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This article presents a new algorithm that uses techniques from the field of artificial intelligence to automatically estimate the physical parameters of massive stars from a grid of stellar spectral models. This is the first grid to consider hydrodynamic solutions for stellar winds and radiative transport, containing more than 573 thousand synthetic spectra. The methodology involves grouping spectral models using deep learning and clustering techniques. The goal is to delineate the search regions and differentiate the "species" of spectra based on the shapes of the spectral line profiles. Synthetic spectra close to an observed stellar spectrum are selected using deep learning and unsupervised clustering algorithms. As a result, for each spectrum, we found the effective temperature, surface gravity, micro-turbulence velocity, and abundance of elements, such as helium and silicon. In addition, the values of the line force parameters were obtained. The developed algorithm was tested with 40 observed spectra, achieving 85 % of the expected results according to the scientific literature. The execution time ranged from 6 to 13 min per spectrum, which represents less than 5 % of the total time required for a one-to-one comparison search under the same conditions. [ABSTRACT FROM AUTHOR]

To determine the relative distances and peculiar velocities of 140 groups and clusters of galaxies at low redshifts (z < 0.12), we used the fundamental plane (FP) of early-type galaxies (from the Sloan Digital Sky Survey (SDSS) data). We constructed the Hubble diagram for the relative distances of galaxy groups/clusters versus their radial velocities in the cosmic microwave background (CMB) reference frame in the flat Λ cold dark matter (ΛLCDM) model (Ωm = 0.3 and H0 = 70 km s–1 Mpc–1). We have found that the standard logarithmic deviation for groups and clusters of galaxies on the Hubble diagram (minus peculiar velocities) is ±0.0173 (N = 140), which corresponds to a deviation of 70 ± 2.8 km s–1 Mpc–1 in the Hubble constant. For a sample of galaxy systems (N = 63), the X-ray luminosity of which is in an interval of (0.151‒4) × 1044 erg/s, this quantity turned out to be 70 ± 2.1 km s–1 Mpc–1. The root-mean-square deviations of peculiar velocities with quadratic accounting for errors are = 714 ± 7 and 600 ± 7 km/s, respectively. For five large superclusters of galaxies from the SDSS region, the average peculiar velocity relative to the CMB reference frame is +240 ± 250 km/s. We detected no outflow of galaxy systems from the void (Giant Void; α ≈ 13h, δ ≈ 40°, and z ≈ 0.107) formed by groups and clusters of galaxies. [ABSTRACT FROM AUTHOR]

Eclipsing binary systems are significant objects for astrophysics in that direct observations can determine the fundamental parameters of stars. In this study, we precisely determined the fundamental parameters of the binary component stars obtained by simultaneous analysis of radial velocities and the TESS light curve using the Wilson and Devinney code. Following the analysis, the masses and radii of the primary and secondary components were determined as M1=1.58±0.01M⊙$$ {M}_1=1.58\pm 0.01{M}_{\odot } $$, M2=0.48±0.02M⊙$$ {M}_2=0.48\pm 0.02{M}_{\odot } $$, and R1=1.93±0.01R⊙$$ {R}_1=1.93\pm 0.01{R}_{\odot } $$, R2=1.14±0.01R⊙$$ {R}_2=1.14\pm 0.01{R}_{\odot } $$, respectively. Furthermore, the distance of IS CMa is calculated as 92.7±6.5$$ 92.7\pm 6.5 $$ pc. On the basis of the analysis of the mid‐eclipse times, it was found that the variation in the orbital period is represented by an upward parabola. It has an increasing rate of dP/dt$$ dP/ dt $$ = 1.09 ×$$ \times $$ 10−7$$ {}^{-7} $$ day year−1$$ {}^{-1} $$. Using PARSEC stellar evolutionary tracks and isochrones with solar metallicity estimated the age of IS CMa as 1.3±0.1$$ 1.3\pm 0.1 $$ Gyr. Kinematic and Galactic orbital parameters of IS CMa were obtained from the astrometric and spectroscopic data of the system. The Galactic orbit analysis reveals that IS CMa formed inside the solar circle and it is a member of the young thin‐disc population. [ABSTRACT FROM AUTHOR]

This article presents a new algorithm that uses techniques from the field of artificial intelligence to automatically estimate the physical parameters of massive stars from a grid of stellar spectral models. This is the first grid to consider hydrodynamic solutions for stellar winds and radiative transport, containing more than 573 thousand synthetic spectra. The methodology involves grouping spectral models using deep learning and clustering techniques. The goal is to delineate the search regions and differentiate the “species” of spectra based on the shapes of the spectral line profiles. Synthetic spectra close to an observed stellar spectrum are selected using deep learning and unsupervised clustering algorithms. As a result, for each spectrum, we found the effective temperature, surface gravity, micro-turbulence velocity, and abundance of elements, such as helium and silicon. In addition, the values of the line force parameters were obtained. The developed algorithm was tested with 40 observed spectra, achieving 85% of the expected results according to the scientific literature. The execution time ranged from 6 to 13 min per spectrum, which represents less than 5% of the total time required for a one-to-one comparison search under the same conditions.

