Miracle-dz/UniFAR-FTUs huggingface dataset:
Kinematic Properties of Globally-Propagating Waves in the Solar Corona

Globally-propagating coronal bright fronts (CBFs) in the solar corona are among the most dramatic manifestations of solar activity, but are not well understood despite strong links with both solar flares and coronal mass ejections. Extreme UltraViolet (EUV) observations from the STEREO and SDO spacecraft are used here to study their kinematics and morphology. The first STEREO observations of a CBF are presented, with the pulse observed in all available EUV passbands (171, 195, 284 and for the first time, 304A). The pulse displayed similar kinematics in all passbands, although the derived pulse velocity and acceleration were found to be strongly influenced by the observing cadence, implying that previous kinematics may have been underestimated. Different techniques for identifying CBFs and deriving their true kinematics were tested, with traditional techniques shown to be prone to undefined user-dependent errors. This was overcome through the development of a statistically rigorous, semi-automated identification algorithm, which was then used to determine the kinematics of four CBF events observed by STEREO. All of the events studied exhibited clear deceleration as well as increases in both spatial and temporal pulse width, indicating that the CBFs are dispersive. A CBF pulse observed by both STEREO and SDO was also studied using the algorithm, with lower initial velocity and weaker deceleration noted in STEREO observations compared to SDO, reaffirming the effects of image cadence on the derived kinematics. The kinematics obtained using SDO were highly passband dependent, suggesting a compressive nature. Significant pulse broadening was also noted in observations from both spacecraft, allowing the dispersion rate of the pulse to be determined. These results indicate that coronal bright fronts are best interpreted as fast-mode magnetoacoustic waves propagating in an inhomogeneous medium.
Spectral triples for nested fractals

It is shown that, for nested fractals [T.Lindstrom, Mem. Amer. Math. Soc. 420, 1990], the main structural data, such as the Hausdorff dimension and measure, the geodesic distance (when it exists) induced by the immersion in $R^n$, and the self-similar energy can all be recovered by the description of the fractals in terms of the spectral triples considered in [D.Guido, T.Isola, in "Advances in Operator Algebras and Mathematical Physics", Theta Series in Advanced Mathematics, Bucharest 2005].
Stellar population trends in S0 galaxies

We present stellar population age and metallicity trends for a sample of 59 S0 galaxies based on optical Sloan Digital Sky Survey (SDSS) and near-infrared (NIR) J and H photometry. When combined with optical g and r passband imaging data from the SDSS archive and stellar population models, we obtain radial age and metallicity trends out to at least five effective radii for most of the galaxies in our sample. The sample covers a range in stellar mass and light concentration. We find an average central light-weighted age of ∼4 Gyr and central metallicity [Z/H]∼ 0.2 dex. Almost all galaxies show a negative metallicity gradient from the centre out, with an average value of Δ[Z/H]/Δlog (r/Re) =−0.6. An age increase, decrease and minimal change with radius is observed for 58 per cent, 19 per cent and 23 per cent, respectively, for a mean age gradient of Δage/Δlog (r/Re) = 2.3 Gyr dex−1. For 14 out of 59 galaxies, the light-weighted age of the outer region is greater than 10 Gyr. We find that galaxies with both lower mass and lower concentration have younger light-weighted ages and lower light-weighted metallicities. This mass–metallicity relation extends into the outer regions of our S0 galaxies. Our results are consistent with the formation of S0 galaxies through the transformation of spiral galaxy discs. Determining the structural component that makes up the outer region of galaxies with old outskirts is a necessary step to understand the formation history of S0 galaxies.
VLT adaptive optics search for luminous substructures in the lens galaxy towards SDSS J0924+0219

