raffaella morganti (astron, nl) c. tadhunter,t. oosterloo, b. emonts, j. holt and many others atnf...

Raffaella Morganti (Astron, NL)

C. Tadhunter ,T. Oosterloo, B. Emonts, J. Holt and many others

ATNF – July 2004

The interplay between radio-activity and the ISM

in radio galaxies

ATNF – July 2004

Radio galaxies typically hosted by an early-type galaxy: why to look for neutral hydrogen in these objects?

HI on the large scale HI on the nuclear scale AGN triggered by mergers?

HI tracer of the origin and evolution of the galaxy allows to put the AGN activity in the evolutionary sequence (together with the stellar population)

star formation induced by the interaction between the radio jet and the HI?

structure and physical conditions in circumnuclear tori nuclear outflows and feedback

ATNF – July 2004

NGC 7252 an elliptical forming now

light profile is r1/4

shallow, deeper and deep images

NGC 7252 is elliptical formed by gas-rich merger

Schweizer 1982

H I (Hibbard et al.)

deep images reveal irregular features in outer regions

ATNF – July 2004

Large amount of HI (in 5-10% early-type) MHI > 109 Msun Often, very regular kinematics disks

Very extended structures (~ hundred kpc)

Long-lived gas structures, no diffuse starformation

Major mergers BUT OLD! (well over 5x109 years, provided the environment is not too

hostile) not related to recent accretion

HI and early-type galaxies

Results from ATCA +VLA+from HIPASS (and follow-up ATCA): statistical study of the occurrence and characteristics of HI in normal early-type galaxies.

20

0 k

pc

Sadler, Oosterloo & Morganti

(ATCA data) HI total intensity + optical

Oosterloo et al. 2001

ATNF – July 2004







Results from ATCA +from HIPASS (and follow-up ATCA): statistical study of the occurrence and characteristics of HI in normal early-type galaxies.

80kpc

ATNF – July 2004







Results from ATCA +from HIPASS (and follow-up ATCA): statistical study of the occurrence and characteristics of HI in normal early-type galaxies.

20

0 k

pc

Sadler, Oosterloo & Morganti

(ATCA data) HI total intensity + optical

ATNF – July 2004

18

0kp

c

ATCA

80kpc

230k

pc

HI observation of early-type galaxies:The great majority of the detections are large, regular disks (Oosterloo et al. in prep)

190kpc

ATNF – July 2004

SAURON + WSRT (stellar+gas - neutral and ionized - kinematics)

9 of Sauron sample observed in H I (so far….), with high sensitivity (12 hr of WSRT, 4x12h for NGC4278)H I detection limit (few times) 107 M (i.e. factor 50-75 better than HIPASS)

• 7 galaxies detected, 5 have HI ‘disks’• some of very low column density (few times 1019 cm-2)• detection rate 77%!!!

‘complicated kinematics’

These are mainly radio quiet galaxies: any connection to radio loud galaxies?

NGC 4278

NGC 3414

Morganti, Oosterloo, de Zeeuw et al.

HI very often detected in early-type (and sometimes in large amount)tracing origin external, (major) mergers

ATNF – July 2004

Heckman et al. 1986

also emission line kinematics consistent with accretion origin(Tadhunter et al. 1989; Baum et al. 1990)

Morphological features: double nuclei, arcs, tails and bridges

Are radio galaxies the results of major mergers?(Merger as a way to bring the gas to the central regions)

~ 5 kpc (5’’)

3C 293 Molecular gas (CO)Radio cont. (5 GHz)

4C 12.50

HST image+ CO contours

Nuclear concentration of molecular gas (Evans et al. 1999,2004)

presence of a starburst phase

rich ISM in the central regions (at least in the initial phase of the AGN)

ATNF – July 2004

Veron-Cetty et al. 1995

100 kpc

Survey of radio galaxies in HI to look for similar extended structures

(Emonts PhD thesis)

HI in radio galaxies: Do we see similar structures as in “normal” early-type?

Southern radio galaxy PKS B1718-649Very extended disk with more than 1010 M of HI

Total HI intensity

VLBI continuum (Tingay et al. 1997)

<10pc

ATCA

ATNF – July 2004

Preliminary results from a statistical study (Emonts PhD thesis)

Sample of radio galaxies (up to ~12000 km/s): looking for HI emission (and absorption)Some interesting cases also in radio galaxies a number of HI disk-like structures are seen next: relation with stellar population

ATCA (Emonts et al. in prep.)

NGC 612

How about the large HI disks? so far large, HI-rich disks (~1010 Msun of HI) have been found only in compact radio galaxies

~4

0 k

pc

ATNF – July 2004

Very extended HI disks in radio galaxies

125 kpc

~1kpcBoth compact radio galaxies

young(<<107 yr)

WSRT

more than 1010 M of HI!

~1kpc

remarkably regular distribution and kinematics

~160 kpcHI total intensity

Morganti et al. 2003

Emonts et al. in prep.

