Variability of the Faraday Rotation Measure in the Parsec-scale Jet of AGN 1633+382

Fuente: arXiv
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Autores principales: Lai, Kah Chun, Marcos, Juan Carlos Algaba, Abidin, Zamri bin Zainal
Formato: Preprint
Publicado: 2025
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author Lai, Kah Chun
Marcos, Juan Carlos Algaba
Abidin, Zamri bin Zainal
author_facet Lai, Kah Chun
Marcos, Juan Carlos Algaba
Abidin, Zamri bin Zainal
contents We study the Faraday rotation measure (RM) variability of flat spectrum radio quasar 1633+382 on 5 epochs spanning from 2004 to 2008. We used 4 to 43~GHz VLBI polarization data from VLBA. Core RM across 4 to 15 GHz scales with a power index $a\sim2$, for $a$ in RM$\propto ν^a$. We detected sign changes across epochs, both in the core and in the jet region. RM time variability in the core and jet region are not correlated, hence limiting the size of a possible Faraday screen. We relate the core RM variability to a new component emerging from the core region. For the jet region, we consider the jet-medium interaction to be a less likely cause of the RM variability because of the uniform spectral index distribution. The observed RM value variation requires a huge fluctuation in electron density or magnetic field, hence a foreground Faraday screen is less favoured. We further discuss other possibilities of the RM variability based on jet kinematics.
format Preprint
id arxiv_https___arxiv_org_abs_2505_03602
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Variability of the Faraday Rotation Measure in the Parsec-scale Jet of AGN 1633+382
Lai, Kah Chun
Marcos, Juan Carlos Algaba
Abidin, Zamri bin Zainal
High Energy Astrophysical Phenomena
We study the Faraday rotation measure (RM) variability of flat spectrum radio quasar 1633+382 on 5 epochs spanning from 2004 to 2008. We used 4 to 43~GHz VLBI polarization data from VLBA. Core RM across 4 to 15 GHz scales with a power index $a\sim2$, for $a$ in RM$\propto ν^a$. We detected sign changes across epochs, both in the core and in the jet region. RM time variability in the core and jet region are not correlated, hence limiting the size of a possible Faraday screen. We relate the core RM variability to a new component emerging from the core region. For the jet region, we consider the jet-medium interaction to be a less likely cause of the RM variability because of the uniform spectral index distribution. The observed RM value variation requires a huge fluctuation in electron density or magnetic field, hence a foreground Faraday screen is less favoured. We further discuss other possibilities of the RM variability based on jet kinematics.
title Variability of the Faraday Rotation Measure in the Parsec-scale Jet of AGN 1633+382
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2505.03602