The X/Ka Celestial Reference Frame

C., Garcia-Miro I., Sotuela C. S., Jacobs 1 J. E., Clark 2 C. J., Naudet 3 L. A., White 4 R., Madde M., Mercolino D., Pazos G. Bourda 5 P. Charlot 5 S., Horiuchi P., Pope L. G., Snedeker
5 M2A 2014
L3AB - Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux, OASU - Observatoire aquitain des sciences de l'univers, LAB - Laboratoire d'Astrophysique de Bordeaux [Pessac], Université Sciences et Technologies - Bordeaux 1
Abstract : An X/Ka-band (8.4/32 GHz) celestial reference frame has been constructed using single baselines from the combined NASA and ESA Deep Space Networks for approximately 100 sessions each of ∼24-hour duration. The frame solution has dramatically improved with respect to the last reported frame due to the inclusion of Southern NASA-ESA baselines, routine 2-Gbps data rates, and correction of instrumental delays by recently deployed Ka-band phase calibration tones. Comparisons with the S/X-band (2.3/8.4 GHz) ICRF-2 reference frame will be presented showing increasing agreement for 525 common sources. About 135 sources are located in the south polar cap (δ < −45◦) which became accessible for first time with the addition of the ESA station in Malargüe, Argentina to our project’s network. There is evidence for systematic errors at the 100 μas level. The known sources of error will be discussed. Frame tie precision with Gaia has been estimated in about ±7 μas (1-σ, per 3-D rotation com- ponent) using measured X/Ka position uncertainties and simulated Gaia uncertainties. Compared to X-band, Ka-band allows access to more compact radio source morphology and reduced core shift which should reduce these systematic errors compared to a tie of Gaia to S/X-band VLBI. However, there is a great deal of uncertainty in the offset between optical and radio centroids from effects such as optical host galaxy asymmetry which may ultimately limit the frame tie accuracy.
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Submitted on : Tuesday, May 26, 2015 - 7:52:55 AM
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C., Garcia-Miro, I., Sotuela, C. S., Jacobs, J. E., Clark, C. J., Naudet, et al.. The X/Ka Celestial Reference Frame. Proceedings of the 12th European VLBI Network Symposium and Users Meeting (EVN 2014). 7-10 October 2014. Cagliari, Italy. Online at, id.33, Oct 2014, Cagliari, Italy. pp.33. ⟨hal-01155020⟩



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