Miracle-dz/UniFAR-FTUs huggingface dataset:
Stable satellites around extrasolar giant planets

In this work, we study the stability of hypothetical satellites of extrasolar planets. Through numerical simulations of the restricted elliptic three-body problem we found the borders of the stable regions around the secondary body. From the empirical results, we derived analytical expressions of the critical semimajor axis beyond which the satellites would not remain stable. The expressions are given as a function of the eccentricities of the planet, ep, and of the satellite, e sat . In the case of prograde satellites, the critical semimajor axis, in the units of Hill's radius, is given by a E ≈ 0.4895 (1.0000 - 1.0305ep - 0.2738e sat ). In the case of retrograde satellites, it is given by a E ≈ 0.9309 (1.0000 - 1.0764ep - 0.9812e sat ). We also computed the satellite stability region (a E ) for a set of extrasolar planets. The results indicate that extrasolar planets in the habitable zone could harbour the Earth-like satellites.
Analytical solution of a pressure transmission experiment on shale using electrochemomechanical theory

Analytical solutions are derived for a pressure transmission experiment of a saturated charged compressible porous medium. The governing equations describe infinitesimal deformations of charged porous media saturated with a monovalent ionic solution. From the governing equations a coupled diffusion equation is derived for the three electrochemical potentials, which is decoupled introducing a set of normal parameters. The magnitude of the eigenvalues of the diffusivity matrix corresponds to the time scales for Darcy flow, diffusion of ionic constituents, and diffusion of electrical potential. The radial strain is very sensitive to the ionization.
Twist-3 distribution amplitudes of K* and phi mesons

We present a systematic study of twist-3 light-cone distribution amplitudes of $K^*$ and $\phi$ mesons in QCD. The structure of SU(3)-breaking corrections is studied in detail. Non-perturbative input parameters are estimated from QCD sum rules. As a by-product, we update the parameters describing the twist-3 distribution amplitudes of the $\rho$ meson. We also review and update predictions for the twist-2 distribution amplitudes of $\rho$, $K^*$ and $\phi$.
Resonant scattering for characterization of axisymmetric dielectric objects

Resonances in the electromagnetic scattering by dielectric objects are investigated both numerically and experimentally with particular emphasis on their direct application to object characterization. Low ka calculations for spheres and an infinite circular cylinder illustrate the modal nature of the resonances and the dependence of the resonance spectra on refractive index and size. Experiments show that the specific wavelengths at which resonances occur in the scattering intensity from a glass fiber can be used to determine its diameter to a high accuracy. The extended boundary condition method is used to calculate the low ka resonances of a prolate spheroid and a finite circulate cylinder with the anticipation that the scattering resonances may be particularly suitable for characterizing randomly oriented nonspherical objects.
Absolute Parameters for the F-type Eclipsing Binary BW Aquarii

BW Aqr is a bright eclipsing binary star containing a pair of F7V stars. The absolute parameters of this binary (masses, radii, etc.) are known to good precision so they are often used to test stellar models, particularly in studies of convective overshooting. Maxted & Hutcheon (2018) analysed the Kepler K2 data for BW Aqr and noted that it shows variability between the eclipses that may be caused by tidally induced pulsations. Table 1 shows the absolute parameters for BW Aqr derived from an improved analysis of the Kepler K2 light curve plus the RV measurements from both Imbert (1979) and Lester & Gies (2018). The values in Table 1 with their robust error estimates from the standard deviation of the mean are consistent with the values and errors from Maxted & Hutcheon (2018) based on the PPD calculated using emcee for a fit to the entire K2 light curve.
A Complete Census of Luminous Stellar Variability on Day to Decade Timescales

