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Raffaella Morganti (Astron, NL) C. Tadhunter ,T. Oosterloo, B. Emonts, J. Holt and many others

The interplay between radio-activity and the ISM in radio galaxies. Raffaella Morganti (Astron, NL) C. Tadhunter ,T. Oosterloo, B. Emonts, J. Holt and many others. ATNF – July 2004. Radio galaxies typically hosted by an early-type galaxy:

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Raffaella Morganti (Astron, NL) C. Tadhunter ,T. Oosterloo, B. Emonts, J. Holt and many others

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  1. The interplay between radio-activity and the ISM in radio galaxies Raffaella Morganti (Astron, NL) C. Tadhunter ,T. Oosterloo, B. Emonts, J. Holt and many others ATNF – July 2004

  2. 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) • structure and physical conditions in • circumnuclear tori • nuclear outflows and feedback • star formation induced by the interaction between the radio jet and the HI?

  3. H I (Hibbard et al.) NGC 7252 an elliptical forming now light profile is r1/4 shallow, deeper and deep images Schweizer 1982 deep images reveal irregular features in outer regions  NGC 7252 is elliptical formed by gas-rich merger

  4. HI and early-type galaxies HI total intensity + optical (ATCA data) Oosterloo et al. 2001 200 kpc Sadler, Oosterloo & Morganti Results from ATCA +VLA + from HIPASS (and follow-up ATCA): statistical study of the occurrence and characteristics of HI in normal early-type galaxies. 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

  5. HI and early-type galaxies 80kpc Results from ATCA + from HIPASS (and follow-up ATCA): statistical study of the occurrence and characteristics of HI in normal early-type galaxies. 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

  6. HI and early-type galaxies HI total intensity + optical (ATCA data) 200 kpc Sadler, Oosterloo & Morganti Results from ATCA + from HIPASS (and follow-up ATCA): statistical study of the occurrence and characteristics of HI in normal early-type galaxies. 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

  7. HI observation of early-type galaxies: The great majority of the detections are large, regular disks (Oosterloo et al. in prep) ATCA 80kpc 190kpc 230kpc 180kpc

  8. 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) 107M (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%!!! NGC 4278 NGC 3414 ‘complicated kinematics’ Morganti, Oosterloo, de Zeeuw et al. HI very often detected in early-type (and sometimes in large amount) tracing origin  external, (major) mergers These are mainly radio quiet galaxies: any connection to radio loud galaxies?

  9. Are radio galaxies the results of major mergers?(Merger as a way to bring the gas to the central regions) 3C 293 Morphological features: double nuclei, arcs, tails and bridges Molecular gas (CO) Radio cont. (5 GHz) also emission line kinematics consistent with accretion origin (Tadhunter et al. 1989; Baum et al. 1990) 4C 12.50 ~ 5 kpc (5’’) Nuclear concentration of molecular gas (Evans et al. 1999,2004) Heckman et al. 1986 HST image+ CO contours • presence of a starburst phase • rich ISM in the central regions (at least in the initial phase of the AGN)

  10. HI in radio galaxies: Do we see similar structures as in “normal” early-type? ATCA Southern radio galaxy PKS B1718-649 Very extended disk with more than 1010 Mof HI Total HI intensity 100 kpc <10pc VLBI continuum (Tingay et al. 1997) Veron-Cetty et al. 1995 Survey of radio galaxies in HI to look for similar extended structures (Emonts PhD thesis)

  11. 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 ~40 kpc NGC 612 ATCA (Emonts et al. in prep.) How about the large HI disks? so far large, HI-rich disks (~1010 Msun of HI) have been found only in compact radio galaxies

  12. Very extended HI disks in radio galaxies ~1kpc 125 kpc ~160 kpc HI total intensity Emonts et al. in prep. ~1kpc Both compact radio galaxies  young (<<107 yr) Morganti et al. 2003 WSRT more than 1010 Mof HI! remarkably regular distribution and kinematics

  13. HI to define an evolutionary sequence? Hibbard et al. AGN phase : >109 yr Many 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 ? The age of the merger derived (to first order) from the HI will need to be compared with the stellar population analysis. long-lived HI structures

  14. Complex morphology of the ionized gas and neutral hydrogen (with similar kinematics) Tadhunter et al. 2000 30 kpc HI absorption Morganti et al. 2002 Radio lobes expanding into gas disk 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! • selection effects? • the gas is ionized? (see Coma A) • different type of merger? • environment?