The anomalous flux ratios between quasar images are suspected of being caused by substructures in lens galaxies. We present new deep and high-resolution H and Ks imaging of the strongly lensed quasar SDSS J0924+0219 obtained using the ESO VLT with adaptive optics and the laser guide star system. SDSS J0924+0219 is particularly interesting because the observed flux ratio between the quasar images vastly disagree with the predictions from smooth mass models. With our adaptive optics observations we find a luminous object, Object L, located similar to 0.3 '' to the north of the lens galaxy, but we show that it cannot be responsible for the anomalous flux ratios. Object L as well as a luminous extension of the lens galaxy to the south are seen in the archival HST/ACS image in the F814W filter. This suggests that Object L is part of a bar in the lens galaxy, as also supported by the presence of a significant disk component in the light profile of the lens galaxy. Finally, we find no evidence of any other luminous substructure that may explain the quasar images flux ratios. However, owing to the persistence of the flux ratio anomaly over time (similar to 7 years), a combination of microlensing and millilensing is the favorite explanation for the observations.
THE DIVERSE HOT GAS CONTENT AND DYNAMICS OF OPTICALLY SIMILAR LOW-MASS ELLIPTICAL GALAXIES

The presence of hot X-ray-emitting gas is ubiquitous in massive early-type galaxies. However, much less is known about the content and physical status of the hot X-ray gas in low-mass ellipticals. In the present paper, we study the X-ray gas content of four low-mass elliptical galaxies using archival Chandra X-ray observations. The sample galaxies, NGC 821, NGC 3379, NGC 4278, and NGC 4697, have approximately identical K-band luminosities, and hence stellar masses, yet their X-ray appearance is strikingly different. We conclude that the unresolved emission in NGC 821 and NGC 3379 is built up from a multitude of faint compact objects, such as coronally active binaries and cataclysmic variables. Despite the non-detection of X-ray gas, these galaxies may host low density, and hence low luminosity, X-ray gas components, which undergo an outflow driven by a Type Ia supernova (SN Ia). We detect hot X-ray gas with a temperature of kT ∼ 0.35 keV in NGC 4278, the component of which has a steeper surface brightness distribution than the stellar light. Within the central 50″ (∼3.9 kpc), the estimated gas mass is ∼3 × 107 M☉, implying a gas mass fraction of ∼0.06%. We demonstrate that the X-ray gas exhibits a bipolar morphology in the northeast–southwest direction, indicating that it may be outflowing from the galaxy. The mass and energy budget of the outflow can be maintained by evolved stars and SNe Ia, respectively. The X-ray gas in NGC 4697 has an average temperature of kT ∼ 0.3 keV and a significantly broader distribution than the stellar light. The total gas mass within 90″ (∼5.1 kpc) is ∼2.1 × 108 M☉, hence the gas mass fraction is ∼0.4%. Based on the distribution and physical parameters of the X-ray gas, we conclude that it is most likely in hydrostatic equilibrium, although a subsonic outflow may be present.
f(R) gravity with torsion: a geometric approach within the J -bundles framework

We discuss the f(R)-theories of gravity with torsion in the framework of -bundles. Such an approach is particularly useful since the components of the torsion and curvature tensors can be chosen as fiber -coordinates on the bundles and then the symmetries and the conservation laws of the theory can be easily achieved. Field equations of f(R)-gravity are studied in empty space and in presence of various forms of matter as Dirac fields, Yang–Mills fields and spin perfect fluid. Such fields enlarge the jet bundles framework and characterize the dynamics. Finally we give some cosmological applications and discuss the relations between f(R)-gravity and scalar-tensor theories.
Star formation efficiency along the radio jet in Centaurus A

