Abstract We here-in demonstrate that the proposed hitherto unknown gravitomagnetic dark-force that hypothetically explains the Flat Rotation Curves of Spiral Galaxies — this same force, explains very well, the logarithmic and as-well, the barred spiral shapes of spiral galaxies. That is, much in line with Edward Arthur Milne (1896-1950)’s 1946 ideas — albeit, on a radically and asymptotically different philosophical train of thought, the galactic disk is here assumed to be in a state of free-fall around the central bulge with the hypothetical gravitomagnetic dark-force being the dominant force determining all gravity-related dynamics of the disk, thus leading to logarithmic and barred spiral orbits, hence the shape of spiral galaxies.

Abstract The paper considers the possibility of using thin films based on samarium sulfide, as well as composite systems of metal-oxide semiconductors doped with rare-earth elements, as radiation-resistant sensitive materials for monitoring leaks of rocket fuel components. The data of electrophysical studies of the obtained sensor layers were processed within the framework of the semiconductor Fourier spectroscopy constructed in relation to gas-analytical systems and the nonlinear regression algorithm of selective calibration. The latter solves really the problem of sensors’ selectivity including distinguishing the substances of the same homology such as methane, propane and n-hexane.

Abstract The data of mean magnetic field (MMF) of the Sun obtained at the Wilcox Solar Observatory (Stanford, USA) in 1975–2020 are analysed. It was concluded that the MMF maximum occurs, on average, 1.5–2 years later relative to the maximum of Wolf numbers. To analyze the changes in the MMF, a new method for searching for periodicities has been developed, which takes into account the change in the sign of the magnetic field from cycle to cycle. This method made it possible to find the main synodic periods of rotation of the magnetic field with values of 27d.021 ± 0d.008, 26d.796 ± 0d.008 and 27d.260 ± 0d.008, each of which has two splitting components associated with a change in the polarity of the magnetic field during the transition from one cycle of solar activity to another. The stability of these periodicities for more than 45 years indicates that the Sun as a star looks like a horizontal magnetic dipole (in addition to the observed vertical one), which changes its sign every 11 years and rotates with different periods.

Abstract We describe the 10-day radio observations of the gamma-ray pulsar J1836+5925. Observations were carried out in the Pushchino Radio Astronomical Observatory at the frequency of 111 MHz using the Large Phased Array of the Lebedev Physical Institute.

Abstract The discovery and subsequent investigations of atmospheric oxygen on Mars are reviewed. Free oxygen is a biomarker produced by photosynthesizing organisms. Oxygen is reactive and on Mars may be destroyed in 10 years and is continually replenished. Diurnal and spring/summer increases in oxygen have been documented, and these variations parallel biologically induced fluctuations on Earth. Data from the Viking biological experiments also support active biology, though these results have been disputed. Although there is no conclusive proof of current or past life on Mars, organic matter has been detected and specimensresemblinggreen algae / cyanobacteria, lichens, stromatolites, and open apertures and fenestrae for the venting of oxygen produced via photosynthesis have been observed. These life-like specimens include thousands of lichen-mushroom-shaped structures with thin stems, attached to rocks, topped by bulbous caps, and oriented skyward similar to photosynthesizing organisms. If these specimens are living, fossilized or abiogenic is unknown. If biological, they may be producing and replenishing atmospheric oxygen. Abiogenic processes might also contribute to oxygenation via sublimation and seasonal melting of subglacial water-ice deposits coupled with UV splitting of water molecules; a process of abiogenic photosynthesis that could have significantly depleted oceans of water and subsurface ice over the last 4.5 billion years.

Abstract The mass measurement of supermassive black holes (SMBHs) is a very complex task. Between several methods for SMBH mass measurements, some of them use the spectral lines, which indicate the motion of the emitting/absorbing material around an SMBH. Mostly, there is an assumption of virialization of line emitting gas in the region which is close to the central SMBH. In this paper we will give an overview of methods for the SMBH mass measurements using broad emission spectral lines observed in Type 1 AGNs. First we give the basic idea to use the parameters of broad lines to SMBH mass measurements. After that we give an overview of broad lines from X-ray (Fe kα) to the IR (Pashen and Brecket lines) which have been used for SMBH mass estimates. Additionally, we describe and discuss a new method for SMBH mass measurements using the polarization in the broad lines emitted from Type 1 AGNs.

