Miracle-dz/UniFAR-FTUs huggingface dataset:
Improved estimates and understanding of global albedo and atmospheric solar absorption

This study integrates available surface‐based and satellite observations of solar radiation at the surface and the top of the atmosphere (TOA) with a comprehensive set of satellite observations of atmospheric and surface optical properties and a Monte Carlo Aerosol‐Cloud‐Radiation (MACR) model to estimate the three fundamental components of the planetary solar radiation budget: Albedo at the TOA; atmospheric solar absorption; and surface solar absorption. The MACR incorporates most if not all of our current understanding of the theory of solar radiation physics including modern spectroscopic water vapor data, minor trace gases, absorbing aerosols including its effects inside cloud drops, 3‐D cloud scattering effects. The model is subject to a severe test by comparing the simulated solar radiation budget with data from 34 globally distributed state‐of‐the art BSRN (Baseline Surface Radiation Network) land stations which began data collection in the mid 1990s. The TOA over these sites were obtained from the CERES (Cloud and Earth's Radiant Energy System) satellites. The simulated radiation budget was within 2 Wm−2for all three components over the BSRN sites. On the other hand, over these same sites, the IPCC‐2007 simulation of atmospheric absorption is smaller by 7–8 Wm−2. MACR was then used with a comprehensive set of model input from satellites to simulate global solar radiation budget. The simulated planetary albedo of 29.0% confirms the value (28.6%) observed by CERES. We estimate the atmospheric absorption to be 82 ± 8 Wm−2 to be compared with the 67 Wm−2 by IPCC models as of 2001 and updated to 76 Wm−2by IPCC‐2007. The primary reasons for the 6 Wm−2 larger solar absorption in our estimates are: updated water vapor spectroscopic database (∼1 Wm−2), inclusion of minor gases (∼0.5 Wm−2), black and brown carbon aerosols (∼4 Wm−2), the inclusion of black carbon in clouds (∼1 Wm−2) and 3‐D effect of clouds (∼1 Wm−2). The fundamental deduction from our study is the remarkable consistency between satellite measurements of the radiation budget and the parameters (aerosols, clouds and surface reflectivity) which determine the radiation budget. Because of this consistency we can account for and explain the global solar radiation budget of the planet within few Wm−2.
Dust and Stellar Populations in the Large Magellanic Cloud

We present an analysis of line-of-sight extinction measurements obtained using data from the Magellanic Clouds Photometric Survey (Zaritsky, Harris, & Thompson), which provides four-filter photometry for millions of stars in the Large Magellanic Cloud. We find that visual extinctions are typically larger by several tenths of a magnitude for stars with effective temperatures greater than 12,000 K than for stars with effective temperatures between 5500 and 6500 K. Several repercussions of this population-dependent extinction are discussed. In particular, LMC distance measurements that utilize old stellar populations, but use extinctions derived from OB stars, may be biased low. As a specific example, we show that the LMC distance modulus derived from field red clump stars is revised upward relative to published measurements by ∼0.2 mag if one uses the extinction measured for a matched stellar population. Conversely, measurements that utilize the youngest stars are subject to greater, and more variable, extinction leading preferentially to results that may be biased high. Population-dependent extinction affects the interpretation of color-magnitude diagrams and results in an effective absorption law that is steeper than that intrinsic to the dust for unresolved stellar systems. We further explore the relation between the stellar populations and dust by comparing our extinction map to the 100 μm image of the region and identifying potential heating sources of the dust. We find that although regions of high 100 μm flux are associated with young stars, young stars are not necessarily associated with regions of high 100 μm flux and that ∼50% of the 100 μm flux is emitted beyond the immediate regions of high OB stellar density. We conclude that 100 μm flux should be used with caution as a star formation tracer, particularly for studies of star formation within galaxies. Finally, we reproduce the observed extinction variation between the hot and cold stellar populations with a simple model of the distribution of the stars and dust in which the scale height of the cooler stars is much greater than that of the dust (which is twice that of the OB stars; Harris, Zaritsky, & Thompson).
Nearby Supernova Factory Observations of SN 2006D: On Sporadic Carbon Signatures in Early Type Ia Supernova Spectra