Centaurus A is the most nearby powerful AGN, widely studied at all wavelengths. Molecular gas has been found in the halo at a distance of ~20 kpc from the galaxy centre, associated with HI shells. The molecular gas lies inside some IR and UV bright star-forming filaments that have recently been observed in the direction of the radio jets. These archival data show that there is dust and very weak star formation on scales of hundreds of parsecs. On top of analysing combined archival data, we have performed searches of HCN(1-0) and HCO+(1-0) emission with ATCA at the interaction of the northern filaments and the HI shell of Cen A. Measuring the dense gas is another indicator of star formation efficiency inside the filaments. However, we only derived upper limits of 1.6x10^3 K.km/s.pc^2 at 3 sigma in the synthesised beam of 3.1". We also compared the CO masses with the SFR estimates in order to measure a star formation efficiency. Using a standard conversion factor leads to long depletion times (7 Gyr). We then corrected the mass estimates from metallicity effect by using gas-to-dust mass ratio as a proxy. From MUSE data, we estimated the metallicity spread (0.4-0.8 Zsun) in the filament, corresponding to gas-to-dust ratios of ~200-400. The CO/H2 conversion ratio is corrected for low metallicity by a factor between 1.4 and 3.2. Such a low-metallicity correction leads to even more massive clouds with higher depletion times (16 Gyr). We finally present ALMA observations that detect 3 unresolved CO(2-1) clumps of size <37x21 pc and masses around 10^4 Msun. The velocity width of the CO emission line is ~10 km/s, leading to a rather high virial parameter. This is a hint of a turbulent gas probably powered by kinetic energy injection from the AGN jet/wind and leading to molecular gas reservoir not forming star efficiently.
THE SWIFT BAT SURVEY DETECTS TWO OPTICAL BROAD LINE, X-RAY HEAVILY OBSCURED ACTIVE GALAXIES: NVSS 193013+341047 AND IRAS 05218−1212

The Swift Burst Alert Telescope (BAT) is discovering interesting new objects while monitoring the sky in the 14–195 keV band. Here we present the X-ray properties and spectral energy distributions (SEDs) for two unusual active galactic nucleus sources. Both NVSS 193013+341047 and IRAS 05218−1212 are absorbed, Compton-thin, but heavily obscured (NH ∼ 1023 cm−2), X-ray sources at redshifts <0.1. The SEDs reveal these galaxies to be very red, with high extinction in the optical and UV. A similar SED is seen for the extremely red objects (EROs) detected in the higher redshift universe. This suggests that these unusual BAT-detected sources are a low-redshift (z ≪ 1) analog to EROs, which recent evidence suggests are a class of the elusive type II quasars. Studying the multi-wavelength properties of these sources may reveal the properties of their high-redshift counterparts.
XMM-Newton confirmation of a new intermediate polar: XMMU J185330.7-012815

We report on the results of a detailed spectro-imaging and temporal analysis of an archival XMM–Newton observation of a new intermediate polar XMMU J185330.7−012815. Its X-ray spectrum can be well described by a multitemperature thermal plasma model with the K lines of heavy elements clearly detected. Possible counterparts of XMMU J185330.7−012815 have been identified in optical and ultraviolet (UV) bands. The low values of the inferred X-ray-to-UV and X-ray-to-optical flux ratios safely rule out the possibility of its being an isolated neutron star. We confirm the X-ray periodicity of ∼238 s but, differently from the previous preliminary results, we do not find any convincing evidence of phase shift in this observation. We further investigate its properties through an energy-resolved temporal analysis and find that the pulsed fraction monotonically increases with energy.
Non-axisymmetric instabilities in discs with imposed zonal flows

We conduct a linear stability calculation of an ideal Keplerian flow on which a sinusoidal zonal flow is imposed. The analysis uses the shearing sheet model and is carried out both in isothermal and adiabatic conditions, with and without self-gravity (SG). In the non-SG regime a structure in the potential vorticity (PV) leads to a non-axisymmetric Kelvin-Helmholtz (KH) instability; in the short-wavelength limit its growth rate agrees with the incompressible calculation by Lithwick (2007), which only considers perturbations elongated in the streamwise direction. The instability's strength is analysed as a function of the structure's properties, and zonal flows are found to be stable if their wavelength is $\gtrsim 8H$, where $H$ is the disc's scale height, regardless of the value of the adiabatic index $\gamma$. The non-axisymmetric KH instability can operate in Rayleigh-stable conditions, and it therefore represents the limiting factor to the structure's properties. Introducing SG triggers a second non-axisymmetric instability, which is found to be located around a PV maximum, while the KH instability is linked to a PV minimum, as expected. In the adiabatic regime, the same gravitational instability is detected even when the structure is present only in the entropy (not in the PV) and the instability spreads to weaker SG conditions as the entropy structure's amplitude is increased. This eventually yields a non-axisymmetric instability in the non-SG regime, albeit of weak strength, localised around an entropy maximum.
EVOLUTIONS OF STELLAR-MASS BLACK HOLE HYPERACCRETION SYSTEMS IN THE CENTER OF GAMMA-RAY BURSTS