Several new models of a layered inhomogeneous elliptical galaxy (EG) having the shape either a triaxial ellipsoid or an oblate or prolate spheroid and consisting of baryonic mass and dark matter with different laws of density distribution—profiles. Based on these models, some key dynamic parameters of the EG were determined: gravitational (potential) energy and rotational kinetic energy, total surface brightness, total luminosity, and velocity dispersion depending on the distance to the EG center. The relationships between the important dynamic parameters of the galaxy have been established: "mass–dimensions", "mass–velocity dispersion", "size–dispersion speeds–luminosity" (surface brightness). Evolutionary scenarios for the formation of EG were studied according to these models. The results obtained were applied to sixty model EGs with parameters exactly matching those that actually exist and are presented in the form of tables. [ABSTRACT FROM AUTHOR]

The morphology and surface composition of silicon are experimentally studied using scanning-electron microscopy, X-ray phase analysis, and Raman spectroscopy. The spectral characteristics of silicon doped with impurity atoms of phosphorus and gallium are investigated. In a silicon lattice doped simultaneously with gallium and phosphorus atoms, impurity atoms form binary complexes. Experimental determination of the concentration of impurity atoms of gallium and phosphorus reveals a significant increase in the concentration of gallium compared to its fundamental solubility in silicon. It is demonstrated that a rather high concentration of such elementary cells can lead to a substantial change in the electrical parameters of silicon, i.e., the possibility of obtaining a new material based on silicon. [ABSTRACT FROM AUTHOR]

The activity of central supermassive black holes might affect the alignment of galaxy spin axes with respect to the closest cosmic filaments. We exploit the Sydney–AAO Multi-object Integral-field Galaxy Survey to study possible relations between black hole activity and the spin–filament alignments of stars and ionized gas separately. To explore the impact of instantaneous black hole activity, active galaxies are selected according to emission-line diagnostics. Central stellar velocity dispersion (σc) is used as a proxy for black hole mass and its integrated activity. We find evidence for the gas spin–filament alignments to be influenced by AGN, with Seyfert galaxies showing a stronger perpendicular alignment at fixed bulge mass with respect to galaxies, where ionization is consequence of low-ionization nuclear emission-line regions (LINERs) or old stellar populations (retired galaxies). On the other hand, the greater perpendicular tendency for the stellar spin–filament alignments of high-bulge mass galaxies is dominated by retired galaxies. Stellar alignments show a stronger correlation with σc compared to the gas alignments. We confirm that bulge mass (M bulge) is the primary parameter of correlation for both stellar and gas spin–filament alignments (with no residual dependency left for σc), while σc is the most important property for secular star formation quenching (with no residual dependency left for M bulge). These findings indicate that M bulge and σc are the most predictive parameters of two different galaxy evolution processes, suggesting mergers trigger spin–filament alignment flips and integrated black hole activity drives star formation quenching. [ABSTRACT FROM AUTHOR]

This review covers characteristics and potential applications of various versions of the X-ray fluorescence (XRF) spectrometry for analyzing both liquid and solid samples. Particular emphasis is given to research published within the past decade, as information on XRF's previous applications can be found in earlier reviews and monographs. The results of experiments on determining fundamental atomic parameters, such as mass absorption coefficients, fluorescence yields, transition probabilities for the emission of specific lines of elements, and nonradiative transition probabilities. Additionally, the review addresses the capabilities of newly designed models of XRF spectrometers developed in recent years. The application of total reflection X-ray fluorescence spectrometry for diverse samples is examined in greater detail. Furthermore, the document presents data on the utilization of XRF in investigating nanoparticles of some typical materials. These particles exhibit qualitatively novel properties and have become a focal point of nanotechnology, an area rapidly developing in the last few decades. [ABSTRACT FROM AUTHOR]

We present an application of unsupervised Machine Learning clustering to the PAU survey of galaxy spectral energy distribution (SED) within the COSMOS field. The clustering algorithm is implemented and optimized to get the relevant groups in the data SEDs. We find 12 groups from a total number of 5234 targets in the survey at 0.01 < z < 0.28. Among the groups, 3545 galaxies (68  per cent) show emission lines in the SEDs. These groups also include 1689 old galaxies with no active star formation. We have fitted the SED to every single galaxy in each group with CIGALE. The mass, age, and specific star formation rates (sSFR) of the galaxies range from 0.15 < age/Gyr <11; 6 < log (M⋆/M⊙) <11.26, and −14.67 < log (sSFR/yr−1) <−8. The groups are well-defined in their properties with galaxies having clear emission lines also having lower mass, are younger and have higher sSFR than those with elliptical like patterns. The characteristic values of galaxies showing clear emission lines are in agreement with the literature for starburst galaxies in COSMOS and GOODS-N fields at low redshift. The star-forming main sequence, sSFR versus stellar mass and UVJ diagram show clearly that different groups fall into different regions with some overlap among groups. Our main result is that the joint of low- resolution (R ∼ 50) photometric spectra provided by the PAU survey together with the unsupervised classification provides an excellent way to classify galaxies. Moreover, it helps to find and extend the analysis of extreme ELGs to lower masses and lower SFRs in the local Universe. [ABSTRACT FROM AUTHOR]

GW Ori is a young hierarchical triple system located in A Orionis, consisting of a binary (GW Ori A and B), a tertiary star (GW Ori C) and a rare circumtriple disk. Due to the limited data with poor accuracy, several short-period signals were detected in this system, but the values from different studies are not fully consistent. As one of the most successful transiting surveys, the transiting exoplanet survey satellite (TESS) provides an unprecedented opportunity to make a comprehensive periodic analysis of GW Ori. In this work we discover two significant modulation signals by analyzing the light curves of GW Ori’s four observations from TESS, i.e., (3.02 ± 0.15) and (1.92 ± 0.06)d, which are very likely to be the rotational periods caused by starspot modulation on the primary and secondary components, respectively. We calculate the inclinations of GW Ori A and B according to the two rotational periods. The results suggest that the rotational plane of GW Ori A and B and the orbital plane of the binary are almost coplanar. We also discuss the aperiodic features in the light curves; these may be related to unstable accretion. The light curves of GW Ori also include a third (possible) modulation signal with a period of (2.51±0.09)d, but the third is neither quite stable nor statistically significant. [ABSTRACT FROM AUTHOR]

