Space Radio Astronomy in the next 1000001 (binary) years

Radio astronomy and active exploration of space are peers: both began by efforts of enthusiasts in the 1930s and got a major technological boost in the 1940s-50s. Thus, for the sake of a brief review at this very special conference, it is fair to estimate the present age of these human endeavours as 1000001 (binary) years. These years saw a lot of challenging and fruitful concerted efforts by radio astronomers and space explorers. Among the high points one can mention several highly successful space-borne CMB observatories, three orbital VLBI missions, the first examples of radio observations at spectral windows hitherto closed for Earth-based observers and many yet to be implemented initiatives which are at various stages of their paths toward launch-pads of all major world space agencies. In this review I will give a bird-eye picture of the past achievements of space-oriented radio astronomy and zoom into several projects and ideas that will further push the presence of radio astronomy into the space agenda of mankind over the next 1000001 (binary) years. In tune with the main themes of this conference, an emphasis will be made on space frontiers of VLBI and the SKA.Comment: 9 pages, 2 figures. Proceedings of the conference "Resolving the Sky - Radio Interferometry: Past, Present and Future", Manchester, UK, 17-20 April 2012, Proceedings of Science, 201

Interferometry in astrophysics as a roadmap for interferometry in multiparticle dynamics

Interferometry is one of the most powerful experimental tools of modern astrophysics. Some of its methods are considered in view of potential applicability to studies of correlations in multiparticle dynamics.Comment: 6 pages, 2 figures in ps, talk given at XXXI International Symposium on Multiparticle Dynamics, Sept 1-7, 2001, Datong China. URL http://ismd31.ccnu.edu.cn

Redshift, Time, Spectrum - the most distant radio quasars with VLBI

The highest-redshift quasars are still rare and valuable objects for observational astrophysics and cosmology. They provide important constraints on the growth of the earliest supermassive black holes in the Universe, and information on the physical conditions in their environment. Among the nearly 60 quasars currently known at redshifts z>5.7, only a handful are "strong" emitters in radio continuum. These can be targets of sensitive high-resolution Very Long Baseline Interferometry (VLBI) observations to reveal their innermost structure, down to ~10 pc linear scales. We review the results of our earlier European VLBI Network (EVN) experiments on three of the most distant radio quasars known to date, and give a preliminary report on the EVN detection of a fourth one. The results obtained so far suggest that we see really young active galactic nuclei - not just in a cosmological sense but also in terms of their active life in radio.Comment: 7 pages, 1 figure. To appear in the proceedings of the RTS 2012 (Resolving The Sky - Radio Interferometry: Past, Present and Future) conference, April 17-20, 2012, Manchester (UK). Proceedings of Science, PoS(RTS2012)04

VSOP observation of the quasar PKS 2215+020: a new laboratory for core-jet physics at z=3.572

We report results of a VSOP (VLBI Space Observatory Programme) observation of a high redshift quasar PKS 2215+020 (z=3.572). The ~1 milliarcsecond resolution image of the quasar reveals a prominent `core-jet' structure on linear scales from 5/h to 300/h pc ($H_0=100*h km/(s*Mpc). The brightness temperatures and sizes of bright features identified in the jet are consistent with emission from relativistic shocks dominated by adiabatic energy losses. The jet is powered by the central black hole with estimated mass of ~4*10^9 solar masses. Comparisons with VLA and ROSAT observations indicate a possible presence of an extended radio/X-ray halo surrounding 2215+020.Comment: 15 pages, 6 figures, aastex macros; accepted for publication in The Astrophysical Journal, V.546, N.2 *(January 10 2001

Multi-frequency investigation of the parsec- and kilo-parsec-scale radio structures in high-redshift quasar PKS 1402+044

We investigate the frequency-dependent radio properties of the jet of the luminous high-redshift (z = 3.2) radio quasar PKS 1402+044 (J1405+0415) by means of radio interferometric observations. The observational data were obtained with the VLBI Space Observatory Programme (VSOP) at 1.6 and 5 GHz, supplemented by other multi-frequency observations with the Very Long Baseline Array (VLBA; 2.3, 8.4, and 15 GHz) and the Very Large Array (VLA; 1.4, 5, 15, and 43 GHz). The observations span a period of 7 years. We find that the luminous high-redshift quasar PKS 1402+044 has a pronounced "core-jet" morphology from the parsec to the kilo-parsec scales. The jet shows a steeper spectral index and lower brightness temperature with increasing distance from the jet core. The variation of brightness temperature agrees well with the shock-in-jet model. Assuming that the jet is collimated by the ambient magnetic field, we estimate the mass of the central object as ~10^9 M_sun. The upper limit of the jet proper motion of PKS 1402+044 is 0.03 mas/yr (~3c) in the east-west direction.Comment: 9 pages, 6 figures

M87 black hole mass and spin estimate through the position of the jet boundary shape break

We propose a new method of estimating a mass of a super massive black hole residing in the center of an active galaxy. The active galaxy M87 offers a convenient test case for the method due to the existence of a large amount of observational data on the jet and ambient environment properties in the central area of the object. We suggest that the observed transition of a jet boundary shape from a parabolic to a conical form is associated with the flow transiting from the magnetically dominated regime to the energy equipartition between plasma bulk motion and magnetic field. By coupling the unique set of observations available for the jet kinematics, environment and boundary profile with our MHD modelling under assumption on the presence of a dynamically important magnetic field in the M87 jet, we estimate the central black hole mass and spin. The method leads us to believe that the M87 super massive black hole has a mass somewhat larger than typically accepted so far.Comment: 10 pages, 1 figure, 3 tables, accepted for publication by MNRA