Cyclotron resonant scattering feature simulations. I. Thermally averaged cyclotron scattering cross sections, mean free photon-path tables, and electron momentum sampling

Electron cyclotron resonant scattering features (CRSFs) are observed as absorption-like lines in the spectra of X-ray pulsars. A significant fraction of the computing time for Monte Carlo simulations of these quantum mechanical features is spent on the calculation of the mean free path for each individual photon before scattering, since it involves a complex numerical integration over the scattering cross section and the (thermal) velocity distribution of the scattering electrons. We aim to numerically calculate interpolation tables which can be used in CRSF simulations to sample the mean free path of the scattering photon and the momentum of the scattering electron. The tables also contain all the information required for sampling the scattering electron's final spin. The tables were calculated using an adaptive Simpson integration scheme. The energy and angle grids were refined until a prescribed accuracy is reached. The tables are used by our simulation code to produce artificial CRSF spectra. The electron momenta sampled during these simulations were analyzed and justified using theoretically determined boundaries. We present a complete set of tables suited for mean free path calculations of Monte Carlo simulations of the cyclotron scattering process for conditions expected in typical X-ray pulsar accretion columns (0.01<B/B_{crit}<=0.12, where B_{crit}=4.413x10^{13} G and 3keV<=kT<15keV). The sampling of the tables is chosen such that the results have an estimated relative error of at most 1/15 for all points in the grid. The tables are available online at http://www.sternwarte.uni-erlangen.de/research/cyclo.Comment: A&A, in pres

ROLE OF LEUCOCYTES IN LIVER DAMAGE IN EXPERIMENTAL MODELS OF TYPE 1 AND 2 DIABETES MELLITUS

Diabetes mellitus is a metabolic disorder, which results from insufficient secretion of insulin and/or its action, thus leading to hyperglycemia. Liver damage is known to be among the most common complications of type 2 diabetes mellitus (T2D) and is common in T1D. Comparison of the leukocyte phenotypes in liver tissue with appropriate blood parameters may assess degree of liver damage and search for approaches to correction of liver destruction in diabetes mellitus. Therefore, we aimed for assessment of changes in liver injury markers in blood and the numbers of leucocytes (CD45+ cells), T lymphocytes (CD3+ cells) and macrophages in the liver in experimental models of types 1 and 2diabetes. The experiment was conducted on 30 male Wistar rats. Alloxan at the dose of 170 mg/kg of body weight was used for T1D modeling. To provide a model of T2D, streptozotocin and nicotinamide were injected at the doses of 65 mg/kg, and 110 mg/kg respectively. Intact animals were used as a comparison control. Biochemical, hematological, immunohistochemical and morphometrical methods were used in the study. In T1D and T2D groups, levels of glucose (10.88±0.47 mmol/l and 10.78±0.42 mmol/l) and glycosylated hemoglobin (6.73±0.78% and 6.60±0.20% correspondingly) were rather close to each other and exceeded the values of intact rats (5.20±0.40 mmol/l and 4.07±0.30%). At the same time, the increase in total leucocyte number and fraction of peripheral blood leucocytes against normal levels were more pronounced in the T2D group than in T2D group. In liver of rats from the both diabetic groups, increased numbers of sinusoidal cells, macrophages, CD45+ cells and CD3+ cells relative to intact rats were detected. However, in rats from T1D group, CD45+ cells were distributed, mainly, in the liver parenchyma, whereas in rats in T2D group they showed sinusoidal location. At a similar degree of increasing macrophage numbers, and total CD45+ cells number, higher counts of sinusoidal cells and CD3+ cells, located both in the parenchyma and perivascular area, were found in rats of T2DM group compared with this parameter in T1DM group. An increase in ALT activity confirms a more significant damage to liver cells in animals of the T2DM group, whereas, in T1DM group, an increased AST activity and a less pronounced increase in ALT activity indicate uniformly distributed cytolysis. The results of our study showed, that, despite similar hyperglycemia level, the inflammatory process at the level of the whole organism and local inflammatory process in the liver are more pronounced in the T2DM group. A more significant severity of inflammatory process and liver damage corresponds to increase in sinusoidal cells and CD3+ cell infiltration of liver tissue. © 2022 Russian Association of Allergologists and Clinical Immunologists, St. Petersburg Regional Branch (SPb RAACI). All rights reserved

