The Compact, Conical, Accretion-Disk Warm Absorber of the Seyfert 1 Galaxy NGC 4051 and Its Implications for IGM-Galaxy Feedback Processes

By Y. Krongold, F. Nicastro, M. Elvis, N. Brickhouse, L. Binette, S. Mathur, E. Jiménez-Bailón. 2007

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Using a 100 ks XMM-Newton exposure of NGC 4051, we show that the time evolution of the ionization state of the X-ray absorbers in response to the rapid and highly variable X-ray continuum constrains all the main physical and geometrical properties of an AGN "warm absorber" wind. The absorber consists of two different ionization components, with a difference of ≈100 in ionization parameter and ≈5 in column density. By tracking the response in the opacity of the gas to changes in the ionizing continuum, we were able to constrain the electron density of the system. We find ne = (5.8-21.0) × 106 cm-3 for the high-ionization absorber and ne > 8.1 × 107 cm-3 for the low-ionization absorber. These densities require that the high- and low-ionization absorbing components of NGC 4051 must be compact, at distances 0.5-1.0 lt-days (2200RS-4400RS) and <3.5 lt-days (<15,800RS) from the continuum source, respectively. This rules out an origin in the dusty obscuring torus, as the dust sublimation radius is at least an order of magnitude larger (~12 lt-days). An accretion-disk origin for the warm absorber wind is strongly suggested, and an association with the high-ionization, He II emitting, broad emission line region (radius <2 lt-days) is possible. The two detected phases are consistent with pressure equilibrium, which suggests that the absorber consists of a two-phase medium. A radial flow in a spherical geometry is unlikely, and a conical wind geometry is preferred. The implied mass outflow rate from this wind can be well constrained and is 2%-5% of the mass accretion rate. If the mass outflow rate scaling with accretion rate is representative of all quasars, our results imply that warm absorbers in powerful quasars are unlikely to produce important evolutionary effects on their larger environment, unless we are observing the winds before they get fully accelerated. Only in such a scenario can AGN winds be important for cosmic feedback.

Subfields: Astronomy and Astrophysics

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MOMENTUM DRIVING: WHICH PHYSICAL PROCESSES DOMINATE ACTIVE GALACTIC NUCLEUS FEEDBACK? (2010, background): “On the theory side, the radiation driven winds found by Proga & Kallman (2004), via detailed hydro radiation-transfer calculations, cover ∼ π steradians, roughly consistent with the observational estimates.”
On the Nature of Seyfert Galaxies with High [O III] λ5007 Blueshifts (2008, background): “…et al. 2005, Gallimore et al. 2006), to the IR (Rodriguez-Ardila et al. 2006), optical (Das et al. 2005), UV (Sulentic et al. 2007, Rodriguez Hidalgo et al. 2007, Crenshaw & Kraemer 2007), and X-ray band (Chelouche & Netzer 2005, Krongold et al. 2007); see Veilleux et al. (2005) for a review.”
Stellar and Quasar Feedback in Concert: Effects on AGN Accretion, Obscuration, and Outflows (2015, background): “…(v ∼ 102− 103 kms−1) associated with the narrow line region and the “warm absorber” (Laor et al. 1997; Crenshaw et al. 2000; Steenbrugge et al. 2005; Krongold et al. 2007), as well as quasar absorption and occultation systems (e.g. McKernan & Yaqoob 1998; Turner et al. 2008; Miller et al.…”
Black Hole Outflows (2009, background): “…U C T I O N Outflows and winds are widely observed in many types of galaxies, from active to normal (e.g. Chartas, Brandt & Gallagher 2003; Pounds et al. 2003; O’Brien et al. 2005; Pounds & Page 2006; Krongold et al. 2007; Tremonti, Moustakas & Diamond-Stanic 2007; Holt, Tadhunter & Morganti 2008).”
A Cosmological Framework for the Co-Evolution of Quasars, Supermassive Black Holes, and Elliptical Galaxies. II. Formation of Red Ellipticals (2007, background): “—Quasars are known to often exhibit strong outflows (for a review, see Veilleux et al. 2005) and to have a large effect on the ionization and temperature state of the inner regions of their host galaxies (e.g., Laor et al. 1997; Krongold et al. 2007; Rupke et al. 2005 and references therein).”
A semi-analytic model for the co-evolution of galaxies, black holes and active galactic nuclei (2008, background): “However, their impact on the host galaxy remains unclear, as the mass outflow rates of these winds are difficult to constrain (though see Steenbrugge et al. 2005; Chartas et al. 2007; Krongold et al. 2007).”
The Hard X-Ray Spectrum as a Probe for Black Hole Growth in Radio-Quiet Active Galactic Nuclei (2008, background): “…large X-ray flux variations (with amplitudes of factors of∼10 or more) and corresponding X-ray spectral slope variations (with∆Γ ∼ 0.4) that are often due to changing spectral contributions from reflection and/or absorption (e.g., Taylor et al. 2003; Krongold et al. 2007; Grupe et al. 2008).”
OUTFLOWS FROM ACTIVE GALACTIC NUCLEI: KINEMATICS OF THE NARROW-LINE AND CORONAL-LINE REGIONS IN SEYFERT GALAXIES, (2011, background): “Recent results from Krongold et al. (2007) and Storchi-Bergmann et al. (2010) indicate that the total kinetic energy released by the AGN outflow is comparable to the energy required to disrupt the hot phase of the ISM, which could then disrupt star formation.”
Unification of X-ray winds in Seyfert galaxies: from ultra-fast outflows to warm absorbers (2012, methodology): “12 of Krongold et al. 2007).”
Quasar feedback: more bang for your buck (2009, background): “…(see e.g. Baum & McCarthy 2000; de Kool et al. 2001, 2002; Steenbrugge et al. 2005; Gabel, Arav & Kim 2006; Holt et al. 2006; Batcheldor et al. 2007; Ganguly et al. 2007; Krongold et al. 2007; McKernan, Yaqoob & Reynolds 2007; Tremonti, Moustakas & Diamond-Stanic 2007; Prochaska & Hennawi 2009).”
The multi-phase winds of Markarian 231: from the hot, nuclear, ultra-fast wind to the galaxy-scale, molecular outflow (2015, methodology): “The mass outflow rate at rmin and rmax can then be estimated using: ṀUFO = 0.8πmpNUFOH vUFOr fg = 0.3 − 2.1 M yr−1 (5) where NUFOH = 2.7 × 1023 cm−2, and fg is a geometrical factor introduced by Krongold et al. (2007) and statistically estimated ∼ 2 by Tombesi et al. (2010).”