Raffaella Morganti (Astron, NL) C. Tadhunter,T. Oosterloo, B. Emonts, J. Holt and many others ATNF...
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Transcript of 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
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 +from HIPASS (and follow-up ATCA): statistical study of the occurrence and characteristics of HI in normal early-type galaxies.
80kpc
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 +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
Tadhunter et al. 1996
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
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
- 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
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
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
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
Tadhunter et al. 2001
[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