The X-ray spectra of many active galactic nuclei (AGNs) show a soft X-ray excess below 1–2 keV on top of the extrapolated high-energy power law. The origin of this component is uncertain. It could be ...a signature of relativistically blurred, ionized reflection or the high-energy tail of thermal Comptonization in a warm (kT ~ 1 keV), optically thick (τ ≃ 10–20) corona producing the optical/UV to soft X-ray emission. The purpose of the present paper is to test the warm corona model on a statistically significant sample of unabsorbed, radio-quiet AGNs with XMM-Newton archival data, providing simultaneous optical/UV and X-ray coverage. The sample has 22 objects and 100 observations. We use two thermal Comptonization components to fit the broadband spectra, one for the warm corona emission and one for the high-energy continuum. In the optical/UV, we also include the reddening, the small blue bump, and the Galactic extinction. In the X-rays, we include a warm absorber and a neutral reflection. The model gives a good fit (reduced χ2 < 1.5) to more than 90% of the sample. We find the temperature of the warm corona to be uniformly distributed in the 0.1–1 keV range, while the optical depth is in the range ~10–40. These values are consistent with a warm corona covering a large fraction of a quasi-passive accretion disk, i.e., that mostly reprocesses the warm corona emission. The disk intrinsic emission represents no more than 20% of the disk total emission. According to this interpretation, most of the accretion power would be released in the upper layers of the accretion flow.
ABSTRACT
Using the results of a previous X‐ray photoionization modelling of blueshifted Fe K absorption lines on a sample of 42 local radio‐quiet AGNs observed with XMM–Newton, in this Letter we ...estimate the location and energetics of the associated ultrafast outflows (UFOs). Due to significant uncertainties, we are essentially able to place only lower/upper limits. On average, their location is in the interval ∼0.0003–0.03 pc (∼ 102–104rs) from the central black hole, consistent with what is expected for accretion disc winds/outflows. The mass outflow rates are constrained between ∼0.01 and 1 M⊙ yr−1, corresponding to >rsim5–10 per cent of the accretion rates. The average lower/upper limits on the mechanical power are log 42.6–44.6 erg s−1. However, the minimum possible value of the ratio between the mechanical power and bolometric luminosity is constrained to be comparable or higher than the minimum required by simulations of feedback induced by winds/outflows. Therefore, this work demonstrates that UFOs are indeed capable to provide a significant contribution to the AGN cosmological feedback, in agreement with theoretical expectations and the recent observation of interactions between AGN outflows and the interstellar medium in several Seyfert galaxies.
The existence of ionized X-ray absorbing layers of gas along the line of sight to the nuclei
of Seyfert galaxies is a well established observational fact. This material is systematically
outflowing ...and shows a large range in parameters. However, its actual nature and dynamics
are still not clear. In order to gain insights into these important issues we performed a literature
search for papers reporting the parameters of the soft X-ray warm absorbers (WAs) in 35 type
1 Seyferts and compared their properties to those of the ultra-fast outflows (UFOs) detected in
the same sample. The fraction of sources with WAs is >60 per cent, consistent with previous
studies. The fraction of sources with UFOs is >34 per cent, >67 per cent of which also
show WAs. The large dynamic range obtained when considering all the absorbers together,
spanning several orders of magnitude in ionization, column, velocity and distance allows us,
for the first time, to investigate general relations among them. In particular, we find significant
correlations indicating that the closer the absorber is to the central black hole, the higher the
ionization, column, outflow velocity and consequently the mechanical power. In all the cases,
the absorbers continuously populate the whole parameter space, with the WAs and the UFOs
lying always at the two ends of the distribution. These evidence strongly suggest that these
absorbers, often considered of different types, could actually represent parts of a single large-scale
stratified outflow observed at different locations from the black hole. The UFOs are likely
launched from the inner accretion disc and the WAs at larger distances, such as the outer disc
and/or torus. We argue that the observed parameters and correlations are, to date, consistent
with both radiation pressure through Compton scattering and magnetohydrodynamic processes
contributing to the outflow acceleration, the latter playing a major role. Most of the absorbers,
especially the UFOs, show a sufficiently high mechanical power (at least approx 0.5 per cent of the
bolometric luminosity) to provide a significant contribution to active galactic nuclei (AGN)
feedback and thus to the evolution of the host galaxy. In this regard, we find possible evidence
for the interaction of the AGN wind with the surrounding environment on large scales.
