Miracle-dz/UniFAR-FTUs huggingface dataset:
Optically thick envelopes around ULXs powered by accreating neutron stars

Magnetized neutron stars power at least some ultraluminous X-ray sources. The accretion flow in these cases is interrupted at the magnetospheric radius and then reaches the surface of a neutron star following magnetic field lines. Accreting matter moving along magnetic field lines forms the accretion envelope around the central object. We show that in case of high-mass accretion rates ≳ 1019 g s-1 the envelope becomes closed and optically thick, which influences the dynamics of the accretion flow and the observational manifestation of the neutron star hidden behind the envelope. Particularly, the optically thick accretion envelope results in a multi-colour blackbody spectrum originating from the magnetospheric surface. The spectrum and photon energy flux vary with the viewing angle, which gives rise to pulsations characterized by high pulsed fraction and typically smooth pulse profiles. The reprocessing of radiation due to interaction with the envelope leads to the disappearance of cyclotron scattering features from the spectrum. We speculate that the super-orbital variability of ultraluminous X-ray sources powered by accreting neutron stars can be attributed to precession of the neutron star due to interaction of magnetic dipole with the accretion disc.
Formation and Fractionation of CO (Carbon Monoxide) in Diffuse Clouds Observed at Optical and Radio Wavelengths

We modeled and CO formation incorporating the fractionation and selective photodissociation affecting CO when ≲ 2 mag. UV absorption measurements typically have N( )/N( ) ≈ 65 that are reproduced with the standard UV radiation and little density dependence at n(H) ≈ 32–1024 : densities n(H) ≲ 256 avoid overproducing CO. Sightlines observed in millimeter wave absorption and a few in UV show enhanced by factors of two to four and are explained by higher n(H) ≳ 256 and/or weaker radiation. The most difficult observations to understand are UV absorptions having N( )/N( ) > 100 and N(CO) ≳ 1015 . Plots of versus N(CO) show that remains linearly proportional to N(CO) even at high opacity owing to sub-thermal excitation. and have nearly the same curve of growth so their ratios of column density/integrated intensity are comparable even when different from the isotopic abundance ratio. For n(H) ≳ 128 , plots of versus N(CO) are insensitive to n(H), and /N(CO) ≈ 1 /(1015 CO ); this compensates for small CO/ to make more readily detectable. Rapid increases of N(CO) with n(H), N(H), and N( ) often render the CO bright, i.e., a small CO- conversion factor. For n(H) ≲ 64 , CO enters the regime of truly weak excitation, where ∝ n(H)N(CO). is a strong function of the average fraction and models with = 1 fall in the narrow range of 0.65–0.8 or 0.4–0.5 at 0.1 . The insensitivity of easily detected CO emission to gas with small implies that even deep CO surveys using broad beams may not discover substantially more emission.
An Empirical Template Library of Stellar Spectra for a Wide Range of Spectral Classes, Luminosity Classes, and Metallicities Using SDSS BOSS Spectra

We present a library of empirical stellar spectra created using spectra from the Sloan Digital Sky Survey’s Baryon Oscillation Spectroscopic Survey. The templates cover spectral types O5 through L3, are binned by metallicity from −2.0 dex through +1.0 dex, and are separated into main-sequence (dwarf) stars and giant stars. With recently developed M dwarf metallicity indicators, we are able to extend the metallicity bins down through the spectral subtype M8, making this the first empirical library with this degree of temperature and metallicity coverage. The wavelength coverage for the templates is from 3650 to 10200 Å at a resolution of better than R ∼ 2000. Using the templates, we identify trends in color space with metallicity and surface gravity, which will be useful for analyzing large data sets from upcoming missions like the Large Synoptic Survey Telescope. Along with the templates, we are releasing a code for automatically (and/or visually) identifying the spectral type and metallicity of a star.
Astrometric Calibration and Performance of the Dark Energy Camera

