Abstract \(UBVJHKLM\) photometry for the carbon Mira star V CrB are presented. The infrared observations were carried out in the time interval 1989–2018, while the \(U\), \(B\), and \(V\) data were obtained in 2001–2014. The light and color curves are analyzed. The pulsation period of V CrB has been found to be \(355\overset{\textrm{d}}{.}2\) in the infrared \(JHKLM\) bands and \(352^{\textrm{d}}\)

Abstract An example of simultaneous spectroscopic redshift measurements for a large number of galaxies in a cluster by multiobject spectroscopy with the medium- and low-resolution TFOSC spectrograph at the RussianTurkish 1.5-m telescope (RTT150) is presented. The redshifts of galaxies in the cluster \(0301.6+0156\) at \(z=0.17057\pm 0.0004\) detected previously by the SunyaevZeldovich signal in the

Abstract This paper is a continuation of our work. The proper motions and radial velocities of stars from the Gaia DR2 with RV catalogue have been decomposed. We have confirmed that the Ogorodnikov-Milne model is consistent with the observational data and found the kinematic components that are not described by this model. The beyond-the-model harmonics have been partially identified with the nonlinear

Abstract For accurate electron density diagnostics in the solar transition region, the principle of electron density diagnostics are discussed by lines from Si VIII ion for kappa and Maxwellian distributions By observed line ratio of the Si VIII 1440.50 to 1445.75 Å lines in quiet sun and active region, the electron density is discussed for any observed line ratio, and results are consistent with reported

Abstract One of the possible bar formation mechanisms in the disks of galaxies was proposed by Lynden-Bell (1979). The presumed amplification of a weak seed oval stellar surface density perturbation in the central regions of the galaxy through the alignment of the major axes of precessing elliptical orbits underlies it. According to his qualitative reasoning, the orbits are aligned along the perturbation

Abstract We present the results of our spectroscopic observations for the classical symbiotic star V1413 Aql in 20122017. In this period the system was in both active and rare (for it) quiescent states. In 2012 the optical spectrum was dominated by the radiation from the erupted hot component of spectral type F47 III. In 2017 the system passed to a quiescent state that lasted at least three months

The possibility of obtaining dynamical estimates of the total masses in the two Trojan asteroid groups of Jupiter is investigated. The compact Greek (L4) and Trojan (L5) groups contain several tens of thousands of asteroids near the stable Lagrange points moving in a 1: 1 resonance with the orbital motion of Jupiter. The dynamical mass estimates $$\begin{array}{*{20}{c}} {{M_{L4}} = (8.63 \pm 0.51)

We show that Compton scattering by electrons of the hot intergalactic gas in galaxy clusters should lead to peculiar distortions of the cosmic background X-ray and soft gamma-ray radiation—an increase in its brightness at hv ≲ 60−100 keV and a drop at higher energies. The background distortions are proportional to the cluster gas surface density, in contrast to the intensity of the thermal gas radiation

The prospects for observations of gravitationally lensed extragalactic sources in the far-infrared and submillimeter ranges of the electromagnetic spectrum by the planned space observatories with active cooling of the telescope mirror to cryogenic temperatures are considered. The possibility of solving topical cosmological and astrophysical problems related to the observations of gravitationally lensed

We continue the study begun in Karasev et al. (2018) and present the results of our optical identifications of four hard X-ray sources from the INTEGRAL sky surveys. Having first improved the positions of these objects in the sky with the X-ray telescope (XRT) of the Swift observatory, we have identified their counterparts using optical and infrared sky survey data. Then, we have obtained optical spectra

The properties of low-mass neutron stars with rigid rotation are considered. The possible evolution paths of such stars in a close binary system with mass transfer are calculated. The properties of the gamma-ray burst GRB 170817A interpreted in terms of the stripping model, a natural ingredient of which is the explosion of a low-mass neutron star—a binary component, are briefly discussed.

The mechanisms of absorption formation in the cosmic microwave background (CMB) spectrum at the frequency of the 21-cm line of the transition between the ground-state hyperfine sublevels of the hydrogen atom are analyzed. We show that a strong nonlinearity at the compression stage of primordial matter density fluctuations can give rise to a significant (in depth) absorption even before the explosions

New versions of the ephemerides for the Galilean satellites of Jupiter (Io, Europa, Ganymede, and Callisto) constructed by numerically integrating the equations of motion of the satellites are presented. The satellite motionmodel takes into account the non-sphericity of Jupiter, the mutual perturbations of the satellites, and the perturbations from the Sun and major planets. The initial satellite motion