We consider energy‐dispersive x‐ray fluorescence (XRF) applications where the fundamental parameters method is impractical such as when instrument parameters are unavailable. For example, on a mining shovel or conveyor belt, rocks are constantly moving (leading to varying angles of incidence and distances) and there may be other factors not accounted for (like dust). Neural networks do not require instrument and fundamental parameters but training neural networks requires XRF spectra labeled with elemental composition, which is often limited because of its expense. We develop a neural network model that learns from limited labeled data and also benefits from domain knowledge by learning to invert a forward model. The forward model uses transition energies and probabilities of all elements and parameterized distributions to approximate other fundamental and instrument parameters. We evaluate the model and baseline models on a rock dataset from a lithium mineral exploration project. Our model works particularly well for some low‐Z elements (Li, Mg, Al, and K) as well as some high‐Z elements (Sn and Pb) despite these elements being outside the suitable range for common spectrometers to directly measure, likely owing to the ability of neural networks to learn correlations and nonlinear relationships. [ABSTRACT FROM AUTHOR]

The accuracy of X-ray fluorescence spectrometry in quantitative element analysis depends on the particular sample composition (so-called matrix effects). Counteracting these effects requires a large number of calibration samples similar in composition to those under analysis. Application of the model constructed for a particular type of samples is not possible for the analysis of samples having a different matrix composition. A possible solution for this problem can be found in the construction of universal calibration models. We propose the development of these universal models using chemometric tools: influence coefficients—partial least squares regression (IC-PLS) and nonlinear kernel regularized least squares regression. We hypothesize that the application of these methods for constructing calibration models would allow embracing the samples of different types in the framework of a single model. We explored this approach for the case of two substantially different types of samples: ores and steels. The performance of these methods was compared with the fundamental parameters (FP) method, which takes into account matrix effects using theoretical equations and allows handling samples of different elemental composition. IC-PLS significantly outperforms traditional FP in terms of accuracy for predicting the content of Al (root mean squared error of prediction 0.96% vs. 3.87%) and Ti (0.05% vs. 0.09%) and yields comparable results for Si and Mn quantification in ores and steels. [ABSTRACT FROM AUTHOR]

The properties of 61 isolated galaxies with active nuclei (isolated AGNs) in the radio frequency range at redshifts z < 0.05 have been studied. The sample is obtained by cross-matching of the 2MIG catalog (2MASS catalog of isolated galaxies based on the 2MASS) with the Véron-Cetty catalog of quasars/AGNs. The sample is limited to a stellar magnitude of 4m < Ks ≤ 12m, a radial velocity of Vr < 15 000 km/s, and the distance to the nearest large satellite galaxy. These limitations indicate that the isolated AGNs have not collided with other galaxies in at least 3 billion years, and the observed activity of their nuclei is due only to physical processes occurring in the torus–accretion disk–nuclear region–supermassive black hole system. This study systematized the radio parameters of isolated AGNs by using data from various databases and the archive of terrestrial and space telescopes. Such characteristics are necessary for the further comparative study of physical properties of regions with active star formation and the active nuclei of these galaxies with the properties that manifest themselves when observing other spectral ranges. As a result, the radio flux densities available from the databases at a frequency of 1.4 or 5 GHz for isolated AGNs from the 2MIG catalog are given. Among the 61 galaxies of the sample, flux densities at 1.4 GHz have been found for 51 galaxies. These values are in the range of 3–20 mJy for most isolated AGNs and in the range of 50–200 mJy for two galaxies PGC35009 and NGC6951, while two galaxies ESO483-009 and ESO097-013 have spectral flux densities of 352 and 1200 mJy, respectively. The flux densities of ten isolated AGNs are less than 3 mJy. Radio flux densities of NGC0157 are not related to the position of this galaxy. Ratio R of the spectral flux densities in the radio frequency range to those in the optical bands have been calculated. Since the flux densities at 5 GHz are measured only for eight isolated AGNs, the required values of spectral flux densities at 5 GHz on the basis of relationship Sν ∝ ν–α for galaxies of the Seyfert type have been calculated by using the radio flux density values at 1.4 GHz and assuming that the spectral index is equal to α = 0.7. The radio fluxes densities at 5 GHz are lower than 3 mJy for 27 isolated AGNs, are in the range of 4–15 mJy for 15 AGNs, and in the range of 15–55 mJy for seven AGNs, while two galaxies ESO097-013 and ESO483-009 have radio fluxes densities of 304 and 132 mJy, respectively. We have found that 51 isolated AGNs are radio quiet sources (R < 10), the radio properties of nine objects are absent, and ESO483-009 is a radio loud galaxy (R = 20.72, Sy3/LINER, and SAB00 pec). We propose the observational methods to determine the flux densities of radio quite isolated AGNs. In conclusion, the systematization of the properties of 61 low-redshift isolated AGNs in the radio frequency range, 36 of which are in the northern sky and 25 in the southern sky, is aimed at pursuing the future goal of establishing a program of radio astronomical observations for the assessment of radiation flux densities and setting up a monitoring study for more detailed mapping of the radio emission characteristics of these galaxies in comparison with their optical and X-ray properties. Observations in the radio frequency range are important since they make it possible to monitor and separate star formation regions of a galaxy and the central region with a supermassive black hole in the active nuclei that is free of absorption, thereby providing information about the nature of nuclear activity. [ABSTRACT FROM AUTHOR]

