# University of Hertfordshire

## The resolved jet of 3C 273 at 150 MHz

Research output: Contribution to journalArticlepeer-review

### Standard

The resolved jet of 3C 273 at 150 MHz. / Harwood, Jeremy J.; Mooney, Sean; Morabito, Leah K.; Quinn, John; Sweijen, Frits; Groeneveld, Christian; Bonnassieux, Etienne; Kappes, Alexander; Moldon, Javier.

In: Astronomy & Astrophysics, 16.08.2021.

Research output: Contribution to journalArticlepeer-review

### Harvard

Harwood, JJ, Mooney, S, Morabito, LK, Quinn, J, Sweijen, F, Groeneveld, C, Bonnassieux, E, Kappes, A & Moldon, J 2021, 'The resolved jet of 3C 273 at 150 MHz', Astronomy & Astrophysics.

### APA

Harwood, J. J., Mooney, S., Morabito, L. K., Quinn, J., Sweijen, F., Groeneveld, C., Bonnassieux, E., Kappes, A., & Moldon, J. (2021). The resolved jet of 3C 273 at 150 MHz. Astronomy & Astrophysics.

### Vancouver

Harwood JJ, Mooney S, Morabito LK, Quinn J, Sweijen F, Groeneveld C et al. The resolved jet of 3C 273 at 150 MHz. Astronomy & Astrophysics. 2021 Aug 16.

### Author

Harwood, Jeremy J. ; Mooney, Sean ; Morabito, Leah K. ; Quinn, John ; Sweijen, Frits ; Groeneveld, Christian ; Bonnassieux, Etienne ; Kappes, Alexander ; Moldon, Javier. / The resolved jet of 3C 273 at 150 MHz. In: Astronomy & Astrophysics. 2021.

### Bibtex

@article{1f7d813b66054e7dac026d89c4a0a5cc,
title = "The resolved jet of 3C 273 at 150 MHz",
abstract = " Since its discovery in 1963, 3C273 has become one of the most widely studied quasars with investigations spanning the electromagnetic spectrum. While much has been discovered about this historically notable source, its low-frequency emission is far less well understood. Observations in the MHz regime have traditionally lacked the resolution required to explore small-scale structures that are key to understanding the processes that result in the observed emission. In this paper we use the first sub-arcsecond images of 3C273 at MHz frequencies to investigate the morphology of the compact jet structures and the processes that result in the observed spectrum. Using the full complement of LOFAR's international stations, we produce $0.31 \times 0.21$ arcsec images of 3C273 at 150 MHz to determine the jet's kinetic power, place constraints on the bulk speed and inclination angle of the jets, and look for evidence of the elusive counter-jet at 150 MHz. Using ancillary data at GHz frequencies, we fit free-free absorption (FFA) and synchrotron self-absorption (SSA) models to determine their validity in explaining the observed spectra. The images presented display for the first time that robust, high-fidelity imaging of low-declination complex sources is now possible with the LOFAR international baselines. We show that the main small-scale structures of 3C273 match those seen at higher frequencies and that absorption is present in the observed emission. We determine the kinetic power of the jet to be in the range of $3.5 \times 10^{43}$ - $1.5 \times 10^{44}$ erg s$^{-1}$ which agrees with estimates made using higher frequency observations. We derive lower limits for the bulk speed and Lorentz factor of $\beta \gtrsim 0.55$ and $\Gamma \geq 1.2$ respectively. The counter-jet remains undetected at $150$ MHz, placing a limit on the peak brightness of $S_\mathrm{cj\_150} < 40$ mJy beam$^{-1}$. ",
keywords = "astro-ph.GA, astro-ph.HE",
author = "Harwood, {Jeremy J.} and Sean Mooney and Morabito, {Leah K.} and John Quinn and Frits Sweijen and Christian Groeneveld and Etienne Bonnassieux and Alexander Kappes and Javier Moldon",
year = "2021",
month = aug,
day = "16",
language = "English",
journal = "Astronomy & Astrophysics",
issn = "0004-6361",
publisher = "EDP Sciences",

}

### RIS

TY - JOUR

T1 - The resolved jet of 3C 273 at 150 MHz

AU - Harwood, Jeremy J.

