raffaella morganti (astron)

Extra-planar Gas – Dwingeloo, June 2004

Raffaella Morganti (Astron)


Outflows of neutral hydrogen

in AGN

T. Oosterloo, C. Tadhunter, B. Emonts , J. Holt

1500 km/s


Detection of neutral hydrogen in the central regions of active galaxies: commonly associated with circumnuclear tori/disks.

butthis is not always the case (perhaps not even the majority). Disturbed/complex kinematics of the gas is observed and provides a more complete picture of what is happening in these regions i.e. presence and occurrence of gas outflows.

NGC 4261

Planar and extra-planar HI in AGNs


Issues related to AGN Outflows

• They can affect the evolution of the host galaxy and its ISM• They influence the ionization of the medium • What structure they have, or how much mass and energy they carry.• They can tell us about the ISM and the interplay between this medium

and the radio source

• Outflows in high z radio galaxies


Importance of gas and outflows in high-z radio galaxies

Large Ly halos

At low-z these effects are less extreme but…

Pentericci et al.

van Ojik et al. 1997

strong blue-ward asymmetries in the Ly emission lines: due to cold gas associated with the radio galaxy

the HI absorption can be extended and stronger in smaller radio galaxies



• They can affect the evolution of the host galaxy and its ISM• They influence the ionization of the medium • What structure they have, or how much mass and energy they carry.

• Outflows in high z radio galaxies:

• Outflows in Seyferts: optical and UV


Blue-shifted absorption lines in many species of several hundred to over 1000 km/s.

Kriss et al. 1995

Gas outflows in Seyfert galaxies

Hutchings et al. 1998



• They can affect the evolution of the host galaxy and its ISM• They influence the ionization of the medium • What structure they have, or how much mass and energy they carry.

• Outflows in high z radio galaxies:

• Outflows in Seyferts: optical and UV

Starburst winds

AGN (radiation) driven outflow

Jet driven outflows

Possible origin of outflows in AGNs


How about nearby radio galaxies?

Evidence of outflows in ionized gas

Clear cases of radio galaxies embedded in very rich ISM (far-IR bright, CO etc.)

They possibly represent the radio galaxies originating from major mergers: young stellar population observed

Study in HI of these cases


WSRT

Deep absorption: Haschick & Baan (1985) Beswick et al. (2002)

broad, shallow absorption by neutral gas

Morganti et al. ApJL (2003)

Broad absorption ~0.15% NH~2 x 1020 cm-

2 for TSPIN=100K

Broad HI absorption in 3C293


Broad HI absorption in 4C12.50

Broad absorption ~ 0.2% NH~1020 cm-2 for TSPIN=100K

WSRT observations, 20 MHz band

Broad HI absorption: full width of ~2000 km/s mostly blueshifted

ADD FIGURA?????

HST image in [OIII] (Axon et al.) VLBI (Stanghellini et al.)

100pc


Schilizzi et al. 2001O’Dea et al. 2001

Optical depth of the broad absorption ~0.15%

~1500 km/s



Other cases: 3C459

800 km/sOptical depth of the broad absorption

~0.05%

Thomasson et al. 2003

~2 kpc


~ ~1000 km/s

Jackson et al. 2002

~3 kpc

WSRT observations

MERLIN+HST


Optical depth of the broad absorption ~0.08%


Relatively high number of objects with broad HI absorption in radio galaxies with young stellar population: biased result?Very low optical depth need very strong radio continuum

In these objects the broad HI is mostlymostly blueshifted (compared to the systemic velocity) outflows

What we find so far:

- Location of the absorption

- Relation with the ionized gas

Next


HI

OII

Emonts et al. in prep

Core

Blueshifted wing at location of lobe

red: radio continuum (MERLIN, Beswick et al.)blue: CO (Evans et al.)

1’’

Ionized and neutral gas in 3C293

it would correspond to a mass of the HI ~3x106 Msun


[OIII]4959,5007fit with 3 components

Ionized and neutral gas in 4C12.50

Holt et al. 2003

Stratified outflow: broader (and highly reddened) component of ionized gascoming from the inner regions

blueshifted component(s) also in the ionized gas broader width compared to HI

Young source surrounded by (and interacting with ) a cocoon of material left over from the even that trigger the radio source.


