conductive volume of the layer.
The Redshift Distribution of Short Gamma-Ray Bursts from Dynamically Formed Neutron Star Binaries

Short-hard γ-ray bursts (SHBs) may arise from gravitational-wave (GW) driven mergers of double neutron star (DNS) systems. DNSs may be "primordial" or can form dynamically by binary exchange interactions in globular clusters during core collapse. For primordial binaries, the time delay between formation and merger is expected to be short, τ ~ 0.1 Gyr, implying that the redshift distribution of merger events should follow that of star formation. We point out here that for dynamically formed DNSs, the time delay between star formation and merger is dominated by the cluster core-collapse time, rather than by the GW inspiraling time, yielding delays comparable to the Hubble time. We derive the redshift distribution of merger events of dynamically formed DNSs and find it to differ significantly from that typically expected for primordial binaries. The observed redshift distribution of SHBs favors dynamical formation, although a primordial origin cannot be ruled out, because of possible detection biases. Future redshift observations of SHBs may allow us to determine whether they are dominated by primordial or dynamically formed DNSs.
Recent developments at the TwinMic beamline at ELETTRA: an 8 SDD detector setup for low energy X-ray Fluorescence

The present manuscript reports the characteristics of a novel Low Energy X-ray Fluorescence (LEXRF) system installed at the TwinMic X-ray Microscopy station operated at Elettra synchrotron (Trieste, Italy). The setup has been recently upgraded to an 8 large area Silicon Drift Detectors (SDD) system able to collect the XRF fluorescence emitted by the specimen in the 180-2200 eV energy range. The LEXRF system in an X-ray microscope has allowed combining chemical specificity of the specimen with the morphological information acquired in transmission at submicron length scales. Distinct advances of the new set-up are related to software system that has introduced new algorithms and methods.
Cosmological evolution of the nitrogen abundance

The abundance of nitrogen in the interstellar medium is a powerful probe of star for- mation processes over cosmological timescales. Since nitrogen can be produced both in massive and intermediate-mass stars with metallicity-dependent yields, its evolution is challenging to model, as evidenced by the differences between theoretical predictions and observations. In this work we attempt to identify the sources of these discrepancies using a cosmic evolution model. To further complicate matters, there is considerable dispersion in the abundances from observations of DLAs at redshift 2 - 3. We study the evolution of nitrogen with a detailed chemical evolution model and find good agreement with observations, including the relative abundances of N/O and N/Si ratios. We find that the principal contribution of nitrogen comes from intermediate mass stars, with the exception of systems with the lowest N/H, where nitrogen production might possibly be dominated by massive stars. This last result could be strengthened if stellar rotation which is important at low metallicity can produce significant amounts of nitrogen. Moreover, these systems likely reside in host galaxies with stellar masses below 10**8.5 solar mass. We also study the origin of the observed dispersion in nitrogen abundances using the cosmological hydrodynamical simulations Horizon-AGN. We conclude that this dispersion can originate from two effects: differ- ence in the masses of the DLA host galaxies, and difference in the their position inside the galaxy.
Oxygen in the Very Early Galaxy

