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      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                  
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      ***  N    E    W    S  ***                        <)                    

AO6

The AO6 deadline for proposals is less than one week away. Proposers submitting their justifications electronically as postscript files are strongly encouraged to submit several days before the deadline so that there is sufficient time for notification and response if there are problems with the transmission of the file. This has happened to at least one proposal in each of the last three AOs!

CORRELATOR COMPARISONS AND CORRECTIONS

On the basis of suspicions raised during analysis of VSOP Survey data, a direct comparison of the ground-based visibilities produced by each of the three VSOP correlators for a single observation (observed with the VLBA, EB and HALCA) has been conducted. The residual phases after fringe-fitting agree very well, however the Mitaka and Penticton amplitudes differed substantially. Penticton has confirmed that a multiplicative factor of sqrt(2) is required for their data, and Mitaka data requires a multiplicative factor of 1.13, a quantization correction which heretofore has not been applied. With these corrections, Mitaka and Penticton agree to within 1%. These corrected amplitudes still differ from the VLBA by ~7%. Investigation of this remaining discrepancy is continuing, with one possibility being that the difference may have been introduced in the copying process required to perform the comparison. See the VSOP web site for more details.

RECENT PUBLICATIONS

Tingay et al. (ApJ 549, L55) used VSOP observations to measure the brightness temperature distribution of a well-defined sub-set of the Pearson-Readhead sample of extragalactic radio sources. A significant proportion of the 27 AGN were found to have brightness temperatures greater than the theoretical estimates of brightness temperature limits of 10^11 to 10^12 K. Many sources have unresolved components on the longest baselines, and some remain completely unresolved. These observations begin to bridge the gap between the extended jets seen with ground-based VLBI and the micro-arcsecond structures inferred from intraday variability. This is demonstrated by the discovery of a relationship between intraday variability and VSOP-measured brightness temperature, likely to be due to the effects of relativistic beaming. In addition, the lower limits on jet Lorentz factors inferred from these VSOP observations are starting to challenge numerical simulations that predict low Lorentz factor jets.

VERA

Good progress is being made with the VERA (VLBI Exploration of Radio Astronomy) project. VERA uses a novel dual-beam system for astrometric VLBI observations. Construction of the first three antennas, at Mizusawa (in northern Honshu), Iriki (near Kagoshima in southern Kyushu), and Ogasawara (on Chichijima island south-east of Tokyo), has been completed. It is planned to have the telescopes out-fitted and first 43 GHz fringes found by March next year. More details are available from the VERA web page at http://veraserver.mtk.nao.ac.jp/.

                Editors: Phil Edwards and Hirax Hirabayashi