Speaker
Dr
Aletha de Witt
(Hartebeesthoek Radio Astronomy Observatory)
Description
K-band (22 GHz) radio observations have the potential to form the basis for the most accurate celestial reference frame ever constructed. Relative to the standard S/X (2.3/8.4 GHz) observing bands, K-band is expected to exhibit a reduction in extended source morphology and core-shift. This reduction in astrophysical systematics should allow for a more stable celestial reference frame at K-band and should also be advantageous in tying the VLBI radio frame to the Gaia optical frame. The current K-band catalogue consists of only 274 sources from a few VLBA sessions and uncertainties in source positions at the ~100 micro-arcsecond level. Modern 2 Gbps data rates are 16 times better than previous observations, yielding a four fold increase in sensitivity. Southern observations to reduce astrometric systematics and to complete the sky coverage at K-band are under way. However, new astrometric and imaging observations are also required in the North to improve K-band precision and spatial coverage, and to map the intrinsic source structure so that their astrometric quality can be evaluated. A proposal for astrometric and imaging observations using the Very Long Baseline Array (VLBA) at K-band have been approved. We discuss some of our first results from our K-band VLBA campaign.
Primary author
Dr
Aletha de Witt
(Hartebeesthoek Radio Astronomy Observatory)
Co-authors
Dr
Alessandra Bertarini
(Max Planck Institut fu ̈r Radioastronomie)
Mr
Christopher Jacobs
(JPL/NASA)
Dr
Geraldine Bourda
(Laboratoire d'Astrophysique de Bordeaux)
Dr
Jamie McCallum
(University of Tasmania)
Dr
Jim Lovell
(University of Tasmania)
Dr
Jonathan Quick
(HartRAO)
Dr
Patrick Charlot
(Laboratoire d'Astrophysique de Bordeaux)
Dr
Shinji Horiuchi
(C.S.I.R.O/Canberra Deep Space Communications Complex)