Oxygen abundances in a sample of ultra-metal-poor subdwarfs have been derived from measurements of the oxygen triplet at 7771-5 Å and OH lines in the near-UV performed in high-resolution and high signal-to-noise ratio spectra obtained with WHT/UES, Keck I/HIRES, and VLT/UVES. Our Fe abundances were derived in LTE and then corrected for non-LTE (NLTE) effects. The new oxygen abundances confirm previous findings for a progressive linear rise in the oxygen-to-iron ratio with a slope -0.33 ± 0.02 from solar metallicity to [Fe/H] ~ -3. A slightly higher slope would be obtained if the Fe NLTE corrections were not considered. Below [Fe/H] = -2.5 our stars show [O/Fe] ratios as high as ~1.17 (G64-12), which can be interpreted as evidence for oxygen overproduction in the very early epoch of the formation of the halo, possibly associated with supernova events with very massive progenitor stars. We show that the arguments against this linear trend given by Fulbright & Kraft in 1999, based on the LTE Fe analysis of two metal-poor stars, cannot be sustained when an NLTE analysis is performed. We discuss how the Fulbright & Kraft LTE ionization balance of Fe lines underestimates the gravity of the very metal-poor star BD +23°3130 ([Fe/H] = -2.43) and how this leads to an underestimation of the oxygen abundance derived from the forbidden line. Gravities from Hipparcos appear to be in good agreement with those determined in NLTE, giving higher values than previously assumed, which reduces the discrepancies between the oxygen abundances determined from OH, triplet, and forbidden lines. Using one-dimensional models, our analysis of three oxygen indicators available for BD +23°3130 gives an average [O/Fe] ratio of 0.78. The high oxygen abundances at very low metallicities do not pose a problem to theoretical modeling since there is a range of parameters in the calculations of nucleosynthesis yields from massive stars at low metallicities that can accommodate our results.
An Astrometric Companion to the Nearby Metal-Poor, Low-Mass Star LHS 1589

We report the discovery of a companion to the high proper motion star LHS 1589, a nearby high-velocity, low-mass subdwarf. The companion (LHS 1589B) is located 0.224′′ ± 0.004′′ to the southwest of the primary (LHS 1589A), and is 0.5 mag fainter than the primary in the Ks band. The pair was resolved with the IRCAL infrared camera at Lick Observatory, operating with the Laser Guide Star Adaptive Optics system. A low-resolution spectrum of the unresolved pair obtained at the MDM observatory shows the source to be consistent with a cool subdwarf of spectral subtype sdK7.5. A photometric distance estimate places the metal-poor system at a distance d = 81 ± 18 pc from the Sun. We also measure a radial velocity Vrad = 67 ± 8 km s-1, which, together with the proper motion and estimated distance, suggests that the pair is roaming the inner Galactic halo on a highly eccentric orbit. With a projected orbital separation s = 18.1 ± 4.8 AU, and a crude estimate of the system's total mass, we estimate the orbital period of the system to be in the range 75 yr < P < 500 yr. This suggests that the dynamical mass of the system could be derived astrometrically, after monitoring the orbital motion over a decade or so. The LHS 1589AB system could thus provide a much needed constraint to the mass-luminosity relationship of metal-poor, low-mass stars.
Low-temperature features in the heat capacity of unary metals and intermetallics for the example of bulk aluminum and Al3Sc

We explore the competition and coupling of vibrational and electronic contributions to the heat capacity of Al and Al$_3$Sc at temperatures below 50 K combining experimental calorimetry with highly converged finite temperature density functional theory calculations. We find that semilocal exchange correlation functionals accurately describe the rich feature set observed for these temperatures, including electron-phonon coupling. Using different representations of the heat capacity, we are therefore able to identify and explain deviations from the Debye behaviour in the low-temperature limit and in the temperature regime 30 - 50 K as well as the reduction of these features due to the addition of Sc.
Charged Higgs contributions to CP violation in $\tau^- \to K^-\pi^0\nu_{\tau}$

In this paper we derive the new contributions to the effective Hamiltonian governs $\vert\Delta S \vert=1$ semileptonic tau decays in the framework of two Higgs doublet model with generic Yukawa structure. We list all operators, in the effective Hamiltonian, generated from the charged Higgs exchange up to one loop-level and provide analytical expression for their corresponding Wilson coefficients. Moreover, we analyze the role of the different contributions, originating from the scalar, vecor and tensor hadronic currents, in generating direct CP asymmetry in the decay rate of $\tau^-\to K^-\pi^0\nu_\tau$. We show that non vanishing direct CP asymmetry in the decay rate of $\tau^-\to K^-\pi^0\nu_\tau$ can be generated due to the presence of both, the weak phase in the Wilson coefficient corresponding to the tensor operator and the strong phase difference resulting from the interference between the form factors expressing the matrix elements of the vector and tensor hadronic currents. After taking into account all relevant constraints, we find that the generated CP asymmetry can be enhanced $6$ orders of magnitude larger than the standard model prediction.
Superconductivity around nematic quantum critical point in two-dimensional metals