Sulfur and its compounds are both very abundant in the environment and very important for technological applications such as batteries. X-ray spectroscopic characterizations of sulfur compounds for a quantitative determination of the present amount of sulfur often requires a good knowledge on the atomic fundamental parameters involved. These quantitatively describe the processes of photoionization and x-ray fluorescence emission, making them crucial for x-ray spectroscopy-based quantifications. By employing the recently demonstrated holistic approach, the atomic fundamental parameters of the sulfur K-shell were experimentally determined using the radiometrically calibrated instrumentation of the Physikalisch-Technische Bundesanstalt. The transition probabilities of the main K-shell fluorescence lines, the K-shell fluorescence yield, the K-shell Auger yield, the subshell photoionization cross section and fluorescence production cross section were determined by means of photon energy dependent x-ray fluorescence and transmission measurements on a thin InS coated silicon nitride membrane. The results are also downloadable from Zenodo as plain text.

We study the alignments of galaxy spin axes with respect to cosmic web filaments as a function of various properties of the galaxies and their constituent bulges and discs. We exploit the SAMI Galaxy Survey to identify 3D spin axes from spatially resolved stellar kinematics and to decompose the galaxy into the kinematic bulge and disc components. The GAMA survey is used to reconstruct the cosmic filaments. The mass of the bulge, defined as the product of stellar mass and bulge-to-total flux ratio M bulge = M ⋆ × (B/T), is the primary parameter of correlation with spin–filament alignments: galaxies with lower bulge masses tend to have their spins parallel to the closest filament, while galaxies with higher bulge masses are more perpendicularly aligned. M ⋆ and B/T separately show correlations, but they do not fully unravel spin–filament alignments. Other galaxy properties, such as visual morphology, stellar age, star formation activity, kinematic parameters, and local environment, are secondary tracers. Focussing on S0 galaxies, we find preferentially perpendicular alignments, with the signal dominated by high-mass S0 galaxies. Studying bulge and disc spin–filament alignments separately reveals additional information about the formation pathways of the corresponding galaxies: bulges tend to have more perpendicular alignments, while discs show different tendencies according to their kinematic features and the mass of the associated bulge. The observed correlation between the flipping of spin–filament alignments and the growth of the bulge can be explained by mergers, which drive both alignment flips and bulge formation. [ABSTRACT FROM AUTHOR]

X-ray fluorescence (XRF) spectroscopy is an analytical technique used to identify chemical elements that has found widespread use in the cultural heritage sector to characterise artists' materials including the pigments in paintings. It generates a spectrum with characteristic emission lines relating to the elements present, which is interpreted by an expert to understand the materials therein. Convolutional neural networks (CNNs) are an effective method for automating such classification tasks—an increasingly important feature as XRF datasets continue to grow in size—but they require large libraries that capture the natural variation of each class for training. As an alternative to having to acquire such a large library of XRF spectra of artists' materials a physical model, the Fundamental Parameters (FP) method, was used to generate a synthetic dataset of XRF spectra representative of pigments typically encountered in Renaissance paintings that could then be used to train a neural network. The synthetic spectra generated—modelled as single layers of individual pigments—had characteristic element lines closely matching those found in real XRF spectra. However, as the method did not incorporate effects from the X-ray source, the synthetic spectra lacked the continuum and Rayleigh and Compton scatter peaks. Nevertheless, the network trained on the synthetic dataset achieved 100% accuracy when tested on synthetic XRF data. Whilst this initial network only attained 55% accuracy when tested on real XRF spectra obtained from reference samples, applying transfer learning using a small quantity of such real XRF spectra increased the accuracy to 96%. Due to these promising results, the network was also tested on select data acquired during macro XRF (MA-XRF) scanning of a painting to challenge the model with noisier spectra Although only tested on spectra from relatively simple paint passages, the results obtained suggest that the FP method can be used to create accurate synthetic XRF spectra of individual artists' pigments, free from X-ray tube effects, on which a classification model could be trained for application to real XRF data and that the method has potential to be extended to deal with more complex paint mixtures and stratigraphies. [ABSTRACT FROM AUTHOR]

In this study, we have explored the frequency separations, Δ ν and δ ν 02 , the height and width of the oscillation power excess, H Gauss and δ ν env , as a function of the frequency of maximum power ν max by analyzing 187 evolved stars in six star clusters observed by the Kepler / K2 missions. We have also examined the asteroseismic relation in the Christensen-Dalsgaard diagram. Given the importance of scaling relations, the dependency of asteroseismic scaling relations on physical quantities must be verified to reduce systematic errors through the exploration of observational data obtained from various sources. In this context, the star cluster provides a valuable means to assess the age and metallicity. Focusing on evolved stars with 30 μ Hz < ν max < 220 μ Hz , we have exploited the mass effect without the need for deriving the individual stellar mass. We have found that the considered relations appear to be associated with the age of star clusters, thereby the mass of the stars in a given evolutionary status for star clusters with different ages. By separately considering red giant branch stars and red clump stars, we have found that red clump stars appear more sensitive to the cluster age compared with red giant branch stars. It has been suggested that conclusions regarding the dependency of metallicity should be drawn with due care as outcomes are subject to how to treat metallicity. Finally, we conclude by briefly pointing out implications of our findings on asteroseismic inferences. • We analyze asteroseismic data of evolved stars in the six Kepler/K2 star clusters. • Asteroseismic relations depend on stellar mass, reflecting the cluster age. • Metallicity should be carefully handled, comparing isochrone fit with spectroscopy. • Red clump stars are more sensitive to cluster age than red giant branch stars. [ABSTRACT FROM AUTHOR]