In this work, I construct a LRG sample with the redshift of 0.6 ≤ z ≤ 0.75 from the Sloan Digital Sky Survey Data Release 15 (SDSS DR15), which contains 184172 CMASS LRGs and 27158 eBOSS LRGs and examine the environmental dependence of the u–r, u–g, g–r, r–i, and i–z colors in this galaxy sample. I divide this LRG sample into subsamples with a redshift binning size of Δz = 0.01, and analyze the environmental

We have investigated the methanol CH3OH lines at frequencies of 19.967 GHz [21-30 E(vt = 0) transition] and 20.971 GHz [101-112 E+(vt = 1) transition] toward the massive region of active star formation G358.931-0.030 with the RT-22 (Simeiz) and RT-26 (HartRAO) radio telescopes. Two new flares have been detected. One of the flares (at 20.971 GHz) is extremely powerful in the frequency range 192-26 GHz

Possible models for the generation of electromagnetic (EM) radiation during the coalescence of neutron star–black hole binaries are considered. The mass of the remnant disk around the black hole during the coalescence of neutron stars and black holes is calculated by taking into account the equation of state for neutron stars and the rotation of the binary components before the coalescence. The parameters

The high-resolution Jet Propulsion Laboratory DE431 and DE432 planetary ephemeris are used to evaluate the instantaneous eccentricity functions of the orbits of the planets of the solar system from 13 000 BC to 17 000 AD at different time scales. Spectral analyses are performed to determine the frequencies and the amplitudes of the detected perturbations from 0.1-year to 10 000-year periods. Taken

The results of observations of the gravitational-wave (GW) event S190425z recorded by the LIGO/Virgo detectors with the anti-coincidence shield (ACS) of the SPI gamma-ray spectrometer onboard the INTEGRAL observatory are presented. With a high probability (>99%) it was associated with a neutron star (NS) merger in a close binary system. This is only the second event of such a type in the history of

Based on archival Hubble Space Telescope images, we have performed stellar photometry for 18 dwarf galaxies. Branches of young and old stars are seen on the constructed Hertzsprung–Russell diagrams. Using the photometry of red giants and applying the TRGB method, we have determined accurate distances for all 18 galaxies for the first time. The galaxies AGC 238890 and AGC 747826 have minimum (D = 5

Based on a sample of 7696 nonrecurrent and 566 recurrent sunspot groups, we have investigated the Gnevyshev–Waldmeier rule using the Catalogue of Solar Activity by R.S. Gnevysheva (1954–1978). The maximum recorded sunspot group lifetime is 160 days. The general Gnevyshev–Waldmeier rule for all lifetimes is Amax = (12.1 ± 0.70)LT (Amax is the maximum sunspot group area during the lifetime and LT is

For the low-amplitude Cepheid V532 Cyg we have constructed an O − C diagram spanning a time interval of 121 years. The O − C diagram has the shape of a parabola, which has made it possible to determine for the first time the quadratic light elements and to calculate the rate of evolutionary decrease in the period, dP/dt = −0.248 (±0.067) s yr−1, which points to the second crossing of the instability

The influence of large-scale perturbations in a circumstellar disk on the linear polarization of UX Ori stars is considered. We show that the position angle of the intrinsic linear polarization of a star surrounded by a geometrically thin flared disk cannot change significantly after the passage through the photometric minimum due to perturbations in the disk. In contrast, perturbations in a disk puffed

A systematic search for cosmic gamma-ray bursts (GRBs) and other short hard X-ray events in the archival data from the IBIS/ISGRI telescope of the INTEGRAL observatory over 2003–2018 has been carried out. Seven previously unknown GRBs have been recorded in the telescope field of view; all of them have been localized with an accuracy ≤2 arcmin. These events were not revealed by the INTEGRAL burst alert

Stellar evolution calculations were performed for population I stars with masses on the main sequence 1 M⊙ ≤ M0 ≤ 1.5 M⊙ up to the stage of a cooling white dwarf. The final helium flash LTP is shown to occur in post-AGB stars with initial masses 1.3 M⊙ ≤ M0 ≤ 1.32 M⊙ for the overshooting parameter f = 0.016. In the case of more effective overshooting (f = 0.018) the final helium flash occurs at initial

The mass distribution of transiting exoplanets has been corrected for observational selection effects: the probability of a mass determination (for planets detected by the Kepler Space Telescope) and the probability of a transiting configuration. The corrected mass distribution of exoplanets can be fitted by a power law with an exponent of \( - 2_{ - 0.16}^{ + 0.1}:\;{\textstyle{{dN} \over {dm}}} \propto

Previously we have reported the detection of a sequence of three particle arrival events at energies above 1019 eV during one day and from a small sky region by two extensive air shower (EAS) arrays. We have shown that the probability of a chance coincidence of the three events is very low and suggested the arrival of a short-lived particle beam at the Earth. Here we refine the energies of the recorded