Context. Ultra-fast outflows (UFOs) are the most powerful disk-driven winds in active galactic nuclei (AGNs). Theoretical and observational evidence shows that UFOs play a key role in the AGN feedback mechanism. The mechanical power of the strongest UFOs may be enough to propagate the feedback to the host galaxies and ultimately shape the AGN-galaxy coevolution. It is therefore of paramount importance to fully characterize UFOs, their location, and energetics. Aims. We study two XMM-Newton archival observations of the narrow-line Seyfert 1 galaxy PG 1448+273. We concentrate on the latest observation, whose spectrum is characterized by a strong absorption feature in the Fe K band. This feature represents the spectral imprint of a UFO, as confirmed by other independent analyses. We study this feature in detail with a novel modeling tool. Methods. In order to constrain the physical properties of the UFO, we implemented the novel model called wind in the ionized nuclear environment (WINE) to fit the photoionized emission and absorption lines from a disk wind in X-ray spectra. WINE is a photoionization model that allows us to self-consistently calculate absorption and emission profiles. It also takes special relativistic effects into account. Results. Our detection of the UFO in PG 1448+273 is very robust. The outflowing material is highly ionized, logξ = 5.53−0.05+0.04 erg s−1 cm, has a high column density, NH = 4.5−1.1+0.8 × 1023 cm−2, is ejected with a maximum velocity v0 = 0.24−0.06+0.08 c (90% confidence level errors), and attains an average velocity vavg = 0.152 c. WINE succeeds remarkably well to constrain a launching radius of r0 = 77−19+31 rS from the black hole. We also derive a lower limit on both the opening angle of the wind (θ > 72°) and the covering factor (Cf > 0.69). We find a mass outflow rate Ṁout = 0.65−0.33+0.44 M⊙ yr−1 = 2.0−1.0+1.3 Ṁacc and a high instantaneous outflow kinetic power Ėout = 4.4−3.6+4.4 × 1044 erg s−1 = 24% Lbol = 18% LEdd (1σ errors). We find that a major error contribution on the energetics is due to r0, stressing the importance of an accurate determination through proper spectral modeling, as done with WINE. Finally, using 20 Swift (UVOT and XRT) observations together with the simultaneous Optical Monitor data from XMM-Newton, we also find that αox varied strongly, with a maximum excursion of Δαox = −0.7, after the UFO was detected, leading to a remarkable X-ray weakness. This may indicate a starving of the inner accretion disk due to the removal of matter through the wind, and it may have repercussions for the larger population of observed X-ray weak quasars.
Improving our understanding of the nuclear properties of high-Eddington-ratio (λEdd) active galactic nuclei (AGN) is necessary since at this regime the radiation pressure is expected to affect the structure and efficiency of the accretion disc-corona system. This may cause departures from the typical nuclear properties of low-λEdd AGN, which have been largely studied so far. We present here the X-ray spectral analysis of 14 radio-quiet, λEdd ≳ 1 AGN at 0.4 ≤ z ≤ 0.75, observed with XMM-Newton. Optical/UV data from simultaneous Optical Monitor observations have also been considered. These quasars were selected to have relatively high values of black hole mass (MBH ∼ 108 − 8.5 M⊙) and bolometric luminosity (Lbol ∼ 1046 erg s−1) in order to complement previous studies of high-λEdd AGN at lower MBH and Lbol. We studied the relation between λEdd and other key X-ray spectral parameters, such as the photon index (Γ) of the power-law continuum, the X-ray bolometric correction (kbol, X), and the optical/UV-to-X-ray spectral index (αox). Our analysis reveals that, despite the homogeneous optical and supermassive black hole accretion properties, the X-ray properties of these high-λEdd AGN are quite heterogeneous. We indeed measured values of Γ between 1.3 and 2.5, at odds with the expectations based on previously reported Γ − λEdd relations, for which Γ ≥ 2 would be a ubiquitous hallmark of AGN with λEdd ∼ 1. Interestingly, we found that ∼30% of the sources are X-ray weak, with an X-ray emission about a factor of ∼10 − 80 fainter than that of typical AGN at similar UV luminosities. The X-ray weakness seems to be intrinsic and not due to the presence of absorption along the line of sight to the nucleus. This result may indicate that high-λEdd AGN commonly undergo periods of intrinsic X-ray weakness. Furthermore, results from follow-up monitoring with Swift of one of these X-ray weak sources suggest that these periods can last for several years.
The lower-energy peak of the spectral energy distribution of blazars has commonly been ascribed to synchrotron radiation from relativistic particles in the jets. Despite the consensus regarding jet emission processes, the particle acceleration mechanism is still debated. Here, we present the first X-ray polarization observations of PG 1553+113, a high-synchrotron-peak blazar observed by the Imaging X-ray Polarimetry Explorer (IXPE). We detect an X-ray polarization degree of (10 ± 2)% along an electric-vector position angle of ψ X = 86° ± 8°. At the same time, the radio and optical polarization degrees are lower by a factor of ∼3. During our IXPE pointing, we observed the first orphan optical polarization swing of the IXPE era, as the optical angle of PG 1553+113 underwent a smooth monotonic rotation by about 125°, with a rate of ∼17° day–1. We do not find evidence of a similar rotation in either radio or X-rays, which suggests that the X-ray and optically emitting regions are separate or, at most, partially cospatial. Our spectropolarimetric results provide further evidence that the steady-state X-ray emission in blazars originates in a shock-accelerated and energy-stratified electron population.
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