Miracle-dz/UniFAR-FTUs huggingface dataset:
A catalogue of nuclear stellar velocity dispersions of nearby galaxies from  Hα STIS spectra to constrain supermassive black hole masses

We present new measurements for the nuclear stellar velocity dispersion $\sigma_{\ast}$ within sub-arcsecond apertures for 28 nearby galaxies. Our data consist of Space Telescope Imaging Spectrograph (STIS) long-slit spectra obtained with the G750M grating centred on the H$\alpha$ spectral range. We fit the spectra using a library of single stellar population models and Gaussian emission lines, while constraining in most cases the stellar-population content from an initial fit to G430L STIS spectra. We illustrate how these $\sigma_{\ast}$ measurements can be useful for constraining the mass $M_{\bullet}$ of supermassive black holes (SBHs) by concentrating on the cases of the lenticular galaxies NGC4435 and NGC4459. These are characterized by similar ground-based half-light radii stellar velocity dispersion $\sigma_{\rm e}$ values but remarkably different $M_{\bullet}$ as obtained from modelling their central ionised-gas kinematics, where NGC4435 appears to host a significantly undermassive SBH compared to what is expected from the $M_{\bullet}-\sigma_{\rm e}$ relation. For both galaxies, we build Jeans axisymmetric dynamical models to match the ground-based stellar kinematics obtained with SAURON integral-field spectrograph, including a SBH with $M_{\bullet}$ value as predicted by the $M_{\bullet}-\sigma_{\rm e}$ relation and using high-resolution HST images taken with the Advanced Camera for Surveys to construct the stellar-mass model. By mimicking the HST observing conditions we use such reference models to make a prediction for the nuclear $\sigma_{\ast}$ value. Whereas this was found to agree with our nuclear $\sigma_{\ast}$ measurement for NGC4459, for NGC4435 the observed $\sigma_{\ast}$ is remarkably smaller than the predicted one, which further suggests that this galaxy could host an undermassive SBH.
Ideal Weyl semimetal induced by magnetic exchange

We report theoretical and experimental evidence that EuCd2As2 in magnetic fields greater than 1.6 T applied along the c axis is a Weyl semimetal with a single pair of Weyl nodes. Ab initio electronic structure calculations, verified at zero field by angle-resolved photoemission spectra, predict Weyl nodes with wave vectors k = (0, 0, +/- 0.03) x 2 pi/c at the Fermi level when the Eu spins are fully aligned along the c axis. Shubnikov-de Haas oscillations measured in fields parallel to c reveal a cyclotron effective mass of m(c)* = 0.08m(e) and a Fermi surface of extremal area A(ext) = 0.24 nm(-2), corresponding to 0.1% of the area of the Brillouin zone. The small values of m(c)* and A(ext) are consistent with quasiparticles near a Weyl node. The identification of EuCd2As2 as a model Weyl semimetal opens the door to fundamental tests of Weyl physics.
Connectedness of spheres in Cayley graphs

We introduce the notion of connection thickness of spheres in a Cayley graph, related to dead-ends and their retreat depth. It was well-known that connection thickness is bounded for finitely presented one-ended groups. We compute that for natural generating sets of lamplighter groups on a line or on a tree, connection thickness is linear or logarithmic respectively. We show that it depends strongly on the generating set. We give an example where the metric induced at the (finite) thickness of connection gives diameter of order $n^2$ to the sphere of radius $n$. We also discuss the rarity of dead-ends and the relationships of connection thickness with cut sets in percolation theory and with almost-convexity. Finally, we present a list of open questions about spheres in Cayley graphs.
Improvement in the electro-optical and electronic properties of the reduced graphene oxide dispersed in a liquid crystalline material 4’-octyl-4-cyano-biphenyl

