LASCO Activity Report for
May 9, 2005 SOHO Science Daily Meeting

Event times are first frame seen in C2 camera unless otherwise noted.
These are preliminary observations for the daily SOHO science discussions.
Final analysis is reported on the Lasco CME list.
An archive of these reports is available.

Points Of Interest

On 2005/05/03 @ 19:06 UT SOHO Telemetry Submode changed to Submode 6.
It will be in Submode 6 until 2005/05/16 @ 12:00 UT. During that time
EIT CME watch at full resolution (1024x1024).

2005/05/06 (Friday)

02:30 UT  WN West	Spray-like front surpassed by following event 
			(03:30 UT) practically before reaching the end of 
			the C2 FOV.

03:30 UT  WN West	Bright ragged loop front with faint and diffuse
			loop-like extensions all around the bright loop. 
			Very bright in C3. GOES reported a C9.3 X-ray flare
			from NOAA AR 10756 (S04W71) between 03:05 - 03:21 UT
			with peak emission at 03:14 UT.

06:06 UT  EN East	Apparently, kind of reconexion event (very faint).
			Difficult to give an exact time of first appearance.

11:06 UT  WS West	Faint and diffuse ragged loop front. By 11:54 UT is
			already surpassed by following event (11:30 UT).

11:30 UT  WN West	Initially bright and small front just appearing. It
			develops as a bright ragged loop front with faint 
			and diffuse loop-like extensions all around the 
			bright loop.  GOES reported a M1.3 X-ray flare
			from NOAA AR 10756 (S04W76) between 01:11 - 11:35 UT
			with peak emission at 11:28 UT.

17:28 UT  S East	Complex event. A Partial Halo event was first seen 
			in C2 at 17:28 UT as a bright and wide loop front
			(hereafter Event #1) above the SE Limb. By 17:54 UT,
			faint and diffuse extensions can be seen above the 
			W Limb and N Pole (Event #2). The Event #2 surrounds 
			the C2 occulting disk by 18:06 UT. The Event #1 was 
			first seen in C3 at 17:42 UT appearing above the SE
			Limb, while the Event #2 shows up at 18:18 UT just 
			above the N Pole. The Event #2 surrounds the C3
			occulting disk by 19:12 UT. The Event #1 spans ~ 185 
			deg by 21:18 UT (LE almost at the end of the C3 FOV),
			from PA 25 - 210. The mean plane-of-sky speed of the 
			LE of Event #1 (based on C3 data) at PA 108 was ~ 
			1100 km/sec, showing an slight deceleration. As for 
			the Event #2, the mean C3-plane-of-sky speed of the 
			LE at PA 355 was about 675 km/sec, showing practically
			no acceleration.
			GOES reported a long duration C8.5 X-ray flare on 
			NOAA AR 10758 (S09E29) between 16:03 - 18:09 UT with
			peak emission at 17:05 UT. EIT 195 images show a 
			strong brightening on the aforementioned region 
			starting at 16:12 UT. A big change in the magnetic 
			field topology in and around the AR between the frames
			taken at 16:24 and 17:21 UT (no frames in between) can
			be observed. By 17:21 UT post-flares loop begin to
			appear as well as dimming regions to N and S of the 
			AR. By that time, EIT 195 running difference images 
			show a huge intensity disturbance all across the 
			eastern hemisphere. The signatures observed in EIT
			clearly indicate the association of the X-ray event 
			with the Event #1 observed by LASCO C2/C3. It is
			difficult to say whether the Event #2 is part of the
			Event #1 or signature of an apparently backsided CME
			with source region on the northern hemisphere.
			Observation of the evolution of the complex event in 
			C3 seems to indicate that the latter does correspond
			to a different event. In summary, the Event #1 has
			therefore been determined as a Partial Halo CME,
			frontsided, associated with a long duration C-class
			X-ray flare on NOAA AR 10758. A faint full halo CME
			(Event #2), apparently backsided, developed by the 
			time.

20:30 UT  WS West	Extremely faint and diffuse front develops in the
			aftermath of previous complex event. Slow development
			of a system of loops can be seen superposed in the LOS.

22:06 UT  S Pole	Extremely faint expanding loop front. It fades
			throughout C3.

23:30 UT  W Limb	Bright spray-like front with faint and diffuse
			extensions to S. It fades throughout C3.

2005/05/07 (Saturday)

01:31 UT  WS West	Bright narrow structure and diffuse brightening follows
			event reported to start at 23:30 UT on previous day.
			Most likely part of the same event.

03:54 UT  N Pole	Faint and wide expanding loop front. It fades
			throughout C3.

08:30 UT  W Limb	Two events partly superposed in the LOS:
		     i) Very bright ragged loop front developing toward W.
		     ii)A faint and diffuse front just appearing a little bit 
			to S. By 09:06 UT, the first front already reached the
			C2 FOV, while the second one becomes clearer developing
			toward WSW. By 09:30 UT, bright material follows this
			second front (bright inner core).
			GOES recorded an M 1.4 X-ray flare on NOAA AR 10756
			(S05W89) between 07:57 - 08:19 UT with peak emission
			at 08:13 UT. A B9.1 X-ray flare follows (S06W80)
			between 09:07 - 09:26 UT with peak emission at 
			09:16 UT.

14:06 UT  N East	Couple of extremely faint expanding fronts. Barely
			visible in C3.		
	
20:06 UT  S West	Extremely faint blob-like front.

2005/05/08 (Sunday)

06:06 UT  S Pole	Very faint and ragged elongated loop front. It is 
			followed by a similar one at around 12:06 UT. They 
			both fade throughout C3.

06:30 UT  S West	Diffuse front superposed in the LOS with existing
			twisted structures. By 07:54 UT, a faint expanding 
			loop front develops.
	
09:54 UT  E Limb	Faint fan-like front. It fades throughout C2.

15:54 UT  W Limb	Bright and ragged loop front. Excess brightness can
			already be seen by 15:30 UT. Extremely faint loop-
			like extensions to N. 

17:06 UT  S East	Ragged and very elongated loop front. It fades 
			throughout C3.

20:06 UT  WN West	Spray-like front. It fades throughout C3.

2005/05/09 (Monday)

01:31 UT  WN West	Elongated and bright loop front.

02:30 UT  WN West	Bright and ragged loop front. Much brighter than 
			the previous one.

05:30 UT  WN West	Faint and ragged (elongated) loop front.

09:54 UT  WN West	Ragged loop front.