Sydney, 23 July 2003 Joint Discussion 18: Quasar cores & jets Central Regions of AGNs probed by the Neutral Hydrogen Raffaella Morganti ASTRON Netherlands Foundation for Research in Astronomy, Dwingeloo in collaboration with Tom Oosterloo, Clive Tadhunter and many others

Sydney, 23 July 2003 Joint Discussion 18: Quasar cores & jets HI detected in absorption against the nuclear regions: Gas settled: circumnuclear disks/tori relevant for unified schemes Gas unsettled: infalling gas (feeding the AGN) cocoon of gas surrounding the central regions gas outflows (feedback effects) The gas in the central regions

Sydney, 23 July 2003 Joint Discussion 18: Quasar cores & jets HI detections presence of HST dust disks absence of optical core. Low detection rate (~10%) of HI absorption: supporting the idea of thin disks in FRI. Low luminosity radio galaxies: thin nuclear disks? (van Langevelde et al. 2000) NGC 4261

Sydney, 23 July 2003 Joint Discussion 18: Quasar cores & jets Powerful radio galaxies: atomic obscuring tori? Constrains on the properties of the obscuring gas HI and X-ray in the Compact Steep Spectrum Peck, Taylor & Conway 1999 Risaliti, Woltjer & Salvati 2003 High detection rate of HI absorption in compact radiogalaxies (Conway 1996) ideal background to detected nuclei tori? Also radio galaxies with young stellar population show an high detection rate of HI absorption. Tracer of a particular stage in the evolution of the galaxy? or a particular merger that trigger the radio source? HI tracing unsettled gas: the most interesting part of the story? (Conway 1996) -40 km/s +40 km/s Cygnus A Atomic torus r>15pc

Sydney, 23 July 2003 Joint Discussion 18: Quasar cores & jets HI detected in absorption against the nuclear regions: Gas settled: circumnuclear disks/tori relevant for unified schemes Gas unsettled: infalling gas (feeding the AGN) cocoon of gas surrounding the central regions gas outflows (feedback effects) The gas in the central regions

Sydney, 23 July 2003 Joint Discussion 18: Quasar cores & jets Infalling gas: no evidence from recent HI observations NGC 315 redshifted narrow HI absorption: extended, tidal debris at large distance from the nucleus? (Peck 1999, Morganti et al. 2002) Vermeulen et al Sample of compact sources

Sydney, 23 July 2003 Joint Discussion 18: Quasar cores & jets HI detected in absorption against the nuclear regions: Gas settled: circumnuclear disks/tori relevant for unified schemes Gas unsettled: infalling gas (feeding the AGN) cocoon of gas surrounding the central regions gas outflows (feedback effects) The gas in the central regions

Sydney, 23 July 2003 Joint Discussion 18: Quasar cores & jets Young radio sources surrounded by a cocoon of material left over from the even that trigger the activity A possible scenario for young (or restarted) radio galaxies Outflows of ionized gas observed : how about the HI?

Sydney, 23 July 2003 Joint Discussion 18: Quasar cores & jets Broad HI absorption in 4C12.50 "Deep" Absorption only 1%, N H ~2x10 20 cm -2 for T SPIN =100K Broad absorption ~0.2% N H ~10 20 cm -2 for T SPIN =100K WSRT observations, 20 MHz band Broad HI absorption: full width of ~2000 km/s mostly blueshifted (already known from Mirabel 1989) Correspondence with ionized gas

Sydney, 23 July 2003 Joint Discussion 18: Quasar cores & jets Broad HI absorption in 3C293 WSRT Deep absorption: Haschick & Baan (1985) Beswick et al. (2002) New broad, shallow absorption Morganti et al. ApJL (astro-ph/ ) Broad absorption ~0.15% N H ~2 x cm -2 for T SPIN =100K HI OII

Sydney, 23 July 2003 Joint Discussion 18: Quasar cores & jets Broad HI absorption more common? A recent candidate: 3C km/s Correspondence with ionized gas PKS ATCA data [OIII] 4959,5007Å ESO-NTT 3C459 an other candidate?

Sydney, 23 July 2003 Joint Discussion 18: Quasar cores & jets Where is the HI located? the VLBI follow up What is the origin of the gas outflows?

