QUASI-PERIODIC OSCILLATIONS OF ∼15 MINUTES IN THE OPTICAL LIGHT CURVE OF THE BL LAC S5 0716+714

Abstract

Over the course of three hours on 27 December 2008 we obtained optical\n(R-band) observations of the blazar S5 0716+714 at a very fast cadence of 10 s.\nUsing several different techniques we find fluctuations with an approximately\n15-minute quasi-period to be present in the first portion of that data at a > 3\nsigma confidence level. This is the fastest QPO that has been claimed to be\nobserved in any blazar at any wavelength. While this data is insufficient to\nstrongly constrain models for such fluctuations, the presence of such a short\ntimescale when the source is not in a very low state seems to favor the action\nof turbulence behind a shock in the blazar's relativistic jet.\n