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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]

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.

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]

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]