Muitiwavelengths observations of lensed quasars: Interband time delays

E. Koptelova, V. Oknyanskij, B. Artamonov, W. P. Chen

Research output: Contribution to journalConference articlepeer-review

3 Scopus citations


The time delays between brightness variations in two different optical bands have been measured for a large number of low-redshift AGN and nonlensed quasars. These time delays represent a light travel time between two different emission regions and can be used to test variability mechanisms in the source. We search for the interband delays in a sample of lensed quasars: Q2237+0305, SBS1520+530, HE2149-2745, HE1104-1805, UM673 in the redshift range 1.7 ≲ z ≲ 2.7. From cross-correlation analysis of light curves of the quasars we find that the brightness variations at longer wavelengths may follow the brightness variations at shorter wavelengths. The observed delays are consistent with the delays expected from reprocessing in accretion disc irradiated by the central variable source.

Original languageEnglish
Pages (from-to)138-143
Number of pages6
JournalMemorie della Societa Astronomica Italiana, Supplementi - Journal of the Italian Astronomical Society, Supplement
Issue number1
StatePublished - 2010
Event8th International Workshop on Multifrequency Behaviour of High Energy Cosmic Sources - Vulcano, Sicily, Italy
Duration: 25 May 200930 May 2009


  • Quasars: accretion discs
  • Quasars: gravitational lensing
  • Quasars: observations


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