Miracle-dz/UniFAR-FTUs huggingface dataset:
The role of stellar radial motions in shaping galaxy surface brightness profiles

Aims. The physics driving features such as breaks observed in galaxy surface brightness (SB) profiles remains contentious. Here, we assess the importance of stellar radial motions in shaping their characteristics. Methods. We use the simulated Milky Way-mass cosmological discs from the Ramses Disc Environment Study (RaDES) to characterise the radial redistribution of stars in galaxies displaying type-I (pure exponentials), II (downbending), and III (upbending) SB profiles. We compare radial profiles of the mass fractions and the velocity dispersions of different sub-populations of stars according to their birth and current location. Results. Radial redistribution of stars is important in all galaxies regardless of their light profiles. Type-II breaks seem to be a consequence of the combined effects of outward-moving and accreted stars. The former produce shallower inner profiles (lack of stars in the inner disc) and accumulate material around the break radius and beyond, strengthening the break; the latter can weaken or even convert the break into a pure exponential. Further accretion from satellites can concentrate material in the outermost parts, leading to type-III breaks that can coexist with type-II breaks, but situated further out. Type-III galaxies would be the result of an important radial redistribution of material throughout the entire disc, as well as a concentration of accreted material in the outskirts. In addition, type-III galaxies display the most efficient radial redistribution and the largest number of accreted stars, followed by type-I and II systems, suggesting that type-I galaxies may be an intermediate case between types-II and III. In general, the velocity dispersion profiles of all galaxies tend to flatten or even increase around the locations where the breaks are found. The age and metallicity profiles are also affected, exhibiting different inner gradients depending on their SB profile, being steeper in the case of type-II systems (as found observationally). The steep type-II profiles might be inherent to their formation rather than acquired via radial redistribution.
Development of Advanced Industrial Furnace Using Highly Preheated Combustion Air

Results are presented on the thermal and chemical characteristics of flames using high-temperature combustion air and liquified petroleum gas (LPG) as the fuel. The stability limits of these flames are extremely wide as compared to any other method of flame stabilization. This study is part of the Japan national project directed to develop advanced industrial furnace designs that provide approximately 30% energy savings and hence CO 2 reduction, 30% reduction in the furnace size, and 25% reduction of pollutants including NO x as compared to current designs. The objective here is to establish conditions that permit significant reduction in energy consumption, high efficiency, and low pollution from a range of furnaces. Data have been obtained on mean flame temperature and temperature fluctuations, flame emission spectra, emission intensity of C 2 and CH species from within the flames, and overall pollutant emission from the flames. The uniformity of temperature in the furnace was found to be far greater with low oxygen concentration combustion air preheated to 1000°C as compared to that obtained with roomtemperature air or that found in conventional flames. Emission of NO x and CO was much lower with combustion air preheated to high temperatures with low oxygen concentration. The chemiluminescence intensity of CH and C 2 radicals is significantly affected by the preheat temperature of the combustion air and oxygen concentration in the oxidant. The flame signatures revealed important flame characteristics under high-temperature air combustion conditions. The advantages of utilizing highly preheated combustion air (in excess of 1000°C) in various types of furnaces are given. The new and advanced furnace design utilizes high-efficiency regenerators and behaves essentially as a well-stirred reactor with uniform thermal and chemical characteristics. Because each furnace design requires unique features, it is imperative that each furnace must be optimized to satisfy the functional requirements of the furnace. In this paper a relatively simple diagnostic methodology is presented, which assists in a rational furnace design and optimization process.
Hemispheric Preference and Cyclic Variation of Solar Filament Chirality from 2000 to 2016

It is well known that solar filaments are features in the solar atmosphere that show a hemispheric preference in their chirality. The hemispheric preference is such that the dextral chirality dominates in the northern hemisphere while the sinistral chirality dominates in the southern. Determining the strength and cyclic variation of the degree of this hemispheric preference however, is challenging and tedious, and thus, needs to be automated. In this paper, we follow Dr. Pietro Bernasconi’s algorithm to detect filament chirality with two parallel channels of application. The algorithm is applied to H-alpha images with the “Advanced Automated Filament Detection and Characterization Code” and the full algorithm (including the detection of filaments and tracking) is explained to the human observer who determines the chirality of the solar filament. We have conducted this exercise on the data during the month of August from years 2000 to 2016 and we found that 83% of our visually determined filaments follow the hemispheric chirality preference, while 58% of automatically determined filaments follow it. Our visually compiled results have over 90% agreement with those of Pevtsov et al., yet the visually determined chiralities of filaments disagree with the automated determinations significantly. We find that the hemispheric preference remained the same between solar cycles 23 and 24, but the preference is very difficult to determine during the solar minimum of 2008–2010 primarily due to the absence of filaments.
Phantom Dirac-Born-Infeld dark energy

