The SMARTS Multi-epoch Optical Spectroscopy Atlas (SAMOSA): Using Emission Line Variability to Probe the Location of the Blazar Gamma-emitting Region

Abstract

We present multi-epoch optical spectroscopy of seven southern Fermi-monitored blazars from 2008 - 2013 using the Small and Medium Aperture Research Telescope System (SMARTS), with supplemental spectroscopy and polarization data from the Steward Observatory. We find that the emission lines are much less variable than the continuum; 4 of 7 blazars had no detectable emission line variability over the 5 years. This is consistent with photoionization primarily by an accretion disk, allowing us to use the lines as a probe of disk activity. Comparing optical emission line flux with Fermi $\gamma$-ray flux and optical polarized flux, we investigate whether relativistic jet variability is related to the accretion flow. In general, we see no such dependence, suggesting the jet variability is likely caused by internal processes like turbulence or shock acceleration rather than a variable accretion rate. However, three sources showed statistically significant emission line flares in close temporal proximity to very large Fermi $\gamma$-ray flares. While we do not have sufficient emission line data to quantitatively assess their correlation with the $\gamma$-ray flux, it appears that in some cases, the jet might provide additional photoionizing flux to the broad line region, which implies some gamma-rays are produced within the broad line region, at least for these large flares.

15 pages, 15 figures, Accepted to the Astrophysical Journal

References in corpus (4)

• Probing the Inner Jet of the Quasar PKS 1510-089 with Multi-waveband Monitoring during Strong Gamma-ray Activity
• Bright AGN Source List from the First Three Months of the Fermi Large Area Telescope All-Sky Survey
• Modeling the Emission Processes in Blazars
• GeV breaks in blazars as a result of gamma-ray absorption within the broad-line region

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• Characterizing the Gamma-Ray Variability of the Brightest Flat Spectrum Radio Quasars Observed with the Fermi LAT
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• Multiwavelength variability study and search for periodicity of PKS 1510-089
• The vanishing of the primary emission region in PKS 1510-089
• An extensive study of blazar broad emission line: Changing-look blazars and Baldwin effect
• Blazars at Very High Energies: Emission Modelling
• Long-term optical spectroscopic variations in blazar 3C 454.3
• Emission Line Variability during a Nonthermal Outburst in the Gamma-Ray Bright Quasar 1156+295
• Locating the GeV Emission Region in the Jets of Blazars from Months-Timescale Multi-Wavelength Outbursts
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• Multi-wavelength observations of the Blazar 4C +28.07
• 20 years of monitoring: PKS 2155-304 and PKS 1510-089 in the eyes of Swift and Fermi. II. PKS 1510-089 and comparison