The Celestial Reference Frame at K Band: Imaging. I. The First 28 Epochs

Abstract We present K -band (24 GHz) images of 731 compact extragalactic radio sources with submilliarcsecond resolution, based on interferometric observations made the Very Long Baseline Array 10 telescopes during 29 day long sessions spanning from 2015 to 2018 and recorded at 2048 Mbps. Many these are imaged resolution for first time frequencies above X band (8 GHz). From each images, we derive following source properties: peak brightness, core total flux density, ratio (compactness measure), radial extent, structure index, size, jet direction. The vast majority multiple epochs, providing insights into their temporal behavior. use was motivated by fact that generally intrinsically more higher frequencies, as well factor 3 improvement in interferometer relative historically standard S / (2.3/8.4 used a large amount reference frame calibrator work. Lastly, most here component third International Celestial Reference Frame, serve characterize objects Astronomical Union standard.