Motivated by the apparent discrepancy between Cosmic Microwave Background measurements of the Hubble constant and measurements from Type-Ia supernovae, we construct a model for Dark Energy with equation of state $w = p / \rho < -1$, violating the Null Energy Condition. Naive canonical models of so-called "Phantom" Dark Energy require a negative scalar kinetic term, resulting in a Hamiltonian unbounded from below and associated vacuum instability. We construct a scalar field model for Dark Energy with $w < -1$, which nonetheless has a Hamiltonian bounded from below in the comoving reference frame, {\it i.e.} in the rest frame of the fluid. We demonstrate that the solution is a cosmological attractor, and find that early-time cosmological boundary conditions consist of a "frozen" scalar field, which relaxes to the attractor solution once the Dark Energy component dominates the cosmological energy density. We consider the model in an arbitrary choice of gauge, and find that, unlike the case of comoving gauge, the fluid Hamiltonian is in fact unbounded from below in the reference frame of a highly boosted observer, corresponding to a nonlinear gradient instability. We discuss this in the context of general NEC-violating perfect fluids, for which this instability is a general property.
Encounters of disk/halo galaxies

The first numerical models of interacting galaxies are presented in which all dynamical components of the participants are modeled as fully three-dimensional N-body systems with thousands of particles each and the equations of motion are integrated by a self-consistent algorithm without arbitrary restrictions on the geometry or spatial extent of the mass distribution. Several encounters between multicomponent galaxy models are described, starting with a lookalike for the 'Antennae', NGC 4038/9. The influence of massive halos is shown by contrasting models run with and without dark matter. The results show that encounters involving pairs of disk/halo galaxies can produce impressive tidal tails while permitting the visible galaxies to merge on a short time scale, mimicking 'double-tailed' objects. Extensive dark halos are very effective at soaking up binding energy and angular momentum from other components, significantly altering the distribution and dynamics of the luminous material. 43 references.
New deformed model of α-decay half-lives with a microscopic potential

The {alpha}-decay half-lives of deformed nuclei are investigated in a new version of the density-dependent cluster model. By the multipole expansion method, the deformation- and orientation-dependent double-folding potential is derived to calculate the {alpha}-decay width through a deformed Coulomb barrier. We perform systematic calculations for the ground-state {alpha} transitions of even-even nuclei with Z=52-104. The theoretical results are in good agreement with the experimental data. This is, to our knowledge, the first deformed calculation of {alpha}-decay half-lives within the framework of microscopic double-folding potentials. A unified description of {alpha}-decay half-lives of both spherical and deformed nuclei is obtained by the microscopic potentials.
Pushing the precision frontier at the LHC with V+jets

This documents the proceedings from a workshop titled `Illuminating Standard candles at the LHC: V+jets' held at Imperial College London on 25th-26th April 2017. It summarises the numerous contributions to the workshop, from the experimental overview of V+jets measurements at CMS and ATLAS and their role in searching for physics beyond the Standard Model to the status of higher order perturbative calculations to these processes and their inclusion in state of the art Monte Carlo simulations. An executive summary of the ensuing discussions including a list of outcomes and wishlist for future consideration is also presented.
The GALAH Survey: Second Data Release

The Galactic Archaeology with HERMES (GALAH) survey is a large-scale stellar spectroscopic survey of theMilkyWay, designed to deliver complementary chemical information to a large number of stars covered by the Gaia mission. We present the GALAH second public data release (GALAH DR2) containing 342 682 stars. For these stars, the GALAH collaboration provides stellar parameters and abundances for up to 23 elements to the community. Here we present the target selection, observation, data reduction, and detailed explanation of how the spectra were analysed to estimate stellar parameters and element abundances. For the stellar analysis, we have used a multistep approach. We use the physics-driven spectrum synthesis of Spectroscopy Made Easy (SME) to derive stellar labels (T eff , logg, [Fe/H], [X/Fe], v mic , vsin i, AK S ) for a representative training set of stars. This information is then propagated to the whole sample with the data-driven method of The Cannon. Special care has been exercised in the spectral synthesis to only consider spectral lines that have reliable atomic input data and are little affected by blending lines. Departures from local thermodynamic equilibrium (LTE) are considered for several key elements, including Li, O, Na, Mg, Al, Si, and Fe, using 1D MARCS stellar atmosphere models. Validation tests including repeat observations, Gaia benchmark stars, open and globular clusters, and K2 asteroseismic targets lend confidence to our methods and results. Combining the GALAH DR2 catalogue with the kinematic information from Gaia will enable a wide range of Galactic Archaeology studies, with unprecedented detail, dimensionality, and scope.
Revisiting the Long-period Transiting Planets from Kepler

