Jet opening angles and gamma-ray brightness of AGN
By A. Pushkarev, Y. Kovalev, M. Lister, T. Savolainen. 2009
208 citations recorded by the source corpus.
We have investigated the differences in apparent opening angles between the parsec-scale jets of the active galactic nuclei (AGN) detected by the Fermi Large Area Telescope (LAT) during its first three months of operations and those of non-LAT-detected AGN. We used 15.4 GHz VLBA observations of sources from the 2 cm VLBA MOJAVE program, a subset of which comprise the statistically complete flux density limited MOJAVE sample. We determined the apparent opening angles by analyzing transverse jet profiles from the data in the image plane and by applying a model fitting technique to the data in the (u,v) plane. Both methods provided comparable opening angle estimates. The apparent opening angles of gamma-ray bright blazars are preferentially larger than those of gamma-ray weak sources. At the same time, we have found the two groups to have similar intrinsic opening angle distributions, based on a smaller subset of sources. This suggests that the jets in gamma-ray bright AGN are oriented at preferentially smaller angles to the line of sight resulting in a stronger relativistic beaming. The intrinsic jet opening angle and bulk flow Lorentz factor are found to be inversely proportional, as predicted by standard models of compact relativistic jets. If a gas dynamical jet acceleration model is assumed, the ratio of the initial pressure of the plasma in the core region P_0 to the external pressure P_ext lies within the range 1.1 to 34.6, with a best fit estimate of P_0/P_ext=2.
Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics
View Paper: https://www.semanticscholar.org/paper/e856811a3180b63fff09b1c9e1868f7b14d17e83
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Citations in the corpus
- Relativistic beaming and gamma-ray brightness of blazars (2009, background): “This interpretation is compatible with the LAT-detected quasars having faster apparent jet speeds (Lister et al. 2009c), wider apparent jet opening angles (Pushkarev et al. 2009), and higher VLBI brightness temperatures (Kovalev et al. 2009).”
- LOCATION OF γ-RAY FLARE EMISSION IN THE JET OF THE BL LACERTAE OBJECT OJ287 MORE THAN 14 pc FROM THE CENTRAL ENGINE (2010, background): “From the angle of the jet axis to the line of sight in OJ287 (1◦.9–4◦.1; see Jorstad et al. 2005; Pushkarev et al. 2009), and the mean projected separation of C1 from C0 at the time of start of Amm and Bmm (0.23±0.01mas), we estimate that C1 is located> 14 pc downstream of C0, the innermost jet…”
- MOJAVE. X. PARSEC-SCALE JET ORIENTATION VARIATIONS AND SUPERLUMINAL MOTION IN ACTIVE GALACTIC NUCLEI (2013, background): “Since the full opening angles of powerful blazar jets are typically less than two degrees (Jorstad et al. 2005; Pushkarev et al. 2009), and most blazar jets in a flux density-limited sample will be viewed at approximately 1/2 the critical superluminal motion angle (Vermeulen & Cohen 1994), examples…”
- Kinematics of Parsec-scale Jets of Gamma-Ray Blazars at 43 GHz within the VLBA-BU-BLAZAR Program (2017, methodology): “A wider opening angle in BLLacs with respect to FSRQs was reported by Pushkarev et al. (2009) in the MOJAVE sample.”
- Reconnection-driven plasmoids in blazars: fast flares on a slow envelope (2012, methodology): “The observational indications that the jet opening angle is related to the jet Lorentz factor through the relationθ jΓ j ∼ 0.2 (Pushkarev et al. 2009) implies that causal contact is established in the transverse direction of a high-σ jet.”
- MOJAVE: Monitoring of Jets in Active galactic nuclei with VLBA Experiments (2012, background): “◦6 (Pushkarev et al. 2009),rcore= 13.2 pc,Rcore= 0.35 pc.”