A neutrino-dominated accretion disk around a stellar-mass black hole (BH) can power a gamma-ray burst (GRB) via annihilation of neutrinos launched from the disk. For the BH hyperaccretion system, high accretion rate should trigger the violent evolution of the BH’s characteristics, which further leads to the evolution of the neutrino annihilation luminosity. In this paper, we consider the evolution of the accretion system to analyze the mean time-dependent neutrino annihilation luminosity with the different mean accretion rates and initial BH parameters. By time-integrating the luminosity, the total neutrino annihilation energy with the reasonable initial disk mass can satisfy most short-duration GRBs and about half of long-duration GRBs. Moreover, the extreme Kerr BH should exist in the cental engines of some high-luminosity GRBs. GRBs with higher energy have to request the alternative magnetohydrodynamics processes in the centers, such as the Blandford–Znajek jet from the accretion system or the millisecond magnetar.
Identifying Young Stellar Objects in the Outer Galaxy: l = 224° Region in Canis Major

We study a very young star-forming region in the outer Galaxy that is the most concentrated source of outflows in the Spitzer Space Telescope GLIMPSE360 survey. This region, dubbed CMa–l224, is located in the Canis Major OB1 association. CMa–l224 is relatively faint in the mid-infrared, but it shines brightly at the far-infrared wavelengths as revealed by the Herschel Space Observatory data from the Hi-GAL survey. Using the 3.6 and 4.5 μm data from the Spitzer/GLIMPSE360 survey, combined with the JHKs Two Micron All Sky Survey (2MASS) and the 70–500 μm Herschel/Hi-GAL data, we develop young stellar object (YSO) selection criteria based on color–color cuts and fitting of the YSO candidates’ spectral energy distributions with YSO 2D radiative transfer models. We identify 293 YSO candidates and estimate physical parameters for 210 sources well fit with YSO models. We select an additional 47 sources with GLIMPSE360-only photometry as “possible YSO candidates. ” The vast majority of these sources are associated with high H2 column density regions and are good targets for follow-up studies. The distribution of YSO candidates at different evolutionary stages with respect to Herschel filaments supports the idea that stars are formed in the filaments and become more dispersed with time. Both the supernova-induced and spontaneous star formation scenarios are plausible in the environmental context of CMa–l224. However, our results indicate that a spontaneous gravitational collapse of filaments is a more likely scenario. The methods developed for CMa–l224 can be used for larger regions in the Galactic plane where the same set of photometry is available.
Observation of the fundamental Nyquist noise limit in an ultra-high Q-factor cryogenic bulk acoustic wave cavity

Thermal Nyquist noise fluctuations of high-Q bulk acoustic wave cavities have been observed at cryogenic temperatures with a DC superconducting quantum interference device amplifier. High Q modes with bandwidths of few tens of milliHz produce thermal fluctuations with a signal-to-noise ratio of up to 23 dB. The estimated effective temperature from the Nyquist noise is in good agreement with the physical temperature of the device, confirming the validity of the equivalent circuit model and the non-existence of any excess resonator self-noise. The measurements also confirm that the quality factor remains extremely high (Q > 108 at low order overtones) for very weak (thermal) system motion at low temperatures, when compared to values measured with relatively strong external excitation. This result represents an enabling step towards operating such a high-Q acoustic device at the standard quantum limit.
Relational Balance in the Workplace: Exploring the Moderating Role of Organizational Commitment

This paper uses a diverse organizational sample to test portions of Heider’s (1946, 1958) balance framework. First, a review of balance theory is provided, and then theoretical relationships between relational balance and organizational outcomes (i.e., job satisfaction, unproductivity, and depressive symptoms) are explicated. Following this, the role of organizational commitment is also considered as a moderator of the aforementioned associations. In the main, the results of this investigation indicate that balance has a substantial, positive effect on job satisfaction. The results also indicate that balance combines non-additively with organizational commitment to impact results, such that the negative effects of balance on unproductivity and depressive symptoms are stronger when members are committed to their jobs. These findings point to the importance of considering the impact of relational patterns within organizations, as opposed to considering the impact of any one relationship in particular.
Gender Differences in Usage and Subjective Appreciation of an Online Cognitive Behavioral Therapy for Wildfire Evacuees: Descriptive Study

