Connecting radio emission to AGN wind properties with broad absorption line quasars

Petley, James; Morabito, L. K.; Alexander, D. M.; Rankine, Amy L.; Fawcett, V. A.; Rosario, D. J.; Matthews, James H.; Shimwell, T.; Drabent, A.

doi:10.1093/mnras/stac2067

Cited by 10 publications

(1 citation statement)

References 90 publications

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“…These shocks may accelerate particles and produce synchrotron and inverse Compton emission [147]. Although there is no definitive detection, there are observational hints of quasar wind contributions to radio and gamma-ray emission [148][149][150][151]. Quasar winds might reach 𝑄 𝑘 ∼ 5 × 10 44 erg s −1 [147], if the outflow is 5% efficient compared to the bolometric power.…”

Section: Radio Galaxies and Agnmentioning

confidence: 99%

How, where and when do cosmic rays reach ultrahigh energies?

Matthews¹,

Taylor²

2023

Preprint

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Understanding the origins of ultrahigh energy cosmic rays (UHECRs) -which reach energies in excess of 10 20 eV -stretches particle acceleration physics to its very limits. In this review, we discuss how such energies can be reached, using general arguments that can often be derived on the back of an envelope. We explore possible particle acceleration mechanisms, with special attention paid to shock acceleration. Informed by the arguments derived, we discuss where UHECRs might come from and which classes of powerful astrophysical objects could be UHECR sources; generally, we favour radio galaxies, GRB afterglows and other sources which are not too compact and dissipate prodigious amounts of energy on large scales, allowing them to generate large products 𝛽𝐵𝑅 without the CRs undergoing restrictive losses. Finally, we discuss when UHECRs are accelerated by highlighting the importance of source variability, and explore the intriguing possibility that the UHECR arrival directions are partly a result of "echoes" from magnetic structures in the local Universe.

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Section: Radio Galaxies and Agnmentioning

confidence: 99%

How, where and when do cosmic rays reach ultrahigh energies?

Matthews¹,

Taylor²

2023

Preprint

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A panchromatic view of infrared quasars: excess star formation and radio emission in the most heavily obscured systems

Andonie

Alexander

Rosario

et al. 2022

Monthly Notices of the Royal Astronomical Society

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To understand the Active Galactic Nuclei (AGN) phenomenon and their impact on the evolution of galaxies, a complete AGN census is required; however, finding heavily obscured AGNs is observationally challenging. Here we use the deep and extensive multi-wavelength data in the COSMOS field to select a complete sample of 578 infrared (IR) quasars ($L_{\rm AGN,IR}>10^{45}\rm \: erg\: s^{-1}$) at z < 3, with minimal obscuration bias, using detailed UV-to-far-IR spectral energy distribution (SED) fitting. We complement our SED constraints with X-ray and radio observations to further investigate the properties of the sample. Overall, 322 of the IR quasars are detected by Chandra and have individual X-ray spectral constraints. From a combination of X-ray stacking and $L_{\rm 2-10\rm keV}$ – $L_{\rm 6\: \mu m}$ analyses, we show that the majority of the X-ray faint and undetected quasars are heavily obscured (many are likely Compton thick), highlighting the effectiveness of the mid-IR band to find obscured AGNs. We find that 355 (≈ 61 per cent) IR quasars are obscured ($N_{\rm H}>10^{22}\rm \: cm^{-2}$) and identify differences in the average properties between the obscured and unobscured quasars: (1) obscured quasars have star-formation rates ≈3 times higher than unobscured systems for no significant difference in stellar mass and (2) obscured quasars have stronger radio emission than unobscured systems, with a radio-loudness parameter $\approx 0.2 \rm \: dex$ higher. These results are inconsistent with a simple orientation model but in general agreement with either extreme host-galaxy obscuration towards the obscured quasars or a scenario where obscured quasars are an early phase in the evolution of quasars.

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A striking relationship between dust extinction and radio detection in DESI QSOs: evidence for a dusty blow-out phase in red QSOs

Fawcett,

Alexander,

Brodzeller

et al. 2023

Monthly Notices of the Royal Astronomical Society

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We present the first eight months of data from our secondary target programme within the ongoing Dark Energy Spectroscopic Instrument (DESI) survey. Our programme uses a mid-infrared and optical colour selection to preferentially target dust-reddened quasi-stellar objects (QSOs) that would have otherwise been missed by the nominal DESI QSO selection. So far, we have obtained optical spectra for 3038 candidates, of which ∼70 per cent of the high-quality objects (those with robust redshifts) are visually confirmed to be Type 1 QSOs, consistent with the expected fraction from the main DESI QSO survey. By fitting a dust-reddened blue QSO composite to the QSO spectra, we find they are well-fitted by a normal QSO with up to AV ∼ 4 mag of line-of-sight dust extinction. Utilizing radio data from the LOFAR Two-metre Sky Survey (LoTSS) DR2, we identify a striking positive relationship between the amount of line-of-sight dust extinction towards a QSO and the radio detection fraction, that is not driven by radio-loud systems, redshift and/or luminosity effects. This demonstrates an intrinsic connection between dust reddening and the production of radio emission in QSOs, whereby the radio emission is most likely due to low-powered jets or winds/outflows causing shocks in a dusty environment. On the basis of this evidence, we suggest that red QSOs may represent a transitional ‘blow-out’ phase in the evolution of QSOs, where winds and outflows evacuate the dust and gas to reveal an unobscured blue QSO.

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Connecting radio emission to AGN wind properties with broad absorption line quasars

Cited by 10 publications

References 90 publications

How, where and when do cosmic rays reach ultrahigh energies?

How, where and when do cosmic rays reach ultrahigh energies?

A panchromatic view of infrared quasars: excess star formation and radio emission in the most heavily obscured systems

A striking relationship between dust extinction and radio detection in DESI QSOs: evidence for a dusty blow-out phase in red QSOs

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