We study the properties of $s$-wave superconductivity induced around a nematic quantum critical point in two-dimensional metals. The strong Landau damping and the Cooper pairing between incoherent fermions have dramatic mutual influence on each other, and hence should be treated on an equal footing. This problem is addressed by analyzing the self-consistent Dyson-Schwinger equations for the superconducting gap and Landau damping rate. We solve the equations at zero temperature without making any linearization, and show that the superconducting gap is maximized at the quantum critical point and decreases rapidly as the system departs from this point. The interplay between nematic fluctuation and an additional pairing interaction, caused by phonon or other boson mode, is also investigated. The total superconducting gap generated by such interplay can be several times larger than the direct sum of the gaps separately induced by these two pairing interactions. This provides a promising way to achieve remarkable enhancement of superconductivity.
Proton radii of 4,6,8He isotopes from high-precision nucleon-nucleon interactions

Recently, precision laser spectroscopy on {sup 6}He atoms determined accurately the isotope shift between {sup 4}He and {sup 6}He and, consequently, the charge radius of {sup 6}He. A similar experiment for {sup 8}He is under way. We have performed large-scale ab initio calculations for {sup 4,6,8}He isotopes using high-precision nucleon-nucleon (NN) interactions within the no-core shell model (NCSM) approach. With the CD-Bonn 2000 NN potential we found point-proton root-mean-square (rms) radii of {sup 4}He and {sup 6}He 1.45(1) fm and 1.89(4), respectively, in agreement with experiment and predict the {sup 8}He point proton rms radius to be 1.88(6) fm. At the same time, our calculations show that the recently developed nonlocal INOY NN potential gives binding energies closer to experiment, but underestimates the charge radii.
INTERFEROMETRIC INVESTIGATION OF THE WAVEFRONT OF LASER BEAMS

A simple interferometric technique which uses a diverging spherical comparison wave for study of laser beams is described. The interference pattern resulting from superposition of the primary beam and a small portion of the expanded comparison wavefront provides information about both the phase and some spatial coherence properties of the primary radiation. Expected interference patterns have been obtained for a spatially coherent beam from a He–Ne gas laser. The phase character and spatial coherence features of the beam from a Q‐switched ruby laser have been investigated.
A New Interpretation of Vortex-Split Sudden Stratospheric Warmings in Terms of Equilibrium Statistical Mechanics

AbstractVortex-split sudden stratospheric warmings (S-SSWs) are investigated by using the Japanese 55-year Reanalysis, a spherical barotropic quasigeostrophic (QG) model, and equilibrium statistical mechanics. The statistical mechanics theory predicts a large-scale steady state as the most probable outcome of turbulent stirring, and such a state can be computed without describing all the details of the dynamics. The theory is applied to a disk domain that is modeled on the polar cap north of 45°N in the stratosphere. The equilibrium state is obtained by computing the maximum of an entropy functional. In the range of parameters relevant to the winter stratosphere, this state is anticyclonic. By contrast, cyclonic states are quasi-stationary states corresponding to saddle points of the entropy functional. These results indicate that the mean state of the stratosphere associated with the polar vortex is not close to an equilibrium state but to a quasi-stationary state. The theoretical calculations are compar.
Local unitary versus local Clifford equivalence of stabilizer states

We study the relation between local unitary (LU) equivalence and local Clifford (LC) equivalence of stabilizer states. We introduce a large subclass of stabilizer states, such that every two LU equivalent states in this class are necessarily LC equivalent. Together with earlier results, this shows that LC, LU, and stochastic local operation with classical communication equivalence are the same notions for this class of stabilizer states. Moreover, recognizing whether two given stabilizer states in the present subclass are locally equivalent only requires a polynomial number of operations in the number of qubits.