Abstract In this work we aimed to develop the image reconstruction algorithm without any analytical simplifications and restrictions. In our method we abandon Fourier’s approach to image reconstruction, and instead use the number of counts recorded in each detector pixel, and then reconstruct each image using a classical Richardson-Lucy algorithm. Among similar works performed in the past, our approach is based, for the first time, on the real geometry of STIX. We made a preliminary analysis of expected differences in STIX imaging which may occur due to usage of slightly different geometries. The other difference is that we use single-pixel-response maps. Namely, knowing the instrument geometry we are able to calculate the detector response for point sources covering entire the solar disc. Next, we iteratively combine them with varying weights until the best match between reconstructed and observed detector responses is achieved. Preliminary tests revealed that the developed algorithm reproduces high quality images. The algorithm is moderately fast, but the result comparable to CLEAN algorithm is obtained within 20-50 iteration steps which takes less than 2 seconds on typical portable computer configuration. The location, size and intensity of reconstructed sources are very close to simulated ones. Therefore the algorithm is very well suited for the detailed photometry of the solar HXR sources. Moreover, its simplicity allows to improve photon transmission calculation in case of any grids uncertainties measured after the launch.

Abstract Among different models for determining the habitable zone (HZ) around a star, a Latitudinal Energy Balance Model (LEBM) is very beneficial due to its parametricity which keeps a good balance between complexity and simulation time. This flexibility makes the LEBM an excellent tool to assess the impact of some key physical parameters on the temperature and the habitability of a planet. Among different physical parameters, some of them, up until now, cannot be determined by any method such as the planet’s spin obliquity, diurnal period, ocean-land ratio, and pressure level. Here we apply this model to study the effect of these unknown parameters on the habitability of three exoplanets located in the inner, outer, and middle of their optimistic HZ. Among the examined parameters, the impact of pressure is more straightforward. It has a nearly direct relation with temperature and also with the habitability in the case of a cold planet. The effect of other parameters is discussed with details. To quantify the impact of all these unknown parameters we utilize a statistical interface which provides us with the conditional probability on habitability status of each planet.

Abstract Solar activity affects geophysical and heliophysical processes. Long-term changes in solar activity are closely related to climate change. Solar physicists and earth science researchers need longer observations of solar activity. Current continuous observations of solar activity are only about 400 years. Some scholars have compiled naked-eye observations of sunspots from 200 BC to 1918 AD from historical documents. In this present work, the authors use the weighted wavelet transform to study the observations series. The results show the Suess - de Vries cycle with a period from 195- to 235-year existing in the discontinuous sunspot series. Meanwhile, the cycle signal changes with time. Especially, the Suess/de Vries cycle is relatively obvious from 200 BC to 400 AD, 800 AD to 1340 AD, 1610 AD to 1918 AD, with a period of about 211-year, about 195-year, and about 235-year, respectively.

Abstract During re-entry objects with low-eccentricity orbits traverse a large portion of the dense atmospheric region almost every orbital revolution. Their perigee decays slowly, but the apogee decays rapidly. Because ballistic coefficients change with altitude, re-entry predictions of objects in low-eccentricity orbits are more difficult than objects in nearly circular orbits. Problems in orbit determination, such as large residuals and non-convergence, arise for this class of objects, especially in the case of sparse observations. In addition, it might be difficult to select suitable initial ballistic coefficient for re-entry prediction. We present a new re-entry prediction method based on mean ballistic coefficients for objects with low-eccentricity orbits. The mean ballistic coefficient reflects the average effect of atmospheric drag during one orbital revolution, and the coefficient is estimated using a semi-numerical method with a step size of one period. The method is tested using Iridium-52 which uses sparse observations as the data source, and ten other objects with low-eccentricity orbits which use TLEs as the data source. We also discuss the performance of the mean ballistic coefficient when used in the evolution of drag characteristics and orbit propagation. The results show that the mean ballistic coefficient is ideal for re-entry prediction and orbit propagation of objects with low-eccentricity orbits.