Exploring the nature of the 2016 γ-ray emission in the blazar 1749+096

Dae Won Kim, Sascha Trippe, Sang Sung Lee, Jae Young Kim, Juan Carlos Algaba, Jeffrey Hodgson, Jongho Park, Motoki Kino, Guang Yao Zhao, Kiyoaki Wajima, Jee Won Lee, Sincheol Kang

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Recent Fermi-Large Area Telescope light curves indicate an active γ-ray state spanning about five months from 2016 June to 2016 October in the BL Lac object 1749+096 (OT 081). During this period, we find two notable γ-ray events: an exceptionally strong outburst followed by a significant enhancement (local peak). In this study, we analyze multi-waveband light curves (radio, optical, X-ray, and γ-ray) plus very long baseline interferometry (VLBI) data to investigate the nature of the γ-ray events. The γ-ray outburst coincides with flux maxima at longer wavelengths. We find a spectral hardening of the γ-ray photon index during the γ-ray outburst. The photon index shows a transition from a softer-when-brighter to a harder-whenbrighter trend at around 1.8×10-7 ph cm-2 s-1. We see indication that both the γ-ray outburst and the subsequent enhancement precede the propagation of a polarized knot in a region near the VLBI core. The highest polarized intensity, 230 mJy, and an electric vector position angle rotation, by ~32°, are detected about 12 days after the γ-ray outburst. We conclude that both γ-ray events are caused by the propagation of a disturbance in the mm-wave core.

Original languageEnglish
Pages (from-to)2324-2333
Number of pages10
JournalMonthly Notices of the Royal Astronomical Society
Volume480
Issue number2
DOIs
StatePublished - Oct 2018

Bibliographical note

Publisher Copyright:
© 2018 The Author(s).

Keywords

  • Galaxies: jets
  • Gamma rays: galaxies
  • Quasars: individual: OT 081
  • Radiation mechanisms: non-thermal

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