Recent X-ray observations show absorbing winds with velocities up to mildly relativistic values of the order of ∼0.1c in a limited sample of six broad-line radio galaxies. They are observed as ...blueshifted Fe xxv–xxvi K-shell absorption lines, similarly to the ultrafast outflows (UFOs) reported in Seyferts and quasars. In this work we extend the search for such Fe K absorption lines to a larger sample of 26 radio-loud active galactic nuclei (AGN) observed with XMM–Newton and Suzaku. The sample is drawn from the Swift Burst Alert Telescope 58-month catalogue and blazars are excluded. X-ray bright Fanaroff–Riley Class II radio galaxies constitute the majority of the sources. Combining the results of this analysis with those in the literature we find that UFOs are detected in >27 per cent of the sources. However, correcting for the number of spectra with insufficient signal-to-noise ratio, we can estimate that the incidence of UFOs is this sample of radio-loud AGN is likely in the range f ≃ (50 ± 20) per cent. A photoionization modelling of the absorption lines with xstar allows us to estimate the distribution of their main parameters. The observed outflow velocities are broadly distributed between v
out ≲ 1000 km s−1 and v
out ≃ 0.4c, with mean and median values of v
out ≃ 0.133c and v
out ≃ 0.117c, respectively. The material is highly ionized, with an average ionization parameter of logξ ≃ 4.5 erg s−1 cm, and the column densities are larger than N
H > 1022 cm−2. Overall, these characteristics are consistent with the presence of complex accretion disc winds in a significant fraction of radio-loud AGN and demonstrate that the presence of relativistic jets does not preclude the existence of winds, in accordance with several theoretical models.
We carry out a comprehensive Bayesian correlation analysis between hot halos and direct masses of supermassive black holes (SMBHs), by retrieving the X-ray plasma properties (temperature, luminosity, ...density, pressure, and masses) over galactic to cluster scales for 85 diverse systems. We find new key scalings, with the tightest relation being − , followed by − . The tighter scatter (down to 0.2 dex) and stronger correlation coefficient of all the X-ray halo scalings compared with the optical counterparts (as the − ) suggest that plasma halos play a more central role than stars in tracing and growing SMBHs (especially those that are ultramassive). Moreover, correlates better with the gas mass than dark matter mass. We show the important role of the environment, morphology, and relic galaxies/coronae, as well as the main departures from virialization/self-similarity via the optical/X-ray fundamental planes. We test the three major channels for SMBH growth: hot/Bondi-like models have inconsistent anticorrelation with X-ray halos and too low feeding; cosmological simulations find SMBH mergers as subdominant over most of cosmic time and too rare to induce a central-limit-theorem effect; the scalings are consistent with chaotic cold accretion, the rain of matter condensing out of the turbulent X-ray halos that sustains a long-term self-regulated feedback loop. The new correlations are major observational constraints for models of SMBH feeding/feedback in galaxies, groups, and clusters (e.g., to test cosmological hydrodynamical simulations), and enable the study of SMBHs not only through X-rays, but also via the Sunyaev-Zel'dovich effect (Compton parameter), lensing (total masses), and cosmology (gas fractions).
