BB325BK / GCN565443 / SGR J1745-29 - The GC Magnetar
Ran with T+30 schedule. Bug in gogrb meant it had to be run manually. Nonetheless it ran and data is coming.
The source wasn't a GRB as it turned out - it looks like SGR J1745-29 (i.e. the Galactic center magnetar that's been causing all the hoopla) according to the Circular
. The ATEL 5032
gives the Chandra position as:
RA 17:45:40.19, Dec: -29:00:30.37 (with a 0.3" 1sigma statistical error; not boresight corrected).
With our observing setup at 1.4 GHz, the scattering disk will be huge, so in all likelihood, the VLBA will resolve out any emission from the magnetar, and we'll see nothing. Apparently, Michael Kramer et al. have measurements of the scattering disk, but haven't published yet. From Nord et al
citing Bower 2004 somewhere, the scattering disk of SgrA
* is roughly
theta = 1.39 mas * (20cm/1cm)**2 = 556 mas
Our resolution is 5 mas (or maybe 10mas if we flag the longer baselines), so we'll probably be hard pressed to detect anything. Oh well.
VERY LONG BASELINE ARRAY OBSERVING LOG
Observer: Bannister, K.
Project type: VLBA
Obs filename: bb325bkcrd.*
Ants Scheduled: SC HN NL FD LA PT KP OV BR
Operator is Paul Padilla
UT1-UTC: 0.05, VClock: 0.020, GPS delta: 2.0
0239-0317 *FD MASER is bad, out of observation C133446 TIME 100 38
0239-0317 *OV,BR out of disk space, not in observation REC 200 76
0314 HN ends
Total downtime : 114 min
Percentage downtime of observing: 33.3%
Average downtime per hour : 20.0 min
Total scheduled observing time (# Antennas): 342 min (9)
* = Entries where data was affected.
% = Entries where data may have been affected.
& = Entries where the site tech was called out.
WEA = Weather entries.
MF# = Maintenance form or major downtime category associated with a problem.
%AD = The percentage of an antenna affected by a problem.
AMD = Total antenna-minutes downtime for a problem.
Tsys = System Temperature (TP/SP x Tcal/2)
ACU = Antenna Control Unit
FRM = Focus/Rotation Mount
RFI = Radio Frequency Interference
VME = Site control computer
CB = Circuit Breaker
vclock = Program that compares site clock time to a standard.
I had a quick look at the calibration source (fringe finder) - there were not finges on it at all. THis isn't surprising, as the fringe finder was Sag Astar and it would have been substantially scattered, which would have washed out the fringes.