We characterize the ability of the Dark Energy Camera (DECam) to perform relative astrometry across its 500 Mpix, 3-deg2 science field of view and across four years of operation. This is done using internal comparisons of ∼4 × 107 measurements of high signal-to-noise ratio stellar images obtained in repeat visits to fields of moderate stellar density, with the telescope dithered to move the sources around the array. An empirical astrometric model includes terms for optical distortions; stray electric fields in the CCD detectors; chromatic terms in the instrumental and atmospheric optics; shifts in CCD relative positions of up to ≈10 μm when the DECam temperature cycles; and low-order distortions to each exposure from changes in atmospheric refraction and telescope alignment. Errors in this astrometric model are dominated by stochastic variations with typical amplitudes of 10–30 mas (in a 30 s exposure) and 5′–10′ coherence length, plausibly attributed to Kolmogorov-spectrum atmospheric turbulence. The size of these atmospheric distortions is not closely related to the seeing. Given an astrometric reference catalog at density ≈ 0.7 arcmin − 2 , e.g., from Gaia, the typical atmospheric distortions can be interpolated to ≈7 mas rms accuracy (for 30 s exposures) with 1 ′ coherence length in residual errors. Remaining detectable error contributors are 2–4 mas rms from unmodelled stray electric fields in the devices, and another 2–4 mas rms from focal plane shifts between camera thermal cycles. Thus the astrometric solution for a single DECam exposure is accurate to 3–6 mas (≈0.02 pixels, or ≈300 nm) on the focal plane, plus the stochastic atmospheric distortion.
Using Dimensional Analysis to Construct Multiple-Scalar-Vector-Tensor Cosmological Field Theories

In this paper I shall consider various possible scalar-vector-tensor field theories which might be used to describe the Universe. After imposing numerous constraints of a physical and mathematical nature on the theories under consideration, we shall see that there still exists a plethora of viable theories from which to choose. But hopefully I shall be able to convince you that a scalar-vector-tensor field theory involving five scalar fields provides a promising cosmological model. The advantage of this theory is that there is no energy-momentum tensor for the matter fields, nor arbitrary functions, only dimensionless constants, that need to be determined. I shall also construct the most general multiple-scalar-vector-tensor field theory which is dimensionally consistent and free of dimensioned constants. It turns out that this field theory yields second-order field equations.
Testing the relativistic precession model using low-frequency and kHz quasi-periodic oscillations in neutron star low-mass X-ray binaries with known spin

We analyse all available RXTE data on a sample of 13 low-mass X-ray binaries with known neutron star spin that are not persistent pulsars. We carefully measure the correlations between the centroid frequencies of the quasi-periodic oscillations (QPOs). We compare these correlations to the prediction of the relativistic precession model that, due to frame dragging, a QPO will occur at the Lense–Thirring precession frequency νLT of a test-particle orbit whose orbital frequency is the upper kHz QPO frequency νu. Contrary to the most prominent previous studies, we find two different oscillations in the range predicted for νLT that are simultaneously present over a wide range of νu. Additionally, one of the low-frequency noise components evolves into a (third) QPO in the νLT range when νu exceeds 600 Hz. The frequencies of these QPOs all correlate to νu following power laws with indices between 0.4 and 3.3, significantly exceeding the predicted value of 2.0 in 80 per cent of the cases (at 3 to >20σ). Also, there is no evidence that the neutron star spin frequency affects any of these three QPO frequencies, as would be expected for frame dragging. Finally, the observed QPO frequencies tend to be higher than the νLT predicted for reasonable neutron star specific moment of inertia. In the light of recent successes of precession models in black holes, we briefly discuss ways in which such precession can occur in neutron stars at frequencies different from test-particle values and consistent with those observed. A precessing torus geometry and other torques than frame dragging may allow precession to produce the observed frequency correlations, but can only explain one of the three QPOs in the νLT range.
Galaxy–Galaxy Weak-lensing Measurements from SDSS. II. Host Halo Properties of Galaxy Groups

