Miracle-dz/UniFAR-FTUs huggingface dataset:
The Brightest z ≳ 8 Galaxies over the COSMOS UltraVISTA Field

We present 16 new ultrabright HAB ≲ 25 galaxy candidates at z ∼ 8 identified over the COSMOS/UltraVISTA field. The new search takes advantage of the deepest-available ground-based optical and near-infrared observations, including the DR3 release of UltraVISTA and full-depth Spitzer/IRAC observations from the SMUVS and SPLASH programs. Candidates are selected using Lyman-break color criteria, combined with strict optical non-detection and SED-fitting criteria, designed to minimize contamination by low-redshift galaxies and low-mass stars. HST/WFC3 coverage from the DASH program reveals that one source evident in our ground-based near-IR data has significant substructure and may actually correspond to 3 separate z ∼ 8 objects, resulting in a total sample of 18 galaxies, 10 of which seem to be fairly robust (with a >97% probability of being at z > 7). The UV-continuum slope β for the bright z ∼ 8 sample is β = −2.2 ± 0.6, bluer but still consistent with that of similarly bright galaxies at z ∼ 6 (β = −1.55 ± 0.17) and z ∼ 7 (β = −1.75 ± 0.18). Their typical stellar masses are M⊙, with the SFRs of yr−1, specific SFR of Gyr−1, stellar ages of Myr, and low dust content mag. Using this sample we constrain the bright end of the z ∼ 8 UV luminosity function. When combined with recent empty field luminosity function estimates at similar redshifts, the resulting z ∼ 8 luminosity function can be equally well represented by either a Schechter or a double-power-law form. Assuming a Schechter parameterization, the best-fit characteristic magnitude is mag with a very steep faint-end slope . These new candidates include some of the brightest objects found at these redshifts, 0.5–1.0 magnitude brighter than those found over CANDELS, and providing excellent targets for spectroscopic and longer-wavelength follow-up studies.
Fast/slow diffusion and collapsing sandpiles

We regard the limit as p →∞ of the flow governed by the p -Laplacian as providing a simplistic model for the “collapse of an initially unstable sandpile. ” Upon rescaling to stretch out the initial layer we obtain some simple dynamics and provide fairly explicit solutions in certain cases involving nonlocal geometric curvature motion. In particular we note that such models entail “instantaneous” mass transfer governed by Monge-Kantorovich theory.
Ruling Out ∼100–300 GeV Thermal Relic Annihilating Dark Matter by Radio Observation of the Andromeda Galaxy

Over the past few years, some studies have claimed that annihilating dark matter with mass ∼10–100 GeV can explain the GeV gamma-ray excess in our Galaxy. However, recent analyses of Fermi-LAT and radio observational data have ruled out the possibility of the thermal relic annihilating dark matter with mass m ≤ 100 GeV for some popular annihilation channels. By using the new observed radio data of the Andromeda galaxy, we rule out the existence of ∼100–300 GeV thermal relic annihilating dark matter for 10 annihilation channels. The lower limits of annihilating dark matter mass are improved to larger than 330 GeV for the most conservative case, which is a few times larger than the current best constraints. Moreover, these limits strongly disfavor the benchmark model of weakly interacting massive particles produced through the thermal freeze-out mechanism.
High-efficiency and low-voltage p‐i‐n electrophosphorescent organic light-emitting diodes with double-emission layers

We demonstrate high-efficiency organic light-emitting diodes by incorporating a double-emission layer (D-EML) into p‐i‐n-type cell architecture. The D-EML is comprised of two layers with ambipolar transport characteristics, both doped with the green phosphorescent dye tris(phenylpyridine)iridium. The D-EML system of two bipolar layers leads to an expansion of the exciton generation region. Due to its self-balancing character, accumulation of charge carriers at the outer interfaces is avoided. Thus, a power efficiency of approximately 77 lm∕W and an external quantum efficiency of 19.3% are achieved at 100cd∕m2 with an operating voltage of only 2.65 V. More importantly, the efficiency decays only weakly with increasing brightness, and a power efficiency of 50 lm∕W is still obtained even at 4000cd∕m2.
Homological systems in module categories over pre-ordered sets