Currently, we have only limited means to probe the presence of planets at large orbital separations. Foreman-Mackey et al. searched for long-period transiting planets in the Kepler light curves using an automated pipeline. Here, we apply their pipeline, with minor modifications, to a larger sample and use updated stellar parameters from Gaia DR2. The latter boosts the stellar radii for most of the planet candidates found by FM16, invalidating a number of them as false positives. We identify 15 candidates, including two new ones. All have sizes from 0.3 to 1 RJ, and all but two have periods from 2 to 10 yr. We report two main findings based on this sample. First, the planet occurrence rate for the above size and period ranges is planets per Sun-like star, with the frequency of cold Jupiters agreeing with that from radial velocity surveys. Planet occurrence rises with decreasing planet size, roughly describable as with , i.e., Neptune-sized planets are some four times more common than Jupiter-sized ones. Second, five out of our 15 candidates orbit stars with known transiting planets at shorter periods, including one with five inner planets. We interpret this high incidence rate to mean: (1) almost all our candidates should be genuine; (2) across a large orbital range (from ∼0.05 to a few astronomical units), mutual inclinations in these systems are at most a few degrees; and (3) large outer planets exist almost exclusively in systems with small inner planets.
THE KOLMOGOROV EQUATION ASSOCIATED TO THE STOCHASTIC NAVIER–STOKES EQUATIONS IN 2D

We consider a 2D Navier–Stokes equation with Dirichlet boundary conditions perturbed by a stochastic term of the form , where Q is a non-negative operator and Ẇ is a spacetime white noise. We solve the corresponding Kolmogorov equation in the space L2(H,ν) where ν is an invariant measure and prove the "carre du champs" identity. The key tool are some sharp estimates on the derivatives of the solution. Our main assumption is that the viscosity is large compared with the norm of Q. As a byproduct, we give a new simple proof of the uniqueness of the invariant measure and obtain an existence result for a Hamilton–Jacobi equation related to a control problem.
THE GAS DUST RATIO IN SPIRAL GALAXIES

IRAS data are used here to calculate warm dust masses, which are then compared with the molecular and atomic gas masses for 58 spiral galaxies in order to constrain the fraction and the phase of the interstellar medium in spiral galaxies that contributes to the emission measured by IRAS. The dispersion in the ratio of dust mass to total gas mass is larger than expected on the basis of measurement errors. The dispersion in the ratio of dust mass to inner disk gas mass is less than the dispersion in the ratio of IR to radio emission. The inner gas to warm dust mass ratio for spiral galaxies is 1080 + or - 70, indicating that 80-90 percent of the dust mass in spiral galaxies is radiating at over 100 microns and has a temperature less than about 30 K. However, the bulk of the dust in spiral galaxies is less than about 15 K regardless of the phase of the ISM. Both H I and H2-associated dust contributes to the warm 30 K emission. 82 refs.
Stochastic vertex corrections: $GW\Gamma_X$ approach for accurate quasiparticle energies

Quasiparticle energies for the highest occupied and lowest unoccupied states are investigated using the stochastic many-body perturbation theory with the inclusion of non-local vertex corrections. Approximate form of a vertex function, labeled $G_0W_0^{tc}\Gamma_X$, is developed and implemented within a real-time stochastic framework. This implementation is tested on acene molecules, C$_{60}$ and PC$_{60}$BM. $G_0W_0^{tc}\Gamma_X$ is compared to the one-shot stochastic $GW$ approach with and without random-phase approximation. Overall, the $G_0W_0^{tc}\Gamma_X$ method has the best agreement with CCSD(T) benchmark data. The vertex correction appears crucial for the description of unoccupied states. All three stochastic methods scale linearly; due to favorable self-averaging in large systems, stochastic $G_0W_0^{tc}\Gamma_X$ is actually less expensive than stochastic $G_0W_0$.
Despin Mechanism for Protogiant Planets and Ionization State of Protogiant Planetary Disks

The giant planets Jupiter and Saturn probably experienced despinning from a rapid rotation rate near rotational break-up to their present rotational states. This is presumed to occur when these planets possessed gaseous disks, during and immediately after planetary accretion. We modeled the despinning mechanism arising from hydromagnetic torque due to the interaction of the planetary magnetic field with the partially conducting gaseous disk, assuming parameters typical of the late stages of the planet's formation. The main idea of the model is that the angular momentum is transferred from the proto_planet to the disk at all radii beyond the corotation point because of the coupling of planetary dipole field lines to the disk fluid and the resulting current and Lorentz force thereby created. The ionization degree of the gas of the protojovian disk was estimated to be about 10^(−15)at one scale height, but increases rapidly with height. The calculations suggest that under the condition of a giant planetary surface magnetic field of 100 G, a mean magnetic diffusivity of the disk of 10^(16)–10^(17) cm^2s^(−1)and the minimum mass of the disk sufficient to create the Galilean satellites, the planetary angular momentum can be reduced to its current value from an initial critical rotational period in about 10^6–10^7years. If the dissipation time scale of the disk is of this order, then this model is capable in principal of explaining the present spin states of Jupiter and Saturn, provided that the protoplanet had a strong magnetic dipole.
Waves on a static water surface beneath a layer of moving air