Sydney, 23 July 2003 Joint Discussion 18: Quasar cores & jets What produces the HI outflows? Despite the highly energetic phenomena involved, gas remains (or become again) neutral Insight on the physical conditions of the medium around the AGN Mellema et al Evolution of clouds in radio galaxy cocoons shock runs over a cloud compression phase (overpressured cocoon) fragmentation & cooling formation of dense, cool & fragmented structures Can they reach the high velocities observed? Starburst wind Radiation pressure (Dopita et al.) but very different ionization in the objects detected Interaction between the radio jet and ISM

Sydney, 23 July 2003 Joint Discussion 18: Quasar cores & jets VLBI absorption against brightest lobe! OUTFLOW! Oosterloo et al The case of the Seyfert galaxy IC 5063

Sydney, 23 July 2003 Joint Discussion 18: Quasar cores & jets Optical and HI data for the Seyfert galaxy IC 5063 [OIII] 4959, 5007 Å H +[NII] ~4arcsec circa 1.3kpc radio core 400 km/s ATCA & NTT

Sydney, 23 July 2003 Joint Discussion 18: Quasar cores & jets 4C12.50: High resolution follow up 4C12.50: new global VLBI experiment 5 GHz (Stanghellini et al.) core ~250 pc Continuum image (~ 20x4 mas beam)

Sydney, 23 July 2003 Joint Discussion 18: Quasar cores & jets Where is the HI? 100 pc ~30%, N H ~3x10 21 for T SPIN =100K black=WSRT red = VLBI Integrated HI profile Mass of the HI cloud ~ M sun

Sydney, 23 July 2003 Joint Discussion 18: Quasar cores & jets 2D simulations Bicknell et al.

Sydney, 23 July 2003 Joint Discussion 18: Quasar cores & jets Conclusions The location of the HI can be a surprise: follow up at higher resolution are important! HI outflows: very broad HI absorption observed in some radio galaxies. We now need complete statistics. Difficult to detect due to technical limitations SO FAR: very broad HI absorption in objects with rich ISM & young stellar population Tracer of a particular stage in the evolution of the galaxy? or a particular merger that trigger the radio source? Possibly resulting from radio jets strongly interacting with the rich medium Not all the HI in the central region of radio galaxies is in circumnuclear disk/tori. But no strong evidence for HI infall.

Sydney, 23 July 2003 Joint Discussion 18: Quasar cores & jets HI emission ~ 160 kpc M HI ~ 1.1 x M sun B : HI-rich, compact radio galaxy Morganti et al. A&A 2003 WSRT Large amount of HI: major merger origin ~1kpc The large-scale gas can trace the origin of these systems. Centaurus A (Schiminovich et al. 2000) PKS B (Veron-Cetty et al. 1995) HI emission the gas ends up in the central kpc and provides the rich ISM around the BH

Sydney, 23 July 2003 Joint Discussion 18: Quasar cores & jets V sys

Sydney, 23 July 2003 Joint Discussion 18: Quasar cores & jets Ionized gas & HI [OIII]4959,5007 fit with 3 components ?

Sydney, 23 July 2003 Joint Discussion 18: Quasar cores & jets Complex morphology of the ionized gas and neutral hydrogen (with similar kinematics) Radio sources can live in gas rich galaxies 30 kpc Coma A Morganti et al HI Tadhunter et al. 2000

Sydney, 23 July 2003 Joint Discussion 18: Quasar cores & jets BUT: only an handful of extended powerful radio galaxies detected so far: radio cores too weak. Powerful radio galaxies: atomic obscuring tori? Constrains on the properties of the obscuring gas (Conway 1996) -40 km/s +40 km/s Cygnus A Atomic torus r>15pc

Sydney, 23 July 2003 Joint Discussion 18: Quasar cores & jets HI absorption mainly in compact sources? HI tracing unsettled gas: the most interesting part of the story? More complete picture now: also radio galaxies with young stellar population show an high detection rate of HI absorption. Peck, Taylor & Conway 1999 Risaliti, Woltjer & Salvati 2003 HI and X-ray in the Compact Steep Spectrum Tracer of a particular stage in the evolution of the galaxy? or a particular merger that trigger the radio source?

Sydney, 23 July 2003 Joint Discussion 18: Quasar cores & jets Molecular cloud regularly rotating gas shocked, ionized gas cooled, fragmented HI clouds

Sydney, 23 July 2003 Joint Discussion 18: Quasar cores & jets Low luminosity radio galaxies: thin nuclear disks? N H cm -2 for T SPIN =100K ~ 1 kpc