Modelling X-ray RMS spectra II: the ultrafast outflow of PDS 456

Härer, L.; Parker, M. L.; Joyce, Aoife; Igo, Z.; Alston, W. N.; Fürst, Felix; Lobban, A.; Matzeu, G. A.; Reeves, J. N.

doi:10.1093/mnras/staa3559

Cited by 8 publications

(10 citation statements)

References 38 publications

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“…This means that it is likely very degenerate with other parameters that have the same function, in this case the UFO ionisation/powerlaw flux correlation parameter 𝑐 UFO . The value of 𝑐 UFO here is 0.2-0.3, which is much lower than the values of 0.6 found in IRAS 13224-3809 (Parker et al 2020) and 0.5-1 in PDS 456 (Härer et al 2021). Secondly, we note that the Fe UFO line is much stronger here than in the other two sources.…”

Section: High Flux Average 𝐹 Var Spectrumcontrasting

confidence: 71%

“…We note in Section 4.1 that the UFO variance in 1H 0707-495 is significantly stronger than that observed in IRAS 13224-3809 and PDS 456 (Parker et al 2020;Härer et al 2021). The reason for this is not clear, but the relatively low value of the ionization correlation 𝑐 UFO suggests that it is not being driven by the UFO gas responding to the continuum.…”

Section: The Ultra-fast Outflowmentioning

confidence: 81%

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The nature of the extreme X-ray variability in the NLS1 1H 0707-495

Parker

Alston

Härer

et al. 2021

Monthly Notices of the Royal Astronomical Society

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We examine archival XMM-Newton data on the extremely variable narrow-line Seyfert 1 (NLS1) active galactic nucleus (AGN) 1H 0707-495. We construct fractional excess variance (Fvar) spectra for each epoch, including the recent 2019 observation taken simultaneously with eROSITA. We explore both intrinsic and environmental absorption origins for the variability in different epochs, and examine the effect of the photoionised emission lines from outflowing gas. In particular, we show that the unusual soft variability first detected by eROSITA in 2019 is due to a combination of an obscuration event and strong suppression of the variance at 1 keV by photoionised emission, which makes the variance below 1 keV appear more extreme. We also examine the variability on long timescales, between observations, and find that it is well described by a combination of intrinsic variability and absorption variability. We suggest that the typical extreme high frequency variability which 1H 0707-495 is known for is intrinsic to the source, but the large amplitude, low frequency variability that causes prolonged low-flux intervals is likely dominated by variable low-ionisation, low velocity absorption.

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Section: High Flux Average 𝐹 Var Spectrumcontrasting

confidence: 71%

Section: The Ultra-fast Outflowmentioning

confidence: 81%

The nature of the extreme X-ray variability in the NLS1 1H 0707-495

Parker

Alston

Härer

et al. 2021

Monthly Notices of the Royal Astronomical Society

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“…In Parker et al (2017) and Pinto et al (2018) we showed that the absorption lines from the UFO in IRAS 13224-3809 respond to the X-ray continuum, weakening as the flux rises in a manner consistent with ionisation of the gas. This has also been observed in PDS 456 (Parker et al 2018a;Härer et al 2021), 1H 0707-495 (Parker et al 2021;Xu et al 2021), and 30-60% of a sample of variable AGN observed with XMM-Newton (Igo et al 2020), suggesting it is a general property of UFOs. If the ionisation interpretation of these observations is correct, then a similar effect may be visible in the emission from winds.…”

Section: Ionisation Changesmentioning

confidence: 52%

“…PDS 456 is a low redshift (𝑧 = 0.184) radio quiet quasar, which hosts one of the earliest detected UFOs (Reeves et al 2003) and has clear evidence for multiple layers of absorption (Reeves et al 2016(Reeves et al , 2018Härer et al 2021). As well as the absorption, a strong, broad Fe emission line is present from ∼ 6-8 keV (rest frame).…”

Section: Pds 456mentioning

confidence: 99%

The X-ray disc/wind degeneracy in AGN

Parker

Matzeu

Matthews

et al. 2022

Monthly Notices of the Royal Astronomical Society

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Relativistic Fe K emission lines from accretion disks and from disk winds encode key information about black holes, and their accretion and feedback mechanisms. We show that these two processes can in principle produce indistinguishable line profiles, such that they cannot be disentangled spectrally. We argue that it is likely that in many cases both processes contribute to the net line profile, and their relative contributions cannot be constrained purely by Fe K spectroscopy. In almost all studies of Fe K emission to date, a single process (either disk reflection or wind Compton scattering) is assumed to dominate the total line profile. We demonstrate that fitting a single process emission model (pure reflection or pure wind) to a hybrid line profile results in large systematic biases in the estimates of key parameters, such as mass outflow rate and spin. We discuss various strategies to mitigate this effect, such as including high energy data covering the Compton hump, and the implications for future X-ray missions.

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“…As two individual samples, PDS 465 and PG 1211+143 are often referenced in previous works (e.g. Pounds et al 2003;2016;Reevies et al 2009;Härer et al 2021;Danehkar et al 2018). PDS 456, a radio-quiet quasar with a bolometric luminosity L bol ∼ 10 47 erg/s, was measured to show the UFOs launched with ∼50r s (Reevies et al 2009).…”

Section: Application To Ufosmentioning

confidence: 99%

Magnetohydrodynamic Winds Driven by the Line Force from the Standard Thin Disk around Supermassive Black Holes. I. The Case of Weak Magnetic Field

Yang,

Ablimit,

2021

Preprint

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The absorption lines with high blue-shifted velocities are frequently found in the ultraviolet (UV) and X-ray spectra of luminous active galactic nuclei (AGNs). This implies that the high-velocity winds/outflows are common in AGNs. In order to study the formation of high-velocity winds, especially ultra-fast outflows (UFOs), we perform two-dimensional magnetohydrodynamic (MHD) simulations. Initially, a magnetic field is set to be weaker than the gas pressure at disk surface. In our simulations, line force operates on the region like filaments, because the X-ray radiation from corona is shielded by dense gas in the inner region at some angle. The location of filaments changes with time and then the line-driven winds are in exposure to X ray and become highly ionized. Line force at UV bands does not directly drive the highly-ionized winds. In the sense of time average, the properties of high-velocity winds meet the formation condition of UFOs. Compared with line force, the function of magnetic field is negligible in directly driving winds. In the MHD model, the region around the rotational axis becomes magnetic-pressure-dominated, which prevents gases from spreading to higher latitudes and then enhances the gas column density at middle and low latitudes (20 o -70 o ). Higher column density is helpful to shield X-ray photons, which causes that line force is more effective in the MHD model than in the HD model. Higher-velocity winds with broader opening angle are produced in the MHD model.

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Modelling X-ray RMS spectra II: the ultrafast outflow of PDS 456

Cited by 8 publications

References 38 publications

The nature of the extreme X-ray variability in the NLS1 1H 0707-495

The nature of the extreme X-ray variability in the NLS1 1H 0707-495

The X-ray disc/wind degeneracy in AGN

Magnetohydrodynamic Winds Driven by the Line Force from the Standard Thin Disk around Supermassive Black Holes. I. The Case of Weak Magnetic Field

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