Large-amplitude waves can exist on an air-water interface where the air is in steady non-uniform flow and the water is stationary. Computations of such waves are provided here, both for periodic nonlinear Stokes-like waves, and for a specific wave-making configuration in which the periodic solution appears as the downstream far field. The wavemaker geometry chosen here is relevant to the edge region of a hovercraft, and the large-amplitude free-surface disturbance caused by the escaping air is computed as a function of the Froude number based on air-jet velocity and thickness.
Mathematical Analysis of Multi-Scale Models of Complex Fluids

The state of the art of the mathematical and numerical analysis of multi-scale models of complex fluids is reviewed. Issues addressed include well-posedness of the models, convergence analysis of the numerical methods, and the structure of stationary solutions of the Doi-Onsager equation. 1. Introduction A polymer is a large molecule made up of many small and simple chemical units, joined together by chemical bonds. For example, polyethylene is a long chain-like molecule composed of ethylene molecules, and DNAs are extremely long chain molecules consists of up to 10 9 nucleotides. Materials composed of macromolecules can display completely different properties other than those composed of small molecules. These polymeric materials are typically very flexible, like rubber, and usually can be easily processed into fibres, thin films, etc. In order to understand these particular properties, we are faced with an issue on how to deal with a large assemble of molecules or monomers. Thus, statistical mechanics is proved to be a very necessary tool even for one single isolated polymer. One approach to investigate one single polymer is to place it in a dilute solution such that interactions between polymers are negligible. As the concentration of the solution increases, the polymers start to overlap and entangle with each other. The limiting state of a polymer solution as concentration increases is known as the polymer melt, which is a state composed only of polymers. Polymer melts have significant industrial applications since most polymeric materials are in this melting state when they are processed into various plastic products. In addition, two or more components of different polymers are usually blended together, and it is important to understand whether and how the polymers mix or separate into different phases. Polymeric structures in melts, blends and solutions can range from nanometer to microns, millimeters and larger scales. The corresponding time scales of dynamic processes associated with different material properties span an even wide range, from femtoseconds to milliseconds or seconds, even hours for large scale ordering processes such as phase separation in blends. No single model or simulation algorithm can fit such a wide range of length and time scales. Therefore one of the important problems in computational polymer dynamics is multiscale simulation: the bridging of different
Halley and Newton are one step apart

One of the central problems of scientific computation is the efficient numerical solution of the system of n equations in n unknowns F (x) = 0 where F: Rn → Rn is sufficiently smooth. While Newton's method is usually used for solving such systems, third order methods will in general use fewer iterations than a second order method to reach the same accuracy. However, the number of arithmetic operations per iteration is higher for third order methods than second order methods. In this note we will consider the case where F = ∇f, where f is three times continuously differentiable. We will show that for a large class of sparse problems the ratio of the number of arithmetic operations of a third order method and Newton's method is constant per iteration. It is shown that
Spectral Energy Distributions of Flat-Spectrum Radio Quasars Observed with BeppoSAX

We report the BeppoSAX observations of six flat-spectrum radio quasars. Three of them have a clear detection up to 100 keV with the PDS instrument. For four objects the X-ray spectrum is satisfactorily fitted by a power-law continuum with Galactic absorption. QSO 2251+158 shows the presence of absorption higher than the Galactic value, while the spectrum of the source QSO 0208-512 shows a complex structure, with evidence of absorption at low energy. We construct the spectral energy distributions adding historical data to the broadband X-ray spectra obtained with BeppoSAX and reproduce them with a one-zone synchrotron-inverse Compton model (including both synchrotron self-Compton and external Compton). The implications are briefly discussed.
Ion heating by nonlinear Landau damping of ion Bernstein waves

It is shown theoretically that efficient ion heating occurs by nonlinear Landau damping because of the self‐interaction of ion Bernstein waves, where heating efficiency, nonlinear damping of ion Bernstein waves, nonlinear wave–particle coupling coefficients, and virtual waves have sharp maxima at ω≂(m/2)ωci (m=3,5,7). Ion heating depends on k∥νti/ ωci and becomes significantly large for k∥νti/ ωci ≲0.1.
Investigation of the influence of edge structure on the micromagnetic behavior of small magnetic elements

Thin film elements of a soft magnetic nickel–iron alloy have been fabricated with structured edges in order to determine their effect on the magnetization reversal processes. Lorentz microscopy was used to study acicular elements with different edge structures and these were compared with standard elements with straight edges. The presence of the structured edges results in deviations of the magnetization along the length of the elements in the remanent state. Switching processes are described for a number of different elements and the effect of structuring the edges is discussed.