Abstract
We present results from a comprehensive study of ultrafast outflows (UFOs) detected in a sample of 14 quasars, 12 of which are gravitationally lensed, in a redshift range of 1.41–3.91, near ...the peak of the active galactic nucleus (AGN) and star formation activity. New XMM-Newton observations are presented for six of them, which were selected to be lensed and contain a narrow absorption line (NAL) in their UV spectra. Another lensed quasar was added to the sample, albeit already studied because it was not searched for UFOs. The remaining seven quasars of our sample are known to contain UFOs. The main goals of our study are to infer the outflow properties of high-
z
quasars, constrain their outflow induced feedback, study the relationship between the outflow properties and the properties of the ionizing source, and compare these results to those of nearby AGN. Our study adds six new detections (> 99% confidence) of UFOs at
z
> 1.4, almost doubling the current number of cases. Based on our survey of six quasars selected to contain a NAL and observed with XMM-Newton, the coexistence of intrinsic UV NALs and UFOs is found to be significant in >83% of these quasars suggesting a link between multiphase AGN feedback properties of the meso- and microscale. The kinematic luminosities of the UFOs of our high-
z
sample are large compared to their bolometric luminosities (median of
L
K
/
L
Bol
≳ 50%). This suggests they provide efficient feedback to influence the evolution of their host galaxies and that magnetic driving may be a significant contributor to their acceleration.
In 2016 we carried out a Swift monitoring programme to track the X-ray hardness variability of eight type-I AGN over a year. The purpose of this monitoring was to find intense obscuration events in ...AGN, and thereby study them by triggering joint XMM-Newton, NuSTAR, and HST observations. We successfully accomplished this for NGC 3783 in December 2016. We found heavy X-ray absorption produced by an obscuring outflow in this AGN. As a result of this obscuration, interesting absorption features appear in the UV and X-ray spectra, which are not present in the previous epochs. Namely, the obscuration produces broad and blue-shifted UV absorption lines of Lyα, C iv, and N v, together with a new high-ionisation component producing Fe xxv and Fe xxvi absorption lines. In soft X-rays, only narrow emission lines stand out above the diminished continuum as they are not absorbed by the obscurer. Our analysis shows that the obscurer partially covers the central source with a column density of few 1023 cm-2, outflowing with a velocity of few thousand km s-1. The obscuration in NGC 3783 is variable and lasts for about a month. Unlike the commonly seen warm-absorber winds at pc-scale distances from the black hole, the eclipsing wind in NGC 3783 is located at about 10 light days. Our results suggest that the obscuration is produced by an inhomogeneous and clumpy medium, consistent with clouds in the base of a radiatively driven disk wind at the outer broad-line region of the AGN.
A soft X-ray excess above the 2–10 keV power-law extrapolation is generally observed in the X-ray spectra of active galactic nuclei. The origin of this excess is still not well understood. Presently ...there are two competitive models: blurred ionized reflection and warm Comptonization. In the case of warm Comptonization, observations suggest a corona temperature in the range 0.1–2 keV and a corona optical depth of about 10–20. Moreover, radiative constraints from spectral fits with Comptonization models suggest that most of the accretion power should be released in the warm corona and the disk below is basically non-dissipative, radiating only the reprocessed emission from the corona. However, the true radiative properties of such a warm and optically thick plasma are not well known. For instance, the importance of the Comptonization process, the potential presence of strong absorption and/or emission features, and the spectral shape of the output spectrum have been studied only very recently. Here, we present simulations of warm and optically thick coronae using the
TITAN
radiative transfer code coupled with the
NOAR
Monte-Carlo code, the latter fully accounting for Compton scattering of continuum and lines. Illumination from above by hard X-ray emission and from below by an optically thick accretion disk are taken into account, as well as (uniform) internal heating. Our simulations show that for a large part of the parameter space, the warm corona with sufficient internal mechanical heating is dominated by Compton cooling and neither strong absorption nor emission lines are present in the outgoing spectra. In a smaller part of the parameter space, the calculated emission agrees with the spectral shape of the observed soft X-ray excess. Remarkably, this also corresponds to the conditions of radiative equilibrium of an extended warm corona covering a non-dissipative accretion disk almost entirely. These results confirm that warm Comptonization is a valuable model that can explain the origin of the soft X-ray excess.