Stellar photometric variability offers a novel probe of the interior structure and evolutionary state of stars. Here we present a census of stellar variability on day to decade timescales across the color–magnitude diagram (CMD) for 73,000 stars brighter than MI,814 = −5 in the Whirlpool Galaxy (M51). Our Cycle 24 Hubble Space Telescope (HST) program acquired V606- and I814-band images over 34 epochs spanning 1 year with pseudo-random cadences enabling sensitivity to periods from days to months. We supplement these data with archival V- and I-band HST data obtained in 1995 and 2005, providing sensitivity to variability on decade timescales. At least 50% of stars brighter than MI,814 = −7 show strong evidence for variability within our Cycle 24 data; among stars with the variability fraction rises to ≈100%. Large amplitude variability (>0.3 mag) on decade timescales is restricted to red supergiants (RSGs) and very luminous blue stars. Both populations display fairly smooth variability on month-year timescales. The Cepheid instability strip is clearly visible in our data, although the variability fraction within this region never exceeds ≈10%. The location of variable stars across the CMD broadly agrees with theoretical sources of variability, including the instability strip, RSG pulsational instabilities, long-period fundamental mode pulsations, and radiation-dominated envelopes in massive stars. Our data can be used to place stringent constraints on the precise onset of these various instabilities and their lifetimes and growth rates.
Simultaneous Chandra and RXTE Spectroscopy of the Microquasar H1743–322: Clues to Disk Wind and Jet Formation from a Variable Ionized Outflow

We observed the bright phase of the 2003 outburst of the Galactic black hole candidate H1743-322 in X-rays simultaneously with Chandra and RXTE on four occasions. The Chandra HETGS spectra reveal narrow, variable (He-like) Fe XXV and (H-like) Fe XXVI resonance absorption lines. In the first observation, the Fe XXVI line has a FWHM of 1800 ± 400 km s-1 and a blueshift of 700 ± 200 km s-1, suggesting that the highly ionized medium is an outflow. Moreover, the Fe XXV line is observed to vary significantly on a timescale of a few hundred seconds in the first observation, which corresponds to the Keplerian orbital period at approximately 104rg (where rg = GM/c2). Our models for the absorption geometry suggest that a combination of changing ionizing flux and geometric effects are required to account for the large changes in line flux observed between observations and that the absorption likely occurs at a radius between 102rg and 104rg for a 10 M☉ black hole. We suggest that the absorption occurs in an inhomogeneous accretion disk wind. If the wind in H1743-322 has unity filling factor, the highest implied mass outflow rate is 5% of the Eddington mass accretion rate. The observed wind may be a hotter, more ionized version of the Seyfert-like, outflowing warm absorber geometries recently found in the Galactic black holes GX 339-4 and XTE J1650-500. We discuss these findings in the context of ionized Fe absorption lines found in the spectra of other Galactic sources, and connections to warm absorbers, winds and jets in other accreting systems.
The Phoenix Deep Survey: 1.4-GHz source counts

We present the first results from the Phoenix Deep Survey, a multiwavelength survey of a 2° diameter region. Observations in the radio continuum at 1.4 GHz carried out with the Australia Telescope Compact Array are described. The catalogue of over 1000 radio sources compiled from these observations is analysed, and the source counts are presented. We model the observational source counts using a two-population model and published luminosity functions for these populations. Upon invoking luminosity and density evolution, we find that a luminosity evolution model best fits the radio observations, consistent with earlier work. The redshift distribution of the two galaxy populations investigated is also modelled and discussed.
Restoring the Heisenberg limit via collective non-Markovian dephasing

In this work an exactly solvable model of N two-level systems interacting with a single bosonic dephasing reservoir is considered to unravel the role played by collective non-Markovian dephasing. We show that phase estimation with entangled states for this model can exceed the standard quantum limit and demonstrate Heisenberg scaling with the number of atoms for an arbitrary temperature. For a certain class of reservoir densities of states decoherence can be suppressed in the limit of large number of atoms and the Heisenberg limit can be restored for arbitrary interrogation times. We identify the second class of densities when the Heisenberg scaling can be restored for any finite interrogation time. We also find the third class of densities when the standard quantum limit can be exceeded only on the initial stage of dynamics in the Zeno-regime.
Temperature Coefficient of Silicon-Based Carrier Selective Solar Cells

