Miracle-dz/UniFAR-FTUs huggingface dataset:
A refined analysis of the low-mass eclipsing binary system T-Cyg1-12664

The observational mass-radius relation of main sequence stars with masses between ~0.3 and 1.0 Msun reveals deviations between the stellar radii predicted by models and the observed radii of stars in detached binaries. We generate an accurate physical model of the low-mass eclipsing binary T-Cyg1-12664 in the Kepler mission field to measure the physical parameters of its components and to compare them with the prediction of theoretical stellar evolution models. We analyze the Kepler mission light curve of T-Cyg1-12664 to accurately measure the times and phases of the primary and secondary eclipse. In addition, we measure the rotational period of the primary component by analyzing the out-of-eclipse oscillations that are due to spots. We accurately constrain the effective temperature of the system using ground-based absolute photometry in B, V, Rc, and Ic. We also obtain and analyze V, Rc, Ic differential light curves to measure the eccentricity and the orbital inclination of the system, and a precise Teff ratio. From the joint analysis of new radial velocities and those in the literature we measure the individual masses of the stars. Finally, we use the PHOEBE code to generate a physical model of the system. T-Cyg1-12664 is a low eccentricity system, located d=360+/-22 pc away from us, with an orbital period of P=4.1287955(4) days, and an orbital inclination i=86.969+/-0.056 degrees. It is composed of two very different stars with an active G6 primary with Teff1=5560+/-160 K, M1=0.680+/-0.045 Msun, R1=0.799+/-0.017 Rsun, and a M3V secondary star with Teff2=3460+/-210 K, M2=0.376+/-0.017 Msun, and R2=0.3475+/-0.0081 Rsun. The primary star is an oversized and spotted active star, hotter than the stars in its mass range. The secondary is a cool star near the mass boundary for fully convective stars (M~0.35 Msun), whose parameters appear to be in agreement with low-mass stellar model.
The GALEX Arecibo SDSS Survey - VI. Second data release and updated gas fraction scaling relations

We present the second data release from the GALEX Arecibo SDSS Survey (GASS), an ongoing large Arecibo program to measure the Hi properties for an unbiased sample of∼1000 galaxies with stellar masses greater than 10 10 M⊙ and redshifts 0.025< z< 0.05. GASS targets are selected from the Sloan Digital Sky Survey (SDSS) spectroscopic and Galaxy Evolution Explorer (GALEX)imaging surveys, and are observed until detected or until a gas mass fraction limit of a few per cent is reached. This second data installment includes new Arecibo observations of 240 galaxies, and marks the 50% of the complete survey. We present catalogs of the Hi, optical and ultraviolet parameters for these galaxies, and their Hi-line profiles. Having more than doubled the size of the sampl e since the first data release, we also revisit the main scaling relations of t he Hi mass fraction with galaxy stellar mass, stellar mass surfac e density, concentration index, and NUV−r color, as well as the gas fraction plane introduced in our ear lier work.
Dark-matter haloes and the M–σ relation for supermassive black holes

