We present the scientific program of the Spectr-M project aimed at the creation and operation of the Millimetron Space Observatory (MSO) planned for launch in the late 2020s. The unique technical capabilities of the observatory will enable broadband observations of astronomical objects from 50 μm to 10 mm wavelengths with a record sensitivity (up to ∼ 0.1 μJy) in the single-dish mode and with an unprecedented high angular resolution (∼ 0.1 μas) in the ground-space very long baseline interferometer (SVLBI) regime. The program addresses fundamental priority issues of astrophysics and physics in general that can be solved only with the MSO capabilities: 1) the study of physical processes in the early Universe up to redshifts z ∼ 2 × 10 6 through measuring μ -distortions of the cosmic microwave background (CMB) spectrum, and investigation of the structure and evolution of the Universe at redshifts z < 15 by measuring y -distortions of the CMB spectrum; 2) the investigation of the geometry of space-time around supermassive black holes (SMBHs) in the center of our Galaxy and M87 by imaging surrounding shadows, the study of plasma properties in the shadow formation regions, and the search for observational manifestations of wormholes; 3) the study of observational manifestations of the origin of life in the Universe — the search for water and biomarkers in the Galactic interstellar medium. Moreover, the technical capabilities of the MSO can help solve related problems, including the birth of the first galaxies and SMBHs ( z ≳ 10), alternative approaches to measuring the Hubble constant, the physics of SMBHs in ‘dusty’ galactic nuclei, the study of protoplanetary disks and water transport in them, and the study of ‘ocean worlds’ in the Solar System.

The possible association with the high-energy neutrino event IceCube-170922A has sparked interest in the blazar TXS 0506+056. We present 72 instantaneous 1-22 GHz spectra measured over the past 20 years with the RATAN-600 telescope and compare them with the results of observations of 700 variable Active Galactic Nuclei (AGN) studied within the same program. The recent radio flare of TXS 0506+056 started from a minimum in 2013 and reached its first peak in December 2017 and a second peak in May-June 2018. This was the third strong radio flare in this source since 1997. The spectrum remains nearly flat during the flares. The spectral shape and variability pattern observed in TXS 0506+056 are typical for variable AGN. RadioAstron Space VLBI observations in 2013-2015 did not detect TXS 0506+056 on space-ground baselines of more than 9 Earth diameters. However, an observation on 23 September 2015 resulted in the detection of interferometric signal on 6 Earth diameter baselines at 18 cm close to the detection limit. We consider the possibility that TXS 0506+056 and other AGN may accelerate relativistic protons more efficiently than electrons. Relativistic protons are necessary to produce both the high-energy neutrinos observed in the IceCube Observatory and the high AGN brightness temperatures implied by the RadioAstron detection. They may also provide the main contribution to the observed synchrotron radiation of parsec-scale AGN jets. This supports the suggestion that relativistic protons may play a much more important part in extragalactic astrophysics than earlier anticipated. (C) 2019 COSPAR. Published by Elsevier Ltd. All rights reserved.

Задачи научной программы космической обсерватории Миллиметрон и технические возможности её реализации, Новиков И.Д., Лихачев С.Ф., Щекинов Ю.А., Андрианов А.С., Барышев А.М., Васюнин А.И., Вибе Д.З., де Граау Т., Дорошкевич А.Г., Зинченко И.И., Кардашев Н.С., Костенко В.И., Ларченкова Т.И., Лихачёва Л.Н., Ляховец А.О., Новиков Д.И., Пилипенко С.В., Пунанова А.Ф., Рудницкий А.Г., Смирнов А.В., Шематович В.И.

The largest Key Science Program of the RadioAstron space VLBI mission is a survey of active galactic nuclei (AGN). The main goal of the survey is to measure and study the brightness of AGN cores in order to better understand the physics of their emission while taking interstellar scattering into consideration. In this paper we present detection statistics for observations on ground-space baselines of a complete sample of radio-strong AGN at the wavelengths of 18, 6, and 1.3 cm. Two-thirds of them are indeed detected by RadioAstron and are found to contain extremely compact, tens to hundreds of μas structures within their cores.

