[vsnet-alert 12178] V406 Vul = XTE J1859+226 outburst in July

[Taichi Kato]

V406 Vul = XTE J1859+226 outburst in July

   Although the object is faint, try watching!  The object underwent a major
outburst in 1999, reaching a visual magnitude of 15.

Recent optical reports:

  YYYYMMDD(UT)   mag  observer
  20100730.076  <170C  (Eddy Muyllaert)
  20100912.962  <181C  (Eddy Muyllaert)

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The Astronomer's Telegram                   http://www.astronomerstelegram.org 
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ATEL #2845							     ATEL #2845

Title:		Optical re-brightening of the black hole binary XTE J1859+226
Author:	J. M. Corral-Santana (IAC, ULL), P. Rodruez-Gil (ING, IAC,
		ULL), D. Hurley (ING, UCC), J. Casares (IAC, ULL)  
Queries:	jcorral at iac.es
Posted:	17 Sep 2010;  17:17  UT
Subjects:	Optical, Binaries, Black Holes, Transients

Observations of the black hole binary XTE J1859+226 revealed an unexpected
optical re-brightening. Images were taken with the Nordic Optical Telescope
(NOT) using ALFOSC on Jul 13-14,   the William Herschel Telescope (WHT)
with ACAM on Aug 8 and the Isaac Newton Telescope (INT) with WFC on Aug
19 at the Observatorio del Roque de los Muchachos, La Palma, Spain. The
target is found ~1 magnitude brighter than its quiescence level of R=22.48
+- 0.07 as reported in Zurita et al. MNRAS 334, 999 (2002).   

Instead of the ellipsoidal modulation seen at quiescence, the light
curves are dominated by the presence of flares and dips with amplitudes
up to 0.4 mag and typical timescales of minutes (see link below). This
behaviour does not seem to be associated to an increase in X-ray activity.
Follow-up observations in the optical and other wavelengths are highly
encouraged.    

The WHT and the INT are operated on the island of La Palma by the Isaac
Newton Group (ING) in the Spanish Observatorio del Roque de los Muchachos
of the Instituto de Astrofica de Canarias (IAC).   The NOT is operated
on the island of La Palma jointly by Denmark, Finland, Iceland, Norway,
and Sweden   in the Spanish Observatorio del Roque de los Muchachos of
the Instituto de Astrofica de Canarias (IAC).   

http://www.iac.es/project/binariasrayosx/jcorral/XTEJ1859+226.html 

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