Emission-line Variability during a Nonthermal Outburst in the Gamma-Ray Bright Quasar 1156+295
M. K. HallumInstitute for Astrophysical Research, Boston University, 725 Commonwealth Avenue, Boston, MA 02215, USA; [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]Svetlana G. JorstadInstitute for Astrophysical Research, Boston University, 725 Commonwealth Avenue, Boston, MA 02215, USA; [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]V. M. LarionovPulkovo Observatory, St.-Petersburg, 196140, RussiaAlan P. MarscherInstitute for Astrophysical Research, Boston University, 725 Commonwealth Avenue, Boston, MA 02215, USA; [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]M. JoshiInstitute for Astrophysical Research, Boston University, 725 Commonwealth Avenue, Boston, MA 02215, USA; [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]Z. R. WeaverInstitute for Astrophysical Research, Boston University, 725 Commonwealth Avenue, Boston, MA 02215, USA; [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]Karen E. WilliamsonInstitute for Astrophysical Research, Boston University, 725 Commonwealth Avenue, Boston, MA 02215, USA; [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]I. AgudoInstituto de Astrofísica de Andalucía, CSIC, Apartado 3004, E-18080 Granada, Spain; [email protected], [email protected]Г. А. БорманCrimean Astrophysical Observatory RAS, P/O Nauchny, 298409, Russia; [email protected]C. CasadioDepartment of Physics, University of Crete, 71003, Heraklion, GreeceAntonio FuentesInstituto de Astrofísica de Andalucía, CSIC, Apartado 3004, E-18080 Granada, Spain; [email protected], [email protected]T. S. GrishinaSobolev Astronomical Institute, St. Petersburg State University, St. Petersburg, Russia; [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]E. N. KopatskayaSobolev Astronomical Institute, St. Petersburg State University, St. Petersburg, Russia; [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]Е. Г. ЛарионоваSobolev Astronomical Institute, St. Petersburg State University, St. Petersburg, Russia; [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]Liyudmila V. LarionovaSobolev Astronomical Institute, St. Petersburg State University, St. Petersburg, Russia; [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]D. A. MorozovaSobolev Astronomical Institute, St. Petersburg State University, St. Petersburg, Russia; [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]A. A. NikiforovaSobolev Astronomical Institute, St. Petersburg State University, St. Petersburg, Russia; [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]С. С. СавченкоPulkovo Observatory, St.-Petersburg, 196140, RussiaI. S. TroitskySobolev Astronomical Institute, St. Petersburg State University, St. Petersburg, Russia; [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]Yu. V. TroitskayaSobolev Astronomical Institute, St. Petersburg State University, St. Petersburg, Russia; [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]A. A. VasilyevSobolev Astronomical Institute, St. Petersburg State University, St. Petersburg, Russia; [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]
2022en
ABI
Abstract
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 λ 2798 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 ≲2 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.
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