We introduce the so-called homological systems in a module category over a pre-ordered set, which generalize the notion of a stratifying system over a linearly ordered set, and study both the corresponding modules filtrated by the systems and algebras stratified by the systems. In particular, we recover the tilting theory for pre-standardly stratified algebras, and get a general formula for computing the Cartan determinants of pre-standardly stratified algebras in terms of standard modules and simple modules. Also, the finitistic dimension of a given algebra, and the relative homological dimensions of full subcategories of the modules related to a homological system, are discussed. As an application, we get a new bound for the finitistic dimension of a pre-standardly stratified algebra.
A white dwarf catalogue from Gaia-DR2 and the Virtual Observatory

We present a catalogue of 73,221 white dwarf candidates extracted from the astrometric and photometric data of the recently published Gaia DR2 catalogue. White dwarfs were selected from the Gaia Hertzsprung-Russell diagram with the aid of the most updated population synthesis simulator. Our analysis shows that Gaia has virtually identified all white dwarfs within 100 pc from the Sun. Hence, our sub-population of 8,555 white dwarfs within this distance limit and the colour range considered, $-\,0.52<(G_{\rm BP}-G_{\rm RP})<0.80$, is the largest and most complete volume-limited sample of such objects to date. From this sub-sample we identified 8,343 CO-core and 212 ONe-core white dwarf candidates and derived a white dwarf space density of $4.9\pm0.4\times10^{-3}\,{\rm pc^{-3}}$. A bifurcation in the Hertzsprung-Russell diagram for these sources, which our models do not predict, is clearly visible. We used the Virtual Observatory tool VOSA to derive effective temperatures and luminosities for our sources by fitting their spectral energy distributions, that we built from the UV to the NIR using publicly available photometry through the Virtual Observatory. From these parameters, we derived the white dwarf radii. Interpolating the radii and effective temperatures in hydrogen-rich white dwarf cooling sequences, we derived the surface gravities and masses. The Gaia 100 pc white dwarf population is clearly dominated by cool ($\sim$ 8,000 K) objects and reveals a significant population of massive ($M \sim 0.8 M_{\odot}$) white dwarfs, of which no more than $\sim$ $30-40 \%$ can be attributed to hydrogen-deficient atmospheres, and whose origin remains uncertain.
Milky Way Tomography with the SkyMapper Southern Survey. I. Atmospheric Parameters and Distances of One Million Red Giants

Accurate determinations of atmospheric parameters (effective temperature Teff, surface gravity log g, and metallicity [Fe/H]) and distances for large complete samples are of vital importance for various Galactic studies. We have developed a photometric method to select red giant stars and estimate their atmospheric parameters from the photometric colors provided by SkyMapper Southern Survey (SMSS) data release (DR) 1.1, using stars in common with the LAMOST Galactic spectroscopic surveys as a training set. Distances are estimated with two different approaches: one based on the Gaia DR2 parallaxes for nearby (d ≤ 4.5 kpc) bright stars and another based on the absolute magnitudes predicted by intrinsic color (g − i)0 and photometric metallicity [Fe/H] for distant (d > 4.5 kpc) faint stars. Various tests show that our method is capable of delivering atmospheric parameters with a precision of ∼80 K for Teff, ∼ 0.18 dex for [Fe/H], and ∼0.35 dex for log g but with a significant systematic error at log g ∼ 2.3. For distances delivered from (g − i)0 and photometric [Fe/H], our test with the member stars of globular clusters show a median uncertainty of 16% with a negligible zero-point offset. Using this method, the atmospheric parameters and distances of nearly one million red giant stars are derived from SMSS DR1.1. Proper motion measurements from Gaia DR2 are available for almost all of the red giant stars, and radial velocity measurements from several large spectroscopic surveys are available for 44% of these. This sample will be accessible at https://yanghuang0.wixsite. com/yangh/research.
Reconstructing the dark energy potential

Dark energy equation of state can be effectively described by that of a barotropic fluid. The barotropic fluid model describes the background evolution and the functional form of the equation of state parameter is well constrained by the observations. Equally viable explanations of dark energy are via scalar field models, both canonical and non-canonical; these scalar field models being low energy descriptions of an underlying high energy theory. In this paper, we attempt to reconcile the two approaches to dark energy by way of reconstructing the evolution of the scalar field potential. For this analysis, we consider canonical quintessence scalar field and the phantom field for this reconstruction. We attempt to understand the analytical or semi-analytical forms of scalar field potentials corresponding to typical well behaved parameterisations of dark energy using the constraints from recent observations.
Ab initio calculation of phonon polaritons in silicon carbide and boron nitride.

