Halo CME Mail

Date: Thu, 23 Oct 2003 12:49

From: Gareth Lawrence

Subject: 'Full' Halo CME on 2003/10/23, frontsided

Status: O

UCMEO 93001 301023 1800/
31023 60854 91342 0001/ 360// 233// 41110
31023 60824 90924 25510 10486 1111/

LASCO and EIT observed a 'full halo CME' on 2003/10/23. The 
event was first observed in C2 at 08:54 UT as a bright loop 
front over the E limb; this had developed to a full halo
CME by 00:30 UT, albeit faint in the W. The front first 
appeared in C3 at 09:18 UT with full coverage of the C3 
occultor by 10:20 UT. Note that the emission in the W is
brighter in C3 than C2, though still faint by comparison
to that in the E. The mean plane-of-sky speed for this 
event was 1110 km/s at PA69, with possible evidence for 
moderate deceleration. 

The CME was probably associated with an X5.4 X-ray flare
observed by EIT between 08:24 - 09:24 UT, centered at S10E55
with peak emission at 08:36 UT. Note that very strong emission 
is also seen to the E of this, around S10E75. GOES records 
this flare from AR 0486 between 08:19 - 08:49 UT with peak 
emission at 08:35 UT. A very large EIT wave, and dimming 
were observed in association with this event. Considering 
the location of the flare, the faint emission in the W 
hemisphere and ongoing activity in the region between
AR 0486 and AR 0484 centered N04E13 during this period,
this event has been determined frontsided.

Movies and images of this event will shortly be 
available at: 

Best wishes,
	Gareth Lawrence.

+----------PLEASE NOTE NEW EMAIL ADDRESS-----------+
Gareth Lawrence,           grl@grace.nascom.nasa.gov 
SOHO-LASCO Operations Scientist,                                           
CUA, MC 682.3, Bldg 26, Rm 001,   F: +1-301-286-0264         
NASA Goddard Space Flight Center,
Greenbelt, MD 20771.              P: +1-301-286-2941