In this second paper in a series studying galaxy–galaxy lensing signals using Sloan Digital Sky Survey Data Release 7 (SDSS DR7), we present our measurement and modeling of the lensing signals around groups of galaxies. We divide the groups into four halo mass bins and measure the signals around four different halo-center tracers: brightest central galaxies (BCGs), luminosity-weighted centers, number-weighted centers, and X-ray peak positions. For groups cross-identified in both X-ray and SDSS DR7, we further split the groups into low and high X-ray emission subsamples, both of which are assigned to two halo-center tracers, BCGs and X-ray peak positions. The galaxy–galaxy lensing signals show that BCGs, among the four candidates, are the best halo-center tracers. We model the lensing signals using a combination of four contributions: the off-center NFW host halo profile, subhalo contribution, stellar contribution, and projected two-halo term. We sample the posterior of five parameters, i.e., the halo mass, concentration, off-centering distance, subhalo mass, and fraction of subhalos, via a Monte Carlo Markov Chain (MCMC) package using the galaxy–galaxy lensing signals. After taking into account the sampling effects (e.g., Eddington bias), we found that the best-fit halo masses obtained from lensing signals are quite consistent with those obtained in the group catalog based on an abundance matching method, except in the lowest mass bin.
Overdensity of galaxies in the environment of quasar pairs

We report on a study of the galaxy environments of low redshift physical quasars pairs. We selected 20 pairs having projected separation $<$ 0.5 Mpc and difference of systemic velocity $<$ 800 km s$^{-1}$. Using Sloan Digital Sky Survey images we evaluated the galaxy overdensity around these quasars in pairs and then compare it with that of a sample of isolated quasars with same redshift and luminosity. It is found that on average there is a systematic larger overdensity of galaxies around quasars in pairs with respect to that of isolated quasars. This may represent a significant link between nuclear activity and galaxy environment. However, at odds with that, the closest quasar pairs seem to inhabit poorer environments. Implications of present results and perspectives for future work are briefly discussed.
Dust extinction in the first galaxies

Using cosmological volume simulations and a custom built sub-grid model for Pop III star formation, we examine the baseline dust extinction in the first galaxies due to Pop~III metal enrichment in the first billion years of cosmic history. We find that while the most enriched, high-density lines of sight in primordial galaxies can experience a measurable amount of extinction from Pop III dust ($E(B-V)_{\rm max}=0.07,\ A_{\rm V,max}\approx0.28$), the average extinction is very low with $\left \lesssim 10^{-3}$. We derive a power-law relationship between dark matter halo mass and extinction of $E(B-V)\propto M_{\rm halo}^{0.80}$. Performing a Monte Carlo parameter study, we establish the baseline reddening of the UV spectra of dwarf galaxies at high redshift due to Pop III enrichment only. With this method, we find $\left -2.72\pm0.12$, which is both nearly halo mass and redshift independent.
Blinded by the light: on the relationship between CO first overtone emission and mass accretion rate in massive young stellar objects

To date, there is no explanation as to why disc-tracing CO first overtone (or ‘bandhead’) emission is not a ubiquitous feature in low- to medium-resolution spectra of massive young stellar objects (MYSOs), but instead is only detected towards approximately 25 per cent of their spectra. In this paper, we investigate the hypothesis that only certain mass accretion rates result in detectable bandhead emission in the near-infrared spectra of MYSOs. Using an analytic disc model combined with an LTE model of the CO emission, we find that high accretion rates (≳10⁻⁴ M⊙ yr⁻¹) result in large dust sublimation radii, a larger contribution to the K-band continuum from hot dust at the dust sublimation radius, and therefore correspondingly lower CO emission with respect to the continuum. On the other hand, low accretion rates (≲10⁻⁶ M⊙ yr⁻¹) result in smaller dust sublimation radii, a correspondingly smaller emitting area of CO, and thus also lower CO emission with respect to the continuum. In general, moderate accretion rates produce the most prominent, and therefore detectable, CO first overtone emission. We compare our findings to a recent near-infrared spectroscopic survey of MYSOs, finding results consistent with our hypothesis. We conclude that the detection rate of CO bandhead emission in the spectra of MYSOs could be the result of MYSOs exhibiting a range of mass accretion rates, perhaps due to the variable accretion suggested by recent multi-epoch observations of these objects.
The Influence of Forming Companions on the Spectral Energy Distributions of Stars with Circumstellar Discs