Carrier selective (CS) Silicon solar cells are increasingly explored as a low-cost alternative to PN junction Silicon solar cells. While the recent trends on power conversion efficiency are encouraging, the temperature coefficient and hence the power output under elevated temperatures are not well explored for such solar cells. Here, we address this issue through detailed numerical simulations to explore the influence of interface and material parameters on the temperature coefficient. Our results indicate that irrespective of the interface quality, the temperature coefficient of CS solar cells improves with an increase in band discontinuities. Interestingly, contrary to the trends related to efficiency, our results indicate that the temperature coefficient of CS solar cells is more critically affected by the interface quality of the minority carrier extraction layer than the majority carrier extraction layer. These insights have important implications toward the choice of optimal material and processing conditions for Si-based CS solar cells
Chandra/High Energy Transmission Grating Spectrometer Spectroscopy of the Galactic Black Hole GX 339–4: A Relativistic Iron Emission Line and Evidence for a Seyfert-like Warm Absorber

We observed the Galactic black hole GX 339-4 with the Chandra High Energy Transmission Grating Spectrometer (HETGS) for 75 ks during the decline of its 2002-2003 outburst. The sensitivity of this observation provides an unprecedented glimpse of a Galactic black hole at about a tenth of the luminosity of the outburst peak. The continuum spectrum is well described by a model consisting of multicolor disk blackbody (kT ≃ 0.6 keV) and power-law (Γ ≃ 2.5) components. X-ray reflection models yield improved fits. A strong, relativistic Fe Kα emission line is revealed, indicating that the inner disk extends to the innermost stable circular orbit. The breadth of the line is sufficient to suggest that GX 339-4 may harbor a black hole with significant angular momentum. Absorption lines from H- and He-like O and He-like Ne and Mg are detected, as well as lines that are likely due to Ne II and Ne III. The measured line properties make it difficult to associate the absorption with the coronal phase of the interstellar medium. A scenario wherein the absorption lines are due to an intrinsic AGN-like warm-absorber geometry—perhaps produced by a disk wind in an extended disk-dominated state—may be more viable. We compare our results to Chandra observations of the Galactic black hole candidate XTE J1650-500 and discuss our findings in terms of prominent models for Galactic black hole accretion flows and connections to supermassive black holes.
Nonuniversality of the one-particle Green’s function of a Luttinger liquid

The one-particle Green's function of the Tomonaga-Luttinger model for one-dimensional interacting Fermions is discussed. Far away from the origin of the plane of space-time coordinates the function falls off like a power law. The exponent depends on the direction within the plane. For a certain form of the interaction potential or within an approximated cut-off procedure the different exponents only depend on the strength of the interaction at zero momentum and can be expressed in terms of the Luttinger liquid parameters $K_{\rho}$ and $K_{\sigma}$ of the model at hand. For a more general interaction and directions which are determined by the charge velocity $v_{\rho}$ and spin velocity $v_{\sigma}$ the exponents also depend on the smoothness of the interaction at zero momentum and the asymptotic behavior of the Green's function is not given by the Luttinger liquid parameters alone. This shows that the physics of large space-time distances in Luttinger liquids is less universal than is widely believed.
Physical interpretation of unstable modes of a linear shear flow in shallow water on an equatorial beta-plane

Unstable modes of a linear shear flow in shallow water on an equatorial $\beta$-plane are obtained over a wide range of values of a non-dimensional parameter and are interpreted in terms of resonance between neutral waves. The non-dimensional parameter in the system is $E \,{\equiv}\, \gamma^{4} / (gH\beta^{2})$, where $\gamma$, $g$, $H$ and $\beta$ are the meridional shear of basic zonal flow, gravitational constant, equivalent depth and the north–south gradient of the Coriolis parameter, respectively. The value of $E$ is varied within the range $-2.50 \,{\le}\,\log E \,{\le}\,7.50$. The problem is solved numerically in a channel of width $5\gamma/\beta$. The structures of the most unstable modes, and the combinations of resonating neutral waves that cause the instability, change according to the value of $E$ as follows. For $\log E \,{<}\, 2.00$, the most unstable modes have zonally non-symmetric structures; the most unstable modes for $\log E \,{<}\, 1.00$ are caused by resonance between equatorial Kelvin modes and continuous modes, and those for $1.00 \,{\le}\,\log E \,{<}\, 2.00$ are caused by resonance between equatorial Kelvin modes and westward mixed Rossby–gravity modes. The most unstable modes for $\log E \,{\ge}\, 2.00$ have symmetric structures and are identical with inertially unstable modes. Examinations of dispersion curves suggest that non-symmetric unstable modes for $1.00 \,{\le}\,\log E \,{<}\, 2.00$ and inertially unstable modes for $\log E \,{\ge}\, 2.00$ are the same kind of instability.
Universal Mechanisms in the Growth of Voluntary Organizations