We present the results from a ~ 500 ks Chandra observation of the z = 6.31 QSO SDSS J1030 + 0524. This is the deepest X-ray observation to date of a z ~ 6 QSO. The QSO is detected with a total of 125 ...net counts in the full (0.500A0–7 keV) band and its spectrum can be modeled by a single power-law model with photon index of Γ = 1.81 ± 0.18 and full band flux of f = 3.95 × 10−15 erg s−1 cm−2. When compared with the data obtained by XMM-Newton in 2003, our Chandra observation in 2017 shows a harder (ΔΓ ≈ −0.6) spectrum and a 2.5 times fainter flux. Such a variation, in a timespan of ~ 2 yr rest-frame, is unexpected for such a luminous QSO powered by a > 109M⨀ black hole. The observed source hardening and weakening could be related to an intrinsic variation in the accretion rate. However, the limited photon statistics does not allow us to discriminate between an intrinsic luminosity and spectral change, and an absorption event produced by an intervening gas cloud along the line of sight. We also report the discovery of diffuse X-ray emission that extends for 30″ × 20″ southward of the QSO with a signal-to-noise ratio (S/N) of approximately six, hardness ratio of HR = 0.03+0.20−0.25 HR = 0.03 - 0.25 + 0.20 $\text{HR} = {0.03}_{-0.25}^{+0.20}$ , and soft band flux of f0.5– keV = 1.1+0.3−0.3 × 10−15 erg s−1 cm−2 f 0.5 - 2 keV = 1.1 - 0.3 + 0.3 × 10 - 15 erg s - 1 cm - 2 $ f_{0.5-2\,\text{keV}}={1.1}_{-0.3}^{+0.3}\enspace \times \enspace 1{0}^{-15\enspace }\mathrm{erg}\enspace {\mathrm{s}}^{-1}\;\rm{cm}^{-2}$ , that is not associated to a group or cluster of galaxies. We discuss two possible explanations for the extended emission, which may be either associated with the radio lobe of a nearby, foreground radio galaxy (at z ≈ 1 – 2), or ascribed to the feedback from the QSO itself acting on its surrounding environment, as proposed by simulations of early black hole formation.
Ongoing studies with XMM–Newton have shown that powerful accretion disc winds, as revealed through highly ionized Fe K-shell absorption at E ≥ 6.7 keV, are present in a significant fraction of active ...galactic nuclei (AGNs) in the local Universe (Tombesi et al. 2010a). In Gofford et al., we analysed a sample of 51 Suzaku-observed AGNs and independently detected Fe K absorption in ∼40 per cent of the sample, and we measured the properties of the absorbing gas. In this work, we build upon these results to consider the properties of the associated wind. On average, the fast winds (v
w > 0.01c) are located 〈r〉 ∼ 1015−18 cm (typically ∼102−4 r
s) from their black hole, their mass outflow rates are of the order of
$\langle \skew{3}\dot{M}_{\rm w}\rangle \sim 0.01\hbox{--}1$
M⊙ yr−1 or
${\sim }(0.01\hbox{--}1)\skew{3}\dot{M}_{\rm Edd}$
and kinetic power is constrained to 〈L
w〉 ∼ 1043−45 erg s−1, equivalent to ∼(0.1–10 per cent)L
Edd. We find a fundamental correlation between the source bolometric luminosity and the wind velocity, with
$v_{\rm w} \propto L_{\rm bol}^{\alpha }$
and
$\alpha =0.4^{+0.3}_{-0.2}$
(90 per cent confidence), which indicates that more luminous AGN tend to harbour faster Fe K winds. The mass outflow rate
$\skew{3}\dot{M}_{\rm w}$
, kinetic power L
w and momentum flux
$\dot{p}_{\rm w}$
of the winds are also consequently correlated with L
bol, such that more massive and more energetic winds are present in more luminous AGN. We investigate these properties in the framework of a continuum-driven wind, showing that the observed relationships are broadly consistent with a wind being accelerated by continuum-scattering. We find that, globally, a significant fraction (∼85 per cent) of the sample can plausibly exceed the L
w/L
bol ∼ 0.5 per cent threshold thought necessary for feedback, while 45 per cent may also exceed the less conservative ∼5 per cent of L
bol threshold as well. This suggests that the winds may be energetically significant for AGN–host-galaxy feedback processes.
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