AU - Mooney, Sean

AU - Morabito, Leah K.

AU - Quinn, John

AU - Sweijen, Frits

AU - Groeneveld, Christian

AU - Bonnassieux, Etienne

AU - Kappes, Alexander

AU - Moldon, Javier

PY - 2021/8/16

Y1 - 2021/8/16

N2 - Since its discovery in 1963, 3C273 has become one of the most widely studied quasars with investigations spanning the electromagnetic spectrum. While much has been discovered about this historically notable source, its low-frequency emission is far less well understood. Observations in the MHz regime have traditionally lacked the resolution required to explore small-scale structures that are key to understanding the processes that result in the observed emission. In this paper we use the first sub-arcsecond images of 3C273 at MHz frequencies to investigate the morphology of the compact jet structures and the processes that result in the observed spectrum. Using the full complement of LOFAR's international stations, we produce $0.31 \times 0.21$ arcsec images of 3C273 at 150 MHz to determine the jet's kinetic power, place constraints on the bulk speed and inclination angle of the jets, and look for evidence of the elusive counter-jet at 150 MHz. Using ancillary data at GHz frequencies, we fit free-free absorption (FFA) and synchrotron self-absorption (SSA) models to determine their validity in explaining the observed spectra. The images presented display for the first time that robust, high-fidelity imaging of low-declination complex sources is now possible with the LOFAR international baselines. We show that the main small-scale structures of 3C273 match those seen at higher frequencies and that absorption is present in the observed emission. We determine the kinetic power of the jet to be in the range of $3.5 \times 10^{43}$ - $1.5 \times 10^{44}$ erg s$^{-1}$ which agrees with estimates made using higher frequency observations. We derive lower limits for the bulk speed and Lorentz factor of $\beta \gtrsim 0.55$ and $\Gamma \geq 1.2$ respectively. The counter-jet remains undetected at $150$ MHz, placing a limit on the peak brightness of $S_\mathrm{cj\_150} < 40$ mJy beam$^{-1}$.

AB - Since its discovery in 1963, 3C273 has become one of the most widely studied quasars with investigations spanning the electromagnetic spectrum. While much has been discovered about this historically notable source, its low-frequency emission is far less well understood. Observations in the MHz regime have traditionally lacked the resolution required to explore small-scale structures that are key to understanding the processes that result in the observed emission. In this paper we use the first sub-arcsecond images of 3C273 at MHz frequencies to investigate the morphology of the compact jet structures and the processes that result in the observed spectrum. Using the full complement of LOFAR's international stations, we produce $0.31 \times 0.21$ arcsec images of 3C273 at 150 MHz to determine the jet's kinetic power, place constraints on the bulk speed and inclination angle of the jets, and look for evidence of the elusive counter-jet at 150 MHz. Using ancillary data at GHz frequencies, we fit free-free absorption (FFA) and synchrotron self-absorption (SSA) models to determine their validity in explaining the observed spectra. The images presented display for the first time that robust, high-fidelity imaging of low-declination complex sources is now possible with the LOFAR international baselines. We show that the main small-scale structures of 3C273 match those seen at higher frequencies and that absorption is present in the observed emission. We determine the kinetic power of the jet to be in the range of $3.5 \times 10^{43}$ - $1.5 \times 10^{44}$ erg s$^{-1}$ which agrees with estimates made using higher frequency observations. We derive lower limits for the bulk speed and Lorentz factor of $\beta \gtrsim 0.55$ and $\Gamma \geq 1.2$ respectively. The counter-jet remains undetected at $150$ MHz, placing a limit on the peak brightness of $S_\mathrm{cj\_150} < 40$ mJy beam$^{-1}$.

KW - astro-ph.GA

KW - astro-ph.HE

M3 - Article

JO - Astronomy & Astrophysics

JF - Astronomy & Astrophysics

SN - 0004-6361

ER -