ABSTRACT Herein, a small concentration (0.05 wt %) of reduced graphene oxide is dispersed in the liquid crystalline media. Thermodynamic study shows the reduction of the transition temperature, enthalpy and entropy of the reduced graphene oxide dispersed nanocomposite. Optical study suggests the decrease of the optical bandgap of the dispersed nanocomposite as compared to that of the pure sample. Dielectric spectroscopic measurement is done for measuring the permittivity and conductivity of the pure and the dispersed samples. The value of dielectric anisotropy has decreased for the dispersed nanocomposite whereas the value of ionic (DC) conductivity of the dispersed nanocomposite has increased by 3 orders of the magnitude as compared to that of the pristine sample. The activation energy for DC conductivity has reduced in the dispersed nanocomposite which is responsible for the increment in DC conductivity of the system. The cut-off region of DC conductivity has increased in the dispersed nanocomposite. Electro-optical studies suggest the reduction of the threshold voltage for the Freedericksz transition, splay elastic constant and rotational viscosity for the dispersed nanocomposite. GRAPHICAL ABSTRACT
First results from the IllustrisTNG simulations: a tale of two elements - chemical evolution of magnesium and europium

The distribution of elements in galaxies provides a wealth of information about their production sites and their subsequent mixing into the interstellar medium. Here we investigate the distribution of elements within stars in the IllustrisTNG simulations. In particular, we analyze the abundance ratios of magnesium and europium in Milky Way-like galaxies from the TNG100 simulation (stellar masses ${\log} (M_\star / {\rm M}_\odot) \sim 9.7 - 11.2$). As abundances of magnesium and europium for individual stars in the Milky Way are observed across a variety of spatial locations and metallicities, comparison with the stellar abundances in our more than $850$ Milky Way-like galaxies provides stringent constraints on our chemical evolutionary methods. To this end we use the magnesium to iron ratio as a proxy for the effects of our SNII and SNIa metal return prescription, and a means to compare our simulated abundances to a wide variety of galactic observations. The europium to iron ratio tracks the rare ejecta from neutron star -- neutron star mergers, the assumed primary site of europium production in our models, which in turn is a sensitive probe of the effects of metal diffusion within the gas in our simulations. We find that europium abundances in Milky Way-like galaxies show no correlation with assembly history, present day galactic properties, and average galactic stellar population age. In general, we reproduce the europium to iron spread at low metallicities observed in the Milky Way, with the level of enhancement being sensitive to gas properties during redshifts $z \approx 2-4$. We show that while the overall normalization of [Eu/Fe] is susceptible to resolution and post-processing assumptions, the relatively large spread of [Eu/Fe] at low [Fe/H] when compared to that at high [Fe/H] is very robust.
On the magnetization and the radiative efficiency of BL Lac jets

Theoretical modelling and observations of AGN jets suggest that the non-thermal electrons emitting the observed radiation should (i) carry an amount of energy comparable to the magnetic fields ($U_e\sim U_B$), which is likely the case if the magnetic fields play a dynamically important role in the jet's acceleration process; (ii) cool efficiently in a dynamical time ($t_{\rm cool}\lesssim t_{\rm dyn}$), which is suggested by the fact that a large fraction of the jet's kinetic energy is promptly converted into radiation. These expectations are at odds with the results of the simplest one-zone Self-Synchro-Compton (SSC) model for the Spectral Energy Distribution (SED) of BL Lacs. Indeed, the model predicts $U_e\gg U_B$ and $t_{\rm cool}\gg t_{\rm dyn}$ for most of the objects. Here we closely investigate one of the key assumptions of this model, namely that the momentum distribution of the non-thermal electrons is isotropic. We find that this assumption may be an oversimplification. If the magnetic energy is dissipated via a turbulent MHD cascade, the highest energy electrons may instead retain a small pitch angle. Since the synchrotron emissivity is suppressed when the pitch angle is small, this effect may importantly affect the modelling of the SED. As an illustrative example, we present an anisotropic model for the electron momentum distribution such that $U_e\sim U_B$ and $t_{\rm cool}\lesssim t_{\rm dyn}$ at the same time. Our model manages to simultaneously solve the two problems with one only more free parameter with respect to the usual isotropic one-zone SSC model.
Testing predictions of the quantum landscape multiverse 1: the Starobinsky inflationary potential

