_                   
                                                         |_|                  
      V   V   SSSS   OOO   PPPP                 \__      |_|      __/         
      V   V  S      O   O  P   P                   --____/ \____--            
      V   V   SSS   O   O  PPPP                    _ _ _ --- _ _ _            
       V V       S  O   O  P                      |_|_|_|  @|_|_|_|           
        V    SSSS    OOO   P                             o-o                  
                                                          /                   
      ***  N    E    W    S  ***                        <)                    

HALCA STATUS

Following the long eclipse season from mid-October to mid-November, reconditioning of HALCA's two batteries is being carried out, with the first battery being reconditioned over four days this week. HALCA's last observation for the year will take place on Friday 28th December, after which HALCA (and supporting staff and subcontractors) will take a break until the new year.

ISAS EXTERNAL REVIEW

An external review of ISAS, the first since 1993, was held on December 19th and 20th. The 12-member review panel contained five members from overseas. The VSOP mission was one of three projects selected for a 40 minute oral presentation to the review panel. The presentation, by Project Scientist "Hirax" Hirabayashi, drew criticism from one panel member: "Why is this excellent mission not more widely known?" !

JAPANESE VLBI

The annual Japanese VLBI symposium was held from December 11th to 13th in Kagoshima. Results from existing arrays and plans for the future, including VSOP and VSOP-2, were discussed. The final half-day consisted of a tour to the 20 m Iriki antenna of the VERA array, which recently had "first light" with the auto-correlation detection of water masers in W49N. The Mizusawa VERA antenna had first light in October. It is planned to find first VERA fringes between these two telescopes in the next few months. On December 14th, a meeting was held with colleagues from South Korea to discuss future VLBI collaborations (see VSOP news 131, and Science vol.294, p.977 November 2001).

RECENT PUBLICATION

Finding direct evidence for plasma instability in extragalactic jets is crucial for understanding the nature of relativistic outflows from active galactic nuclei. VSOP observations of the quasar 3C273 at 5 GHz are reported by Lobanov & Zensus in Science, vol.294, pp.128-131 (2001). The observation yielded an image in which the emission across the jet is resolved, revealing two threadlike patterns that form a double helix inside the jet. This double helical structure is consistent with a Kelvin-Helmholtz instability, and at least five different instability modes can be identified and modeled by a light jet with a Lorentz factor of 2 and Mach number of 3.5. The model reproduces in detail the internal structure of the jet on scales of up to 30 milli-arc seconds (~300 parsecs) and is consistent with the general morphology of the jet on scales of up to 1 kiloparsec.

SEASONS GREETINGS

We wish all VSOP news readers a Merry Christmas and a Happy New Year!

                Editors: Phil Edwards and Hirax Hirabayashi