Background: Based on the most common psychological difficulties of the evacuees from the 2016 Fort McMurray wildfires in Alberta, Canada, a therapist-guided cognitive behavioral self-treatment was developed. This study aimed to explore how gender influences the usage and subjective appreciation of the RESILIENT online treatment. Methods: Our study included 81 English-speaking evacuees with significant posttraumatic symptoms, or with some posttraumatic symptoms accompanied by at least mild depression symptoms or subclinical insomnia, and who logged into the platform at least once. Various usage and subjective appreciation variables were analyzed, including number of completed sessions, number of logins, number of words per session, perceived efforts, perception of usefulness and intention to continue using the different strategies. Results: No difference was detected in most objective usage indicators. The number of words written in sessions 7 and 10 was significantly greater for women than for men. Regarding subjective appreciation, men had a greater perception of having put strong efforts in the cognitive restructuring strategy, while women reported in a greater proportion that they wanted to continue using physical exercise as a behavioral activation strategy. Conclusions: Our study offers a first look into how women and men use online treatments, and what their preferences are.
Signatures of Klein tunneling in disordered graphene p-n-p junctions

We present a method for obtaining quantum transport properties in graphene that uniquely combines three crucial features: microscopic treatment of charge disorder, fully quantum-mechanical analysis of transport, and the ability to model experimentally relevant system sizes. As a pertinent application we study the disorder dependence of Klein tunneling dominated transport in p-n-p junctions. Both the resistance and the Fano factor show broad resonance peaks due to the presence of quasi-bound-states. This feature is washed out by the disorder when the mean free path becomes of the order of the distance between the two p-n interfaces.
Resonant inelastic x-ray scattering studies of magnons and bimagnons in the lightly doped cuprate La 2- x Sr x CuO 4

We investigated the doping dependence of magnetic excitations in the lightly doped cuprate La2-xSrxCuO4 via combined studies of resonant inelastic x-ray scattering (RIXS) at the Cu L3-edge and theoretical calculations. With increasing doping, the magnon dispersion is found to be essentially unchanged, but the spectral width broadens and the spectral weight varies differently at different momenta. Near the Brillouin zone center, we directly observe bimagnon excitations which possess the same energy scale and doping dependence as previously observed by Raman spectroscopy. They disperse weakly in energy-momentum space, and are consistent with a bimagnon dispersion that is renormalized by the magnon-magnon interaction at the zone center.
Yu-Shiba-Rusinov states of impurities in a triangular lattice of NbSe 2 with spin-orbit coupling

We study topography of the spin-polarized bound states of magnetic impurities embedded in triangular lattice of a superconducting host. Such states have been observed experimentally in 2H-NbSe$_{2}$ crystal [G. C. M'enard et al., Nat.Phys. 11, 1013 (2015)] and revealed the oscillating particle-hole asymmetry extending to tens of nanometers. Using the Bogoliubov-de Gennes approach we explore the Yu-Shiba-Rusinov states in presence of spin-orbit interaction. We also study the bound states of double impurities for several relative positions in a triangular lattice.
Accretion rates and beaming in ultraluminous X-ray sources

I show that extreme beaming factors b are not needed to explain ultraluminous X-ray sources (ULXs) as stellar-mass binaries. For neutron-star accretors, one typically requires b∼ 0.13, and for black holes almost no beaming (b∼ 0.8). The main reason for the high apparent luminosity is the logarithmic increase in the limiting luminosity for super-Eddington accretion. The required accretion rates are explicable in terms of thermal-time-scale mass transfer from donor stars of mass 6–10 M⊙, or possibly transient outbursts. Beaming factors ≲0.1 would be needed to explain luminosities significantly above 1040L40 erg s−1, but these requirements are relaxed somewhat if the accreting matter has low hydrogen content.