Astronomy Letters
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Determining the Characteristics of Lan 30 from Optical Observations
Astronomy Letters - Tập 47 - Trang 307-315 - 2021
We have performed a model analysis of the optical radiation from the young pre-cataclysmic variable Lan 30 and determined the set of its fundamental characteristics. Spectroscopic and multiband photometric observations have been carried out with the BTA and Zeiss-1000 telescopes at the Special Astrophysical Observatory of the Russian Academy of Sciences. The technique for modeling irradiated atmos...... hiện toàn bộ
Laboratory studies of the HNCO molecular spectrum for precise spectroscopy of dark clouds
Astronomy Letters - - 2007
Detailed studies of the internal motions of dark clouds using spectral lines of many molecules require a laboratory frequency accuracy of the order of a few m s−1. Based on our laboratory studies of the HNCO rotational spectrum in the ground vibrational state, we have increased significantly the accuracy of frequency calculation in a wide range of quantum numbers. We have achieved an (1σ) uncertai...... hiện toàn bộ
A hydrodynamic model for asymmetric explosions of rapidly rotating collapsing supernovae with a toroidal atmosphere
Astronomy Letters - Tập 30 - Trang 803-815 - 2004
We numerically solved the two-dimensional axisymmetric hydrodynamic problem of the explosion of a low-mass neutron star in a circular orbit. In the initial conditions, we assumed a nonuniform density distribution in the space surrounding the collapsed iron core in the form of a stationary toroidal atmosphere that was previously predicted analytically and computed numerically. The configuration of ...... hiện toàn bộ
Models of Magnetospheric Accretion onto Young Stars in the Absence of Ionization Equilibrium
Astronomy Letters - Tập 48 - Trang 29-37 - 2022
The formation of hydrogen emission lines in the magnetospheres of young stars is considered. The magnetosphere is assumed to be formed by a dipole magnetic field whose axis is aligned with the stellar rotation axis. The radiative transfer in spectral lines is considered in the Sobolev approximation with nonlocal radiative coupling. We have taken into account the effect of gas ionization fraction t...... hiện toàn bộ
Search for Distant and X-ray Luminous Quasars during the SRG/eROSITA Sky Survey (the DaLeQo Program). The First Results from Observations at the BTA Telescope
Astronomy Letters - Tập 48 - Trang 69-86 - 2022
We discuss the results of our spectroscopy for 17 candidates for distant quasars selected by the SRGz classification system based on data from the first and second sky surveys with the eROSITA telescope onboard the SRG X-ray observatory. Most of the quasar candidates were selected within the DaLeQo observing program, whose goal is a search for the most X-ray luminous quasars with luminosities
...... hiện toàn bộ
Môi trường không gian của các thiên hà vòng cực từ SDSS Dịch bởi AI
Astronomy Letters - Tập 43 - Trang 146-151 - 2017
Dựa trên dữ liệu của SDSS, chúng tôi đã xem xét môi trường không gian của các thiên hà có vòng cực mở rộng. Chúng tôi đã sử dụng hai phương pháp: ước lượng khoảng cách chiếu đến bạn đồng hành gần nhất và đếm số lượng bạn đồng hành theo hàm của khoảng cách đến thiên hà. Cả hai phương pháp đều cho thấy rằng môi trường không gian của các thiên hà vòng cực ở quy mô hàng trăm kiloparsec thường ít dày đ...... hiện toàn bộ
#thiên hà vòng cực #môi trường không gian #SDSS #khoảng cách chiếu #bạn đồng hành
Extended emission from short gamma-ray bursts detected with SPI-ACS/INTEGRAL
Astronomy Letters - Tập 36 - Trang 707-720 - 2010
The short duration (T
90 < 2 s) gamma-ray bursts (GRBs) detected in the SPI-ACS experiment onboard the INTEGRAL observatory are investigated. Averaged light curves have been constructed for various groups of events, including short GRBs and unidentified short events. Extended emission has been found in the averaged light curves of both short GRBs and unidentified short even...... hiện toàn bộ
Chemical composition and stratification of chemical elements in the atmosphere of the Ap star HD 8441
Astronomy Letters - Tập 38 - Trang 721-730 - 2012
We present the results of our abundance analysis for the atmosphere of the chemically peculiar Ap star HD 8441. HD 8441 is interesting in that the lines of rare-earth elements in its spectrum are weak and the longitudinal magnetic field component is small, being only several hundred gauss. Our estimates of the evolutionary status for HD 8441 have confirmed that it belongs to the group of Ap stars ...... hiện toàn bộ
The Seyfert Galaxy NGC 1275: Superfine Structure
Astronomy Letters - Tập 45 - Trang 475-489 - 2019
Based on VLBA observations (NRAO archive) at λ = 2 cm, we have constructed radio maps of the Seyfert galaxy NGC 1275 with a resolution of 25 µas, the epochs of 1995–2015, and at λ = 7 mm (Boston University archive), the epochs of 2000–2015, with a resolution of 20 µas. We have identified a ring structure with a diameter ϕ ≈ 2 mas (1 pc) inclined at 60° to the plane of the sky that includes three c...... hiện toàn bộ
Determination of the Spiral Pattern Speed in the Milky Way from Young Open Star Clusters
Astronomy Letters - - 2023
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