We analyze the growth statistics of Swedish trade unions and find a universal functional form for the probability distribution of growth rates of union size, and a power law dependence of the standard deviation of this distribution on the number of members of the union. We also find that the typical size and the typical number of local chapters scales as a power law of the union size. Intriguingly, our results are similar to results reported for other human organizations of a quite different nature. Our findings are consistent with the possibility that universal mechanisms may exist governing the growth patterns of human organizations.
Interpretation of the Phase Functions Measured by the OSIRIS Instrument for Comet 67P/Churyumov–Gerasimenko

We show that the scattering phase functions of the coma and the nucleus of the comet 67P/Churyumov–Gerasimenko measured by the Rosetta/Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) instrument can be reproduced by a particle model involving clustered, densely packed submicrometer-sized grains composed of organic material and larger micrometer-sized silicate grains. The simulated and measured coma phase functions suggest that near the nucleus scattering is dominated by large particles, and the size distribution of dust particles varies with time and/or local coma environment. Further, we show that the measured nucleus phase function is consistent with the coma phase function by modeling a nucleus-sized object consisting of the same particles that explain the coma phase functions.
Electromagnetic coupling of twisted multi-filament superconducting tapes in a ramped magnetic field

We theoretically investigate the magnetization loss and electromagnetic coupling of twisted multi-filament superconducting (SC) tapes in a ramped magnetic field. Based on the two-dimensional reduced Faraday–Maxwell equation for a tape surface obtained with a thin-sheet approximation, we numerically simulate the power loss P per unit length on twisted multi-filament tapes in the steady state. The current density profile clearly shows electromagnetic coupling between the SC filaments upon increasing the field sweep rate β. Although the β dependence of P / β for twisted multi-filament SC tapes closely resembles that for filaments in an alternating field, we show that the mechanism for electromagnetic coupling in a ramped field differs from that in an alternating field. We also identify the conditions under which electromagnetic coupling is suppressed for the typical sweep rate of a magnet used for magnetic resonance imaging.
On identically closed forms locally constructed from a field

Let M be an n‐dimensional manifold with derivative operator ∇a and let B(M) be an arbitrary vector bundle over M, equipped with a connection. A cross section of B defines a field φ on M. Let α be a p‐form on M (with p<n) which is locally constructed from φ and finitely many of its derivatives (as well as, possibly, some ‘‘background fields’’ ψ and their derivatives) such that dα=0 for all cross sections φ. Suppose further that α=0 for the zero cross section, φ=0. It is proven here that there exists a (p−1)‐form β that also is a local function of φ,ψ and finitely many of their derivatives, such that α=dβ. A number of applications of this result are described. In particular, gauge invariance is established for the charges and the total fluxes derived from gauge‐dependent conserved currents, and severe limitations are established on the the possibilities for gravitational analogs of magnetic charges.
Universal continuous transition to turbulence in a planar shear flow

We examine the onset of turbulence in Waleffe flow – the planar shear flow between stress-free boundaries driven by a sinusoidal body force. By truncating the wall-normal representation to four modes, we are able to simulate system sizes an order of magnitude larger than any previously simulated, and thereby to attack the question of universality for a planar shear flow. We demonstrate that the equilibrium turbulence fraction increases continuously from zero above a critical Reynolds number and that statistics of the turbulent structures exhibit the power-law scalings of the (2 + 1)-D directed-percolation universality class.
MAXI upper limits of the electromagnetic counterpart of GW170817

