The ALEXIS Satellite has detected a signal in telescope 3A (176 Angstrom Bandpass) integrated over the 48 hours prior to 01/28/97 17:15:50 UT from a location coincident with the CV U Gem. This system has been seen before by ALEXIS in outburst, and though data coverage of that location is currently poor, an outburst may be underway.
-------------------------------------------------------------------------- Jeffrey Bloch Office: (505) 665-2568 Astrophysics and Radiation Measurements Group ALEXIS SOC:(505) 665-5975 Los Alamos National Laboratory FAX: (505) 665-4414 Group NIS-2, Mail Stop D436 e-mail: jbloch@lanl.gov Los Alamos, NM 87545 Digital Pager: (505)665-9800 #104-8074 --------------------------------------------------------------------------
To All,
Sorry to bother you all again, but while the source detection statistics of this event are very suggestive, U Gem actually puts most of its outburst power out at shorter wavelengths. In fact in previous outbursts we have usually seen this system only in our 130 angstrom channel during another outbursts, but we have in the past on another outburst occasion detected some flux in the longer wavelength channels too. Unfortunately our 3A/3B telescopes that are currently covering this part of the sky do not include a 130 angstrom channel.
Jeff
The ALEXIS Satellite has had complete coverage of the current outburst of U Gem in telescopes 2A (130 Angstrom Bandpass) and 2B (186 Angstrom Bandpass). The source has been detected in our 2A (130 Angstrom Bandpass) telescope, and strong EUV emission began on 02/19/97 sometime between 00:00:00 UT and 01:00:00 UT, approximately one day after the visual magnitude rise. Flux has so far only been detected in our 2A telescope, at a count rate consistent with previous ALEXIS observations of U Gem outbursts.
Visit our web site and register to get a first hand look at the data on this and other bright EUV sources. (http://nis-www.lanl.gov/nis-projects/alexis)
To those VSNET readers, the ALEXIS alert mentioned and described at http://www.kusastro.kyoto-u.ac.jp/vsnet/ALEXIS/ugem9701.html bears some further explaination. This marginal constrained search detection of U Gem in January by ALEXIS upon further examination was most likely a statistical artifact, and upon detailed examination did not appear to be real. Daily processing of ALEXIS data produces 36 maps of the sky per day (6 telescopes x two telemetry dumps per day x 3 time exposure period maps (the previous 12, 24 and 48 hours)) so there are a lot of "typing monkeys" (i.e. separate trials or dice throws) and occasionally a line of Hamlet will appear by random chance.
Cheers, Jeff -------------------------------------------------------------------------- Jeffrey Bloch Office: (505) 665-2568 Astrophysics and Radiation Measurements Group ALEXIS SOC:(505) 665-5975 Los Alamos National Laboratory FAX: (505) 665-4414 Group NIS-2, Mail Stop D436 e-mail: jbloch@lanl.gov Los Alamos, NM 87545 Digital Pager: (505)665-9800 #104-8074 --------------------------------------------------------------------------
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