The Astrophysical JournalSun-sized Water Vapor Masers in Cepheus AA. M. Sobolev1, J. M. Moran2, M. D. Gray3, A. Alakoz4, H. Imai5, W. A. Baan6, A. M. Tolmachev4, V. A. Samodurov4,7, and D. A. Ladeyshchikov1Published 2018 March 26 • © 2018. The American Astronomical Society. All rights reserved.The Astrophysical Journal, Volume 856, Number 1Article informationAbstractWe present the first VLBI observations of a Galactic water maser (in Cepheus A) made with a very long baseline interferometric array involving the RadioAstron Earth-orbiting satellite station as one of its elements. We detected two distinct components at −16.9 and 0.6 km s−1 with a fringe spacing of 66 μas. In total power, the 0.6 km s−1 component appears to be a single Gaussian component of strength 580 Jy and width of 0.7 km s−1. Single-telescope monitoring showed that its lifetime was only eight months. The absence of a Zeeman pattern implies the longitudinal magnetic field component is weaker than 120 mG. The space–Earth cross power spectrum shows two unresolved components smaller than 15 μas, corresponding to a linear scale of 1.6 × 1011 cm, about the diameter of the Sun, for a distance of 700 pc, separated by 0.54 km s−1 in velocity and by 160 ± 35 μas in angle. This is the smallest angular structure ever observed in a Galactic maser. The brightness temperatures are greater than 2 × 1014 K, and the line widths are 0.5 km s−1. Most of the flux (about 87%) is contained in a halo of angular size of 400 ± 150 μas. This structure is associated with the compact H ii region HW3diii. We have probably picked up the most prominent peaks in the angular size range of our interferometer. We discuss three dynamical models: (1) Keplerian motion around a central object, (2) two chance overlapping clouds, and (3) vortices caused by flow around an obstacle (i.e., von Kármán vortex street) with a Strouhal number of about 0.3.
Control Over Russia's Only Space Telescope Lost - Scientists© Sputnik / Oleg Urusov10:58 12.01.2019 (updated 12:27 12.01.2019) The connection with Russia's only space telescope, Spektr-R, is partially lost; the device isn't accepting commands from the Earth, Nikolai Kardashev, the head of the Astro Space Centre at the PN Lebedev Physics Institute told Sputnik.“We're trying to fix the problem […], there are different communications systems; some of them work, some do not work. We still receive some signals. Such failures have occurred earlier. It can return to normal,” the scientist explained.According to Nikolai Kardashev, scientists continue to receive data from the orbital telescope, despite its failure to respond to remote commands. Specialists from the company which build the device are working on restoring two-way communications.Meanwhile, the head of the project told Sputnik that the Russian Spektr-R space telescope project will be terminated if control over the vehicle is not restored."If the satellite is not controlled, that will mean termination of the RadioAstron project," Yury Kovalev said.He added that the next attempt to restore control over the space telescope would take place on Sunday.
On January 14, the station receiving scientific data in the USA managed to record the carrier radiation of a separate transmitter of the Spektr-R apparatus, which indirectly confirms the information that the onboard systems as a whole operate in accordance with the logic embedded in them.From 19:00 Moscow time on January 14, when the device will be in the radio visibility zone of the Russian stations, work will be continued to restore communication with the radio telescope over the command radio link.