The accuracy of absolute parameters' estimation in contact binary systems is important for investigating their evolution and solving some challenges. The Gaia DR3 parallax is one of the methods used for estimating the absolute parameters, in cases where photometric data is the only one that is available. The use of this method includes advantages and limitations that we have described and examined in this study. We selected 48 contact binary systems whose mass ratios were mostly obtained by spectroscopic data, in addition to a number of photometric studies. The target systems were suitable for A V and the Re-normalized Unit Weight Error (RUWE), and their absolute parameters were calculated based on Gaia DR3 parallax, observational information, orbital period, and light cure solution from the literature and catalogs. The outcomes of OO Aql differed significantly from those reported in the literature. Upon analyzing the system's light curve with TESS data, we concluded that the stars' temperatures were the reason for this difference, and utilizing Gaia DR3 parallax provided reasonable results. We displayed the target systems on the Hertzsprung–Russell (HR), q − L r a t i o , P − M V , and l o g M t o t − l o g J 0 diagrams, and the systems are in good agreement with the theoretical fits. We showed that the estimation of absolute parameters with this method might be acceptable if Δ a (R ⊙) is less than ∼ 0. 1 (R ⊙). There are open questions regarding the existence of l 3 in the light curve analysis and its effect on the estimation of absolute parameters with this method. • We discussed using Gaia DR3 parallax to estimate absolute parameters. • We performed light curve analysis for OO Aql using TESS data. • Parameters such as A V , V , and T have an important effect on the acceptable results. [ABSTRACT FROM AUTHOR]

The accuracy of X-ray fluorescence spectrometry in quantitative element analysis depends on the particular sample composition (so-called matrix effects). Counteracting these effects requires a large number of calibration samples similar in composition to those under analysis. Application of the model constructed for a particular type of samples is not possible for the analysis of samples having a different matrix composition. A possible solution for this problem can be found in the construction of universal calibration models. We propose the development of these universal models using chemometric tools: influence coefficients—partial least squares regression (IC-PLS) and nonlinear kernel regularized least squares regression. We hypothesize that the application of these methods for constructing calibration models would allow embracing the samples of different types in the framework of a single model. We explored this approach for the case of two substantially different types of samples: ores and steels. The performance of these methods was compared with the fundamental parameters (FP) method, which takes into account matrix effects using theoretical equations and allows handling samples of different elemental composition. IC-PLS significantly outperforms traditional FP in terms of accuracy for predicting the content of Al (root mean squared error of prediction 0.96% vs. 3.87%) and Ti (0.05% vs. 0.09%) and yields comparable results for Si and Mn quantification in ores and steels.

A methodology is developed where a fundamental parameters approach (FPA) description of a laboratory powder diffraction instrument (configured in divergent‐beam Bragg–Brentano geometry) is used to determine GSAS‐II profile parameters for peak asymmetry and instrumental peak widths. This allows the instrumental contribution to peak shapes to be robustly determined directly from a physical description of the instrument, even though GSAS‐II does not directly implement FPA for peak shape computation. The FPA‐derived parameters can be used as the starting point for instrument characterization, or to characterize sample broadening without the use of a standard to determine the instrument profile function. This new method can facilitate generation of training sets for machine learning. A plot is generated that shows the differences between the two approaches, demonstrating upper bounds for the accuracy of the GSAS‐II profile model for a particular instrumental configuration. [ABSTRACT FROM AUTHOR]

We report on the masses (M WD), effective temperatures (⁠|$\rm{T_\mathrm{eff}}$|⁠), and secular mean accretion rates (⁠|$\langle \dot{M} \rangle$|⁠) of 43 cataclysmic variable (CV) white dwarfs, 42 of which were obtained from the combined analysis of their Hubble Space Telescope ultraviolet data with the parallaxes provided by the Early Third Data Release of the Gaia space mission, and one from the white dwarf gravitational redshift. Our results double the number of CV white dwarfs with an accurate mass measurement, bringing the total census to 89 systems. From the study of the mass distribution, we derive |$\langle M_\mathrm{WD} \rangle = 0.81^{+0.16}_{-0.20}\, \mathrm{M_\odot }$|⁠ , in perfect agreement with previous results, and find no evidence of any evolution of the mass with orbital period. Moreover, we identify five systems with M WD < 0.5 M⊙, which are most likely representative of helium-core white dwarfs, showing that these CVs are present in the overall population. We reveal the presence of an anticorrelation between the average accretion rates and the white dwarf masses for the systems below the |$2\!-\!3\,$| h period gap. Since |$\langle \dot{M} \rangle$| reflects the rate of system angular momentum loss, this correlation suggests the presence of an additional mechanism of angular momentum loss that is more efficient at low white dwarf masses. This is the fundamental concept of the recently proposed empirical prescription of consequential angular momentum loss (eCAML) and our results provide observational support for it, although we also highlight how its current recipe needs to be refined to better reproduce the observed scatter in |$\rm{T_\mathrm{eff}}$| and |$\langle \dot{M} \rangle$|⁠ , and the presence of helium-core white dwarfs. [ABSTRACT FROM AUTHOR]

