A New Relativistic Component of the Accretion Disk Wind in PDS 456

Reeves, J. N.; Braito, V.; Nardini, E.; Lobban, A.; Matzeu, G. A.; Costa, M.

doi:10.3847/2041-8213/aaaae1

Cited by 68 publications

(102 citation statements)

References 34 publications

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“…The Fe K absorber Abs1 is observed in both XMM-Newton observations and is consistent with a Fe xxv. Abs2, a candidate UFO, is characterised by a mildly outflowing velocity (v out =(0.23±0.03)c) and its ionisation and column density are compatible with what often observed for UFOs (Tombesi et al 2011;Parker et al 2017;Reeves et al 2018;Parker et al 2018;Braito et al 2018;Serafinelli et al 2019;Matzeu et al 2019).…”

Section: Conclusion and Summarysupporting

confidence: 80%

A broadband X-ray view of the NLSy1 1E 0754.6+3928

Middei

Tombesi

Vagnetti

et al. 2020

A&A

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Context. The soft X-ray band of many active galactic nuclei (AGN) is affected by obscuration due to partially ionised matter crossing our line of sight. In this context, two past XMM-Newton observations (6 months apart) and a simultaneous NuSTAR-Swift (∼8 years later) exposure of the Narrow Line Seyfert 1 galaxy 1E 0754.6+392.8 revealed an intense and variable WA and hints of additional absorbers in the Fe Kα band. Aims. We aim at providing the first X-ray characterisation of this AGN discussing its broadband (0.3-79 keV) spectrum and temporal properties. Methods. We conduct a temporal and spectroscopic analysis on two ∼10 ks (net exposure) XMM-Newton snapshots performed in April and October 2006. We also study the high energy behaviour of 1E 0754.6+392.8 modelling its broadband spectrum using simultaneous Swift-NuSTAR data. Both phenomenological and physically motivated models are tested. Results. We find the presence of flux variability (∼150% and 30% for 0.3-2 and 2-10 keV bands, respectively) and spectral changes at months timescales (∆Γ ∼0.4). A reflection component that is consistent with being constant over years and arising from relatively cold material far from the central super massive black hole is detected. The main spectral feature shaping the 1E 0754.6+392.8 spectrum is a warm absorber. Such a component is persistent over the years and variability of its ionisation and column density is observed down on months in the ranges 3×10 22 cm −2 N H 7.2 × 10 22 cm −2 and 1.5 log(ξ/erg s −1 cm) 2.1. Despite the short exposures, we find possible evidence of two additional high-ionisation and high-velocity outflow components in absorption. Conclusions. Our analysis suggests the existence of a complex system of absorbers in 1E 0754.6+392.8. Longer exposures are mandatory in order to characterise, on more solid grounds, the absorbers in this AGN.

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Section: Conclusion and Summarysupporting

confidence: 80%

A broadband X-ray view of the NLSy1 1E 0754.6+3928

Middei

Tombesi

Vagnetti

et al. 2020

A&A

Self Cite

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“…Interestingly, evidences for velocities ≥ 0.4 − 0.5c have indeed already been reported for some high luminosity quasars, such as PDS 456 and APM 08279+5255 (see e.g. Reeves et al 2018;Chartas et al 2009). Figure 5 shows the ratio between the relativistic-corrected mass loss rate,Ṁ rel out , and the mass accretion rateṀ acc , as a function of λ Edd ≡ L bol /L Edd , i.e., the ratio between bolometric and Eddington luminosities.…”