The ability to use photonic quasiparticles to control electromagnetic energy far below the diffraction limit is a defining paradigm in nanophotonics. An important recent development in this field is the measurement and manipulation of extremely confined phonon-polariton modes in polar dielectrics such as silicon carbide and hexagonal boron nitride, which pave the way for nanophotonics and extreme light-matter interactions in the mid-IR to THz frequency range. To further advance this promising field, it is of great interest to predict the optical response of recently discovered and yet-to-be-synthesized polaritonic materials alike. Here we develop a unified framework based on quantum linear response theory to calculate the spatially non-local dielectric function of a polar lattice in arbitrary dimensions. In the case of a three-dimensional bulk material, the spatially local limit of our calculation reproduces standard results for the dielectric response of a polar lattice. Using this framework, we provide ab initio calculations of the dielectric permittivity of important bulk polar dielectrics such as silicon carbide and hexagonal boron nitride in good agreement with experiments. From the ab initio theory, we are able to develop a microscopic understanding of which phonon modes contribute to each component of the dielectric function, as well as predict features in the dielectric function that are a result of weak TO phonons. This formalism also identifies regime(s) where quantum nonlocal effects may correct the phonon polariton dispersion, extremely relevant in recent atomic-scale experiments which confine electromagnetic fields to the scale of 1~nm. Finally, our work points the way towards first principles descriptions of the effect of interface phonons, phonon strong coupling, and chiral phonons on the properties of phonon polaritons.
Transverse Schottky spectra and beam transfer functions of coasting ion beams with space charge

A study of the transverse dynamics of coasting ion beams with moderate space charge is presented in this work. From the dispersion relation with linear space charge, an analytic model describing the impact of space charge on transverse beam transfer functions (BTFs) and the stability limits of a beam is derived. The dielectric function obtained in this way is employed to describe the transverse Schottky spectra with linear space charge as well. The difference between the action of space charge and impedances is highlighted. The setup and the results of an experiment performed in the heavy ion synchrotron SIS-18 at GSI to detect space-charge effects at different beam intensities are explicated. The measured transverse Schottky spectra and BTFs are compared with the linear space-charge model. The stability diagrams constructed from the BTFs are presented. The space-charge parameters evaluated from the Schottky and BTF measurements are compared with estimations based on measured beam parameters. The impact of collective effects on the Schottky and BTF diagnostics is also investigated through numerical simulations. For this purpose the self-field of beams with linear and non-linear transverse density-distributions is computed on a two-dimensional grid. The noise of the random particle distribution causes fluctuations of the dipole moment of the beam which produce the Schottky spectrum. BTFs are simulated by exciting the beam with transverse kicks. The simulation results are used to verify the space-charge model.
Is There a Deficit of S0 Galaxies at Intermediate Redshift?

Two contradictory results on the evolution of SO galaxies now exist in the recent literature: either S0's are old (zformation > 2) and are evolving passively or most of them form at z < 0.5, as implied by the deficit of S0's in intermediate-redshift (z ~ 0.5) clusters. The resolution of this controversy may be that the apparent deficit of S0's has been derived from a quantity—the E-to-S0 ratio—that is prone to morphological classification errors. Once all sources of error are taken into account, the E-to-S0 ratios of clusters at different redshifts are fully compatible, and no additional creation of S0's at z < 0.5 is required by the data. Furthermore, there is no deficit at all of S0's in the intermediate-redshift cluster for which we have morphological types of very high quality and thus derive an E-to-S0 ratio with a small error.
Figure rotation and the mass of the galactic bulge