We report the MAXI observation of the gravitational-wave (GW) event GW170817 and the electromagnetic counterpart of GW170817. GW170817 is a binary neutron star coalescence candidate detected by the Advanced LIGO and Advanced Virgo detectors, and it is the first event for which the optical counterpart has been discovered. In the MAXI observation, the Gas Slit Camera (GSC) covered approximately 62% of the sky region of the GW event within 90% probability during the first 92 min of orbit after the trigger. No significant X-ray transient was detected in the error region, and the upper limit of the average flux with a significance of 3 $\sigma$ in the 2--10 keV band was 53/26 mCrab (one-orbit observation/one-day observation). In the optical counterpart of GW170817, the observational window of GSC at the position started at 20 s after the GW trigger, but the high voltage of GSC was unfortunately off at the time because the ISS was entering a high-particle-background region. The first observation of the position by GSC was eventually performed at 16797 sec (4.6 hours) since the GW trigger, yielding the 3 $\sigma$ upper limit of 8.60$\times$10$^{-9}$ erg cm$^{-2}$ s$^{-1}$ in the 2--10 keV band, though it was the earliest X-ray observation of the counterpart.
Rotational Instability in the Theta Pinch

An experimental study of the rotation and associated instability was made in a theta pinch with a peak field of 85 kG reached in 2.3 μsec. The starting deuterium gas pressure was in the range 50–150 μ Hg, and for operation on the second half‐cycle of the sinusoidal driving field the magnetic flux trapped within the plasma varied between ±100 kMx. In most conditions the circular cross section of the plasma became perturbed along its length by the growth of two flutes which rotated at an angular velocity of up to 6 × 107 rad/sec. It is deduced from measurements on the rotation that the plasma acquires its angular momentum at the start of the half‐cycle, and the results are interpreted on the basis that the angular momentum is initially in a diamagnetic (azimuthal) ion current. A model is described for establishing this current as a consequence of contact between the plasma and the walls. Results on the time of onset of the instability, and on the growth rate of the flutes, point to the existence of some dam.
Calculated magnetic exchange interactions in the Dirac magnon material 
Cu3TeO6

Recently, topological aspects of magnon band structure have attracted much interest, and especially, the Dirac magnons in ${\mathrm{Cu}}_{3}{\mathrm{TeO}}_{6}$ have been observed experimentally. In this work, we calculate the magnetic exchange interactions $J$'s using the first-principles linear-response approach and find that these $J$'s are short range and negligible for the Cu-Cu atomic pair longer than 7 \AA{}. Moreover, there are only five sizable magnetic exchange interactions, and according to their signs and strengths, modest magnetic frustration is expected. Based on the obtained magnetic exchange couplings, we successfully reproduce the experimental spin-wave dispersions. The calculated neutron scattering cross section also agrees very well with the experiments. We also calculate Dzyaloshinskii-Moriya interactions (DMIs) and estimate the canting angle ($\ensuremath{\sim}1.3{}^{\ensuremath{\circ}}$) of the magnetic noncollinearity based on the competition between DMIs and $J$'s, which is consistent with the experiment. The small canting angle agrees with that current experiments cannot distinguish the DMI-induced nodal line from a Dirac point in the spin-wave spectrum. Finally, we analytically prove that the ``sum rule'' conjectured in W. Yao et al. [Nat. Phys. 14, 1011 (2018)] holds but only up to the 11th-nearest neighbor.
Dense gas and star formation in individual Giant Molecular Clouds in M31

Studies both of entire galaxies and of local Galactic star formation indicate a dependency of a molecular cloud's star formation rate (SFR) on its dense gas mass. In external galaxies, such measurements are derived from HCN(1-0) observations, usually encompassing many Giant Molecular Clouds (GMCs) at once. The Andromeda galaxy (M31) is a unique laboratory to study the relation of the SFR and HCN emission down to GMC scales at solar-like metallicities. In this work, we correlate our composite SFR determinations with archival HCN, HCO+, and CO observations, resulting in a sample of nine reasonably representative GMCs. We find that, at the scale of individual clouds, it is important to take into account both obscured and unobscured star formation to determine the SFR. When correlated against the dense-gas mass from HCN, we find that the SFR is low, in spite of these refinements. We nevertheless retrieve an SFR-dense-gas mass correlation, confirming that these SFR tracers are still meaningful on GMC scales. The correlation improves markedly when we consider the HCN/CO ratio instead of HCN by itself. This nominally indicates a dependency of the SFR on the dense-gas fraction, in contradiction to local studies. However, we hypothesize that this partly reflects the limited dynamic range in dense-gas mass, and partly that the ratio of single-pointing HCN and CO measurements may be less prone to systematics like sidelobes. In this case, the HCN/CO ratio would importantly be a better empirical measure of the dense-gas content itself.