We develop models of two-component spherical galaxies to establish scaling relations linking the properties of spheroids at $z=0$ (total stellar masses, effective radii $R_e$ and velocity dispersions within $R_e$) to the properties of their dark-matter halos at both $z=0$ and higher redshifts. Our main motivation is the widely accepted idea that the accretion-driven growth of supermassive black holes (SMBHs) in protogalaxies is limited by quasar-mode feedback and gas blow-out. The SMBH masses, $M_{\rm{BH}}$, should then be connected to the dark-matter potential wells at the redshift $z_{\rm{qso}}$ of the blow-out. We specifically consider the example of a power-law dependence on the maximum circular speed in a protogalactic dark-matter halo: $M_{\rm{BH}}\propto V^4_{\rm{d,pk}}$, as could be expected if quasar-mode feedback were momentum-driven. For halos with a given $V_{\rm{d,pk}}$ at a given $z_{\rm{qso}}\ge 0$, our model scaling relations give a typical stellar velocity dispersion $\sigma_{\rm{ap}}(R_e)$ at $z=0$. Thus, they transform a theoretical $M_{\rm{BH}}$-$V_{\rm{d,pk}}$ relation into a prediction for an observable $M_{\rm{BH}}$-$\sigma_{\rm{ap}}(R_e)$ relation. We find the latter to be distinctly non-linear in log-log space. Its shape depends on the generic redshift-evolution of halos in a {$\Lambda$}CDM cosmology and the systematic variation of stellar-to-dark matter mass fraction at $z=0$, in addition to any assumptions about the physics underlying the $M_{\rm{BH}}$-$V_{\rm{d,pk}}$ relation. Despite some clear limitations of the form we use for $M_{\rm{BH}}$ versus $V_{\rm{d,pk}}$, and even though we do not include any SMBH growth through dry mergers at low redshift, our results for $M_{\rm{BH}}$-$\sigma_{\rm{ap}}(R_e)$ compare well to data for local early types if we take $z_{\rm{qso}} \sim$ 2-4.
The Mass and Absorption Column Densities of Galactic Gaseous Halos. II. The High Ionization State Ions

The high ionization state ions trace the hot gases in the universe, of which gaseous halos around galaxies are a major contributor. Following Qu & Bregman, we calculate the gaseous halo contribution to the observed column density distributions for these ions by convolving the gaseous halo model with the observed stellar mass function. The predicted column density distribution reproduces the general shape of the observed column density distribution—a broken power law with the break point at for O vi. Our modeling suggests that the high column density systems originate from galaxies for which the virial temperature matches the temperature of the ionization fraction peak. Specifically, this mass range is for O vi, for Ne viii, and higher for higher ionization state ions (assuming ). A comparison with the observed O vi column density distribution prefers a large radius model, where the maximum radius is twice the virial radius. This model may be in conflict with the more poorly defined Ne viii column density distribution, suggesting that further observations are warranted. The redshift evolution of the high column density systems is dominated by the change of the cosmic star formation rate, which decreases from z = 1.0 to the local universe. Some differences at lower column densities between our models and observations indicate that absorption by the intragroup (cluster) medium and intergalactic medium is also a contributor to the total column density distributions.
COVID-19 Emergency Remote Teaching: The Perceptions, Challenges And Coping Strategies Of Higher Education Students In Ghana.

Emergency Remote Teaching (ERT) is a mode of teaching usually triggered by disasters and pandemics such as the deadly Coronavirus. This study used a self-reported questionnaire to investigate student perceptions, challenges, and coping strategies during ERT at a public university in Ghana. Using a randomly selected sample of 80 students, the study established the relationships between student perceptions and coping strategies, perceptions, and challenges. Out of the 80 respondents, 76 questionnaires were duly completed and were analysed using partial least square structural equation modelling (PLS-SEM). The bootstrapping results indicate that student perceptions of ERT have a significantly positive relationship with their coping strategies, and the challenges have a significant negative relationship with coping strategies. However, student perceptions did not significantly correlate with students’ challenges. Results recommend that the university put appropriate measures in place to reduce the challenges associated with ERT, which will improve students’ perceptions since the pandemic is still raging with a series of waves. Challenges such as lack of access to digital devices and high-speed internet should also be addressed urgently.
Light Curve and SED Modeling of the Gamma-Ray Binary 1FGL J1018.6–5856: Constraints on the Orbital Geometry and Relativistic Flow

We present broadband spectral energy distributions and light curves of the gamma-ray binary 1FGL J1018.6−5856 measured in the X-ray and the gamma-ray bands. We find that the orbital modulation in the low-energy gamma-ray band is similar to that in the X-ray band, suggesting a common spectral component. However, above a GeV the orbital light curve changes significantly. We suggest that the GeV band contains significant flux from a pulsar magnetosphere, while the X-ray to TeV light curves are dominated by synchrotron and Compton emission from an intrabinary shock (IBS). We find that a simple one-zone model is inadequate to explain the IBS emission, but that beamed Synchrotron-self Compton radiation from adiabatically accelerated plasma in the shocked pulsar wind can reproduce the complex multiband light curves, including the variable X-ray spike coincident with the gamma-ray maximum. The model requires an inclination of ∼50° and an orbital eccentricity of ∼0.35, consistent with the limited constraints from existing optical observations. This picture motivates searches for pulsations from the energetic young pulsar powering the wind shock.
INDIVIDUAL ALPHA ELEMENTS, C, N, AND Ba IN EARLY-TYPE GALAXIES

