Outflows and Feedback

Smita MathurOhio State

[Yair Krongold et al. 2007 ApJ 659, 1022]

Feedback from AGNs

Absolutely necessary to explain a variety of astronomical observations:

- M-- relation

- cluster cooling flows

- sizes of galaxies

- star formation rates

- enrichment of IGM

Methods of Feedback Jets : accepted for cluster cooling flows.

Outflows are ubiquitous

Seen in 50% of Seyfert galaxies.

NGC 3783 HST and FUSE

Do outflows carry sufficient energy and momentum to be effective agents of feedback?

Parameters we need to know:

Mass

Velocity

Column density of ions

Total column density

Mass

Ionization correction

Geometry Metallicity

What is the distance of the absorber from the nucleus?

Proposals span a factor of > 106

from accretion disk to Kpc scale

narrow line region

n R2

Variability

Density Distance

XMM Observations of NGC 4051

• RGS High resolution spectrum

• EPIC Variability

R (HIP) = 0.5-1.0 lt days. (2300-4600 RS)

R (LIP) = < 3.5 lt days. (< 15800 RS)

BH mass in NGC 4051 is 2 x 106 M⊙

The outflow is clearly compact

…consistent with an accretion disk origin.

Rule out various models:

- wind off torus edge (Krolik & Kriss)

- continuous range of ionization

parameter

Mass & Energy outflow rates

HIP & LIP mass outflow rates:

~ 1 x 10-4 M⊙ yr-1

c.f. accretion rate: ~ 5 x 10-3 M⊙ yr-1

Kinetic power released: ~1038 erg/s

c.f. bolometric luminosity: 2.5 x 1043 erg/s

Energy injection rate in the surrounding medium is significantly smaller than that in feedback models

ScannapiecoSilk

What about luminous quasars?

Total energy output: ~ 1057 erg.

(if outflow to accretion rate is the same as in NGC 4051)

c.f. feedback requirement of ~ 1060 erg

Hopkins et al

Scannapieco et al.

The measured energy output

falls significantly short of what’s

needed for effective feedback

unless………..

1. Outflow rate does not scale simply with

accretion rate

2. We observe outflow before it is fully accelerated.

In NGC 4051 vwind << vescape

How common is this?

Are powerful quasars different?