NuSTAR observation of GRO J1744-28 at low mass accretion rate

We present the spectral analysis of the LMXB GRO J1744-28 using $\sim$29 ks of NuSTAR data taken in 2017 February at a low luminosity of $3.2\times 10^{36}$ erg/s (3-50 keV). The continuum spectrum is modeled with an absorbed power-law with exponential cut-off, and an additional iron line component. We find no obvious indications for a CRSF and therefore perform a detailed cyclotron line search using statistical methods on the pulse phase-averaged as well as phase-resolved spectra. The previously detected Type II X-ray bursts are absent. Clear pulsations at a period of 2.141124(9) Hz are detected. The pulse profile shows an indication of a secondary peak, which was not seen at higher flux. The 4$\sigma$ upper limit for the strength of a CRSF in the 3-20 keV band is 0.07 keV, lower than the strength of the line found at higher luminosity. The detection of pulsations shows that the source did not enter the "propeller" regime, even though the source flux of $4.15\times 10^{-10}$ erg/cm$^{2}$/s was almost one order of magnitude below the threshold for the propeller regime claimed in previous studies on this source. The transition into the propeller regime in GRO J1744-28 must therefore be below a luminosity of $3.2\times 10^{36}$ erg/s, which implies a surface magnetic field $\lesssim 2.9\times 10^{11}$ G and mass accretion rate $\lesssim 1.7\times 10^{16}$ g/s. A change of the CRSF depth as function of luminosity is not unexpected and has been observed in other sources. This result possibly implies a change in emission geometry as function of mass accretion rate to reduce the depth of the line below our detection limit

Localized high-intensity light structures during multiple filamentation of Ti:sapphire-laser femtosecond pulses along an air path

The results of experimental studies of the transverse structure of a laser beam after multiple filamentation are presented. A ring structure of radiation is formed around individual filaments in a beam cross section inside the multiple filamentation domain, and at a dozen meters from it a common ring structure starts forming surrounding postfilamentation light channels (PFC). It is shown that the spectra of the PFC, rings, and beam are significantly different. The ring spectrum broadens asymmetrically relative to the carrier wavelength and is mainly concentrated in the short wavelength region. The PFC spectrum has a significant and more symmetrical broadening and covers the range 630–1000 nm

Filamentation of focused and collimated laser beams in liquids

Experimental results of investigations into the transformation of the spectral and spatial characteristics of femtosecond collimated and focused Ti:Sapphire-laser beams with wavelengths of 800 and 400 nm upon filamentation in continuous liquid media are presented. It is shown that broadening of the laser pulse spectrum due to phase self-modulation in the medium with a cubic nonlinearity depends on the pulse power and beam diameter. Dependences of the number of filaments, width of laser radiation spectrum, nonlinear focusing distance, and diameter of the filamentation region on the laser pulse power are measured. The existence of a relative power interval in which the explosive growth of the number of filaments occurs, is established. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only

Multiple filamentation of laser pulses in the glass

Results are presented of experiments on investigation of the spatial characteristics of multi-filamentation region of giga- and terawatt pulses of a Ti:sapphire laser in a glass. Dependences are obtained of the coordinate of the beginning of filamentation region, number of filaments, their distribution along the laser beam axis, and length of filaments on the pulse power. It is shown that with increasing radiation power, the number of filaments in the multi-filamentation region decreases, whereas the filament diameter has a quasiconstant value for all powers realized in the experiments. It is shown that as a certain power of the laser pulse with Gauss energy density distribution is reached, the filamentation region acquires the shape of a hollow cone with apex directed toward the radiation source

Filamentation of collimated Ti:sapphire-laser pulses in the glass

The results of experiments to study the spatial characteristics of multiple filamentation gigawatt laser pulses in the glass are presented. It is shown that with increasing pulse power multiple filamentation region increases in length and diameter, the distribution of filaments within the region has a maximum value when the power > 105 Pcr area filamentation takes the form of a hollow cone, the apex directed to the source of the laser radiation

Evolution of the Type IIb SN 2011fu

The UBVRI photometric follow-up of SN 2011fu has been initiated a few days after the explosion, shows a rise followed by steep decay in all bands and shares properties very similar to that seen in case of SN 1993J, with a possible detection of the adiabatic cooling phase at very early epochs. The spectral modeling performed with SYNOW suggests that the early-phase line velocities for H and Fe ii features were ~ 16000 km s−1 and ~ 14000 km s−1, respectively. Studies of rare class of type IIb SNe are important to understand the evolution of the possible progenitors of core-collapse SNe in more details