Other cases: 3C459

800 km/sOptical depth of the broad absorption

~0.05%

Thomasson et al. 2003

~2 kpc

No HI absorption in high resolution (VLBI) data


3C459: HI and ionised gas

[OIII]

width of the ionized gas much larger

in this case, is the deeperHI component to be blueshifted


Relatively high number of objects with broad HI absorption in radio galaxies with young stellar population: biased result?


Indication that at least in some cases the HI absorption (and the broad optical lines) happens off-nucleus (~ 1 kpc) case of IC 5063



The case of the radio-loud Seyfert IC 5063

H+[NII]

~4arcseccirca 1.3kpc

ATCA & NTT

radio core

VelATCA – 17 GHz


Similarities with the ionized gas (a blueshifted component is always seen in neutral and ionized): are the two outflows due to the same mechanism?

The width of the optical lines could be systematically larger: could indicate that they come from different regions?


Relatively high number of objects with broad HI absorption in radio galaxies with young stellar population: biased result?


Indication that at least in some cases the HI absorption (and the broad optical lines) happens off-nucleus (~ 1 kpc) case of IC 5063


Starburst wind Post-starburst galaxies (typical ages between 0.5 and 2 Gyr)

Adiabatically expanded broad emission line clouds (Elvis 2002) located in the nuclear regions

Radiation pressure+Dust (Dopita et al.)

Despite the very energetic phenomena involved, gas remains - or becomes again - neutralInsight on the physical conditions of the medium around the AGN

What produces the HI outflows

Interaction between the radio jet and ISM


Interaction between the radio jet and ISM: a possible scenario


Mellema et al. 2002

looks promising also to explain the broad HI BUT can the fragmented clouds be accelerated to such high velocities?

Evolution of clouds in radio galaxy cocoons:

shock runs over a cloud compression phase (overpressured cocoon)

fragmentation & cooling

formation of dense, cool & fragmented structures

What jet/cloud interaction can do for us?

Simulations show that cooled fragmented clouds do form as result of the interaction Mellema et al. 2002, Fragile et al. 2003


How common is broad HI absorption?

Relatively large number of objects with broad HI absorption in radio galaxies with young stellar population: suggesting a rich medium around these radio sources (against which the radio plasma is interacting)?

biased result? probably yes!

Not in every radio galaxy (few cases without)

But some new cases …………


Some new cases……

Taylor et al. (2004)

4C37.11

Optical depth of the peak absorption ~0.3%

~ 1500 km/s

WSRT

Very little known about the optical …………

VLBA


A recent new case: OQ208

known to have fast outflow in the broad emission lines (Marziani et al.)

particularly rich medium fromX-ray absorption: radio jets possibly piercing their way through a Compton-thick mediumpervading the nuclear environment(Guainazzi et al. 2004)

~10 pc

Stanghellini et al. 1993

Optical depth of the peak absorption ~0.5%

WSRT1500 km/s


Relevant for the evolution of the radio sources

the radio jet has to “fight” against a rich medium:the jet is not confined but can be momentarily disrupted (slowing down the evolution of the radio source)

If the interaction between the radio emission and the ISM is so important


Rich ISM against which the jet has to fight against in order to expand out of the galaxy

“Fighting” its way out

4C12.50

Core

Mass of the HI cloud ~105-6 Msun

High column density (NH~1022 cm-2)

HI absorption

VLBI

Morganti et al. 2004 A&A in press

2D simulationsBicknell et al. 2003

radio jet

dense cloud

black=WSRTred = VLBI

Integrated HI profile


Conclusions

Fast outflows (~ 1000 km/s) and disturbed kinematics of the neutral hydrogen in the central regions of radio galaxies

Fast HI outflows possibly coming from jet interacting with the ISM

Relatively large number of objects with broad HI absorption in radio galaxies with young stellar population: suggesting a rich medium around these radio sources?

Relevant for the evolution of the radio sources: the radio jet has to “fight” against a rich medium.The jet is not confined but can be momentarily disrupted.

raffaella morganti (astron)

Documents

broad absorption

kpcextraplanar gas dwingeloo

uv extraplanar gas dwingeloo

bandbroad hi absorption

kbroad hi absorption

kmsbroad hi absorption

wsrtdeep absorption

shallow absorption