ATNF – July 2004

:

long-lived HI structures

HI to define an evolutionary sequence?

AGN phase

>109 yrMany free parameters:every major merger produces AGN ?effect of environment effect of the radio plasma and/or AGN on the neutral gas

few x 108 yr ?

Hibbard et al.

The age of the merger derived (to first order) from the HI will need to be compared with the stellar population analysis.

ATNF – July 2004

Some preliminary results from the statistical study

Major merger is the possible scenario for some BUT…….

so far large, HI-rich disks only in compact radio galaxies: no idea why!

Complex morphology of the ionized gas

and neutral hydrogen(with similar kinematics) 30 kpc

Morganti et al. 2002

HI absorption

Tadhunter et al. 2000

Radio lobes expanding into gas disk

selection effects?

the gas is ionized?

(see Coma A)

different type of merger?

environment?

ATNF – July 2004

Origin of radio galaxies:the study of the stellar population

ATNF – July 2004

young stellar populations (YSP) make a significant contribution to the optical/UV continua in 25 to 40% of radio galaxies

at low and intermediate redshifts and of different radio powers

Consistent with the idea of (major?) mergers triggering the activity

these mergers are known to producecircum-nuclear starburst as the material is driven toward the central regions

connection with UV excess and IR luminosity tendency for the galaxies with YSP to be detected by IRAS

Tadhunter et al., Wills et al. 2002, 2003

Recent results from the study of the stellar population


3C321

old stellar pop.

young stellar pop. power law

ATNF – July 2004

Evolution of the host galaxy from the YSP

Results on 3C293, 3C305 and 4C12.50 (Tadhunter, Robinson, Gonzalez-Delgado et al. 2004)

typical ages of the YSP between 0.5 and 2.5 Gyr

massive YSP: 109 <MYSP < 5x 1010 Msun

(comparable to the mass of molecular gas) that makes up a large proportion of the total stellar mass (~ 1 to 50%)

link between radio galaxies and luminous- and ultra luminous infrared galaxies

consistent with AGN activity (in some radio galaxies) triggered by major merger AGN appears late after the merger

ULIG

LIG

3C293

3C305

Assuming instantaneous burst model (BC96)

Age (Gyr)

L BO

L

ATNF – July 2004

How about the radio galaxies with no YSP?

Wills et al. 2002

Mass of the YSP is relatively minor minor merger

Sources observed long after the merger

Reddened starburst (but none of the undetected are luminous in far-IR)

Radio galaxies without YSP are • triggered by a small merger, or• are seen very late after the merger

Also from the study of the stellar population,different type of mergers at the origin of radio galaxies

ATNF – July 2004

The nuclear regions

ATNF – July 2004

radio

jet

The nuclear regions

radi a

tion

shocksGas outflows often detected.Relevance for the evolution of the AGN.

extra-gas surrounding the AGN,e.g. left over from the merger that triggered the AGN

Study of these phenomena using HI (in absorption)

HI absorption from the torus/circumnuclear disk

ATNF – July 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

Extended HI absorption (against the Ly )

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

Kriss et al. 1995

Hutchings et al. 1998

Starburst winds

AGN (radiation) driven outflow

Jet driven outflows

Possible origin of outflows in AGNs

ATNF – July 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 (e.g. young stellar population observed)

Study in HI of these cases HI associated with outflows and disturbed kinematics

ATNF – July 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

ATNF – July 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

ATNF – July 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

ATNF – July 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

NH~8x1020 cm-2 for TSPIN=100K

ATNF – July 2004

Relatively high number of objects with broad HI absorption in radio galaxies with: - young stellar population - compact (young) or restarted activity biased result? Very low optical depth (<0.005) need very strong radio continuum

What we find so far:

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

…but not always……

ATNF – July 2004

…..just to make everything more complicated……

Taylor et al. (2004)

4C37.11

Optical depth of the peak absorption ~0.3%

~ 1500 km/s

WSRT

Redshifted component detected also by the VLBIBlueshifted component detected only by low resolution observations (WSRT)

VLBA

ATNF – July 2004




- Location of the absorption

- Relation with the ionized gas

Next

ATNF – July 2004

• H I disk rotating aligned with the dust lane

• broad, blue-shifted (~700km/s) H I absorption

H I Position-velocity slice along major axis (PA 120)

ATCA (8 GHz) + HST WFPC2 [O III]5007 image

Triple radio structure aligned along dust lane

IC 5063Seyfert

Morganti et al. 1997; Oosterloo et al. 1999 VLBI: absorption against lobe

ATNF – July 2004

The case of the radio-loud Seyfert IC 5063

H+[NII]

~4arcseccirca 1.3kpc

ATCA & NTT

radio core

VelATCA – 17 GHz

Morganti, Saripalli, Subrahmanyan, Oosterloo

ATNF – July 2004

[SII]

flux

Eastern radio hot-spot

Fast outflow of ionized gas!