Spectral data on early-type galaxies are analyzed for chemical abundance with an emphasis on obtaining detailed abundances for the elements O and Si in addition to C, N, Na, Mg, Ca, Fe, and Ba. The abundance trends with velocity dispersion fit preconceptions based upon previous Mg conclusions, namely, that larger galaxies have a higher alpha element to iron peak ratio indicative of a higher ratio of Type II to Type Ia supernova products. The heaviest alpha elements, Ca and Ti, do not participate in this trend, although this fact does not necessarily alter the basic picture given the uncertainties in nucleosynthetic yields. Elements that likely have significant contributions from intermediate-mass stars, namely, C, N, and Ba, also gain ground relative to Fe in massive galaxies at a modest level, with the Ba conclusion uncertain from our data alone. After the velocity dispersion trend is subtracted, [M/H], [N/Fe], [Na/Fe], [Mg/Fe], and [Ca/Fe] probably have cosmic scatter, and no quantity can be shown to not have cosmic scatter.
APEX-CHAMP$^+$ high-J CO observations of low-mass young stellar objects - II. Distribution and origin of warm molecular gas

Context. The origin and heating mechanisms of warm (50 <T <200 K) molecular gas in low-mass young stellar objects (YSOs) are strongly debated. Both passive heating of the inner collapsing envelope by the protostellar luminosity as well as active heating by shocks and by UV associated with the outflows or accretion have been proposed. Most data so far have focussed on the colder gas component. Aims. We aim to characterize the warm gas within protosteller objects, and disentangle contributions from the (inner) envelope, bipolar outflows and the quiescent cloud. Methods. High-J CO maps ((CO)-C-12 J = 6-5 and 7-6) of the immediate surroundings (up to 10 000 AU) of eight low-mass YSOs are obtained with the CHAMP(+) 650/850 GHz array receiver mounted on the APEX telescope. In addition, isotopologue observations of the (CO)-C-13 J = 6-5 transition and [C I] P-3(2)-P-3(1) line were taken. Results. Strong quiescent narrow-line (CO)-C-12 6-5 and 7-6 emission is seen toward all protostars. In the case of HH 46 and Ced 110 IRS 4, the on-source emission originates in material heated by UV photons scattered in the outflow cavity and not just by passive heating in the inner envelope. Warm quiescent gas is also present along the outflows, heated by UV photons from shocks. This is clearly evident in BHR 71 for which quiescent emission becomes stronger at more distant outflow positions. Shock-heated warm gas is only detected for Class 0 flows and the more massive Class I sources such as HH 46. Outflow temperatures, estimated from the CO 6-5 and 3-2 line wings, are similar to 100 K, close to model predictions, with the exception of the L 1551 IRS 5 and IRAS 12496-7650, for which temperatures Conclusions. APEX-CHAMP(+) is uniquely suited to directly probe the protostar's feedback on its accreting envelope gas in terms of heating, photodissociation, and outflow dispersal by mapping similar to 1' x 1' regions in high-J CO and [C I] lines. Photon-heating of the surrounding gas may prevent further collapse and limit stellar growth.
Source Model and Characteristics of the 27 July 2022 MW 7.0 Northwestern Luzon Earthquake, Philippines