  15. Origin of radio galaxies: the study of the stellar population

  16. Recent results from the study of the stellar population Tadhunter et al., Wills et al. 2002, 2003 • 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 produce circum-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 3C321 old stellar pop. young stellar pop. power law Tadhunter et al. 1996

  17. Evolution of the host galaxy from the YSP Results on 3C293, 3C305 and 4C12.50 (Tadhunter, Robinson, Gonzalez-Delgado et al. 2004) Assuming instantaneous burst model (BC96) ULIG • 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 LIG 3C305 LBOL 3C293 • consistent with AGN activity (in some radio galaxies) triggered by major merger • AGN appears late after the merger Age (Gyr)

  18. How about the radio galaxies with no YSP? Also from the study of the stellar population, different type of mergers at the origin of radio galaxies 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 Wills et al. 2002

  19. The nuclear regions

  20. extra-gas surrounding the AGN, e.g. left over from the merger that triggered the AGN shocks radiation radio jet HI absorption from the torus/circumnuclear disk Study of these phenomena using HI (in absorption) The nuclear regions Gas outflows often detected. Relevance for the evolution of the AGN.

  21. Extended HI absorption (against the Ly ) • Starburst winds van Ojik et al. • AGN (radiation) driven outflow • Jet driven outflows Kriss et al. 1995 Blue-shifted absorption lines in many species of several hundred to over 1000 km/s. Possible origin of outflows in AGNs Hutchings et al. 1998 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

  22. 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

  23. Broad HI absorption in 3C293 broad, shallow absorption by neutral gas WSRT Broad absorption ~0.15% NH~2 x 1020 cm-2 for TSPIN=100K Deep absorption: Haschick & Baan (1985) Beswick et al. (2002) Morganti et al. ApJL (2003)

  24. Broad HI absorption in 4C12.50 WSRT observations, 20 MHz band • Broad HI absorption: • full width of ~2000 km/s • mostly blueshifted Broad absorption  ~0.2% NH~1020 cm-2 for TSPIN=100K 100pc ADD FIGURA????? VLBI (Stanghellini et al.) HST image in [OIII] (Axon et al.)

  25. Broad HI absorption in 3C236 ~1500 km/s Optical depthof the broad absorption  ~0.15% Schilizzi et al. 2001 O’Dea et al. 2001

  26. WSRT 1500 km/s Optical depthof the peak absorption  ~0.5% A recent new case: OQ208 • known to have fast outflow in the broad emission lines (Marziani et al.) • particularly rich medium from X-ray absorption: radio jets possibly piercing their way through a Compton-thick medium pervading the nuclear environment (Guainazzi et al. 2004) ~10 pc Stanghellini et al. 1993 NH~8x1020 cm-2 for TSPIN=100K

  27. What we find so far: • 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 • In these objects the broad HI is mostly blueshifted (compared to the systemic velocity)  outflows …but not always……

  28. ~ 1500 km/s WSRT Optical depthof the peak absorption  ~0.3% …..just to make everything more complicated…… 4C37.11 VLBA Taylor et al. (2004) Redshifted component  detected also by the VLBI Blueshifted component  detected only by low resolution observations (WSRT)

  29. Next - Location of the absorption - Relation with the ionized gas What we find so far: • 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 • In these objects the broad HI is mostly blueshifted (compared to the systemic velocity)  outflows

  30. IC 5063 Seyfert • H Idisk rotating • aligned with the dust lane • broad, blue-shifted (~700km/s) • H Iabsorption H IPosition-velocity slice along major axis (PA 120) Triple radio structure aligned along dust lane ATCA (8 GHz) + HST WFPC2 [O III]5007 image VLBI: absorption against lobe Morganti et al. 1997; Oosterloo et al. 1999

  31. H+[NII] Vel ~4arcsec circa 1.3kpc radio core ATCA & NTT The case of the radio-loud Seyfert IC 5063 ATCA – 17 GHz Morganti, Saripalli, Subrahmanyan, Oosterloo

  32. Eastern radio hot-spot [SII] Fast outflow of ionized gas! FWHM = ~1000 km/s Blueshifted by ~500 km/s Densities: Also seen in other lines, e.g. [OII] Narrow: ~102 cm-3 Broad: ~103 cm-3 flux l [SII]

  33. What we find so far: • 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 • In these objects the broad HI is mostly 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?

