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Дата изменения: Mon Mar 22 18:38:54 2004
Дата индексирования: Sun Apr 10 03:50:27 2016
- There were 16 runs in total during the year 2003 covering a wide range of topics from proper motion measurements of weak pulsars through HI absorption in Seyfert-2 nuclei to Gamma Ray Burst afterglows. Here is a breakdown of these runs. These used L-wide, C-band and the recently available X-band receiver. The table below shows the number of runs with various VLBI networks and the total hours spent (this is about double the number of hours used in the previous year).
|Total||With VLBA||With EVN||Global||Adhoc|
|16 / 41.5 hr||9 / 22.5 hr||4 / 7 hr||2 / 6 hrs||1 / 6 hr|
- New Antcn (antenna control program in PCFS) that communicates with the CIMA executive. Tracking status logging is now possible within the PCFS.
- PCFS can issue VW commands via a new SNAP command, "AO_send". This is used to control noise-cal firing directly from the FS -- IF/LO control to come soon.
- New and improved VLBI webpage (by E. Momjian)
- We are in the process of procuring a Mk5A system plus 10 x 8-disk packs at a cost of about $60K. So why Mark5 at Arecibo?
- At present, most of the EVN antennas are using MK5 systems. However, in order to co-observe with the VLBA and the GBT we will continue to use the tape recorder as well. Current plans are that VLBA will be equiped with MK5B system (formatter independent). When that happens (within the next year hopefully), MK5A here will have to be upgraded.
- There is an additional task that Haystack is undertaking -- use of digital filters in the baseband converter units of the data acquisition rack. Again, we will need to upgrade our DAR when this comes into effect. In other words, we need to stay in step with worldwide developments.
- HSA- A High Sensitive (VLBI) Array is now being formed consisting of the VLBA, Phased-VLA, GBT, and Arecibo as a way to provide smooth access to these antennas with a uniform way of scheduling , data taking and analysis. By adding the GBT, Y27, and AR to a VLBA experiment the sensitivity can be increased by more than an order of magnitude. This capability opens up promising new avenues for scientific discovery. In a 1 hour integration at 1.4GHz, the predicted image sensitivity is 6.5 microJy/beam, compared to 94 microJy/beam for the VLBA alone. Details of this mode of operation are currently being worked out The projection is that a total of up to 100 hours in each trimester (~25 hours/month) may be scheduled for highly rated projects that can justify the increase in sensitivity. This is in addition to any other Global, VLBA+Ar or EVN+Ar observing requests.
- Recently, under the stewardship of Greg Taylor (NRAO) and Colin Lonsdale (Haystack Obs.), the US VLBI community has drafted a white paper charting the direction of Astronomical VLBI operations in the US. They layed out a three-phase plan which aims at a move from the tape based system to first, a disk-based recording system and ultimately to e-VLBI. As a significant contributor to the high sensitivity requirements for the science goals listed in this white paper (at cm-wavelengths), Arecibo will also move along the same lines.