We use two volume-limited active galactic nucleus (AGN) host galaxy samples constructed by Deng & Wen [47], and explore the environmental dependence of the stellar velocity dispersion in these two volume-limited AGN host galaxy samples. In the luminous volume-limited AGN host galaxy sample, the stellar velocity dispersion of AGN host galaxies apparently depends on local environments: AGN host galaxies with large stellar velocity dispersion exist preferentially in high density regime, while AGN host galaxies with small stellar velocity dispersion are located preferentially in low density regions. But in the faint volume-limited AGN host galaxy sample, this dependence is fairly weak. We also examine the dependence of the clustering properties of AGN host galaxies on the stellar velocity dispersion by cluster analysis, and find that in the luminous volume-limited AGN host galaxy sample, AGN host galaxies with small stellar velocity dispersion preferentially form isolated galaxies, close pairs and small groups, while AGN host galaxies with large stellar velocity dispersion preferentially inhabit the dense groups and clusters. In the faint volume-limited AGN host galaxy sample, although the fraction of isolated galaxies with small stellar velocity dispersion is apparently higher than the one with large stellar velocity dispersion, the trend in the luminous volume-limited sample is very difficultly observed. This likely is due to the galaxy number of the faint volume-limited AGN host galaxy sample being too small to ensure an ideal statistical analysis. [ABSTRACT FROM AUTHOR]

We present new BVRI light curves of UY UMa with no O’Connell effect and a flat bottom secondary eclipse. Light curve synthesis with the Wilson-Devinney code gives a new solution, which is quite different from the previous study: UY UMa is an A-subtype over-contact binary with a small mass ratio of q = 0.21, a high inclination of 81˚.4, a small temperature difference of ΔT = 18˚, a large fill-out factor of f = 0.61, and a third light of approximately 10% of the total systemic light. The absolute dimensions were newly determined. Seventeen new times of minimum light have been calculated from our observations. The period study indicates that the orbital period has intricately varied in a secular period increase in which two cyclical terms with periods of 12y.0 and 46y.3 are superposed. The secular period increase was interpreted to be due to a conservative mass transfer of 2.68 × 10^–8 M⊙/yr from the less massive to the more massive star. The cyclical components are discussed in terms of double-light time contributions from two additional bound stars. The statistical relations of Yang & Qian (2015) among the physical parameters of 45 deep, low mass ratio contact binaries were revisited by using the physical parameters of UY UMa and 25 Kepler contact binaries provided by Şenavci et al. (2016).

Runaway stars are characterized by their remarkably high space velocities, and the study of their formation mechanisms has attracted considerable interest. Young, nearby runaway stars are the most favorable for identifying their place of origin, and for searching for possible associated objects such as neutron stars. Usually, the research field of runaway stars focuses on O‐ and B‐type stars, because these objects are better detectable at larger distances than late‐type stars. Early‐type runaway stars have the advantage that they evolve faster and can therefore better be confirmed to be young. In contrast to this, the catalog of Young runaway stars within 3 kpc by Tetzlaff, N., Neuhäuser, R., & Hohle, M. M. (2011, MNRAS, 410(1), 190–200) contains also stars of spectral type A and later. The objects in this catalog were originally classified as young (≤50 Myr) runaway stars by using Hipparcos data to estimate the ages from their location in the Hertzsprung‐Russell diagram and evolutionary models. In this article, we redetermine and/or constrain their ages not only by using the more precise second data release of the Gaia mission, but also by measuring the equivalent width of the lithium (6,708 Å) line, which is a youth indicator. Therefore, we searched for lithium absorption in the spectra of 51 target stars, taken at the University Observatory Jena between March and September 2020 with the Échelle spectrograph FLECHAS, and within additional TRES‐spectra from the Fred L. Whipple Observatory. The main part of this campaign with its 308 reduced spectra, accessible at VizieR, was already published. In this work, which is the continuation and completion of the in 2015 initiated observing campaign, we found three additional young runaway star candidates. [ABSTRACT FROM AUTHOR]

Current state-of-the-art computational modeling makes it possible to build realistic models of stellar convection zones and atmospheres that take into account chemical composition, radiative effects, ionization, and turbulence. The standard 1D mixing-length-based evolutionary models are not able to capture many physical processes of the stellar interior dynamics. Mixing-length models provide an initial approximation of stellar structure that can be used to initialize 3D radiative hydrodynamics simulations which include realistic modeling of turbulence, radiation, and other phenomena. In this paper, we present 3D radiative hydrodynamic simulations of an F-type main-sequence star with 1.47 solar mass. The computational domain includes the upper layers of the radiation zone, the entire convection zone, and the photosphere. The effects of stellar rotation is modeled in the f-plane approximation. These simulations provide new insight into the properties of the convective overshoot region, the dynamics of the near-surface, highly turbulent layer, and the structure and dynamics of granulation. They reveal solar-type differential rotation and latitudinal dependence of the tachocline location. [ABSTRACT FROM AUTHOR]

Microcalorimeter x-ray detectors offer the specific advantage of being high-resolution energy-dispersive detectors. Furthermore, they can be designed to cover almost any energy range, from soft x-rays to γ rays. Many of the current energy values of L, M, and N x-ray lines in the soft x-ray range (below 1.2 keV) have not been established through a chain of calibration. Based on our experience, we propose here a method of measuring the energies of these lines that should establish peak positions to a few tenths of an electron volt. It would involve the calibration of a microcalorimeter detector with diagram line energy values determined by a grating x-ray spectrometer calibrated by a plane grating monochromator using synchrotron radiation. We present L-line spectra from Cu, Co, and Ni obtained with a microcalorimeter detector to demonstrate the feasibility of obtaining high-resolution spectra in the energy range below 1 keV. • Microcalorimeter x-ray detectors are energy dispersive and have high resolution. • Microcalorimeter x-ray detectors can be calibrated accurately by standard atomic transitions. • Many x-ray emission lines have not been accurately measured. • Microcalorimeter x-ray detectors can detect multiple x-ray lines over a broad spectrum. • For low energies, a grating monochromator and grating spectrometer can be used to calibrate a microcalorimeter detector. [ABSTRACT FROM AUTHOR]