We present four spectra of the Type Ia supernova (SN Ia) 2006D extending from -7 to +13 days with respect to B-band maximum. The spectra include the strongest signature of unburned material at photospheric velocities observed in a SN Ia to date. The earliest spectrum exhibits C II absorption features below 14,000 km s-1, including a distinctive C II λ6580 absorption feature. The carbon signatures dissipate as the SN approaches peak brightness. In addition to discussing implications of photospheric-velocity carbon for white dwarf explosion models, we outline some factors that may influence the frequency of its detection before and around peak brightness. Two effects are explored in this regard, including depopulation of the C II optical levels by non-LTE effects, and line-of-sight effects resulting from a clumpy distribution of unburned material with low volume filling factor.
Sparse Reconstruction of the Merging A520 Cluster System

Merging galaxy clusters present a unique opportunity to study the properties of dark matter in an astrophysical context. These are rare and extreme cosmic events in which the bulk of the baryonic matter becomes displaced from the dark matter halos of the colliding subclusters. Since all mass bends light, weak gravitational lensing is a primary tool to study the total mass distribution in such systems. Combined with X-ray and optical analyses, mass maps of cluster mergers reconstructed from weak-lensing observations have been used to constrain the self-interaction cross-section of dark matter. The dynamically complex Abell 520 (A520) cluster is an exceptional case, even among merging systems: multi-wavelength observations have revealed a surprising high mass-to-light concentration of dark mass, the interpretation of which is difficult under the standard assumption of effectively collisionless dark matter. We revisit A520 using a new sparsity-based mass-mapping algorithm to independently assess the presence of the puzzling dark core. We obtain high-resolution mass reconstructions from two separate galaxy shape catalogs derived from Hubble Space Telescope observations of the system. Our mass maps agree well overall with the results of previous studies, but we find important differences. In particular, although we are able to identify the dark core at a certain level in both data sets, it is at much lower significance than has been reported before using the same data. As we cannot confirm the detection in our analysis, we do not consider A520 as posing a significant challenge to the collisionless dark matter scenario.
Nonlinear electrostatic oscillations in a cold magnetized electron-positron plasma

We study the spatio-temporal evolution of the nonlinear electrostatic oscillations in a cold magnetized electron-positron (e-p) plasma using both analytics and simulations. Using a perturbative method, we demonstrate that the nonlinear solutions change significantly when a pure electrostatic mode is excited at the linear level instead of a mixed upper-hybrid and zero-frequency mode that is considered in a recent study. The pure electrostatic oscillations undergo phase-mixing nonlinearly. However, the presence of the magnetic field significantly delays the phase-mixing compared to that observed in the corresponding unmagnetized plasma. Using one dimensional particle-in-cell simulations, we then analyze the damping of the primary mode of the pure oscillations in detail and infer the dependence of the phase-mixing time on the magnetic field and the amplitude of the oscillations. The results are remarkably different from those found for the mixed mode study mentioned earlier. Exploiting the symmetry of the e-.
Enhanced sensitivity of the electron electric dipole moment from YbOH: The role of theory

The prospect of laser cooling of polyatomic molecules has opened a new avenue in the search for the electric dipole moment of the electron (eEDM). An upper bound on the eEDM would probe new physics arising from beyond the Standard Model of elementary particles. In this work, we report the first theoretical results for the effective electric field experienced by the electron in YbOH, and its molecular electric dipole moment, using a relativistic coupled cluster theory. We compare these two properties of YbOH with YbF, which also has a singly unoccupied orbital on the Yb ion. We also present the results of the effective electric field for different bond angles, which sheds light on the sensitivity that can be expected from an eEDM experiment with YbOH.
Remote sensing-based quantification of spatial variation in canopy phenology of four dominant tree species in Europe

