A Momentum-conserving Accretion Disk Wind in the Narrow-line Seyfert 1 I Zwicky 1

Abstract

I Zw 1 is the prototype optical narrow line Seyfert 1 galaxy. It is also a nearby (z = 0.0611), luminous QSO, accreting close to the Eddington limit. XMM-Newton observations of I Zw 1 in 2015 reveal the presence of a broad and blueshifted P-Cygni iron K profile, as observed through a blue-shifted absorption trough at 9 keV and a broad excess of emission at 7 keV in the X-ray spectra. The profile can be well fitted with a wide angle accretion disk wind, with an outflow velocity of at least −0.25c. In this respect, I Zw 1 may be an analogous to the prototype fast wind detected in the QSO, PDS 456, while its overall mass outflow rate is scaled down by a factor ×50 due to its lower black hole mass. The mechanical power of the fast wind in I Zw 1 is constrained to within 5 − 15% of Eddington, while its momentum rate is of the order unity. Upper-limits placed on the energetics of any molecular outflow, from its CO profile measured by IRAM, appear to rule out the presence of a powerful, large scale, energy conserving wind in this AGN. We consider whether I Zw 1 may be similar to a number of other AGN, such as PDS 456, where the large scale galactic outflow is much weaker than what is anticipated from models of energy conserving feedback.

Searching for ultra-fast outflows in AGN using variability spectra

“…IZW1, alternatively UGC00545, is a luminous NLSy1 galaxy, accreting at near-Eddington rates with literature outflow values > 0.25c from (Reeves & Braito 2019), which is in slight disagreement to our results. However, the energy binning had to be increased from optimal values to obtain physical fractional variance results.…”

AGN-driven galactic outflows: comparing models to observations

“…In contrast, in the cases of I Zw 1, PDS 456, and MCG-03-58-007, the observed momentum rates lie nearly two orders of magnitude below the predicted relation in the energy-conserving scenario. In these sources, the observed energetics might be more consistent with momentum-driven outflows (Bischetti et al 2019;Reeves & Braito 2019;Sirressi et al 2019). More in general, some objects may belong to the momentum-driven regime, while others may be closer to the energy-driven mode, depending on the specific physical conditions in each particular source (Smith et al 2019;Chartas et al 2020).…”

“…Comparison of the momentum rate versus outflow velocity indicates that the measured momentum boosts can be significantly lower than the values expected from the wind energy-conserving mechanism. For instance, Reeves & Braito (2019) note that only Mrk 231 and IRAS 17020+4544 (which is a radio-loud source) are consistent with a purely energy-conserving shock. In contrast, in the cases of I Zw 1, PDS 456, and MCG-03-58-007, the observed momentum rates lie nearly two orders of magnitude below the predicted relation in the energy-conserving scenario.…”

Ionized outflows from active galactic nuclei as the essential elements of feedback

“…The opening angle of the UFOs is a vital parameter to estimate the total kinetic power carried by the winds and hence a measure of the feedback, but the detection of the absorption lines alone does not provide us this information. The PCygni profiles of FeK emission and absorption lines detected in a few bright quasars gives us a rare view of the opening angle of the UFOs (Nardini et al 2015;Reeves & Braito 2019). The principle here is that the UFO plasma absorbs (along the line of sight) and also re-emits (isotropic) and hence if we detect both emission and absorption from the same plasma, the relative strength can give us an estimate of the opening angle.…”