We monitored 3C 273 with VLBI at 15–86 GHz since 1990. We discuss component trajectories, opacity effects, a rotating jet, and outburst-ejection relations from Gamma-ray to radio bands.

Very-long-baseline interferometry (VLBI) is a challenging observational technique, which requires in-depth knowledge about radio telescope instrumentation, interferometry, and the handling of noisy data. The reduction in raw data mostly left to scientists demands use complex algorithms implemented comprehensive software packages. correct application these necessitates good understanding underly...

We have obtained 8.4 GHz VLBA observations of a 31-GHz complete sample of ∼ 100 sources between 10 and 100 mJy. The main goals of these observations are: to determine the angular size, radio spectra and identification for a weak sample of high frequency sources; to find the fraction of sources which have sufficiently compact emission for use as calibrators for VLBI observations; and for design ...

The Canadian Hydrogen Intensity Mapping Experiment (CHIME) has emerged as the prime telescope for detecting fast radio bursts (FRBs). CHIME/FRB Outriggers will be a dedicated very-long-baseline interferometry (VLBI) instrument consisting of outrigger telescopes at continental baselines working with CHIME and its specialized real-time transient-search backend (CHIME/FRB) to detect localize FRBs ...

In our standard geodetic VLBI solutions, we estimate the positions of quasars assuming that their positions do not vary in time. However, in solutions estimating proper motion, a significant number of quasars show apparent proper motion greater than 50 μas/yr. For individual quasars, there are source structure effects that cause apparent proper motion. To examine how coherent the pattern of app...

A model of VLBI observables includes eeects of geometry, environment of signal propagation and delays in the data acquisition system itself. Imperfection of the model of instrumental eeects can be a considerable source of errors in the estimates of the targeted parameters. Two eeects: spurious signals in phase calibration and instrumental polarization are considered in details. Methods of their...

We report on two epochs of VLBI observations of the Type Ib/c supernova SN 2008D, which was associated with the X-ray outburst XRF 080109, At our first epoch, at t = 30 days after the explosion, we observed at 22 and 8.4 GHz, and at our second, at t = 133 days, at 8.4 and 5.0 GHz. The VLBI observations allow us to accurately measure the source’s size and position at each epoch, and thus constra...

Abstract The development of the Atacama Large Millimeter/submillimeter Array (ALMA) phasing system (APS) has allowed ALMA to function as an extraordinarily sensitive station for very long baseline interferometry (VLBI) at frequencies up 230 GHz ( λ ≈ 1.3 mm). Efforts are now underway extend use APS 345 0.87 Here we report a characterization performance based on series tests carried out between ...

The extremely high-redshift (z = 5.3) radio source SDSS J102623.61+254259.5 (J1026+2542) is among the most distant and most luminous radio-loud active galactic nuclei (AGN) known to date. Its one-sided radio jet structure on milliarcsecond (mas) and ∼10-mas scales typical for blazars was first imaged at 5 GHz with very long baseline interferometry (VLBI) in 2006. Here we report on our dual-freq...

We present Very Long Baseline Interferometry (VLBI) observations of the high mass X-ray binary LS I +61 • 303, carried out with the European VLBI Network (EVN). Over the 11 hour observing run, performed ∼10 days after a radio outburst, the radio source showed a constant flux density, which allowed sensitive imaging of the emission distribution. The structure in the map shows a clear extension t...