— The results of polarimetric observations of blazar S5 0716+714, carried out with the 6-meter BTA telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences, are presented. The polarized emission microvariability of blazar S5 0716+714 was observed in the R band with an initial time resolution of 3–5 seconds. Exposures were integrated at 1-minute intervals with a total observation time of several hours over two nights. Microvariability of the polarization degree with amplitude of 3–4% was detected during 7–11 minutes and flux oscillations within 9–10% during 25 minutes. A partial synchronism of the flux oscillations and the polarization degree of this blazar was found. Possible interpretations of the detected microvariability are briefly described.

Theoretical and observational evidence is examined to verify the hypothesis put forward by N S Kardashev that some of the double images of galactic nuclei can be entrances to the same wormhole.

In 2015–2016 regular observations within the SETI program were carried out at the RATAN-600 radio telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences. The aim of observations was to search for artificial signals from about 30 Sun-like stars and two metal-rich globular clusters. The main underlying idea of these studies was to perform multiple repeated observations (monitoring) of the same objects. The data were analyzed using three methods: we (1) searched for a strong single signal, (2) estimated the flux averaged over the entire observing time, and (3) analyzed the correlations between signals at different frequencies. Collecting the data over two observing years made it possible to perform a search for weak signals at the detection level of several mJy at 2.7 and 6.3 cm wavelengths. The power limits on the signals of extraterrestrial civilizations averaged over the entire data set lie in the 10 16 –10 20 Winterval practically for all objects, whereas the upper luminosity limits for single observations (the beam crossing time was 7–19 s) are 10 17 –10 21 W and the effective isotropic emitted power of the hypothetical transmitters of the said civilizations do not exceed 2 × 10 9 –2 × 10 13 W, which is close to the corresponding parameter for the biggest planetary radars. The resulting luminosity limits are indicative of the absence of radio emission from the observed Sun-like stars, which is stationary on average and exhibits flare-like behavior during some observing sessions.

The role of pressure as a source of gravity in general relativity is considered. In homogeneous, anisotropic cosmological models, the anisotropic pressure components along different coordinate axes are included as terms in the equations determining the accelerations along these axes; in this sense, this situation is similar to how the mass density is included in these equations. A change in the pressure component along one of the coordinates leads to an anisotropic change in the accelerations along all three coordinates. However, the pressure components are not present in the equation determining the initial conditions. On the other hand, with an inhomogeneous matter density distribution, the mass density and pressure play fundamentally different roles as sources of gravity. The consequences of this are considered.

The active core of the galaxy AO0235+164 is monitored in the optical and radio bands at millimeter wavelengths. Using the multifrequency data obtained in gamma, optical and radio bands, the characteristics of its radiation in the active phase of 2015–2016 are studied. The cross-correlation method was used to determine the delays of the 2015 flare that took place in AO0235+164 in different bands. The analysis made it possible to establish that, in comparison with the previous flare phenomena, changes in the orientation of the emissions (jets) have occurred. The angle θ between the jets and the direction towards the observer has decreased by a factor of \(\sqrt 2 \), resulting in a twofold increase in the γ-factor. The obtained value γ ≈ 40 is the most extreme value ever observed in AO0235+164 over the entire span of observations.

The transition from the radio to the millimeter and submillimeter ranges is very promising for studies of galactic nuclei, as well as detailed studies of processes related to supermassive black holes, wormholes, and possible manifestations of multi-element Universe (Multiverse) models. This is shown by observations with the largest interferometer available—RadioAstron observatory—that will be used for the scientific program forMillimetron observatory. Observations have also shown the promise of this range for studies of the formation and evolution of planetary systems and searches for manifestations of intelligent life. This is caused by the requirements to use a large amount of condensedmatter and energy in large-scale technological activities. This range can also be used efficiently in the organisation of optimal channels for the transmission of information.

The results of updating the parameters of motion of the Spektr-R spacecraft at the end of 2016 have shown that, in January 2018, with a probability close to unity, the condition that a spacecraft stay in the Earth’s shadow is violated; however, in May of the same year, the ballistic life of the spacecraft will be terminated. Thus, in 2017, the question arose of how to design the correction of flight of this spacecraft using its onboard propulsion system. The correction was designed with allowance for the fact that, for the first time since it was launched, the spacecraft in the course of several years, beginning with 2017, repeatedly approaches the Moon, deeply immersing into its sphere of influence. This paper presents the technologically and organizationally convenient, allowable versions of upcoming correction of the Spektr-R spacecraft trajectory and justifies the particular scheme of its implementation.

