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Resolving the Multiple Component Outflows in PG 1211+143: I. The Fe-K Absorption Structure and UFO Forest

Misaki Mizumoto, James N. Reeves, Valentina Braito, Ehud Behar, Chris Done, Kouichi Hagino, Steven B. Kraemer, Gabriele A. Matzeu, Hirofumi Noda, Mariko Nomura, Shoji Ogawa, Ken Ohsuga, Atsushi Tanimoto, Tracey J. Turner, Yoshihiro Ueda, Satoshi Yamada, Sreeparna Ganguly, Paolo Somenzi

TL;DR

This work uses XRISM Resolve, Xtend, and simultaneous XMM-Newton and NuSTAR observations to resolve the Fe-K absorption in PG 1211+143, revealing a six-component Ultra-Fast Outflow (UFO) forest with velocities from $v/c\approx-0.074$ to $-0.405$. Through XSTAR modeling and joint spectral fitting, the authors show a P Cygni profile and a complex wind structure that includes both slower and faster components, with narrow line widths indicating limited velocity shear and possible terminal speeds. The analysis estimates a wind radius near $R\sim 2000\,R_g$ and a mass outflow rate of $\dot{M}_{\rm out} \sim 1\,M_{\odot}\,\mathrm{yr}^{-1}$, consistent with the Eddington accretion rate and implying a significant channel for mass ejection. The results, together with similarities to PDS 456 and implications for UV-line driving and MHD processes, suggest that UFO forests may be a common feature of near-Eddington-luminosity AGN and call for continued multi-wavelength and theoretical studies of wind energetics and launching physics.

Abstract

We present the initial high-resolution X-ray spectroscopic observations of the Fe-K absorption structure in the luminous nearby quasar PG 1211+143, utilizing the X-ray Imaging and Spectroscopy Mission (XRISM). The primary objective is to characterize the Fe-K absorption features due to Ultra-Fast Outflow (UFO) in this Eddington-luminosity source. Observations were conducted with XRISM's Resolve and Xtend instruments, complemented by simultaneous data from XMM-Newton and NuSTAR. A historically bright phase was captured. The Resolve spectra clearly reveal a prominent P Cygni profile and resolves the Fe-K absorption into six distinct velocity components, ranging from $v = -0.074c$ to $-0.405c$. A similar superposition of multiple UFOs has been reported in PDS~456, suggesting that such a ``UFO forest'' structure may be a common feature of near Eddington-luminosity sources. Some UFO components exhibit narrow line widths of approximately $σ\sim 200\,\mathrm{km\,s^{-1}}$, which may indicate that the outflows have reached their terminal velocities, thereby resulting in a smaller velocity shear. The mass outflow rate is estimated to be $\dot{M}_\mathrm{out} \sim 1~M_{\odot}~\text{yr}^{-1}$, which is of the order of the Eddington accretion rate. This suggests a physically plausible scenario where the outflow is a significant channel for mass ejection.

Resolving the Multiple Component Outflows in PG 1211+143: I. The Fe-K Absorption Structure and UFO Forest

TL;DR

This work uses XRISM Resolve, Xtend, and simultaneous XMM-Newton and NuSTAR observations to resolve the Fe-K absorption in PG 1211+143, revealing a six-component Ultra-Fast Outflow (UFO) forest with velocities from to . Through XSTAR modeling and joint spectral fitting, the authors show a P Cygni profile and a complex wind structure that includes both slower and faster components, with narrow line widths indicating limited velocity shear and possible terminal speeds. The analysis estimates a wind radius near and a mass outflow rate of , consistent with the Eddington accretion rate and implying a significant channel for mass ejection. The results, together with similarities to PDS 456 and implications for UV-line driving and MHD processes, suggest that UFO forests may be a common feature of near-Eddington-luminosity AGN and call for continued multi-wavelength and theoretical studies of wind energetics and launching physics.

Abstract

We present the initial high-resolution X-ray spectroscopic observations of the Fe-K absorption structure in the luminous nearby quasar PG 1211+143, utilizing the X-ray Imaging and Spectroscopy Mission (XRISM). The primary objective is to characterize the Fe-K absorption features due to Ultra-Fast Outflow (UFO) in this Eddington-luminosity source. Observations were conducted with XRISM's Resolve and Xtend instruments, complemented by simultaneous data from XMM-Newton and NuSTAR. A historically bright phase was captured. The Resolve spectra clearly reveal a prominent P Cygni profile and resolves the Fe-K absorption into six distinct velocity components, ranging from to . A similar superposition of multiple UFOs has been reported in PDS~456, suggesting that such a ``UFO forest'' structure may be a common feature of near Eddington-luminosity sources. Some UFO components exhibit narrow line widths of approximately , which may indicate that the outflows have reached their terminal velocities, thereby resulting in a smaller velocity shear. The mass outflow rate is estimated to be , which is of the order of the Eddington accretion rate. This suggests a physically plausible scenario where the outflow is a significant channel for mass ejection.

Paper Structure

This paper contains 15 sections, 12 equations, 11 figures, 4 tables.

Table of Contents

  1. Introduction
  2. Observations and data reduction
  3. Results
  4. Overall features
  5. XSTAR modeling
  6. Spectral fitting
  7. Discussion
  8. Origin of the narrow absorption line width
  9. Geometry of the wind
  10. Coexistence of Slower and Faster UFOs
  11. Estimation of mass outflow rate
  12. Conclusion
  13. BH mass
  14. Resolve NXB spectrum
  15. Time variability

Figures (11)

  • Figure 1: (Upper) Simultaneous XRISM/XMM-Newton/NuSTAR spectra for PG 1211+143. The model line is the power-law continuum without including the Fe-K emission or absorption line features. Error bars correspond to $1\sigma$, and the horizontal axis (energy) is in the rest frame. The lower panel shows the residuals against the continuum model. (Lower) Inset of the residual plots against a simple powerlaw continuum of photon index of $\Gamma=2.2$. Broad absorption troughs are seen in the Xtend, NuSTAR, and XMM-Newton data between 7--8 keV, and they are resolved as multiple narrow lines in the Resolve data. Other absorption features in the 10--11 keV band are also seen in Resolve, NuSTAR, and XMM-Newton; that it is less prominent in the Xtend data is likely due to poor photon statistics.
  • Figure 2: SED in PG 1211+143. XMM-Newton/EPIC-pn is in black, NuSTAR in red, and XMM-Newton/OM (U, UVW1 and UVW2) photometric points are in green. The OM data are corrected for a Galactic reddening of $E(B-V)=0.035$. The solid magenta curve and dotted blue curve are the SED model, but the latter includes the effects of the neutral Galactic absorption of $N_\mathrm{H}=3\times10^{20}$ cm$^{-2}$.
  • Figure 3: The Resolve spectrum with the best-fit model. The black dotted line shows the emission lines, while the colored, the absorption lines. A spectral model for each absorption component (zones 1--6) is overplotted with some vertical offset; zone 1 = red, zone 2 = blue, zone 3 = green, zone 4 = magenta, zone 5 = orange, and zone 6 = purple.
  • Figure 4: Residual plots against the power law continuum, with multiple energy binning. Each color corresponds to the one in Figure \ref{['fig:spec1']}. The lower panel shows the transmission of each absorption component. The top three panels show the contribution of zones 1--3, the middle panels zone 4, and the lower panels zones 5--6. The color code is the same as Figure \ref{['fig:spec1']}.
  • Figure 5: The cumulative histogram for $\Delta C$ as a result of the spectral simulations. Each vertical line show the threshold for each null probability.
  • ...and 6 more figures