IAA authors:
Agudo, Iván;Fuentes, Antonio
Authors:
Hallum, Melissa K.;Jorstad, Svetlana G.;Larionov, Valeri M.;Marscher, Alan P.;Joshi, Manasvita;Weaver, Zachary R.;Williamson, Karen E.;Agudo, Iván;Borman, George A.;Casadio, Carolina;Fuentes, Antonio;Grishina, Tatiana S.;Kopatskaya, Evgenia N.;Larionova, Elena G.;Larionova, Liyudmila V.;Morozova, Daria A.;Nikiforova, Anna A.;Savchenko, Sergey S.;Troitsky, Ivan S.;Troitskaya, Yulia V.;Vasilyev, Andrey A.
Abstract:
We present multi-epoch optical spectra of the γ-ray bright blazar 1156+295 (4C +29.45, Ton 599) obtained with the 4.3 m Lowell Discovery Telescope. During a multiwavelength outburst in late 2017, when the γ-ray flux increased to 2.5 × 10-6 phot cm-2 s-1 and the quasar was first detected at energies ≥100 GeV, the flux of the Mg ii λ2798 emission line changed, as did that of the Fe emission complex at shorter wavelengths. These emission-line fluxes increased along with the highly polarized optical continuum flux, which is presumably synchrotron radiation from the relativistic jet, with a relative time delay of ≥22 weeks. This implies that the line-emitting clouds lie near the jet, which points almost directly toward the line of sight. The emission-line radiation from such clouds, which are located outside the canonical accretion-disk related broad-line region, may be a primary source of seed photons that are up-scattered to γ-ray energies by relativistic electrons in the jet.
URL:
https://ui.adsabs.harvard.edu/#abs/2022ApJ...926..180H/abstract