This study aims at optimising the graphene coverage in a microresonator for the design of an efficient modulator by using a combination of graphene induced losses and phase shift. The graphene integration in the ring can provide tunability by means of altering the loss and coupling coefficient by changing the graphene coverage or its chemical potential. The fundamental parameters of graphene integrated all‐pass ring resonator are extracted based on the transmission characteristics using finite‐difference time‐domain method. As compared to conventional graphene‐oxide‐semiconductor straight waveguide, graphene integrated on an all‐pass ring resonator shows enhanced optical absorption and phase shift due to field enhancement factor. A modulator based on graphene tunable loss and phase shift is investigated taking into account the field enhancement factor. For 1.55 μm radiation and ring radius of 3.75 μm with 22% graphene coverage, a maximum modulation depth of 12.6 dB is demonstrated based on electrostatic control of graphene chemical potential. The proposed modulator can feature operational speed in the range of 10 GHz that is useful in a variety of electro‐optic applications. [ABSTRACT FROM AUTHOR]

Using the high-resolution near-infrared adaptive optics imaging from the NaCo instrument at the Very Large Telescope, we report the discovery of a new binary companion to the M-dwarf LP 1033-31 and also confirm the binarity of LP 877-72. We have characterized both the stellar systems and estimated the properties of their individual components. We have found that LP 1033-31 AB with the spectral type of M4.5+M4.5 has a projected separation of 6.7 ± 1.3 AU. Whereas with the spectral type of M1+M4, the projected separation of LP 877-72 AB is estimated to be 45.8 ± 0.3 AU. The binary companions of LP 1033-31 AB are found to have similar masses, radii, effective temperatures, and log  g with the estimated values of 0.20 ± 0.04  |$\rm {M}_{\odot }$|⁠ , 0.22 ± 0.03  |$\rm {R}_{\odot }$|⁠ , and 3200 K, 5.06 ± 0.04. However, the primary of LP 877-72 AB is found to be twice as massive as the secondary with the derived mass of 0.520 ± 0.006  |$\rm {M}_{\odot }$|⁠. The radius and log  g for the primary of LP 877-72 AB are found to be 1.8 and 0.95 times that of the secondary component with the estimated values of 0.492 ± 0.011  |$\rm {R}_{\odot }$| and 4.768 ± 0.005, respectively. With an effective temperature of 3750 ± 15 K, the primary of LP 877-72 AB is also estimated to be ∼400 K hotter than the secondary component. We have also estimated the orbital period of LP 1033-31 and LP 877-72 to be ∼28 and ∼349 yr, respectively. The binding energies for both systems are found to be >1043 erg, which signifies that both systems are stable. [ABSTRACT FROM AUTHOR]

I review the spatially resolved spectroscopic properties of low-redshift star-forming galaxies (and their retired counterparts) using results from the most recent optical integral field spectroscopy galaxy surveys. First, I briefly summarize the global spectroscopic properties of these galaxies, discussing the main ionization processes and the global relations described by the star-formation rates, gas-phase oxygen abundances, and average properties of their stellar populations (age and metallicity) in comparison with the stellar mass. Second, I present the local distribution of the ionizing processes down to kiloparsec scales, and I show how the global scaling relations found using integrated parameters (like the star-formation main sequence, mass–metallicity relation, and Schmidt–Kennicutt law) have local/resolved counterparts, with the global ones being, for the most part, just integrated/average versions of the local ones. I discuss the local/resolved star-formation histories (SFHs) and chemical-enrichment histories and their implications on the inside-out growth of galaxies. Third, I present the radial distributions of the surface densities of the properties explored globally and how they depend on the integrated galaxy properties. In conclusion, I find that the evolution of galaxies is mostly governed by local processes but clearly affected by global ones: Many global scaling relations present resolved counterparts (verified down to kiloparsec scales) that can explain them as well as the observed radial gradients in galaxies. These relations are consequences of the local SFHs, the narrow range of the depletion times, and a local metal enrichment. Deviations from these relations are due to dynamical and mixing processes, local exchange of gas (inflows, outflows, and fountains), depletion time differences, and/or differences in the resolved SFHs. Ionization happens at local scales that may be driven by different physical processes, and it cannot be clearly understood using purely integrated quantities. The dominant ionization in galaxies has a stellar origin. [ABSTRACT FROM AUTHOR]

We present new results on the Galactic bar/bulge transverse velocity structure using Gaia and the VISTA Variables in Via Lactea (VVV) survey. Gaia is complemented in high extinction regions by the multi-epoch infrared VVV observations for which derived relative proper motions can be tied to Gaia's absolute frame. We extract kinematic maps (both 2D and 3D) of the Galactic bar/bulge, from which we measure the pattern speed of the bar using a novel technique. We focus on the evidence of an X-shaped bulge from the kinematic maps. [ABSTRACT FROM AUTHOR]

Photometric and spectral observations of the W UMa binaries FI Lyn, UV Lyn, and NSVS 781878 with periods of around 9.5–10 hr were carried out in order to determine their global parameters by simultaneous light curve and radial velocity curve solutions. We found that the three targets have shallow‐contact configurations with close in mass and radius components. UV Lyn is of W‐subtype, NSVS 781878 is of A‐subtype, while FI Lyn may be considered as binary in thermal contact. Our data show evidences of photospheric activity of the targets but not of emission in the Hα line. The surface inhomogeneity of UV Lyn is stable during the last several decades. Its O–C diagram implies presence of third body with a period of 24 years. The distances of FI Lyn, UV Lyn, and NSVS 781878 calculated from the derived luminosities coincide with those obtained by GAIA astrometrically. [ABSTRACT FROM AUTHOR]