The 2015 Planck data release has placed tight constraints on the allowed class of inflationary models. The current data favors concave downwards inflationary potentials while offering interesting hints on possible deviations from the standard picture of CMB perturbations. We here test the predictions of the theory of the origin of the universe from the landscape multiverse, against the most recent Planck data, for the case of concave downwards inflationary potentials, such as the Starobinsky model of inflation. By considering the quantum entanglement correction of the multiverse, we can place a lower limit on the local `SUSY breaking' scale b > 1.2 × 107 GeV at 95% c.l. from Planck TT+lowTEB. We find that this limit is consistent with the range for b that allows the landscape multiverse to explain a serie of anomalies present in the current data.
Metallicity distributions of mono-age stellar populations of the Galactic disc from the LAMOST Galactic spectroscopic surveys

We have investigated the metallicity distributions of mono-age stellar populations across the disc of $6 \lesssim R \lesssim 12$\,kpc and $|Z| \lesssim 2$\,kpc using samples selected from the main-sequence turn-off and sub-giant (MSTO-SG) stars targeted by the LAMOST Galactic Spectroscopic surveys. Both the mean values and the profiles of the distributions exhibit significant variations with age and position. We confirm that the oldest ($>11$\,Gyr) stars have nearly flat radial [Fe/H] gradients at all heights above the disc but show negative vertical [Fe/H] gradients. For stars younger than 11\,Gyr, the radial [Fe/H] gradients flatten with $|Z|$, while the vertical [Fe/H] gradients flatten with $R$. Stars of 4--6\,Gyr exhibit steeper negative radial [Fe/H] gradients than those of either younger or older ages. Values of [$\alpha$/Fe] of mono-age stellar populations also show significant radial and vertical gradients, with patterns varying with age. The [Fe/H] distribution profiles of old ($>8$\,Gyr) stars vary little with $R$, while those of younger stars exhibit strong radial variations, probably a consequence of significant radial migration. The [$\alpha$/Fe] radial distribution profiles show opposite patterns of variations with age compared to those of [Fe/H]. We have also explored the impacts of stellar mixing by epicycle motions (blurring) on the [Fe/H] and [$\alpha$/Fe] distributions, and found that blurring mainly change the widths of the distribution profiles. Our results suggest that the disc may have experienced a complex assemblage history, in which both the "inside-out" and "upside-down" formation processes may have played an important role.
Combining timing characteristics with physical broad-band spectral modelling of black hole X-ray binary GX 339–4

GX 339–4 is a black hole X-ray binary that is a key focus of accretion studies, since it goes into outburst roughly every 2–3 yr. Tracking of its radio, infrared (IR), and X-ray flux during multiple outbursts reveals tight broad-band correlations. The radio emission originates in a compact, self-absorbed jet; however, the origin of the X-ray emission is still debated: jet base or corona? We fit 20 quasi-simultaneous radio, IR, optical, and X-ray observations of GX 339–4 covering three separate outbursts in 2005, 2007, 2010–2011, with a composite corona+jet model, where inverse Compton emission from both regions contributes to the X-ray emission. Using a recently proposed identifier of the X-ray variability properties known as power-spectral hue, we attempt to explain both the spectral and evolving timing characteristics, with the model. We find the X-ray spectra are best fit by inverse Compton scattering in a dominant hot corona (kTe ∼ hundreds of keV). However, radio and IR-optical constraints imply a non-negligible contribution from inverse Compton scattering off hotter electrons (kTe ≥ 511 keV) in the base of the jets, ranging from a few up to ∼50 per cent of the integrated 3–100 keV flux. We also find that the physical properties of the jet show interesting correlations with the shape of the broad-band X-ray variability of the source, posing intriguing suggestions for the connection between the jet and corona.
Global correlations between the radio continuum, infrared, and CO emissions in dwarf galaxies

