Extra-planar Gas – Dwingeloo, June 2004
Raffaella Morganti (Astron)
Extra-planar Gas – Dwingeloo, June 2004
Outflows of neutral hydrogen
in AGN
T. Oosterloo, C. Tadhunter, B. Emonts , J. Holt
1500 km/s
Extra-planar Gas – Dwingeloo, June 2004
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
Extra-planar Gas – Dwingeloo, June 2004
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
Extra-planar Gas – Dwingeloo, June 2004
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
Extra-planar Gas – Dwingeloo, June 2004
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.
• Outflows in high z radio galaxies:
• Outflows in Seyferts: optical and UV
Extra-planar Gas – Dwingeloo, June 2004
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
Extra-planar Gas – Dwingeloo, June 2004
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.
• 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
Extra-planar Gas – Dwingeloo, June 2004
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
Extra-planar Gas – Dwingeloo, June 2004
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
Extra-planar Gas – Dwingeloo, June 2004
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
Extra-planar Gas – Dwingeloo, June 2004
Schilizzi et al. 2001O’Dea et al. 2001
Optical depth of the broad absorption ~0.15%
~1500 km/s
Broad HI absorption in 3C236
Extra-planar Gas – Dwingeloo, June 2004
Other cases: 3C459
800 km/sOptical depth of the broad absorption
~0.05%
Thomasson et al. 2003
~2 kpc
Extra-planar Gas – Dwingeloo, June 2004
~ ~1000 km/s
Jackson et al. 2002
~3 kpc
WSRT observations
MERLIN+HST
Broad HI absorption in 3C305
Optical depth of the broad absorption ~0.08%
Extra-planar Gas – Dwingeloo, June 2004
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
Extra-planar Gas – Dwingeloo, June 2004
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
Extra-planar Gas – Dwingeloo, June 2004
[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.
Extra-planar Gas – Dwingeloo, June 2004
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
Extra-planar Gas – Dwingeloo, June 2004
3C459: HI and ionised gas
[OIII]
width of the ionized gas much larger
in this case, is the deeperHI component to be blueshifted
Extra-planar Gas – Dwingeloo, June 2004
Relatively high number of objects with broad HI absorption in radio galaxies with young stellar population: biased result?
In these objects the broad HI is mostlymostly blueshifted (compared to the systemic velocity) outflows
Indication that at least in some cases the HI absorption (and the broad optical lines) happens off-nucleus (~ 1 kpc) case of IC 5063
What we find so far:
Extra-planar Gas – Dwingeloo, June 2004
The case of the radio-loud Seyfert IC 5063
H+[NII]
~4arcseccirca 1.3kpc
ATCA & NTT
radio core
VelATCA – 17 GHz
Extra-planar Gas – Dwingeloo, June 2004
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?
What we find so far:
Relatively high number of objects with broad HI absorption in radio galaxies with young stellar population: biased result?
In these objects the broad HI is mostlymostly blueshifted (compared to the systemic velocity) outflows
Indication that at least in some cases the HI absorption (and the broad optical lines) happens off-nucleus (~ 1 kpc) case of IC 5063
Extra-planar Gas – Dwingeloo, June 2004
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
Extra-planar Gas – Dwingeloo, June 2004
Interaction between the radio jet and ISM: a possible scenario
Extra-planar Gas – Dwingeloo, June 2004
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
Extra-planar Gas – Dwingeloo, June 2004
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 …………
Extra-planar Gas – Dwingeloo, June 2004
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
Extra-planar Gas – Dwingeloo, June 2004
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
Extra-planar Gas – Dwingeloo, June 2004
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
Extra-planar Gas – Dwingeloo, June 2004
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
Extra-planar Gas – Dwingeloo, June 2004
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.