Enhanced Polarized Emission from the One-Parsec-Scale Hotspot of 3C 84 as a Result of the Interaction with Clumpy Ambient Medium

Abstract

We present Very Long Baseline Array polarimetric observations of the innermost jet of 3C$\sim$84 (NGC$\sim$1275) at 43$\sim$GHz. A significant polarized emission is detected at the hotspot of the innermost re-started jet, which is located $\sim$1 pc south from the radio core. While the previous report presented a hotspot at the southern end of the western limb, the hotspot location has been moved to the southern end of the eastern limb. Faraday rotation is detected within an entire bandwidth of the 43-GHz band. The measured rotation measure (RM) is at most (6.3$\pm$1.9)$\times 10^5$$\sim$rad$\sim$m${}^{-2}$ and might be slightly time variable on the timescale of a month by a factor of a few. Our measured RM and the RM previously reported by the CARMA and SMA observations cannot be consistently explained by the spherical accretion flow with a power-law profile. We propose that a clumpy/inhomogeneous ambient medium is responsible for the observed rotation measure. Using equipartition magnetic field, we derive the electron density of $2\times 10^4$$\sim$cm${}^{-3}$. Such an electron density is consistent with the cloud of narrow line emission region around the central engine. We also discuss the magnetic field configuration from black hole scale to pc scale and the origin of low polarization.

8 pages, 8 figures, accepted for publication in ApJ

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Cited by in corpus (19)

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• GPCAL: a generalized calibration pipeline for instrumental polarization in VLBI data
• RadioAstron discovery of a mini-cocoon around the restarted parsec-scale jet in 3C 84
• Jet kinematics in the transversely stratified jet of 3C 84 A two-decade overview
• The Dynamics and Energetics of Remnant and Restarting RLAGN
• A detailed kinematic study of 3C 84 and its connection to Gamma-rays
• Constraints on Circumnuclear Disk through Free-Free Absorption in the Nucleus of 3C 84 with KaVA and KVN at 43 and 86 GHz
• Evidence for a toroidal magnetic field in the core of 3C 84
• Polarization Observations of AGN Jets: Past and Future
• Diffuse Synchrotron Emission Associated with the Starburst in the Circumnuclear Disk of NGC 1275
• Probing the Heart of Active Narrow-line Seyfert 1 Galaxies with VERA Wideband Polarimetry
• Discovery of Radio Jets in Phoenix Galaxy Cluster Center
• Evolution, speed, and precession of the parsec-scale jet in the 3C 84 radio galaxy
• The Japanese Vision for the Black Hole Explorer Mission
• A revised view of the linear polarization in the subparsec core of M87 at 7 mm
• Where within the 3C 84 jet are $\gamma$-rays produced?