Parsec-scale evolution of the gigahertz-peaked spectrum quasar PKS 0858-279
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| Autores principales: | , , , |
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| Formato: | Preprint |
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2024
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| _version_ | 1866910294981214208 |
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| author | Kosogorov, N. A. Kovalev, Y. Y. Perucho, M. Kovalev, Yu. A. |
| author_facet | Kosogorov, N. A. Kovalev, Y. Y. Perucho, M. Kovalev, Yu. A. |
| contents | We conducted multi-epoch, multi-frequency parsec-scale studies on the gigahertz-peaked spectrum quasar PKS 0858-279 with the Very Long Baseline Array (VLBA). Our observations on 2005-11-26 elucidated a weak core, characterized by an inverted spectrum, and a distinctly bent jet that exhibited a notable bright feature in its Stokes I emission. Through comprehensive analysis of polarization and spectral data, we inferred the formation of a shock wave within this feature, stemming from interactions with a dense cloud in the ambient medium. In this paper, VLBI-Gaia astrometry further reinforces the core identification. With a deep analysis of six additional VLBA epochs spanning from 2007 to 2018, we observed that while the quasar's parsec-scale structure remained largely consistent, there were discernible flux density changes. These variations strongly imply the recurrent ejection of plasma into the jet. Complementing our VLBA data, RATAN-600 observations of the integrated spectra suggested an interaction between standing and travelling shock waves in 2005. Moreover, our multi-epoch polarization analysis revealed a drastic drop in rotation measure values from 6000 rad/m^2 to 1000 rad/m^2 within a single year, attributable to diminishing magnetic fields and particle density in an external cloud. This change is likely instigated by a shock in the cloud, triggered by the cloud's interaction with the jet, subsequently prompting its expansion. Notably, we also observed a significant change in the magnetic field direction of the jet, from being perpendicular post its observed bend to being perpendicular prior to the bend - an alteration possibly induced by the dynamics of shock waves. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2401_03603 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Parsec-scale evolution of the gigahertz-peaked spectrum quasar PKS 0858-279 Kosogorov, N. A. Kovalev, Y. Y. Perucho, M. Kovalev, Yu. A. Astrophysics of Galaxies High Energy Astrophysical Phenomena We conducted multi-epoch, multi-frequency parsec-scale studies on the gigahertz-peaked spectrum quasar PKS 0858-279 with the Very Long Baseline Array (VLBA). Our observations on 2005-11-26 elucidated a weak core, characterized by an inverted spectrum, and a distinctly bent jet that exhibited a notable bright feature in its Stokes I emission. Through comprehensive analysis of polarization and spectral data, we inferred the formation of a shock wave within this feature, stemming from interactions with a dense cloud in the ambient medium. In this paper, VLBI-Gaia astrometry further reinforces the core identification. With a deep analysis of six additional VLBA epochs spanning from 2007 to 2018, we observed that while the quasar's parsec-scale structure remained largely consistent, there were discernible flux density changes. These variations strongly imply the recurrent ejection of plasma into the jet. Complementing our VLBA data, RATAN-600 observations of the integrated spectra suggested an interaction between standing and travelling shock waves in 2005. Moreover, our multi-epoch polarization analysis revealed a drastic drop in rotation measure values from 6000 rad/m^2 to 1000 rad/m^2 within a single year, attributable to diminishing magnetic fields and particle density in an external cloud. This change is likely instigated by a shock in the cloud, triggered by the cloud's interaction with the jet, subsequently prompting its expansion. Notably, we also observed a significant change in the magnetic field direction of the jet, from being perpendicular post its observed bend to being perpendicular prior to the bend - an alteration possibly induced by the dynamics of shock waves. |
| title | Parsec-scale evolution of the gigahertz-peaked spectrum quasar PKS 0858-279 |
| topic | Astrophysics of Galaxies High Energy Astrophysical Phenomena |
| url | https://arxiv.org/abs/2401.03603 |