Abstract We study a possibility to detect signatures of brown dwarf companions in a circumstellar disc based on spectral energy distributions. We present the results of spectral energy distribution simulations for a system with a 0.8 M⊙ central object and a companion with a mass of 30 M J embedded in a typical protoplanetary disc. We use a solution to the one-dimensional radiative transfer equation to calculate the protoplanetary disc flux density and assume, that the companion moves along a circular orbit and clears a gap. The width of the gap is assumed to be the diameter of the brown dwarf Hill sphere. Our modelling shows that the presence of such a gap can initiate an additional minimum in the spectral energy distribution profile of a protoplanetary disc at λ = 10–100 μm. We found that it is possible to detect signatures of the companion when it is located within 10 AU, even when it is as small as 3 M J. The spectral energy distribution of a protostellar disc with a massive fragment (of relatively cold temperature ~400 K) might have a similar double peaked profile to the spectral energy distribution of a more evolved disc that contains a gap.
Extremes, intermittency, and time directionality of atmospheric turbulence at the crossover from production to inertial scales

The effects of mechanical generation of turbulent kinetic energy and buoyancy forces on the statistics of air temperature and velocity increments are experimentally investigated at the cross over from production to inertial range scales. The ratio of an approximated mechanical to buoyant production (or destruction) of turbulent kinetic energy can be used to form a dimensionless stability parameter $\zeta$ that classifies the state of the atmosphere as common in many atmospheric surface layer studies. Here, we assess how $\zeta$ affects the scale-wise evolution of the probability of extreme air temperature excursions, their asymmetry and time reversibility. The analysis makes use of high frequency velocity and air temperature time series measurements collected at $z$=5 m above a grass surface at very large Reynolds numbers $Re=u_* z/\nu > 1\times 10^5$ ($u_*$ is the friction velocity and $\nu$ is the kinematic viscosity of air). Using conventional higher-order structure functions, temperature exhibits larger intermittency and wider multifractality when compared to the longitudinal velocity component, consistent with laboratory studies and simulations conducted at lower $Re$. Moreover, deviations from the classical Kolmogorov scaling for the longitudinal velocity are shown to be reasonably described by the She-Leveque vortex filament model that has no 'tunable' parameters and is independent of $\zeta$. The work demonstrates that external boundary conditions, and in particular the magnitude and sign of the sensible heat flux, have a significant impact on temperature advection-diffusion dynamics within the inertial range. In particular, atmospheric stability affects both the buildup of intermittency and the persistent asymmetry and time irreversibility observed in the first two decades of inertial sub-range scales.
CADSim: Robust and Scalable in-the-wild 3D Reconstruction for Controllable Sensor Simulation

Realistic simulation is key to enabling safe and scalable development of % self-driving vehicles. A core component is simulating the sensors so that the entire autonomy system can be tested in simulation. Sensor simulation involves modeling traffic participants, such as vehicles, with high quality appearance and articulated geometry, and rendering them in real time. The self-driving industry has typically employed artists to build these assets. However, this is expensive, slow, and may not reflect reality. Instead, reconstructing assets automatically from sensor data collected in the wild would provide a better path to generating a diverse and large set with good real-world coverage. Nevertheless, current reconstruction approaches struggle on in-the-wild sensor data, due to its sparsity and noise. To tackle these issues, we present CADSim, which combines part-aware object-class priors via a small set of CAD models with differentiable rendering to automatically reconstruct vehicle geometry, including articulated wheels, with high-quality appearance. Our experiments show our method recovers more accurate shapes from sparse data compared to existing approaches. Importantly, it also trains and renders efficiently. We demonstrate our reconstructed vehicles in several applications, including accurate testing of autonomy perception systems.
Mean field and beyond description of nuclear structure with the Gogny force: a review