The mass of the Galactic bulge, $M_B$, is estimated from the tensor virial theorem. By including the effects of a barred stellar distribution and figure rotation (81 \kms kpc $^{-1}$) and by assuming that the bar is oriented at $\theta$ $=$ 20\deg \ to our line of sight, $M_B$ is found to be as high as 2.8$\times$10$^{10}$ M$_{\odot}$. This estimate is in good agreement with the total mass inferred from the observed optical depth to microlensing for stars toward the inner Galaxy. For larger angles, $\theta$ $\sim$ 40\deg, or smaller pattern speeds (20 \kms kpc $^{-1}$), $M_B$ is found to be $\sim$ 1.7 $-$ 1.9$\times$10$^{10}$ M$_{\odot}$, similar to previous estimates for a barred bulge (2$\times$10$^{10}$ M$_{\odot}$) and axisymmetric bulge (1.8$\times$10$^{10}$ M$_{\odot}$).
Galactic WARPS and the shape of heavy halos

The outer disks of many spiral galaxies are bent away from the plane of the inner disk; the abundance of these warps suggests that they are long-lived. Isolated galactic disks have long been thought to have no discrete modes of vertical oscillation under their own gravity, and so to be incapable of sustaining persistent warps. However, the visible disk contains only a fraction of the galactic mass; an invisible galactic halo makes up the rest. This paper presents an investigation of vertical warping modes in self-gravitating disks, in the imposed potential due to an axisymmetric unseen massive halo. If the halo matter is distributed so that the free precession rate of a test particle decreases with radius near the edge of the disk, then the disk has a discrete mode of vibration; oblate halos which become rapidly more flattened at large radii, and uniformly prolate halos, satisfy this requirement. Otherwise, the disk has no discrete modes and so cannot maintain a long-lived warp, unless the edge is sharply truncated. Computed mode shapes which resemble the observed warps can be found for halo masses consistent with those inferred from galactic rotation curves.
Fault Heterogeneity and the Connection between Aftershocks and Afterslip

Whether aftershocks originate directly from the mainshock and surrounding stress environment or from afterslip dynamics is crucial to the understanding of the nature of aftershocks. We build on a classical description of the fault and creeping regions as two blocks connected elastically, subject to different friction laws. We show analytically that, upon introduction of variability in the fault plane’s static friction threshold, a non trivial stick-slip dynamics ensues. In particular we support the hypothesis that the aftershock occurrence rate is proportional to the afterslip rate, up to a corrective factor that is also computed. Thus, the Omori law originates from the afterslip’s logarithmic evolution in the velocity-strengthening region. We confirm these analytical results with numerical simulations, generating synthetic catalogs with statistical features in good agreement with instrumental catalogs. In particular we recover the Gutenberg-Richter law with a realistic b-value (b'1) when Coulomb stress thresholds obey a power law distribution.
Effect of nitrogen at SiO2/Si interface on reliability issues—negative-bias-temperature instability and Fowler–Nordheim-stress degradation

Degradation process of a metal–oxide–semiconductor (MOS) structure with NO-nitrided SiO2 under negative-bias-temperature (NBT) and Fowler–Nordheim (FN) stresses has been investigated. The FN stress immunity improves with increasing nitrogen concentration at the SiO2/Si interface, while the incorporation of excess nitrogen (more than 3 at. %) at the SiO2/Si interface accelerates NBT instability (NBTI). This stronger immunity of NO-nitrided SiO2 under FN stress is due to the stronger Si–N bonds formed by NO nitridation at the interface. Without hydrogen annealing to form Si–H bonds, the MOS capacitors do not show NBTI. This indicates that the Si–N bonds are not broken under NBT stress and the main cause of the NBTI is the breaking of the Si–H bonds. The NO nitridation decreases the number of Si–H bonds and thus suppresses NBTI. However, nitrogen provides hole-trap centers. Hydrogen at the interface is dissociated and bonds to the hole-trapping nitrogen, so interface traps are left behind. An excess amount o.
Threshold bifurcation in tissue interaction models for spatial pattern generation

