Scientific results

We present the multiwavelength variability of the BL Lac object PKS 0735+178, associated with the high-energy neutrino event IC211208A. The light curves cover the radio (1-230 GHz), optical, and Fermi-LAT γ-ray bands over a ∼30 years time-scale. read more →

We report large day-timescale variations in the orientation of the southeast--northwest jet in the prototype microquasar GRS 1915+105. read more →

We carry out the multi-frequency monitoring of the Galactic microquasars with the RATAN-600 radio telescope on 10 January, 6 and 26 April, and now on 6 June 2026 we detected the giant flares from the X-ray and Gamma-ray binary, microquasar Cygnus X-3 at frequencies 1.45 - 30 GHz (see ATel #17742). read more →

Solar flares and coronal mass ejections, originating from solar active regions (ARs), are the primary drivers of space weather and can disrupt technological systems. read more →

We carry out the multi-frequency monitoring of the Galactic microquasars with the RATAN-600 radio telescope and on 6 April 2026 detected the giant flare from the microquasar Cygnus X-3 at frequencies 4.7-30 GHz. read more →

Modern radio sky surveys have shown that compact radio sources, so called FR0 radio galaxies, are the majority among the radio-loud active galactic nuclei in the local Universe. The question about the nature of FR0s and their evolutionary status is open. read more →

During the last 40─50 yr, the TeV blazar Ton 599 has systematically experienced major outbursts detected in a wide wavelength range from radio to  γ-rays.  read more →

An iterative method is presented for reconstructing the height-temperature profile of the solar atmosphere above a sunspot using multi-frequency spectro-polarimetric microwave observations. read more →

Following the increased activity of the compact steep-spectrum quasar 3C 138 in the radio, optical and gamma-ray bands over the recent months (ATels #17539, #17540, #17461), we conducted a pointed X-ray observation of this object with the Mikhail Pavlinsky ART-XC telescope on board the SRG observatory on 28-29 January, 2026, with a total duration of 23.3 hours. read more →

Quasiperiodic fast-propagating (QFP) waves excited by an impulsive, spatially localized velocity perturbation in a curved coronal loop are investigated with three-dimensional numerical simulations. read more →

During the multi-frequency monitoring of the Galactic microquasars with the RATAN-600 radio telescope we detected the giant flare from the microquasar Cygnus X-3 on 15 January 2026 at frequencies 1.42-30 GHz. Cyg X-3 entered in so-called hyper-soft X-ray state 40 day ago, when hard X-ray emission dropped to almost zero (Swift/BAT), showing high soft X-ray (MAXI) fluxes. read more →

We report continued long-term broadband radio and optical brightening of the compact steep-spectrum (CSS) quasar 3C 138, with the variability amplitude increasing toward higher frequencies.  read more →

В работе детально представлены методы анализа многоволновых кривых блеска активных ядер галактик с неравномерной временнoй дискретизацией, включая применение структурной функции, автокорреляционной и кросс-корреляционной функций, периодограммы Ломба-Скаргла и весового вейвлет-анализа. read more →

The physical mechanisms driving neutrino and electromagnetic flares in blazars remain poorly understood. We investigate a prominent multi-messenger flare in the quasar PKS 0446+11 to identify the processes responsible for its high-energy emission.  read more →

We present a technique to search for fast radio bursts in records obtained with broadband radiometers having few radio channels. read more →

We report significant cm-band radio brightening of the flat-spectrum radio quasar (FSRQ) PKS 1725+123 observed with the RATAN-600 and RT-32 radio telescopes. read more →

There is an ongoing need in ground-based astronomy for ultra-sensitive receivers, both coherent (e.g., superheterodyne) and incoherent types, the latter offering potentially higher sensitivity. Both types rely on superconducting or cryogenically cooled semiconductor materials. read more →

We present results from our European VLBI Network (EVN) and Giant Meterwave Radio Telescope (GMRT) observations of the radio continuum and spectral line emission in IRAS 17526+3253, along with an analysis of its arcsecond-scale radio properties using archival Very Large Array (VLA) data. read more →

A sample of objects with steep and ultra-steep spectra was prepared from radio sources of the Cold experiment surveys conducted on the RATAN-600 radio telescope.  read more →

A sample of high-frequency peaker (HFP) candidates was formed from the AT20G catalog radio sources with spectral indices of the optically thick emission region  α_below exceeding +0.5.  read more →

This study is denoted to the cosmological "angular size - redshift" test. An analysis is performed of the angular and linear sizes of galaxies from the new ASTRODEEP-JWST catalogue, which contains over 500,000 objects at high redshifts (up to ~20 photometrically determined and up to ~14 spectroscopically determined). read more →