Mt Abu Faint Object Spectrograph and Camera (MFOSC-P) is an in-house-developed instrument for the Physical Research Laboratory (PRL) 1.2 m telescope at Mt Abu, India, commissioned in 2019 February. Here we present the first science results derived from the low-resolution spectroscopy programme of a sample of M dwarfs carried out during the commissioning run of MFOSC-P between 2019 February and June. M dwarfs carry great significance for exoplanet searches in the habitable zone and are among the promising candidates for the observatory's several ongoing observational campaigns. Determination of their accurate atmospheric properties and fundamental parameters is essential to constrain both their atmospheric and evolutionary models. In this study, we provide a low-resolution (R  ∼ 500) spectroscopic catalogue of 80 bright M dwarfs (J < 10) and classify them using their optical spectra. We have also performed spectral synthesis and χ2 minimization techniques to determine their fundamental parameters regarding effective temperature and surface gravity by comparing the observed spectra with the most recent BT-Settl synthetic spectra. The spectral type of M dwarfs in our sample ranges from M0 to M5. The derived effective temperature and surface gravity range from 4000–3000 K and 4.5–5.5 dex, respectively. In most of the cases, the derived spectral types are in good agreement with previously assigned photometric classifications. [ABSTRACT FROM AUTHOR]

Photometric observations in g0 and i0 bands of the newly-discovered W UMa stars WISEJ004327.7+722407 and WISEJ234557.8+510456 are presented. The two targets are with shallow-contact configurations and their components are of G{K spectral type. We found that WISEJ004327.7+722407 is of A subtype while WISEJ234557.8+510456 is of W subtype. The dif- ferent light levels at the quadratures were reproduced by cool spots on the bigger components. The procedure for calculation of the global parameters of eclipsing binaries by light curve solutions and GAIA distances was refined for stars with deep eclipses. The obtained global parameters reveal that at least one of the components of WISEJ004327.7+722407 and WISEJ234557.8+510456 is oversized, overluminous and too hot compared with an MS star with the same mass. [ABSTRACT FROM AUTHOR]

Observations of exoplanetary systems provide clues about the intrinsic distribution of planetary systems, their architectures, and how they formed. We develop a forward modelling framework for generating populations of planetary systems and 'observed' catalogues by simulating the Kepler detection pipeline (SysSim). We compare our simulated catalogues to the Kepler DR25 catalogue of planet candidates, updated to include revised stellar radii from Gaia DR2. We constrain our models based on the observed 1D marginal distributions of orbital periods, period ratios, transit depths, transit depth ratios, transit durations, transit duration ratios, and transit multiplicities. Models assuming planets with independent periods and sizes do not adequately account for the properties of the multiplanet systems. Instead, a clustered point process model for exoplanet periods and sizes provides a significantly better description of the Kepler population, particularly the observed multiplicity and period ratio distributions. We find that |$0.56^{+0.18}_{-0.15}$| of FGK stars have at least one planet larger than 0.5 R ⊕ between 3 and 300 d. Most of these planetary systems (⁠|$\sim 98{{\ \rm per\ cent}}$|⁠) consist of one or two clusters with a median of three planets per cluster. We find that the Kepler dichotomy is evidence for a population of highly inclined planetary systems and is unlikely to be solely due to a population of intrinsically single planet systems. We provide a large ensemble of simulated physical and observed catalogues of planetary systems from our models, as well as publicly available code for generating similar catalogues given user-defined parameters. [ABSTRACT FROM AUTHOR]

CHARMed PyMca is a protocol for researchers using energy‐dispersive X‐ray fluorescence spectroscopy (ED‐XRF) who wish to maximize interlaboratory reproducibility of quantitative results from copper alloys found in heritage materials. This paper reports the results of a study evaluating the interlaboratory reproducibility expected when following this protocol. Five institutions participated in this study, using nine tube‐based instruments of seven types. A set of 12 reference materials not used for calibration was analysed according to the protocol. The results show an improvement in reproducibility of between 65% and 83%, depending on the element, in comparison with a similar study carried out in 2010. The protocol allowed the consistent reporting of concentrations for 15 elements, in contrast to only eight elements that were reported in the 2010 study. Finally, the protocol was shown to generate accurate quantitative results with a well‐characterized precision. It is hoped the information presented here can help researchers studying heritage copper alloys to collaborate more effectively and with greater confidence in the reproducibility of their results. It should also aid researchers to make realistic and informed decisions about whether or not the degree of reproducibility that they may expect from ED‐XRF makes the protocol suitable for their specific purposes. [ABSTRACT FROM AUTHOR]

Forward asteroseismic modeling plays an important role toward a complete understanding of the physics taking place in deep stellar interiors. With a dynamical mass in the range over which models develop convective cores while in the main sequence, the solar-like oscillator α Centauri A presents itself as an interesting case study. We address the impact of varying the metallicity mixture on the determination of the energy transport process at work in the core of α Centauri A. We find that ≳ 70% of models reproducing the revised dynamical mass of α Centauri A have convective cores, regardless of the metallicity mixture adopted. This is consistent with the findings of Nsamba et al., where nuclear reaction rates were varied instead. Given these results, we propose that α Centauri A be adopted in the calibration of stellar model parameters when modeling solar-like stars with convective cores.