Experimental evidence indicates that tissue interaction plays an essential role during skin pattern formation. Here we focus on the mathematical aspects of two specific tissue interaction models. Introducing interaction mechanisms into the traditional pattern formation models is not only biologically consistent, but also leads to results agreeing more closer to those observed in embryogenesis. We specifically examine the bifurcations from spatially simple solutions to spatially complex patterns. In both models this increased complexity in solution is obtained by increasing the effect of the interaction mechanism through a certain threshold. The role of tissue interaction in sequential patterning is also considered.
Radio Supernova 1987A at 843 MHz

We report here the flux densities of the evolving radio source SN 1987A at 843 MHz measured from observations made with the Molonglo Observatory Synthesis Telescope between 1994 September and 2000 May. The radio light curve shows that the rate of increase of the flux density jumped markedly around days 2800-3000 (i.e., in the first half of 1995) and that since then the radio evolution has been remarkably well fitted by a simple linear increase of 62.7 ± 0.5 μJy day-1. We discuss in detail the relationship between the radio light curve and the recent brightening of the system at optical wavelengths.
The X-ray/UV ratio in active galactic nuclei: dispersion and variability

Context. The well established negative correlation between the αOX spectral slope and the optical/ultraviolet (UV) luminosity, a by-product of the relation between X-rays and optical/UV luminosity, is affected by relatively large dispersion. The main contributors to this dispersion can be variability in the X-ray/UV ratio and/or changes in fundamental physical parameters. Aims. We want to quantify the contribution from variability within single sources (intra-source dispersion) and that from variations of other quantities different from source to source (inter-source dispersion). Methods. We use archival data from the XMM-Newton Serendipitous Source Catalog (XMMSSC) and from the XMM-OM Serendipitous Ultraviolet Source Survey (XMMOM-SUSS3). We select a sub-sample in order to decrease the dispersion of the relation due to the presence of radio-loud and broad absorption line objects, and that due to absorptions in both X-ray and optical/UV bands. We use the structure function (SF) to estimate the contribution from variability to the dispersion. We analyse the dependence of the residuals of the relation on various physical parameters in order to characterise the inter-source dispersion. Results. We find a total dispersion of σ ∼ 0.12 and find that intrinsic variability contributes 56% of the variance of the αOX − LUV relation. If we select only sources with a larger number of observational epochs (≥3) the dispersion of the relation decreases by approximately 15%. We find weak but significant dependencies of the residuals of the relation on black-hole mass and on Eddington ratio, which are also confirmed by a multivariate regression analysis of αOX as a function of UV luminosity and black-hole mass and/or Eddington ratio. We find a weak positive correlation of both the αOX index and the residuals of the αOX − LUV relation with inclination indicators, such as the full width at half maximum (Hβ) and the equivalent width (EW)[OIII], suggesting a weak increase of X-ray/UV ratio with the viewing angle. This suggests the development of new viewing angle indicators possibly applicable at higher redshifts. Moreover, our results suggest the possibility of selecting a sample of objects, based on their viewing angle and/or black-hole mass and Eddington ratio, for which the αOX − LUV relation is as tight as possible, in light of the use of the optical/UV – X-ray luminosity relation to build a distance modulus (DM)-z plane and estimate cosmological parameters.
The Relationship between Luminosity and Broad-Line Region Size in Active Galactic Nuclei

We reinvestigate the relationship between the characteristic broad-line region size (RBLR) and the Balmer emission-line, X-ray, UV, and optical continuum luminosities. Our study makes use of the best available determinations of RBLR for a large number of active galactic nuclei (AGNs) from Peterson et al. Using their determinations of RBLR for a large sample of AGNs and two different regression methods, we investigate the robustness of our correlation results as a function of data subsample and regression technique. Although small systematic differences were found depending on the method of analysis, our results are generally consistent. Assuming a power-law relation RBLR ∝ Lα, we find that the mean best-fitting α is about 0.67 ± 0.05 for the optical continuum and the broad Hβ luminosity, about 0.56 ± 0.05 for the UV continuum luminosity, and about 0.70 ± 0.14 for the X-ray luminosity. We also find an intrinsic scatter of ~40% in these relations. The disagreement of our results with the theoretical expected slope of 0.5 indicates that the simple assumption of all AGNs having on average the same ionization parameter, BLR density, column density, and ionizing spectral energy distribution is not valid and there is likely some evolution of a few of these characteristics along the luminosity scale.