Abstract Spatial variation of phenology is a central feature of global change research. Satellite remote sensing is used for continental to global monitoring due to the limitations of long-term field observations of plant phenology. A threshold method was used to estimate the start of the season, length of the season, maximum normalized difference vegetation index (NDVI), and integral NDVI for selected tree species using remote sensing based NDVI data acquired by the VEGETATION instrument on board Satellite Pour l’Observation de la Terre (SPOT VGT NDVI). Afterward, the spatial patterns in the satellite-derived phenological metrics for four dominant tree species (i.e., beech, birch, pine, and spruce) across Europe were characterized. The results indicate that: (1) The SOS occurs 1.6–2.9 days later and the average LOS is 2.7–3 days shorter per 1 deg of latitude increase from south to north. (3) The SOS occurs 0.7–1.8 days later and the LOS was 0.6–2 days shorter per 100-m increase in altitude for the four species. (4) The SOS and LOS across Europe are well correlated with the mean annual air temperature (1°C correlates with a 4.5-day advance in the SOS and a 7-day extension in the LOS). Our research is the first one to characterize the spatial and temporal variations of phenology for different tree species across Europe using remote sensing.
BLUE COMPACT DWARF GALAXIES AND NEW VELOCITIES IN VIRGO

We present new spectral observations of 303 galaxies brighter than B-J = 17.6 in the central 30 deg(2) of the Virgo cluster field. The galaxies were selected from two overlapping samples designed for a search for blue compact dwarf (BCD) galaxies and for a more general study of Virgo dwarf elliptical (dE) galaxies. Many of these galaxies were designated 'background' (i.e., not members of the Virgo cluster) on morphological grounds by Binggeli, Sandage Br Tammann in their Virgo Cluster Catalog (VCC). Our principal aim was to measure radial velocities of these galaxies in order to determine which were members of the cluster, looking in particular for any cluster members previously misclassified as background galaxies.
Quasi-linear absorption of lower hybrid waves by fusion generated alpha particles

Lower hybrid waves are expected to be used in a steady state reactor to produce current and to control the current profile and the stability of internal modes. In the ignition phase, however, the presence of energetic alpha particles may prevent wave-electron interaction, thus reducing the current drive efficiency. This is due to the very high birth energy of the alpha particles that may absorb much of the lower hybrid wave power. This unfavourable effect is absent at high frequencies (∼8 GHz for typical reactor parameters). Nevertheless, because of the technical difficulties involved in using such high frequencies, it is very important to investigate whether power absorption by alpha particles would be negligible also at relatively low frequencies. Such a study has been carried out on the basis of the quasi-linear theory of wave-alpha particle interaction, since the distortion of the alpha distribution function may enhance the radiofrequency absorption above the linear level. New effects have been found, such as local alpha concentration and acceleration. The model for alpha particles is coupled with a 1-D deposition code for lower hybrid waves to calculate the competition in the power absorption between alphas and electrons as the waves propagate into the plasma core for typical reactor (ITER) parameters. It is shown that at a frequency as low as 5 GHz, power absorption by alpha particles is negligible for conventional plasma conditions and realistic alpha particle concentrations. In more ‘pessimistic’ and severe conditions, negligible absorption occurs at 6 GHz.
A Multiwavelength Look at Galactic Massive Star-forming Regions

