Constraints on the Location of the Gamma-ray Emission Region for the Gamma-ray-loud Radio Source GB 1310+487

Abstract

We employ a single-zone leptonic jet model, with synchrotron, synchrotron self-Compton (SSC) and external Compton (EC) process, to reproduce the quasi-simultaneous multi-wavelength spectral energy distributions in active and quiescent states of the narrow-line gamma-ray-loud radio source GB 1310+487. In the case of the EC process, the external seed photons from both broad line region (BLR) and dust torus are considered by assuming that the gamma-ray emission region is located at the outside boundary of the BLR and inside the dust torus. Comparing the energy density of external photon fields U BLR obtained by model fitting with that constrained from the BLR observations. We find that the location of the gamma-ray emitting region of GB 1310+487 can be tightly constrained at the outer edge of the BLR (the dissipation distance of the γ-ray emission region from central black hole r diss ∼ a few times of R BLR ). The ratio of magnetic energy and emitting-electron energy in the radiation blob (ǫ B = L B /L e ) is gradually increased from Flare 1, Flare 2 to Post-Flare, where the magnetic energy increase and matter energy decrease. These results suggest that the conversion of the magnetic field and the matter (radiation electrons) energy and the location of the γ-ray emission region (or ambient photon field) may play an important role in different radiation states of GB 1310+487.

Evaluating the Classification of Fermi BCUs from the 4FGL Catalog Using Machine Learning

“…This indicates the FSRQ jet has a complex external physical environment, which may lead to complex physical properties in Fermi energy bands (e.g., see Kang et al 2019 for similar discussions). For instance, the photon spectral index of FSRQs is greater than that the index of BL Lacs (see Abdo et al 2010b;Ackermann et al 2011Ackermann et al , 2015 The Fermi-LAT collaboration 2019a,b) which may be the result of the spectrum being superposed with other spectra components for the FSRQs (e.g., Zheng & Kang 2013;Kang et al 2014;Zheng et al 2016;Kang et al 2016;Kang 2017). Therefore, the Fermi band of FSRQs, located at the intersection of both the SSC component and the EC component, may result in more complex observational features (e.g., a hard spectrum, Abdo et al 2009Abdo et al , 2010bAckermann et al 2011Ackermann et al , 2015.…”

The Fourth Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope

“…2 , where N is the number of observed data points; dof is the degrees of freedom, i.e., the number of free parameters used for the model; Theŷ i denotes the expected values from the model; and y i denotes the observed data (Ivezić et al 2014;Massaro et al 2004a). In addition, σ represents the uncertainty of the parameter in Table 1, which can be calculated by the error transfer formula according to the equation (Feigelson & Babu 2012)…”

On the origin of GeV spectral break for Fermi blazars: 3C 454.3

“…In the current study, the conventional one-zone synchrotron + inverse Compton model is employed to fit the SED of 3C 454.3, a model that has been extensively utilized in blazars (see Ghisellini et al 2010 and references in). The model has been employed in our previous works (see Kang et al 2014bKang et al , 2016Kang 2017). A homogeneous sphere with radius R installed in a magnetic field B is considered.…”

“…According to newly published studies, the -ray radiation area of blazar jets should be placed at about the outer border of (or beyond) the BLR and in the dust tours (e.g., Böttcher & Els 2016;Kang 2017;Shah et al 2017;Zheng et al 2017;MAGIC Collaboration et al 2018;H. E. S. S. Collaboration et al 2019;Traianou et al 2020), where portions of both BLR and torus photons should be provided to illustrate the detected -ray spectrum.…”