A harmonic analysis of the light variation of 3C273
Abstract
A 79.9yr photographic record of the light variation of 3C273 was sampled every 100 days to determine the harmonic content by Fourier transform methods. The variation is best described by a power density spectrum which is virtually flat at frequencies less than 0.12 cycles per year, with at most a weak and broad resonance centered at about 0.06 cycles per year. From 0.12 to 1.83 cydes per year the power spectral density drops off with the inverse square of the frequency. Although sinusoidal components were identified by periodogram analysis, their strength with respect to adjacent spectral components, as well as the effects of extending the observations in time, point to the presence of no outstanding periodicities.
 Publication:

The Astronomical Journal
 Pub Date:
 December 1967
 DOI:
 10.1086/110414
 Bibcode:
 1967AJ.....72.1341K