Nowadays, the Gogny force is a referent in the theoretical description of nuclear structure phenomena. Its phenomenological character manifests in a simple analytical form that allows for implementations of techniques both at the mean field and beyond all over the nuclide chart. Over the years, multiple applications of the standard many-body techniques in an assorted set of nuclear structure applications have produced results which are in a rather good agreement with experimental data. The agreement allows for a simple interpretation of those intriguing phenomena in simple terms and gives confidence on the predictability of the interaction. The present status on the implementation of different many body techniques with the Gogny force is reviewed with a special emphasis on symmetry restoration and large amplitude collective motion.
Kajian Efisiensi Bank Umum Syariah Indonesia

The aim of this study is to measure the efficiency of Islamic Bank in Indonesia and to analyze the factors that affect the level of efficiency. The objects of this study are ten Islamic Bank (BUS) in Indonesia which analyzes from the second quarter of 2012 until the first quarter of 2016. There are three method which are used in this study, two in first stage, namely non parametric method of Data Envelopment Analysis (DEA) and parametric method of Stochastic Frontier Approach (SFA) then the second stage is Tobit estimaton. Overall, the results showed that the efficiency level of Islamic banks in Indonesia during the time period in this study have not reached the optimum level of efficiency yet. Tobit estimation showed that total financing, total wadiah funds, CAR, ROE, total overhead cost significantly affect the Islamic bank`s efficiency in Indonesia. Keywords: Banking, DEA, efficiency, SFA, Tobit
Status of Complex Langevin

I review the status of the Complex Langevin method, which was invented to make simulations of models with complex action feasible. I discuss the mathematical justification of the procedure, as well as its limitations and open questions. Various pragmatic measures for dealing with the existing problems are described. Finally I report on the progress in the application of the method to QCD, with the goal of determining the phase diagram of QCD as a function of temperature and baryonic chemical potential.
Topological classification of Chern-type insulators by means of the photonic Green function

The Chern topological numbers of a material system are traditionally written in terms of the Berry curvature which depends explicitly on the material band structure and on the Bloch eigenwaves. Here, we demonstrate that it is possible to calculate the gap Chern numbers of a photonic platform without having any detailed knowledge of its band structure, relying simply on the system photonic Green function. It is shown that the gap Chern number is given by an integral of the photonic Green function along a line of the complex frequency plane parallel to the imaginary axis. Our theory applies to arbitrary frequency dispersive fully three-dimensional photonic crystals, as well as to the case of electromagnetic continua with no intrinsic periodicity.
Quasilinear Consequences of Turbulent Ion Heating by Magnetic Moment Breaking

The fast solar wind emerging from coronal holes is likely heated and accelerated by the dissipation of magnetohydrodynamic turbulence, but the specific kinetic mechanism resulting in the perpendicular ion heating required by observations is not understood. A promising mechanism has been proposed by Chandran et al., which in this paper we call “magnetic moment breaking” (MMB). As currently formulated, MMB dissipation operates only on the ion perpendicular motion, and does not influence their parallel temperature. Thus, the MMB mechanism acting by itself produces coronal hole proton distributions that are unstable to the ion-cyclotron (IC) anisotropy instability. This quasilinear instability is expected to operate faster than the nonlinear turbulent cascade, scattering ions into the parallel direction and generating quasi-parallel-propagating IC waves. To investigate the consequences of this instability on the MMB-heated protons, we construct a homogeneous model for protons with coronal hole properties. Using a simplified version of the resonant cyclotron interaction, we heat the protons by the MMB process and instantaneously scatter them to lower anisotropy while self-consistently generating parallel-propagating IC waves. We present several illustrative cases, finding that the extreme anisotropies implied by the MMB mechanism are limited to reasonable values, but the distinctive shape of the proton distribution derived by Klein & Chandran is not maintained. We also find that these combined processes can result in somewhat higher particle energization than the MMB heating alone. These quasilinear consequences should follow from any kinetic mechanism that primarily increases the perpendicular ion temperature in a collisionless plasma.