Fast variability of BL Lacertae at 1 μm |
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| Authors: | E Massaro R Nesci M Maesano F Montagni & F D'Alessio |
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| Institution: | Istituto Astronomico, Univ. 'La Sapienza', via G. M. Lancisi 29, I-00161 Roma, Italy,;Osservatorio di Collurania-Teramo, Teramo, Italy |
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| Abstract: | We present the results of photometric observations of BL Lacertae at 1 μm performed during the strong outburst that occurred in the summer of 1997. Measurements were carried out using the F99 filter of the Arizona system. Simultaneous observations in the B V bands were made with other telescopes. Large and fast variations were observed on the night of August 2 when the brightness of BL Lacertae changed by ～ 0.5 mag in about 2 h: the variation amplitude is greater at higher frequency. Some implications of these results for the origin of the fast variations are discussed. We also report the first F99 calibration for three reference stars in the BL Lac field. |
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| Keywords: | BL Lacertae objects: individual: BL Lacertae galaxies: photometry |
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