1 / 30

Raffaella Morganti (Astron)

Outflows of neutral hydrogen in AGN. 1500 km/s. Raffaella Morganti (Astron). T. Oosterloo, C. Tadhunter, B. Emonts , J. Holt. Extra-planar Gas – Dwingeloo, June 2004. Planar and extra-planar HI in AGNs. Detection of neutral hydrogen in the central regions of active galaxies:

azize
Télécharger la présentation

Raffaella Morganti (Astron)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Outflows of neutral hydrogen in AGN 1500 km/s Raffaella Morganti(Astron) T. Oosterloo, C. Tadhunter, B. Emonts , J. Holt Extra-planar Gas – Dwingeloo, June 2004

  2. Planar and extra-planar HI in AGNs Detection of neutral hydrogen in the central regions of active galaxies: commonly associated with circumnuclear tori/disks. NGC 4261 but this 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.

  3. 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

  4. Importance of gas and outflows in high-z radio galaxies 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 Pentericci et al. Large Ly halos At low-z these effects are less extreme but…

  5. 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

  6. Gas outflows in Seyfert galaxies Blue-shifted absorption lines in many species of several hundred to over 1000 km/s. Kriss et al. 1995 Hutchings et al. 1998

  7. Starburst winds • AGN (radiation) driven outflow • Jet driven outflows Possible origin of outflows in AGNs 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

  8. 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

  9. 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)

  10. 100pc VLBI (Stanghellini et al.) HST image in [OIII] (Axon et al.) 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 ADD FIGURA?????

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

  12. Other cases: 3C459 Optical depthof the broad absorption  ~0.05% 800 km/s ~2 kpc Thomasson et al. 2003

  13. Broad HI absorption in 3C305 MERLIN+HST ~ ~1000 km/s ~3 kpc Jackson et al. 2002 WSRT observations Optical depthof the broad absorption  ~0.08%

  14. What we find so far: • 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 mostly blueshifted (compared to • the systemic velocity)  outflows Next - Location of the absorption - Relation with the ionized gas

  15. HI OII Ionized and neutral gas in 3C293 Blueshifted wing at location of lobe it would correspond to a mass of the HI ~3x106 Msun Core 1’’ red: radio continuum (MERLIN, Beswick et al.) blue: CO (Evans et al.) Emonts et al. in prep

  16. [OIII]4959,5007 fit with 3 components Ionized and neutral gas in 4C12.50 Holt et al. 2003 • blueshifted component(s) also in the ionized gas • broader width compared to HI Stratified outflow: broader (and highly reddened) component of ionized gas coming from the inner regions Young source surrounded by (and interacting with ) a cocoon of material left over from the even that trigger the radio source.

  17. No HI absorption in high resolution (VLBI) data Other cases: 3C459 Optical depthof the broad absorption  ~0.05% 800 km/s ~2 kpc Thomasson et al. 2003

  18. 3C459: HI and ionised gas in this case, is the deeper HI component to be blueshifted [OIII] • width of the ionized • gas much larger

  19. 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 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

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

  21. 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 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? • The width of the optical lines could be systematically larger: could indicate that they come from different regions?

  22. 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

  23. Interaction between the radio jet and ISM: a possible scenario

  24. 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?

  25. 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 …………

  26. ~ 1500 km/s WSRT Optical depthof the peak absorption  ~0.3% Some new cases…… 4C37.11 VLBA Taylor et al. (2004) Very little known about the optical …………

  27. 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

  28. If the interaction between the radio emission and the ISM is so important 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)

  29. “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 Mass of the HI cloud ~105-6 Msun Morganti et al. 2004 A&A in press

  30. Conclusions • Fast outflows (~ 1000 km/s) and disturbed kinematics of the neutral hydrogen in the central regions of radio galaxies • Relatively large number of objects with broad HI absorption in radio galaxies with young stellar population: suggesting a rich medium around these radio sources? • Fast HI outflows possibly coming from jet interacting with the ISM • 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.

More Related