The RadioAstron ground-space interferometer provides the highest angular resolution achieved now in astronomy. The detection of interferometric fringes from quasars with this angular resolution on baselines of 100–200 thousand km suggests the brightness temperatures which exceed the Compton limit by two orders of magnitude. Polarimetric measurements on ground-space baselines have revealed fine structure testifying to recollimation shocks on scales of 100–250 μas and a helical magnetic field near the base of radio emission in BL Lacertae. Substructure within a the scattering disk of pulsar emission on interferometer baselines (from 60000 to 250000 km) was discovered. This substructure is produced by action of the interstellar interferometer with an effective baseline of about 1 AU and the effective angular resolution of better than 1 μas. Diameters of scattering disks were measured for several pulsars, and distances to diffusing screens were evaluated. The ground-space observations of sources of the maser radiation in lines of water and hydroxyl have shown that the maser sources in star-forming regions remain unresolved on baselines, which considerably exceed the Earth diameter. These very compact and bright features with angular sizes of about 20–60 μas correspond to linear sizes of about 5–10 million km (several solar diameters).

We have resolved the scatter-broadened image of PSR B0329+54 and detected substructure within it. These results are not influenced by any extended structure of a source but instead are directly attributed to the interstellar medium. We obtained these results at 324 MHz with the ground-space interferometer RadioAstron which included the space radio telescope (SRT), ground-based Westerbork Synthesis Radio Telescope and 64-m Kalyazin Radio Telescope on baseline projections up to 330,000 km in 2013 November 22 and 2014 January 1 to 2. At short 15,000 to 35,000 km ground-space baseline projections the visibility amplitude decreases with baseline length providing a direct measurement of the size of the scattering disk of 4.8$\pm$0.8 mas. At longer baselines no visibility detections from the scattering disk would be expected. However, significant detections were obtained with visibility amplitudes of 3 to 5% of the maximum scattered around a mean and approximately constant up to 330,000 km. These visibilities reflect substructure from scattering in the interstellar medium and offer a new probe of ionized interstellar material. The size of the diffraction spot near Earth is 17,000$\pm$3,000 km. With the assumption of turbulent irregularities in the plasma of the interstellar medium, we estimate that the effective scattering screen is located 0.6$\pm$0.1 of the distance from Earth toward the pulsar.

The RadioAstron ground–space interferometer has been used to measure the angular sizes of the scattering disks of the three distant pulsars B1641–45, B1749–28, and B1933+16. The observations were carried out with the participation of the Westerbork Synthesis Radio Telescope; two 32-m telescopes at Torun, Poland and Svetloe, Russia (the latter being one antenna of the KVAZAR network); the Saint Croix VLBA antenna; the Arecibo radio telescope; the Parkes, Narrabri (ATCA), Mopra, Hobart, and Ceduna Australian radio telescopes; and the Hartebeesthoek radio telescope in South Africa. The full widths at half maximum of the scattering disks were 27 mas at 1668 MHz for B1641–45, 0.5 mas at 1668 MHz for B1749–28, and 12.3 at 316 MHz and 0.84 mas at 1668 MHz for B1933+16. The characteristic time scales for scatter-broadening of the pulses on inhomogeneities in the interstellar plasma τsc were also measured for these pulsars using various methods. Joint knowledge of the size of the scattering disk and the scatter-broadening time scale enables estimation of the distance to the effective scattering screen d. For B1641–45, d = 3.0 kpc for a distance to the pulsar D = 4.9 kpc, and for B1749–28, d = 0.95 kpc for D = 1.3 kpc. Observations of B1933+16 were carried out simultaneously at 316 and 1668 MHz. The positions of the screen derived using the measurements at the two frequencies agree: d 1 = 2.6 and d 2 = 2.7 kpc, for a distance to the pulsar of 3.7 kpc. Two screens were detected for this pulsar from an analysis of parabolic arcs in the secondary dynamic spectrum at 1668 MHz, at 1.3 and 3.1 kpc. The scattering screens for two of the pulsars are identified with real physical objects located along the lines of sight toward the pulsars: G339.1–04 (B1641–45) and G0.55–0.85 (B1749–28).