Correlations between the radio continuum, infrared and CO emission are known to exist for several types of galaxies and across several orders of magnitude. However, the low-mass, low-luminosity and low-metallicity regime of these correlations is not well known. A sample of metal-rich and metal-poor dwarf galaxies from the literature has been assembled to explore this extreme regime. The results demonstrate that the properties of dwarf galaxies are not simple extensions of those of more massive galaxies; the different correlations reflect different star-forming conditions and different coupling between the star formation and the various quantities. It is found that dwarfs show increasingly weaker CO and infrared emission for their luminosity, as expected for galaxies with a low dust content, slower reaction rates, and a hard ionizing radiation field. In the higher-luminosity dwarf regime (L_1.4GHz > 10^27 W, where L_1.4GHz ~ 10^29 W for a Milky Way star formation rate of ~1 M_sun yr^-1), the total and non-thermal radio continuum emission appear to adequately trace the star formation rate. A breakdown of the dependence of the (Halpha-based) thermal, non-thermal, and, hence, total radio continuum emission on star formation rate occurs below L_1. 4GHz ~ 10^27 W, resulting in a steepening or downturn of the relations at extreme low luminosity. Below L_FIR ~ 10^36 W ~ 3 x 10^9 L_sun, the infrared emission ceases to adequately trace the star formation rate. A lack of a correlation between the magnetic field strength and the star formation rate in low star formation rate dwarfs suggests a breakdown of the equipartition assumption. As extremely metal-poor dwarfs mostly populate the low star formation rate and low luminosity regime, they stand out in their infrared, radio continuum and CO properties.
Star Formation Efficiency per Free-fall Time in nearby Galaxies

We estimate the star formation efficiency per gravitational free-fall time, , from observations of nearby galaxies with resolution matched to the typical size of a giant molecular cloud. This quantity, , is theoretically important but so far has only been measured for Milky Way clouds or inferred indirectly in a few other galaxies. Using new, high-resolution CO imaging from the Physics at High Angular Resolution in nearby Galaxies-Atacama Large Millimeter Array (PHANGS-ALMA) survey, we estimate the gravitational free-fall time at 60–120 pc resolution, and contrast this with the local molecular gas depletion time in order to estimate . Assuming a constant thickness of the molecular gas layer (H = 100 pc) across the whole sample, the median value of in our sample is 0.7%. We find a mild scale dependence, with higher measured at coarser resolution. Individual galaxies show different values of , with the median ranging from 0.3% to 2.6%. We find the highest in our lowest-mass targets, reflecting both long free-fall times and short depletion times, though we caution that both measurements are subject to biases in low-mass galaxies. We estimate the key systematic uncertainties, and show the dominant uncertainty to be the estimated line-of-sight (LOS) depth through the molecular gas layer and the choice of star formation tracers.
Hematene Nanoflakes: A Non-van der Waals Material with Superior Nonlinear Optical Properties

Stable and efficient optical limiters for eye and sensor protection have been of great demand ever since the advent of high-power lasers. In this study, we report the preparation of highly stable hematene nanoflakes for optical limiting applications by a facile exfoliation method from a low-cost, non-van der Waals material. Optical and structural characterization have been carried out to confirm the structure, morphology and composition of the hematene nanoflakes. Open aperture Z-scan measurements have been carried out in near-transparent samples (87% linear transmission at the excitation wavelength of 532 nm), using 5 ns laser pulses. Despite the high transparency of the sample, a high nonlinear absorption coefficient of up to 13.0 ± 1.1 cm GW -1 has been determined, signifying the potential of this material for fabricating highly efficient optical power limiting devices.
Characteristics of inpatients with atopic asthma in a tertiary center: do age and gender have an influence?

Background Several studies have demonstrated gender influence on asthma prevalence, being higher among males during early childhood. Little is known about the impact of gender and age on asthma exacerbation characteristics in pediatrics. This study aimed to determine the differences in acute asthma between males and females in three different age groups regarding perinatal characteristics of asthmatic patients, comorbidities, medication adherence, level of blood eosinophils, and pattern of hospitalization. Methods The medical records of 130 pediatric patients with asthma, who presented to the emergency department at Jordan University hospital with asthma exacerbations, were retrospectively reviewed. Demographic information and clinical characteristics were collected. Results The mean age of patients was 10.7±4.7 years. The age at diagnosis and gestational age were significantly higher in older children. Furthermore, younger children were significantly more likely to experience winter exacerbations and more emergency presentations. Male patients were considerably younger than their female counterparts and were diagnosed younger. In addition, male patients were more likely to have eosinophil levels higher than 3% than female patients. Conclusion Gender plays a role in the development and outcome of asthma exacerbations at different ages of pediatrics. A better understanding of gender-based and age-based differences in asthma dictates a personalized approach to treatment.
Using N-body simulations to understand the chemo-dynamical evolution of the inner Milky Way

