SXT Status Report 12 - 25 March, 2001 (Weeks 11-12) N. Nitta, A. Takeda SOLAR ACTIVITY During week 11, the X-ray background slightly decreased, and no flares above the M-class occurred. There was a pair of regions AR 9373 and AR 9384 across the equator, and a sigmoidal structure was seen for long time to the west of the latter region. This structure transformed to an arcade on 16 March, probably corresponding to one of the halo CMEs observed by LASCO. Week 12 is characterized by 13 M-class (but not exceeding M2.5) flares with spiky light curves. They originated from AR 9373, 9390 or 9393. SXT observed some of them, but the data were downlinked at NASA stations, and we are eagerly waiting for them to be reformatted. The region AR 9393 contains a naked-eye spot (approaching 1000 millionth) and it is predicted to produce major events. OBSERVING CAMPAIGNS There was a second VLA campaign (JOP 140) to study metric noise storms, and we participated in two of the three runs (on the 18th and 23rd in UT). One more run on the 24th coincided with our spacecraft holiday. We continued to be on the alert for sigmoids as Target Of Oportunity. Please see our webpages for more details about campaigns past and future: http://isass1.solar.isas.ac.jp/sxt_co/sxt_catalog.html http://isass1.solar.isas.ac.jp/sxt_co/sxt_future.html SXT INSTRUMENT STATUS AND CALIBRATION ACTIVITIES SXT continued to work well. No new problem has been reported. TELEMETRY DOWNLINKS Week Wallops Santiago Goldstone Canberra Madrid NASA Japan 11 29 0 0 2 4 35 27 12 30 0 4 0 13 47 32 Kagoshima should average 6*5+2 = 32 and the NASA target is 7*6 = 42. SXT OBSERVING SEQUENCE TABLES ============================================================== JST Day UT Date & Time Pass Table ID -------------------------------------------------------------- Monday AM 12-MAR-01 02:31 4 010311 P4 ARS1 STD* Tuesday AM 12-MAR-01 21:28 1 010312 P1 ARS1 DARK* Tuesday AM 13-MAR-01 02:33 4 010312 P4 ARS1 DIF* Wednesday AM 13-MAR-01 23:12 2 010313 P2 ARS1 STD* Thursday AM 14-MAR-01 21:33 2 010314 P2 ARS1 STD* Friday AM 15-MAR-01 21:35 2 010315 P2 ARS1 STD* Saturday AM 16-MAR-01 21:37 2 010316 P2 ARS1 STD* Monday AM 18-MAR-01 18:19 1 010318 P1 ARS2 VLA* Monday AM 18-MAR-01 23:24 4 010318 P4 ARS1 STD* Tuesday AM 19-MAR-01 18:21 1 010319 P1 ARS1 DARK* Tuesday AM 19-MAR-01 23:26 4 010319 P4 ARS1 DIF* Wednesday AM 20-MAR-01 18:23 2 010320 P2 ARS1 STD* Thursday AM 21-MAR-01 18:25 2 010321 P2 ARS1 STD* Friday AM 22-MAR-01 18:27 2 010322 P2 ARS1 STD* Saturday AM 23-MAR-01 16:47 1 010323 P1 ARS2 VLA* Saturday AM 23-MAR-01 21:53 4 010323 P4 ARS1 STD* -------------------------------------------------------------- Data reformatting is complete through 3-Mar-2001 (week 01_09). OBSERVING SEQUENCES: For the VLA campaign, we observed the target regions in ARS2 mode in PFIs. On 18 March, the target (AR9370) had long N-S extension, so that we tracked it in 2x3 mosaic in QT/H mode. On the 23rd, we observed the target (AR9390) in usual 2x2 mosaic. In the FFI sequence, we took extra images in thick filters to check if they can detect coronal hole boundaries. The answer has been negative at least for the Al.12 filter. SCIENCE NUGGETS: 16-Mar-01: "Twin-dimming event of 28 February 2001", describes an eruptive event which accompanied a pair of dimming regions and partial halo CME. The S-shaped structure see in SXT images at the time of the eruption was not cospatial with the pre-eruption dark filament seen in EIT images. 23-Mar-01: "The 'Magnificent Cusp' now analyzed", describes a cusp event observed on 18 March 1999, and further challenges the analysis made and published by Yokoyama et al. The full list of recent nuggets is kept on http://isass1.solar.isas.ac.jp/sxt_co/index.html and the current week's nugget also normally resides on http://isass1.solar.isas.ac.jp/sxt_co/SXTweekly.html For the complete nugget archive, see one of the following sites. http://isass1.solar.isas.ac.jp/sxt_co/index.html SEMINARS: S. W. Kahler (AFRL) "A synoptic view of particle acceleration in coronal/interplanetary shocks" R. Jain (PRL, India) "Proposed 'Solar X-ray Spectrometer (SoXS)' onboard GSAT-2 Indian Mission" PERSONNEL: H. Hudson left for Berkeley but will be back toward the end of March. N. Nitta returned to Palo Alto on 16 March. VISITOR: Stephen Kahler continues his intensive study on coronal hole boundaries. Rajmal Jain at PRL, India stayed at ISAS for several days to look at selected SXT and HXT flare data. TOHBANS (spacecraft operators) Tohbans for week 11 SSOC: Y. Nishino, M. Hata / S. Kubo KSC: M. Hagino, T. Miyawaki SXT_CO: N. Nitta / A. Takeda SXT_SW: J. Bartus Tohbans for week 12 SSOC: K. Akita, T. Koyama KSC: T. Miyawaki, H. Tonooka / Y. Katsukawa SXT_CO: A. Takeda SXT_SW: J. Bartus