We present a multiwavelength study of 28 Galactic massive star-forming H ii regions. For 17 of these regions, we present new distance measurements based on Gaia DR2 parallaxes. By fitting a multicomponent dust, blackbody, and power-law continuum model to the 3.6 μm through 10 mm spectral energy distributions, we find that ∼34% of Lyman continuum photons emitted by massive stars are absorbed by dust before contributing to the ionization of H ii regions, while ∼68% of the stellar bolometric luminosity is absorbed and reprocessed by dust in the H ii regions and surrounding photodissociation regions. The most luminous, infrared-bright regions that fully sample the upper stellar initial mass function (ionizing photon rates NC ≥ 1050 s−1 and dust-processed LTIR ≥ 106.8 L⊙) have on average higher percentages of absorbed Lyman continuum photons (∼51%) and reprocessed starlight (∼82%) compared to less luminous regions. Luminous H ii regions show lower average polycyclic aromatic hydrocarbon (PAH) fractions than less luminous regions, implying that the strong radiation fields from early-type massive stars are efficient at destroying PAH molecules. On average, the monochromatic luminosities at 8, 24, and 70 μm combined carry 94% of the dust-reprocessed LTIR. L70 captures ∼52% of LTIR, and is therefore the preferred choice to infer the bolometric luminosity of dusty star-forming regions. We calibrate star formation rates (SFRs) based on L24 and L70 against the Lyman continuum photon rates of the massive stars in each region. Standard extragalactic calibrations of monochromatic SFRs based on population synthesis models are generally consistent with our values.
Noncommutative spacetime effects and gravitation

In recent years Quantum Superstrings and Quantum Gravity approaches have come to rely on non differenciable spacetime manifolds. These throw up a noncommutative spacetime geometry and we consider the origin of mass and a related modification of the Dirac equation in this context. This also throws some light on gravitation itself.
Outer Architecture of Kepler-11: Constraints from Coplanarity

The outer architectures of Kepler’s compact systems of multiple transiting planets remain poorly constrained, and few of these systems have lower bounds on the orbital distance of any massive outer planets. We infer a minimum orbital distance and upper limits on the inclination of a hypothetical Jovian-mass planet orbiting exterior to the six transiting planets at Kepler-11. Our constraints are derived from dynamical models together with observations provided by the Kepler mission. First, the lack of transit timing variations (TTV) in the outermost transiting planet Kepler-11 g imply that the system does not contain a Jovian-mass perturber within 2 au from the star. Second, we test under what initial conditions a Jovian-mass planet moderately inclined from the transiting planets would make their co-transiting configuration unlikely. The transiting planets are secularly coupled and exhibit small mutual inclinations over long timescales, although the outermost transiting planet, Kepler-11 g, is weakly coupled to the inner five. We rule out a Jovian-mass planet on a 3° inclination within 3.0 au, and higher inclinations out to farther orbital distances, unless an undetected planet exists orbiting in the dynamical gap between Kepler-11 f and Kepler-11 g. Our constraints depend little on whether we assume the six transiting planets of Kepler-11 were initially perfectly coplanar or whether a minimum initial mutual inclination between the transiting planets is adopted based on the measured impact parameters of the transiting planets.
System initial mass function of the 25 Ori group from planetary-mass objects to intermediate/high-mass stars

The stellar initial mass function (IMF) is an essential input for many astrophysical studies but only in a few cases has it been determined over the whole cluster mass range, limiting the conclusions about its nature. The 25 Orionis group (25 Ori) is an excellent laboratory for investigating the IMF across the entire mass range of the population, from planetary-mass objects to intermediate/high-mass stars. We combine new deep optical photometry with optical and near-infrared data from the literature to select 1687 member candidates covering a 1.1° radius area in 25 Ori. With this sample we derived the 25 Ori system IMF from 0.012 to 13.1 M⊙. This system IMF is well described by a two-segment power law with Γ = −0.74 ± 0.04 for m < 0.4 M⊙ and Γ = 1.50 ± 0.11 for m ≥ 0.4 M⊙. It is also well described over the whole mass range by a tapered power-law function with Γ = 1.10 ± 0.09, mp = 0.31 ± 0.03 and β = 2.11 ± 0.09. The best lognormal representation of the system IMF has mc = 0.31 ± 0.04 and σ = 0.46 ± 0.05 for m < 1 M⊙. This system IMF does not present significant variations with the radii. We compared the resultant system IMF as well as the brown dwarf/star ratio of 0.16 ± 0.03 that we estimated for 25 Ori with that of other stellar regions with diverse conditions and found no significant discrepancies. These results support the idea that general star-formation mechanisms are probably not strongly dependent on environmental conditions. We found that the substellar and stellar objects in 25 Ori do not have any preferential spatial distributions and confirmed that 25 Ori is a gravitationally unbound stellar association.
Characterising the high-mass star forming filament G351.776–0.527 with Herschel and APEX dust continuum and gas observations

