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      https://www.ias.ac.in/article/fulltext/joaa/032/01-02/0239-0242

    • Keywords

       

      Gamma-rays; quasars: 1633+382(4C+38.41); radio jets; polarization.

    • Abstract

       

      We perform monthly monitoring of the quasar 1633+382 (4C+38.41) within a sample of 𝛾-ray blazars with the VLBA at 43 GHz along with optical photometric and polarimetric observations. We construct the 𝛾-ray light curve of 1633+382 using data obtained by the Fermi LAT. We find that a high 𝛾-ray state of the quasar starting in 2009 September is simultaneous with an increase of the flux in the mm-wave VLBI core. We resolve a superluminal feature on the VLBA images that appears to be responsible for the mm-wave flux increase. We find a strong correlation between optical and 𝛾-ray light curves with a delay of 𝛾-ray variations of 5 ± 3 days, as well as a strong correlation between optical flux and degree of polarization during the high 𝛾-ray state. Comparison between the optical polarization position angle and that in the VLBI core supports the idea that in the quasar 1633+382 a high 𝛾-ray state is connected with processes originating near the mm-VLBI core.

    • Author Affiliations

       

      S. G. Jorstad1 2 A. P. Marscher1 I. Agudo1 P. S. Smith3 V. M. Larionov2 A. Lähteenmäki4

      1. IAR, Boston U., 725 Commonwealth Ave., Boston, MA 02215, USA.
      2. St.Petersburg State U., Petrodvorets, 198504 St. Petersburg, Russia.
      3. Steward Obs., University of Arizona, Tucson, AZ 85721, USA.
      4. Metsähovi Radio Obs., Aalto U., FIN-02540 Kylmälä, Finland.
    • Dates

       
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