FWHM = ~1000 km/sBlueshifted by ~500 km/s

Densities:

Narrow: ~102 cm-3

Broad: ~103 cm-3

Also seen inother lines,e.g. [OII]

[SII]

ATNF – July 2004




Indication that at least in some cases the HI absorption (and the broad optical lines) happens off-nucleus (~ 1 kpc case of IC 5063) Similarities with the ionized gas (a blueshifted component is always seen in neutral and ionized): are the two outflows due to the same mechanism?

ATNF – July 2004

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

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

Adiabatically expanded broad emission line clouds (Elvis 2002)

located in the nuclear regions

ATNF – July 2004

Energy flux estimate: case of 4C12.50 and OQ208

• log Energy flux ~ 40.4 – 41.1 erg/sfrom the HI outflows

big uncertainties: size of the HI and shock area

• Energy flux from the radio jets log FE ~ 42 – 42.4 erg/s

efficiency between 0.01 and 0.1

• From X-ray luminosity:acceleration of the gas due to radiationif coupled with dust (van Bemmel et al., Dopita et al.)

The acceleration of the gas should start on the pc scale

ATNF – July 2004

van Bemmel et al.

Energy flux estimate: case of 4C12.50 and OQ208

• log Energy flux ~ 40.4 – 41.1 erg/sfrom the HI outflows

big uncertainties: size of the HI and shock area

• Energy flux from the radio jets log FE ~ 42 – 42.4 erg/s

efficiency between 0.01 and 0.1

• From X-ray luminosity:acceleration of the gas due to radiationif coupled with dust (van Bemmel et al., Dopita et al.)

The acceleration of the gas should start on the pc scale Broad Line regions? Galaxies like 3C293: very low ionization

ATNF – July 2004

A possible scenario from the ionized gas


[OIII]

Young source surrounded by a cocoon of material left over from the even that trigger the radio source

Undisturbed gas

ATNF – July 2004

Young source surrounded by a cocoon of material left over from the even that trigger the radio source

Cooled & fragmented clouds: HI outflow?

A possible scenario from the neutral hydrogen

Undisturbed HI?molecular cloud

ATNF – July 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

~50 pc

ATNF – July 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

ATNF – July 2004

Jet-induced starformation

ATNF – July 2004

Considered to be very important for high-z radio galaxies,

Nearby examples:

Centaurus A

Minkowsky object (van Breugel et al. 1985)

Jet induced star formation (observations)

What do we learn from the HI?NGC 541

15 kpc

ATNF – July 2004

Cen-A Orientation: Jet and Filaments

• Jet/radio lobes extend 40 kpc from nucleus

• Emission line filaments (high ionization) extend ~20 kpc from nucleus

• Very turbulent (>200 km/s) over 1 arcsec, jet-cloud interaction?

photo-ionized by nucleus?

• Jet and filaments interrelated

– Induced star formation– ISM heating by

shocks /bulk motions

H

Outer filaments

Innerfilaments

Schiminovich et al. 1994

HICO

Charmandaris et al.

Radio

Morganti et al.

ATNF – July 2004

outer filament

H I cloud

H I ring at large radius, regular rotationOne H I cloud near outer filament & jetJet-induced star formation? Rejkuba et al. 2002

Graham 1998

Filaments contain young stars (10 Myr)

ATNF – July 2004

jet flow

blue: FUV from GALEX (Neff et al. AAS 2004)red : H from WFI ESO-2.2m

Outer filament: FUV + H

FUVH I H

young stars

~1kpc

shocks?

jet flow

Jet hitting HI cloud near the outer filament?

• UV emission from:

– young blue stars

– ionized gas in the filaments

• Far-UV “leads” optical continuum and line emission –> shocks?

ATNF – July 2004

Kinematical signature of interaction?

jet

Kinematics of H I ring smoothexcept at the southern tip!

velocity range of ionized gas

New ATCA data higher spatial (20’’) and velocity resolution (6 km/s)

Kinematical signature of interaction in the HI?

~1 kpc

Oosterloo & Morganti 2004

ATNF – July 2004

Recent results on the Minkowski object

Region of star formation: numerical simulations from Fragile, van Breugel et al. (2003)

ATNF – July 2004

Recent results on the Minkowski object

Morganti, van Breugel, van Gorkom, Oosterloo

Detected (VLA observations) a cloud of about 5 x 108 M of HIclose to the location of the starformation region

ATNF – July 2004

Some conclusions…..

Large amount of HI in regular disks observed in compact radio sources: (old) major mergers?

However, a variety of possible mergers at the origin of radio galaxies is derivedfrom the study of the stellar population.

HI with extreme kinematics observed in the nuclear regions of radio galaxies: mostly outflows

Interaction between the radio plasma and the ISM (or radiation pressure in some cases?)

The interaction between the radio jet and HI clouds can trigger star formations. Examples so far Centaurus A & Minkowski’s object

raffaella morganti (astron, nl) c. tadhunter,t. oosterloo, b. emonts, j. holt and many others atnf...

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