[vsnet-alert 13337] (ATEL) BL Lac active

[Taichi Kato]

  (ATEL) BL Lac is reported to be active.

Recent visual observations:

  YYYYMMDD(UT)   mag  observer
  20110311.508  14.53V  (Stefan Karge)
  20110330.100  <143  (Pavol A. Dubovsky)
  20110404.087   150: (Pavol A. Dubovsky)
  20110411.085   153  (Pavol A. Dubovsky)
  20110505.025   148  (Pavol A. Dubovsky)
  20110506.012   147  (Pavol A. Dubovsky)
  20110512.035   147  (Pavol A. Dubovsky)
  20110513.069   146  (Klaus Wenzel)

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ATEL #3371							     ATEL #3371

Title:	Fast optical brightening of BL Lacertae
Author:	V. M. Larionov, E.G.Larionova and N.V.Efimova (Astronomical
		Institute, St.-Petersburg State University, Russia, and Pulkovo Observatory,
		Russia), M. Villata and C. M. Raiteri (INAF, Osservatorio Astronomico
		di Torino, Italy), for the GASP Collaboration
Queries:	raiteri at oato.inaf.it
Posted:	23 May 2011; 08:50 UT
Subjects:Optical, AGN, Blazar

With reference to ATel #3368, announcing the Fermi LAT detection of increasing
gamma-ray activity of BL Lacertae, we report on its optical brightening.

Observations in St. Petersburg reveal R = 13.87 +/- 0.01 on May 14.99,
R = 13.06 +/- 0.01 on May 21.95 and R = 12.71 +/- 0.01 on May 22.97, with
a brightness increase of 0.36 mag in 24.5 hours. 
These brightness levels are comparable to those reached during the outbursts
of 1997-2004. 

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