2013/02/18 by R. Edelson, R. Mushotzky, S. Vaughan +4 · 2 citations
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics and Cosmic Phenomena #Autocorrelation #BL Lac object #Flux (metallurgy) #Galaxies: Formation, Evolution, Phenomena #Kepler #Light curve #Measure (data warehouse) #Variable star #astro-ph.CO #astro-ph.HE
paper · pdf · doi:10.1088/0004-637x/766/1/16
12 pages, 7 figures, accepted for publication in ApJ, 2013 March 20 edition
arxiv created 2013/02/18 · openalex publication_date 2013/03/01 · arxiv updated 2014/09/08 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present the first Kepler monitoring of a strongly variable BL Lac, W2R1926+42. The light curve covers 181 days with ∼0.2% errors, 30 minute sampling and >90% duty cycle, showing numerous δ I / I > 25% flares over timescales as short as a day. The flux distribution is highly skewed and non-Gaussian. The variability shows a strong rms-flux correlation with the clearest evidence to date for nonlinearity in this relation. We introduce a method to measure periodograms from the discrete autocorrelation function, an approach that may be well-suited to a wide range of Kepler data. The periodogram is not consistent with a simple power-law, but shows a flattening at frequencies below 7 × 10 −5 Hz. Simple models of the power spectrum, such as a broken power law, do not produce acceptable fits, indicating that the Kepler blazar light curve requires more sophisticated mathematical and physical descriptions than currently in use.