G351.776-0.527 is among the most massive, closest, and youngest filaments in the inner Galactic plane and therefore it is an ideal laboratory to study the kinematics of dense gas and mass replenishment on a large scale. In this paper, we present far-infrared and submillimetre wavelength continuum observations combined with spectroscopic C18O (2–1) data of the entire region to study its temperature, mass distribution, and kinematics. The structure is composed of a main elongated region with an aspect ratio of ~23, which is associated with a network of filamentary structures. The main filament has a remarkably constant width of 0.2 pc. The total mass of the network (including the main filament) is ≥2600M⊙, while we estimate a mass of ~2000M⊙ for the main structure. Therefore, the network harbours a large reservoir of gas and dust that could still be accreted onto the main structure. From the analysis of the gas kinematics, we detect two velocity components in the northern part of the main filament. The data also reveal velocity oscillations in C18O along the spine in the main filament and in at least one of the branches. Considering the region as a single structure, we find that it is globally close to virial equilibrium indicating that the entire structure is approximately in a stable state.
Aerodynamic shape optimization using preconditioned conjugate gradient methods

In an effort to further improve upon the latest advancements made in aerodynamic shape optimization procedures, a systematic study is performed to examine several current solution methodologies as applied to various aspects of the optimization procedure. It is demonstrated that preconditioned conjugate gradient-like methodologies dramatically decrease the computational efforts required for such procedures. The design problem investigated is the shape optimization of the upper and lower surfaces of an initially symmetric (NACA 0012) airfoil in inviscid transonic flow and at zero degrees angle of attack. The complete surface shape is represented using a Bezier-Bernstein polynomial
Phase fluctuations and Kosterlitz-Thouless transition in two-dimensional Fulde-Ferrell-Larkin-Ovchinnikov superconductors

Effects of the phase fluctuations of the order parameter on the stability of the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) states are examined in exactly two-dimensional (2D) type-II superconductors with cylindrically symmetric Fermi surface on the basis of a generalized Ginzburg-Landau theory. It is found that for the FFLO states with oscillations in a single direction, not only the long-range order but also quasi-long-range order (QLRO), which is characterized by a power law decay of the order parameter correlation function, is suppressed by the phase fluctuations at any finite temperatures. On the other hand, for the FFLO states with order parameter structures such as triangular and square lattices, it is shown that the QLRO is possible as the uniform BCS state. Systems with anisotropy in the Fermi surface and pairing are also discussed.
The 10 phases of spin chains with two Ising symmetries

We explore the topological properties of quantum spin-1/2 chains with two Ising symmetries. This class of models does not possess any of the symmetries that are required to protect the Haldane phase. Nevertheless, we show that there are 4 symmetry-protected topological phases, in addition to 6 phases that spontaneously break one or both Ising symmetries. By mapping the model to one-dimensional interacting fermions with particle-hole and time-reversal symmetry, we obtain integrable parent Hamiltonians for the conventional and topological phases of the spin model. We use these Hamiltonians to characterize the physical properties of all 10 phases, identify their local and nonlocal order parameters, and understand the effects of weak perturbations that respect the Ising symmetries. Our study provides the first explicit example of a class of spin chains with several topologically non-trivial phases, and binds together the topological classifications of interacting bosons and fermions.