The geometry and kinematics of the causative fault of the 27 July 2022 moment magnitude (Mw) 7.0 earthquake, which is one of the strongest to hit northern and central Luzon in the past 30 years, were estimated through inverse modeling of line-of-sight interferometric synthetic aperture radar deformation. We modeled rupture along multiple candidate faults based on fit with the pattern of line-of-sight deformation, consistency with focal mechanisms, and compatibility with the known kinematics of the mapped active faults in the region. Our preferred fault model, located west of and parallel to the Abra River Fault (ARF), exhibits localized reverse-slip (average 67° rake) at 15-35 km down-dip. Peak slip occurs at 13-16 km depth, with 95 cm of pure reverse-slip. The existence of a reverse-slip dominated ARF-parallel fault rupture is consistent with a complex shear partitioning model, wherein the NW-SE oblique plate convergence is accommodated not only by the sinistral strike-slip Philippine Fault Zone and the major subduction zones, but also by minor faults in intervening crustal blocks.
Comparison of the performances of non-parametric k-sample test procedures as an alternative to one-way analysis of variance

Objectives: The performances of the Kruskal-Wallis test, the van der Waerden test, the modified version of Kruskal-Wallis test based on permutation test, the Mood's Median test and the Savage test, which are among the non-parametric alternatives of one-way analysis of variance and included in the literature, to protect the Type-I error probability determined at the beginning of the trial at a nominal level, were compared with the F test. Methods: Performance of the tests to protect Type-I error; in cases where the variances are homogeneous/heterogeneous, the sample sizes are balanced/unbalanced, the distribution of the data is in accordance with the normal distribution/the log-normal distribution, how it is affected by the change in the number of groups to be compared has been examined on simulation scenarios. Results: The Kruskal-Wallis test, the van der Waerden test, the modified version of the Kruskal-Wallis test based on the permutation test were not affected by the distribution of the data, but by the violation of the homogeneity of the variances. The performance of the Mood's Median test and the Savage test were not found to be sufficient in terms of protection of theType-I error compared to other tests. Conclusions: It was determined that the Kruskal-Wallis test, the van der Waerden test, the modified version of Kruskal-Wallis test based on permutation test were not affected by the distribution of the data and tended to preserve the Type-І error when the variances were homogeneous.
Cosmological density perturbations from conformal scalar field: infrared properties and statistical anisotropy

We consider a scenario in which primordial scalar perturbations are generated when complex conformal scalar field rolls down its negative quartic potential. Initially, these are the perturbations of the phase of this field; they are converted into the adiabatic perturbations at a later stage. A potentially dangerous feature of this scenario is the existence of perturbations in the radial field direction, which have red power spectrum. We show, however, that to the linear order in the small parameter — the quartic self-coupling — the infrared effects are completely harmless, as they can be absorbed into field redefinition. We then evaluate the statistical anisotropy inherent in the model due to the existence of the long-ranged radial perturbations. To the linear order in the quartic self-coupling the statistical anisotropy is free of the infrared effects. The latter show up at the quadratic order in the self-coupling and result in the mild (logarithmic) enhancement of the corresponding contribution to the statistical anisotropy. The resulting statistical anisotropy is a combination of a larger term which, however, decays as momentum increases, and a smaller term which is independent of momentum.
DETECTION, LOCALIZATION, AND CHARACTERIZATION OF GRAVITATIONAL WAVE BURSTS IN A PULSAR TIMING ARRAY

Efforts to detect gravitational waves by timing an array of pulsars have traditionally focused on stationary gravitational waves, e.g., stochastic or periodic signals. Gravitational wave bursts—signals whose duration is much shorter than the observation period—will also arise in the pulsar timing array waveband. Sources that give rise to detectable bursts include the formation or coalescence of supermassive black holes (SMBHs), the periapsis passage of compact objects in highly elliptic or unbound orbits about an SMBH, or cusps on cosmic strings. Here, we describe how pulsar timing array data may be analyzed to detect and characterize these bursts. Our analysis addresses, in a mutually consistent manner, a hierarchy of three questions. (1) What are the odds that a data set includes the signal from a gravitational wave burst? (2) Assuming the presence of a burst, what is the direction to its source? (3) Assuming the burst propagation direction, what is the burst waveform's time dependence in each of its polarization states? Applying our analysis to synthetic data sets, we find that we can detect gravitational waves even when the radiation is too weak to either localize the source or infer the waveform, and detect and localize sources even when the radiation amplitude is too weak to permit the waveform to be determined. While the context of our discussion is gravitational wave detection via pulsar timing arrays, the analysis itself is directly applicable to gravitational wave detection using either ground- or space-based detector data.
Estimating black hole masses in triaxial galaxies