Abstract I present examples of how chemo-dynamical N-body simulations can help understanding the structure and evolution of the inner Galaxy. Such simulations reproduce the observed links between kinematics, morphology and chemistry in the bar/bulge region and explain them by the self-consistent cohabitation of a number of components. Galactic archaeology, applied to simulation snapshots, explains the sequence in which the stars of the various components were formed. The thick disc stars form earlier than those of the thin disc and in a much shorter time scale. The bar in the thick disc is horizontally thicker than that of the thin disc and has a different vertical morphology. The Galaxy’s inner disc scalelength is much smaller than what is expected from nearby galaxies of similar stellar mass.
Transitions between Turbulent and Laminar Superfluid Vorticity States in the Outer Core of a Neutron Star

We investigate the global transition from a turbulent state of superfluid vorticity (quasi-isotropic vortex tangle) to a laminar state (rectilinear vortex array), and vice versa, in the outer core of a neutron star. By solving numerically the hydrodynamic Hall-Vinen-Bekarevich-Khalatnikov equations for a rotating superfluid in a differentially rotating spherical shell, we find that the meridional counterflow driven by Ekman pumping exceeds the Donnelly-Glaberson threshold throughout most of the outer core, exciting unstable Kelvin waves that disrupt the rectilinear vortex array, creating a vortex tangle. In the turbulent state, the torque exerted on the crust oscillates, and the crust-core coupling is weaker than in the laminar state. This leads to a new scenario for the rotational glitches observed in radio pulsars: a vortex tangle is sustained in the differentially rotating outer core by the meridional counterflow, a sudden spin-up event (triggered by an unknown process) brings the crust and core into corotation, the vortex tangle relaxes back to a rectilinear vortex array (in ≲105 s), and then the crust spins down electromagnetically until enough meridional counterflow builds up (after ≲1 yr) to reform a vortex tangle. The turbulent-laminar transition can occur uniformly or in patches; the associated timescales are estimated from vortex filament theory. We calculate numerically the global structure of the flow with and without an inviscid superfluid component, for Hall-Vinen (laminar) and Gorter-Mellink (turbulent) forms of the mutual friction. We also calculate the postglitch evolution of the angular velocity of the crust and its time derivative and compare the results with radio pulse timing data, predicting a correlation between glitch activity and Reynolds number. Terrestrial laboratory experiments are proposed to test some of these ideas.
Investigation of the Inhomogeneous Mechanical and Crack Driving Force of Low Alloy Steel SA508 and Its Welded 309L/308L Stainless Steel Cladding

Abstract Low alloy steel SA508 autogenously welded with Type 309L/308L austenitic stainless steel cladding is one of the common forms of the dissimilar metal weld joint (DMWJ) in the primary water of a pressurized water reactor (PWR). Accurate evaluation of the inhomogeneous mechanical propriety and crack growth driving force at the corresponding place on the DMWJ is important for integrity analyses of a PWR. In this study, the mechanical propriety of the DMWJ was obtained using a combined Vickers hardness test and the stress-hardness relationship. And, a finite element (FE) model for the DMWJ in a PWR with continuous transition mechanical propriety was built using a predefined temperature field method. Based on consideration of the heterogeneity mechanical properties on the DMWJ with the continuous transition mechanical propriety, the Mises stress distribution and J integral on the crack tip with different crack lengths was analyzed using elastoplastic FE analysis. As shown by the distribution profile of the Mises stress distribution and J integral on the crack tip, the inhomogeneous mechanical propriety distribution is found to significantly affect the crack driving force when the crack tip is close to the fusion boundary.