1. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 1 Extending ICRF to 24, 32, and 43 GHz C.S. Jacobs JPL/Caltech/NASA 23 July 2009 Extending the ICRF to Higher Radio Frequencies: 24, 32, and 43 GHz Global Astrometry URS208977

2. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 2 Extending ICRF to 24, 32, and 43 GHz Motivation for a radio frame above 8 GHz Radio source structure/position/frequency effects Overview of Radio frames at 8, 24, 32, and 43 GHz K-band (24 GHz) frame X/Ka-band (32 GHz) frame Conclusions Outline

3. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 3 Extending ICRF to 24, 32, and 43 GHz Motivation Astrometry, Geodesy and Deep Space navigation have been at 8.4 GHz (X-band) with 2.3 GHz (S-band) plasma calibrations Going to Higher radio frequencies allows Potentially more compact sources Potentially more stable positions Higher Telemetry Rates to Spacecraft Avoid 2.3 GHz RFI issues Ionosphere & solar plasma down 15X !! at 32 GHz (Ka-band) compared to 8 GHz. Drawbacks of Higher radio frequencies: More weather sensitive Weaker sources, shorter coherence times Many sources resolved Antenna Pointing more difficult Picture credit: SOHO/ESA/NASA

4. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 4 Extending ICRF to 24, 32, and 43 GHz The Atmosphere Effects Sensitivity Murphy, R. et al., 1987, Earth Observing System Volume IIe: HMRR High-Resolution Multifrequency Microwave Radiometer. Published by NASA, Goddard Space Flight Centre, Greenbelt, Maryland 20771, USA, 59pp. The three curves show absorption in a dry atmosphere, in the same atmosphere with 20 kg/m2 of added water vapour, and with both water vapour and 0.2 kg/m2 of stratus cloud added.. Valleys are microwave windows Murphy, R. et al., 1987, Earth Observing System Volume IIe: HMRR High-Resolution Multifrequency Microwave Radiometer. Published by NASA, Goddard Space Flight Centre, Greenbelt, Maryland 20771 Atmosphere Background: 3K/atmo @ 8 GHz 10-15K/atmo @32 GHz

5. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 5 Extending ICRF to 24, 32, and 43 GHz Source Structure: Natural radio sources at 8 to 43 GHz are not point-like Credit for this section: E. B. Fomalont, NRAO. Charlottesville, VA & C.S. Jacobs, JPL/Caltech/ NASA, Pasadena, CA presented at DDA meeting, Virginia Beach, May 2009

6. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 6 Extending ICRF to 24, 32, and 43 GHz Structure vs. Frequency: scaled to beam S-band X-band K-band Q-band 2.3 GHz 8.6 GHz 24 GHz 43 GHz 13.6cm 3.6cm 1.2cm 0.7cm Ka-band 32 GHz 0.9cm The sources become better -----> Image credit: P. Charlot, Bordeaux Observatory & KQ VLBI Collaboration 0450-020 = J0501-0159

7. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 7 Extending ICRF to 24, 32, and 43 GHz Structure vs. Frequency: Absolute scale S-band X-band K-band K-band 2.3 GHz 8.6 GHz 24 GHz 24 GHz 6x3 mas 2x1 mas 2x1 mas 0.7x0.3mas Pk = 1.58 Jy Pk = 1.31 Jy Pk = 0.95 Jy Pk = 0.92 Jy The sources becomes more compact -----> Contours: -1, 1, 2, 4, 8, 25, 50, 75, 99% of max Angular scale in milli-arcsec. Same scale for each diagram 0450-020 = J0501-0159 Credit: Petrov et al; Charlot et al., AJ, submitted Nov 2008. Same resolution as 8.6 GHz Nominal resolution

8. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 8 Extending ICRF to 24, 32, and 43 GHz Features of AGN (from Marscher) Features of AGN: Note the Logarithmic length scale. Credit: Alan Marscher, `Relativistic Jets in Active Galactic Nuclei and their relationship to the Central Engine,’ Proc. of Science,VI Microquasar Workshop: Microquasars & Beyond, Societa del Casino, Como, Italy, 18-22 Sep 2006. View angle Doppler enhanced One-sided Most sources >0.1 Jy ~1 mas R s ~ 0.1  as | | >100 2.3 GHz Radio Distant Radio Core Jets Lobes Jet Base Black Hole

9. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 9 Extending ICRF to 24, 32, and 43 GHz Overview of Radio-based Celestial Frames at 8.4, 24, 32, and 43 GHz

10. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 10 Extending ICRF to 24, 32, and 43 GHz S/X (2/8 GHz) ICRF1: 608 Sources 608 sources from S/X data up to 1995 Errors Inflated: scale plus 250 µas RSS’ed Credit: Ma et al, AJ, v. 116, 516, 1998.

11. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 11 Extending ICRF to 24, 32, and 43 GHz S/X Defining: 212 Sources 212 “Defining” sources determine conventional rotation Errors scaled plus 250 µas RSS’ed Credit: Ma et al, AJ, v. 116, 516, 1998.

12. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 12 Extending ICRF to 24, 32, and 43 GHz S/X-band (2/8 GHz): 3500* Sources *Plotted ~2400 sources with Declination uncertainty < 1 mas GSFC-2008b-astro data to June 2008 (some K-band [22 GHz] data) Credit: Petrov, Kovalev, Fomalont, & Gordon, VCS-6, AJ, 2008, 136, 580.

13. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 13 Extending ICRF to 24, 32, and 43 GHz K-band (24 GHz): 275 Sources VLBA Data 10 sessions 2002-07 Formal errors with no inflation Credit: G.E. Lanyi et al, IVS meeting 2008, St. Petersburg

14. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 14 Extending ICRF to 24, 32, and 43 GHz Q-band (43 GHz): 132 Sources VLBA Data 4 sessions 2002-03 Formal errors with no inflation Credit: G.E. Lanyi et al, AJ, submitted Nov 2008

15. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 15 Extending ICRF to 24, 32, and 43 GHz X/Ka (8.4/32 GHz): 339 Sources DSN 2005-09, Dec to - 45 deg. Credit: Jacobs & Sovers, 2008

16. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 16 Extending ICRF to 24, 32, and 43 GHz K-band (24 GHz) Celestial Frame based on VLBA Observations

17. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 17 Extending ICRF to 24, 32, and 43 GHz Game Plan for Observations Phase I - Until 32 GHz available, bracket with VLBA’s closest bands 24 GHz (K-band) 43 GHz (Q-band) - Interpolate behavior to 32 GHz (Ka-band) - identifies likely detectable sources at Ka, time variations - maps sources to provide structure information - accuracy cross-check of X/Ka during Phase-II Phase II - 32 GHz and 8.4 GHz (Ka/X-band) DSN observations 34m Beam-waveguide antennas, 2 baselines: Goldstone California to Madrid, Spain 8,400 km Tidbinbilla, Australia 10,500 km Phase III - Add more antennas to the network - VLBA: 32 GHz proposal in the works - Other sites have Ka, but none with X/Ka to cal plasma

18. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 18 Extending ICRF to 24, 32, and 43 GHz D. Boboltz USNO P. CharlotObservatory of Bordeaux A. Fey USNO E. B. Fomalont NRAO-Charlottesville B. Geldzahler NASA HQ D. GordonGoddard/NASA C. S. JacobsJPL/Caltech NASA G. E. LanyiJPL/Caltech NASA C. Ma Goddard/NASA C. J. NaudetJPL/Caltech NASA J. Romney NRAO-Socorro O. J. SoversRSA Systems/JPL L. D. ZhangJPL/Caltech NASA KQ VLBI Collaboration institutions: JPL, GSFC, USNO, NRAO, and Bordeaux Observatory Phase I: KQ Collaborators

19. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 19 Extending ICRF to 24, 32, and 43 GHz 24 & 43 GHz Observations Mauna Kea OVROBrewsterN. LibertyHancock Kitt PeakPie Town Ft. DavisLos AlamosSt. Croix (photos credit NRAO/NSF/AUI http://www.aoc.nrao.edu/vlba/html/vlbahome/thesites.html) VLBA ten 25m antennas 10 sessions each 24 hours 83K delay/rate obs. pairs ~65-180 sources /session 3-5 snapshots, 2 min each 400 MHz spanned band 128 Mbps record rate Simultaneous astrometry and imaging No Southern Stations

20. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 20 Extending ICRF to 24, 32, and 43 GHz Results: 24 GHz Celestial Frame Credit: G.E. Lanyi et al, IVS meeting 2008, St. Petersburg

21. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 21 Extending ICRF to 24, 32, and 43 GHz ∆RA, ∆ Dec: K vs. S/X Accuracy tested vs. S/X ICRF-2 proto-type RA: 108 µas = 0.5 nrad Dec: 207 µas = 1.0 nrad ICRF-2 Credit: Ma et al, IERS Tech Note 35, in prep. 2009.

22. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 22 Extending ICRF to 24, 32, and 43 GHz K-band zonal Errors: ∆Dec vs. Dec K-band vs. S/X tilts vs. Declination due to uncalibrated Ionosphere and other effects No Dual-band Plasma cals, No stations in the south Without Ion cals -10 +- 0.3 µas/deg With GPS Ion cals -5 +- 0.3 µas/deg (shown at right) Credit: G.E. Lanyi et al, AJ, 2008, in prep., Ma et al, in prep, 2009

23. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 23 Extending ICRF to 24, 32, and 43 GHz X/Ka Frame from Deep Space Network 8.4/ 32 GHz observations

24. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 24 Extending ICRF to 24, 32, and 43 GHz Phase II: X/Ka Phase I - Until 32 GHz available, bracket with VLBA’s closest bands 24 GHz (K-band) 43 GHz (Q-band) - Interpolate behavior to 32 GHz (Ka-band) - identifies likely detectable sources at Ka - maps sources to provide structure information Phase II - 32 GHz and 8.4 GHz (Ka/X-band) DSN observations 34m Beam-waveguide antennas, 2 baselines: Goldstone California to Madrid, Spain 8,400 km Tidbinbilla, Australia 10,500 km Phase III - Add more antennas to the network - VLBA: 32 GHz proposal in the works - Other sites have Ka, but none with X/Ka to calibrate plasma

25. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 25 Extending ICRF to 24, 32, and 43 GHz X/Ka Observations Deep Space Network 34m Beam-waveguide antennas 44 sessions, 9390 delays/rates, ~2K parameters very small data set by S/X standards of 5 x 10^6 delays nominally 24 hours each to cover full range of RA Record rate: now 112 Mbps (MkIV mode A) future 896 Mbps (Mk5-A) = 3X sensitivity 360 MHz spanned bandwidth (receiver 500 MHz, VC limited) 1-2 snapshots, ~2 min each

26. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 26 Extending ICRF to 24, 32, and 43 GHz Reference Frame Modelling X/Ka cannot achieve the results which follow without S/X models! Thus, we cannot get rid of S/X for years to come! Rotational alignment set to S/X ICRF Nutations: MHB model tuned to S/X VLBI Tidal models tuned to fit S/X VLBI UTPM: GPS + S/X VLBI data

27. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 27 Extending ICRF to 24, 32, and 43 GHz X/Ka results: 339 Sources detected DSN data 2005-09 Dec to - 45 deg Ecliptic

28. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 28 Extending ICRF to 24, 32, and 43 GHz ∆RA, ∆ Dec: X/Ka vs. S/X Accuracy tested vs. S/X ICRF-2 proto-type RA: 185 µas = 0.90 nrad Dec: 260 µas = 1.27 nrad ICRF-2 Credit: Ma et al, in prep. 2009.

29. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 29 Extending ICRF to 24, 32, and 43 GHz Zonal Errors: ∆Dec vs. Dec Slope= 1.76 sig

30. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 30 Extending ICRF to 24, 32, and 43 GHz Results limited by Ka-band SNR log10( SNR(Ka) ) Solution: 1) More bits Mk5-A: Gbps 3X SNR increase 2) Ka pointing Potential for 50% increase in SNR from Improved pointing calibrations

31. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 31 Extending ICRF to 24, 32, and 43 GHz Results limited by No Ka-band Phase cal Problem: 180 psec ~diurnal effect Solution: Ka-band Phasecal Prototype Demo’d --- > Operations ~2010

32. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 32 Extending ICRF to 24, 32, and 43 GHz Troposphere Solution 2: Better Calibration JPL Advanced Water Vapor Radiometer ~ 1 deg beam better matches VLBI improved gain stability improved conversion of brightness temperature to path delay Initial demos show 1mm accuracy Goldstone-Madrid 8000 km baseline using X/Ka phase delays (Jacobs et al, AAS Winter 2005). A-WVRs deployed at Goldstone & Madrid Seeking funding for Tidbinbilla, Australia A-WVR not used yet for X/Ka catalog

33. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 33 Extending ICRF to 24, 32, and 43 GHz X/Ka Error Summary 339 sources north of -45 Declination ∆RA ~ 185 µas wRMS (0.9 nrad) ∆Dec ~ 260 µas wRMS (1.27 nrad) Potential for better than 100 µas accuracy: SNR: Mk-5A Gbps allows 3X sensitivity increase better pointing is realizing 50% better SNR Instrumentation: Ka-band phase cal scheduled for ~2010, Digital Back End (RDBE) Troposphere: Estimation with spatial/temporal correlations Advanced Water Vapor Radiometer cals

34. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 34 Extending ICRF to 24, 32, and 43 GHz Conclusions: High Frequency ICRF ICRF now extended to 24 and 32 GHz ~200 µas accuracy! ~300 sources north of -45 Declination Sources unevenly observed both in numbers and geometry Caveat: models & cals still rely on S/X; still need S/X! Observations: 24 GHz: 10 VLBA sessions, 43 GHz: 4 VLBA sessions 32 GHz: 44 DSN sessions Current Accuracy: 100-300 µas wRMS (0.5 - 1.5 nrad) Future Accuracy: 50 µas? Better? Current limiting errors: Lack of southern stations: all bands Troposphere fluctuations: all bands Ionosphere: 24 GHz Instrumental calibrations: 32 GHz SNR: 32 and 43 GHz Copyright 2009 California Institute of Technology. Government sponsorship acknowledged.

35. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 35 Extending ICRF to 24, 32, and 43 GHz Troposphere Solution 1: Better Estimation Day few km Night 1 2 3 Correlated Fluctuations: Temporal & Spatial! Modify Least Squares to account for observation correlations -- both temporal and spatial Use Kolmogorov frozen flow model of Treuhaft & Lanyi (Radio Sci. 1987) This model increases the information available to the estimation process thereby enabling both 1) Reduced parameter biases 2) Reduced parameter sigmas Validation: Improves agreement of X/Ka vs. S/X catalogs by about 10% in Declinations (less in RA)

36. JPL/Caltech NASA 23 Jul 2009, C.S. Jacobs Page 36 Extending ICRF to 24, 32, and 43 GHz Dec-Dec inter-source correlations