Location and energetics of the ultra-fast outflow in PG 1448+273

Abstract

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.

X-ray spectroscopic survey of highly accreting AGN

“…High-λ Edd AGN are also likely to accelerate powerful outflows, which can provide an additional effect contributing to weaken the X-ray emission. Laurenti et al (2021) analysed the UFO in the NLSy1 galaxy PG 1448+273 with λ Edd ∼ 0.75. They found that this source underwent large variations in α ox , with a maximum offset of ∆α ox = −0.7, after the UFO was detected.…”

“…Accordingly, the AGN feedback mechanism should manifest itself in full force in high-λ Edd sources, making them the ideal laboratory for probing the real impact of nuclear activity on the evolution of massive galaxies (e.g. Reeves et al 2009;Nardini et al 2015;Tombesi et al 2015;Marziani et al 2016;Bischetti et al 2017Bischetti et al , 2019Laurenti et al 2021).…”

Speed limits for radiation-driven SMBH winds

“…, r, t are in units of the gravitational radius and time, r G = GM c 2 , t G = r G c respectively, and v is in units of c. We span the interval between 5 and 500 r G for r 0 , to encompass the typical launching radius of UFOs, which usually lies between ∼50 and some hundreds of r G (Tombesi et al 2012(Tombesi et al , 2013(Tombesi et al , 2015Nardini et al 2015;Laurenti et al 2021). We divide this interval in five logarithmically spaced steps: r 0 ∈ [5.…”

“…Fast outflows, particularly ultra-fast outflows (UFOs), are routinely observed in active galactic nuclei (AGN) as blueshifted absorption and emission features imprinted on the X-ray spectrum, with velocities ranging from ∼0.03 to 0.4−0.5 times the speed of light, c (Tombesi et al 2011(Tombesi et al , 2015Nardini et al 2015;Fiore et al 2017;Parker et al 2017;Laha et al 2020). They are launched at accretion disc scales from the central supermassive black hole (SMBH) and may display a kinetic power as high as 20−40% of the bolometric luminosity of the AGN (Feruglio et al 2015;Nardini et al 2015;Nardini & Zubovas 2018;Laurenti et al 2021), which is more than enough to trigger a massive feedback in the host galaxy, according to theoretical models (Di Matteo et al 2005;Hopkins & Elvis 2010;Gaspari et al 2011).…”

X-ray spectroscopic survey of highly-accreting AGN

“…High-λ Edd AGN are also likely to accelerate powerful outflows, which can provide an additional effect contributing to weaken the X-ray emission. Laurenti et al (2021) analysed the UFO in the NLSy1 galaxy PG 1448+273 with λ Edd ∼ 0.75. They found that this source underwent large variations of α ox , with a maximum offset of ∆α ox = −0.7, after the UFO was detected.…”