Weekly Notes from the Yohkoh Soft X-Ray Telescope

(Week 4, 1998)

24-Jan-98 03:00 UT

Instrument Status

The Soft X-ray Telescope continues to work without problems. The bottom sort of dropped out of the solar activity, as shown on the GOES plot below, but at the end of the week things were picking up again. A joint observing program with the VLA took place, and we almost caught an eruption of the S polar crown filament in the PFI's. According to some, this would be of little scientific value, but there are lots of uncertainties about the initial evolution of a CME structure.

A more detailed report of this week's activities is available here.

Observation of the week: A typical data request

The Yohkoh chief observer often gets requests about data at specific times of interest to somebody. This is always exciting, because you never know what great discovery may be out there waiting to be spotted. The following case, courtesy of P.K. Manoharan (Ooty), illustrates the opposite - nothing obvious to be seen, too bad!

The request dealt with an IPS phenomenon seen on 12 Jan. 1998. This would correspond to a solar disturbance on 9 Jan. plus or minus. The Yohkoh data are not yet fully reformatted for this interval of time, but we don't see anything much. The on-line data coverage is listed here. We have taken two standard SFD images (the standard movie images, not the best for this purpose but still good) spanning the time interval shown and made a difference image:

This shows only effects attributable to solar rotation and the normal coming and going of miscellaneous things. There is also nothing outstanding on the GOES plot, which for completeness is shown here also:

The B event on 8 Jan. about 08:00 is a possibility. The extremely fast B event on 10 Jan. at about 20:00 is also interesting, but unlikely to be related to a CME. Finally there is a lot of garbage in the hard channel of GOES (radiation-belt effects, presumably).

HSH, 24-Jan-97 (email hudson@isass0.solar.isas.ac.jp)