Igor I. Zinchenko

Unlike the complicated X-ray and radio structure observed in the North Polar Spur area, the southeastern part of the eROSITA bubbles can be reasonably well described as a propagating forward shock, plausibly created by the transient energy release at the Galactic center. In this model, the physical radius of the bubble is R _b ∼ 7–8 kpc, and the age of the outburst is t _age ∼ 5–8 Myr. The latter quantity is plausibly a lower limit on the true age. The visible segment of the shock front (located at a distance of ∼10–12 kpc above the Galactic disk and at a similar distance from the Sun) is currently expanding with a velocity of ∼700 km s ⁻¹ through gas with a density of n _e ∼ 3×10 ⁻⁴ cm ⁻³ . Moreover, the abundance of heavy elements in this gas is low, Z ∼ 0.1–0.2× Z _⊙ (depending on the adopted reference solar abundances). Unlike the constraints derived from the line-of-sight-integrated quantities, these are effectively in situ measurements of the properties of the circumgalactic medium. Given the simplifying assumptions used in deriving the density and abundance, we assigned a systematic uncertainty of factor of 2 to the final estimates. An eventual decisive test for the shock properties can be provided by the velocity measurements of the X-ray-emitting gas with soft X-ray bolometers. The extended forward shock propagating through low-metallicity gas is a favorable site to accelerate very high-energy cosmic rays, which might contribute to the recently discovered proton-rich Galactic cosmic ray component at PeV energies impinging on the Earth’s atmosphere.

During the period 2023$-$2026, the Special Astrophysical Observatory of the Russian Academy of Sciences (SAO RAS) is implementing a project to create a millimeter-wave observatory based on the BTA optical telescope. The project involves the installation of sub-terahertz receivers at the Nasmyth focus and the performance of test observations. This paper discusses the scientific objectives that can be addressed both at the initial stage of the project using bolometric receivers for continuum observations and, in the future, using receiver systems based on HEMT and SIS technologies for molecular line observations.

We present the SOFIA/HAWC+ 214 μm polarimetric observations toward the infrared dark cloud G351.77-0.53 (hereafter G351), complemented by existing multi-wavelength data sets. Infrared excess from the embedded sources indicate ongoing star formation activity in the cloud. The G351 cloud hosts two prominent star-forming clumps, i.e., c1 and c2. The plane-of-the-sky magnetic field lines from Planck observations are predominantly oriented perpendicular to the filament’s major axis. Magnetic field orientations from SOFIA/HAWC+ 214 μm observations reveal distinct hourglass-shaped field configuration toward c1, while the field lines remain perpendicular to the rest of the filament. Using the Davis-Chandrasekhar-Fermi method, we estimate a mean plane-of-the-sky magnetic field strength of ~147 ± 60 μG in the G351 filament, with values reaching ~0.8 mG toward c1. The mass-to-flux ratio analysis indicates that the filament is magnetically transcritical, where the gravitational and magnetic field energies are comparable. The hourglass-shaped magnetic field observed toward c1 could result from magnetically regulated gravitational collapse, the alignment of converging sub-filaments with the magnetic field, or a combination of both processes. The energy budget analysis further indicates that magnetic fields play an important role in governing the cloud’s gas dynamics, followed by contributions from turbulence and gravity.

During the period of 2023–2026, the scientists of the Special Astrophysical Observatory of the Russian Academy of Sciences (SAO RAS) are implementing a project to create a millimeter-wave observatory based on the BTA optical telescope. The project involves the installation of subterahertz receivers at the Nasmyth focus and the performance of test observations. This paper discusses scientific objectives that can be addressed both at the initial stage of the project using bolometric receivers for continuum observations and, in the future, using receiver systems based on HEMT and SIS technologies for molecular line observations.

We describe the general remaining unclear issues of the star-formation process that could be studied using the millimeter radio telescope on the Suffa plateau (Uzbekistan). A description of possible objects of study is given. The possibilities of solving scientific problems in studying these objects using various instruments are assessed: the 70-m RT-70 radio telescope, a smaller-diameter antenna (15–20 m), and an antenna array consisting of small (3–8 m) antennas.