Most of the supermassive black hole mass (M • ) estimates based on stellar kinematics use the assumption that galaxies are axisymmetric oblate spheroids or spherical. Here, we use fully general triaxial orbit-based models to explore the effect of relaxing the axisymmetric assumption on the previously studied galaxies M32 and NGC 3379. We find that M32 can only be modelled accurately using an axisymmetric shape viewed nearly edge-on, and our black hole mass estimate is identical to previous studies. When the observed 5° kinematical twist is included in our model of NGC 3379, the best shape is mildly triaxial, and we find that our best-fitting black hole mass estimate doubles with respect to the axisymmetric model. This particular black hole mass estimate is still within the errors of that of the axisymmetric model and consistent with the M • -σ relationship. However, this effect may have a pronounced impact on black hole demography, since roughly a third of the most massive galaxies are strongly triaxial.
Analysing neutron star in HESS J1731-347 from thermal emission and cooling theory

The central compact object in the supernova remnant HESS J1731-347 appears to be the hottest observed isolated cooling neutron star. The cooling theory of neutron stars enables one to explain observations of this star by assuming the presence of strong proton superfluidity in the stellar core and the existence of the surface heat blanketing envelope which almost fully consists of carbon. The cooling model of this star is elaborated to take proper account of the neutrino emission due to neutron-neutron collisions which is not suppressed by proton superfluidity. Using the results of spectral fits of observed thermal spectra for the distance of 3.2 kpc and the cooling theory for the neutron star of age 27 kyr, new constraints on the stellar mass and radius are obtained which are more stringent than those derived from the spectral fits alone.
STELLAR ATMOSPHERES, ATMOSPHERIC EXTENSION, AND FUNDAMENTAL PARAMETERS: WEIGHING STARS USING THE STELLAR MASS INDEX

One of the great challenges of understanding stars is measuring their masses. The best methods for measuring stellar masses include binary interaction, asteroseismology, and stellar evolution models, but these methods are not ideal for red giant and supergiant stars. In this work, we propose a novel method for inferring stellar masses of evolved red giant and supergiant stars using interferometric and spectrophotometric observations combined with spherical model stellar atmospheres to measure what we call the stellar mass index, defined as the ratio between the stellar radius and mass. The method is based on the correlation between different measurements of angular diameter, used as a proxy for atmospheric extension, and fundamental stellar parameters. For a given star, spectrophotometry measures the Rosseland angular diameter while interferometric observations generally probe a larger limb-darkened angular diameter. The ratio of these two angular diameters is proportional to the relative extension of the stellar atmosphere, which is strongly correlated to the star’s effective temperature, radius, and mass. We show that these correlations are strong and can lead to precise measurements of stellar masses.
THE FUNDAMENTAL PLANE FOR RADIO MAGNETARS

High magnetic fields are a distinguishing feature of neutron stars and the existence of sources (the soft gamma repeaters, SGRs, and the anomalous X-ray pulsars) hosting an ultramagnetized neutron star (or magnetar) has been recognized in the past few decades. Magnetars are believed to be powered by magnetic energy and not by rotation, as with normal radio pulsars. Until recently, the radio quietness and magnetic fields typically above the quantum critical value (BQ ≃ 4.4 × 1013 G) were among the characterizing properties of magnetars. The recent discovery of radio-pulsed emission from a few of them, and of a low dipolar magnetic field SGR, weakened further the idea of a clean separation between normal pulsars and magnetars. In this Letter, we show that radio emission from magnetars might be powered by rotational energy, similarly to what occurs in normal radio pulsars. The peculiar characteristics of magnetars radio emission should be traced in the complex magnetic geometry of these sources. Furthermore, we propose that magnetar radio activity or inactivity can be predicted from the knowledge of the star's rotational period, its time derivative, and the quiescent X-ray luminosity.