The all sky celestial reference frame at X/Ka-band (8.4/32 GHz)

摘要

We have constructed an X/Ka-band (8.4/32 GHz) celestial reference frame using over seventy ∼24-hour sessions with the Deep Space Network. We detected 631 sources covering the full 24 hours of right ascension and the full range of declinations. Comparison of 520 X/Ka sources in common with the S/X-band (2.3/8.4 GHz) ICRF2 shows wRMS agreement of 180 micro-arcsec μas in RA cos(dec) and 215 μas in Dec. There is evidence for systematic errors at the 100 μas level. Known errors include limited SNR, lack of phase calibration, troposphere mismodelling. We recently began a collaboration with ESA using their Malargüe, Argentina antenna. This site greatly improves our geometry in the south.