|Author||Rani, B. ♦ Wiita, P. J. ♦ Gupta, A. C.|
|Source||Aryabhatta Research Institute of Observational Sciences (ARIES)|
|Subject Domain (in DDC)||Natural sciences & mathematics ♦ Physics|
|Subject Keyword||BL Lacertae objects ♦ General – BL Lacertae objects ♦ Individual (AO 0235+164 ♦ 1ES 2321+419) –galaxies active|
|Abstract||We have performed a structure function analysis of the Rossi X-Ray Timing Explorer All-Sky Monitor data tosearch for variability in 24 blazars using data trains that each exceed 12 yr. Although 20 of them show nominalperiods through this technique, the great majority of these “periods” are clearly related to yearly variations arisingfrom the instrument. Nonetheless, an apparently real periodic component of about 17 days was detected for theblazar AO 0235+164 and it was confirmed by discrete correlation function and periodogram analyses. For 1ES2321+419, a component of variability with a near periodicity of about 420 days was detected by all of thesemethods. We discuss several possible explanations for these nearly periodic components and conclude that theymost likely arise from the intersections of a shock propagating down a relativistic jet that possesses a helical structure.|
|Description||This article published in the Astrophysical Journal in 10 May 2009|
|Education Level||UG and PG|
|Learning Resource Type||Article|
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