  34. What produces the HI outflows Despite the very energetic phenomena involved, gas remains - or becomes again - neutral Insight on the physical conditions of the medium around the AGN • 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.) • Interaction between the radio jet and ISM

  35. Energy flux estimate: case of 4C12.50 and OQ208 • log Energy flux ~ 40.4 – 41.1 erg/s • from 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 radiation • if coupled with dust • (van Bemmel et al., Dopita et al.) • The acceleration of the gas should start • on the pc scale

  36. Energy flux estimate: case of 4C12.50 and OQ208 • log Energy flux ~ 40.4 – 41.1 erg/s • from 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 radiation • if coupled with dust • (van Bemmel et al., Dopita et al.) • The acceleration of the gas should start • on the pc scale

  37. van Bemmel et al. Energy flux estimate: case of 4C12.50 and OQ208 • log Energy flux ~ 40.4 – 41.1 erg/s • from 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 radiation • if 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

  38. Undisturbed gas [OIII] A possible scenario from the ionized gas Young source surrounded by a cocoon of material left over from the even that trigger the radio source Tadhunter et al. 2001

  39. molecular cloud Undisturbed HI? Cooled & fragmented clouds: HI outflow? A possible scenario from the neutral hydrogen Young source surrounded by a cocoon of material left over from the even that trigger the radio source

  40. “Fighting” its way out black=WSRT red = VLBI Integrated HI profile dense cloud radio jet 2D simulations Bicknell et al. 2003 Rich ISM against which the jet has to fight against in order to expand out of the galaxy VLBI High column density (NH~1022cm-2) HI absorption 4C12.50 Core ~50 pc Mass of the HI cloud ~105-6 Msun Morganti et al. 2004 A&A in press

  41. What jet/cloud interaction can do for us? Mellema et al. 2002 Simulations show that cooled fragmented clouds do form as result of the interaction Mellema et al. 2002, Fragile et al. 2003 Evolution of clouds in radio galaxy cocoons: shock runs over a cloud compression phase (overpressured cocoon) fragmentation & cooling formation of dense, cool & fragmented structures looks promising also to explain the broad HI BUT can the fragmented clouds be accelerated to such high velocities?

  42. Jet-induced starformation

  43. Jet induced star formation (observations) Considered to be very important for high-z radio galaxies, Nearby examples: Centaurus A Minkowsky object (van Breugel et al. 1985) What do we learn from the HI? 15 kpc NGC541

  44. 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 Radio CO HI Charmandaris et al. Schiminovich et al. 1994 Morganti et al. Cen-A Orientation: Jet and Filaments H Outer filaments Inner filaments

  45. Filaments contain young stars (10 Myr) H I cloud Graham 1998 outer filament H I ring at large radius, regular rotation One H I cloud near outer filament & jet Jet-induced star formation? Rejkuba et al. 2002

  46. Outer filament: FUV + H blue: FUV from GALEX (Neff et al. AAS 2004) red : H from WFI ESO-2.2m jet flow • UV emission from: • young blue stars • ionized gas in the filaments • Far-UV “leads” optical continuum and line emission –> shocks? FUV H I Ha jet flow shocks? ~1kpc young stars Jet hitting HI cloud near the outer filament?

  47. Kinematical signature of interaction in the HI? New ATCA data higher spatial (20’’) and velocity resolution (6 km/s) Kinematics of H I ring smooth except at the southern tip! velocity range of ionized gas jet ~1 kpc Kinematical signature of interaction? Oosterloo & Morganti 2004

  48. Recent results on the Minkowski object Region of star formation: numerical simulations from Fragile, van Breugel et al. (2003)

  49. Morganti, van Breugel, van Gorkom, Oosterloo Recent results on the Minkowski object Detected (VLA observations) a cloud of about 5 x108 Mof HI close to the location of the starformation region

  50. 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 derived from 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

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