Halo CME MailHalo CME Mail Date: Mon, 27 Oct 2003 19:32 From: Gareth Lawrence Subject: Partial Halo CME on 2003/10/26, frontsided UCMEO 93001 301027 2330/ 31026 60654 91118 3251/ 215// 233// 41197 31026 60624 90800 24216 10486 1111/ 99999 PLAIN BT LASCO and EIT observed a partial halo CME on 2003/10/26. The event was first observed in C2 at 06:54 UT as a bright loop front over the E limb; by 07:31 UT the front spanned ~250 deg from PA 325 - 215. The front first appeared in C3 images at 07:42 UT with maximal coverage of the C3 occultor by 08:18 UT. Note that the emission in the W is dominated by an earlier limb CME, and it is possible that the partial halo CME to the E could have a faint component in the E. The mean plane-of-sky speed for this event was 1197 km/s at PA 77, with possible evidence for modest deceleration. The CME was probably associated with an X1.2 X-ray flare observed by EIT between 06:24 - 08:00 UT, centered at S16E42 with peak emission at 06:48 UT. GOES records this flare from AR 0486 between 05:57 - 07:33 UT with peak emission at 06:54 UT. A very large EIT wave, and dimming, were observed in association with this event. This event has therefore been determined frontsided. Movies and images of this event will shortly be available at: ftp://ares.nrl.navy.mil/pub/lasco/halo/20031026a and please note that a second halo CME report will follow shortly after this one. 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 ++