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THE ASTRONOMER Electronic Circular No 2326      2007 Apr 13 08.41UT
Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise,  Basingstoke,
Hants, RG22 4PP,England.Telephone/FAX(01256)471074Int:+441256471074
INTERNET: GUY@TAHQ.DEMON.CO.UK      Backup: gmh@wdcc1.bnsc.rl.ac.uk
WORLD WIDE WEB                         http://www.theastronomer.org
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GW LIBRAE
Rod Stubbings has reported via VSNET that the cataclysmic
variable GW Lib is currently in outburst. On 2007 Apr. 11.509UT Rod 
noted it not seen and fainter than magnitude 157 whereas on Apr. 12.494, 
the magnitude was 138. A further rapid brightening has taken place to 
11.8 on Apr 12.659UT.

GW Lib has only had one recorded previous outburst, in 1983 (see 
Duerbeck 1987, Space Sci. Rev. 45, 68).

The object is located at RA: 15h 19m 55.4s, Dec: -25d 00m 25s (J2000). 
Matthew Templeton of the AAVSO mentions their chart is available at:

http://www.aavso.org/cgi-bin/searchcharts3.pl?name=GW%20Lib

Andrew Pearce, Western Australia has confirmed the outburst:
Apr. 12.568UT, magnitude 14.0; 2007 Apr. 12.853UT, 9.9

Makoto Uemura and Akira Arai of the KANATA team also confirmed via VSNET 
the rapid brightening trend.  An example of an image and preliminary 
light curve can be seen at:
http://kanatatmp.blogspot.com/search/label/GW%20Lib

They add that the current brightening speed is about -13 mag/day. If the 
maximum magnitude will be about magnitude 9, the object would reach this 
point near Apr 13.0UT.

They have started simultaneous optical and infrared observations with 
TRISPEC/KANATA. The data is now under reduction. If GW Lib is really a 
WZ Sge-type dwarf nova, we are now in an extremely rare chance to 
observe a temporal evolution of "early humps". The Kyoto team obtained 
the data during this early phase of WZ Sge in 2001. The paper has been 
published and can be seen at:
http://jp.arxiv.org/abs/astro-ph/0111432
Follow-up time-series observations are urged.

Guy M Hurst