Sokolovsky, K. V.K. V.SokolovskyD'Ammando, F.F.D'AmmandoCutini, SaraSaraCutini2020-09-172020-09-172011-05-01https://hdl.handle.net/20.500.13025/2176The Astronomer's Telegram, #3377Following the increase in gamma-ray, optical and near-infrared activity of BL Lacertae reported in ATel #3368, #3371, and #3375 we have initiated Swift monitoring observations of the source with 1ks-long pointings planned once every 3 days until 2011 June 04. The first observation of the series was conducted on May 23 16 55 UT and is described here. The 0.3-10 keV X-ray spectrum of BL Lacertae observed by Swift/XRT can be described by an absorbed (N_HI = 3.6x1021 cm-2, Ravasio et al.OpticalUltra-VioletX-rayAGNBlazarhttp://adsabs.harvard.edu/abs/2011ATel.3377....1S2011ATel.3377....1S