Section: Discussionsupporting

confidence: 52%

The importance of special relativistic effects in modelling ultra-fast outflows

Luminari

Tombesi

Piconcelli

et al. 2020

A&A

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Context. Outflows are observed in a variety of astrophysical sources. Remarkably, ultra-fast (v ≥ 0.1c), highly ionised outflows in the UV and X-ray bands are often seen in Active Galactic Nuclei (AGNs). Depending on their kinetic power and mass outflow rate, respectivelyĖ out ,Ṁ out , such outflows may play a key role in regulating the AGN-host galaxy co-evolution process through cosmic time and metal-feeding the surrounding CGM/IGM. It is therefore crucial to provide accurate estimates of the wind properties, includinġ M out ,Ė out . Aims. Here, we concentrate on special relativistic effects concerning the interaction of light with matter moving at relativistic speed relatively to the source of radiation. Our aim is to assess the impact of these effects on the observed properties of the outflows and implement a correction for these effects in the existing spectral modelling routines. Methods. We define a simple procedure to incorporate relativistic effects in radiative transfer codes. Following this procedure, we run a series of simulations to explore the impact of relativistic effects for different outflow velocities and column densities. Results. The observed optical depth of the wind is usually considered a proxy for its column density N H , independently on the velocity of the outflow. However, our simulations show that the observed optical depth of an outflow with a given column density N H decreases rapidly as the velocity of the wind approaches relativistic values. This, in turn, implies that when estimating N H from the optical depth, it is necessary to include a velocity-dependent correction, already for moderate velocities (e.g. v out > ∼ 0.05c). This correction linearly propagates to the derived quantitiesṀ out ,Ė out . Conclusions. We demonstrate that special relativistic effects must be considered in order to obtain correct estimates ofṀ out anḋ E out for an outflow moving at mildly relativistic speed relatively to the illuminating source of radiation. As an example we calculate the relativistically corrected values ofṀ out andĖ out for a sample of ∼ 30 Ultra-Fast Outflows (UFOs) taken from the literature and find correction factors of 20 − 120% within the observed range of outflowing velocities (v out ≈ 0.1 − 0.3c). This brings the ratio betweenṀ out and the disk accretion rate close or even above unity for the vast majority of the sources of the sample, highlighting the importance of the reported relativistic corrections to understand the growth of the most massive black holes. The upcoming next generation of high sensitivity X-ray telescopes such as XRISM and Athena will provide a much more complete census of UFOs, especially in the fastest velocity regime where the relativistic corrections are increasingly important.

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“…This persistent UFO was also identified in Suzaku observations, via an absorption feature near 9 keV corresponding to a Compton-thick and clumpy wind of velocity v out = −0.25-−0.30c (Reeves et al 2009). Rapid variability of the high velocity iron K-shell absorption lines may result from wind clumpiness Reeves et al 2016). The spectral variability of PDS 456 can be explained by the variations in the partial covering absorber observed in most of the data (e.g.…”

Section: Introductionmentioning

confidence: 99%

Relativistic Components of the Ultra-fast Outflow in the Quasar PDS 456 from Chandra/HETGS, NuSTAR, and XMM-Newton Observations

Boissay-Malaquin

Danehkar

Marshall

et al. 2019

ApJ

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We present the spectral analysis of Chandra/HETGS and NuSTAR observations of the quasar PDS 456 from 2015, and XMM-Newton and NuSTAR archival data from 2013-2014, together with Chandra/HETGS data from 2003. We analyzed these three different epochs in a consistent way, looking for absorption features corresponding to highly ionized blueshifted absorption lines from H-like and He-like ions of iron (and nickel), as well as of other elements (O, Ne, Si, and S) in the soft band. We confirm the presence of a persistent ultrafast outflow (UFO) with a velocity of v out = −0.24-−0.29c, previously detected. We also report the detection of an additional faster component of the UFO with a relativistic velocity of v out = −0.48c. We implemented photoionization modeling, using XSTAR analytic model warmabs, to characterize the physical properties of the different kinematic components of the ultra-fast outflow and of the partial covering absorber detected in PDS 456. These two relativistic components of the ultra-fast outflow observed in the three epochs analyzed in this paper are powerful enough to impact the host galaxy of PDS 456 through AGN feedback.

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A New Relativistic Component of the Accretion Disk Wind in PDS 456

Cited by 68 publications

References 34 publications

A broadband X-ray view of the NLSy1 1E 0754.6+3928

A broadband X-ray view of the NLSy1 1E 0754.6+3928

The importance of special relativistic effects in modelling ultra-fast outflows

Relativistic Components of the Ultra-fast Outflow in the Quasar PDS 456 from Chandra/HETGS, NuSTAR, and XMM-Newton Observations

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