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Galaxy evolution in the Virgo cluster. Bernd Vollmer CDS, Observatoire de Strasbourg. Interaction of a spiral galaxy with its environment. Gravitational interaction galaxy - cluster Gravitational interaction galaxy - galaxy Ram pressure galaxy ISM – intracluster medium (ICM).
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Galaxy evolution in the Virgo cluster Bernd Vollmer CDS, Observatoire de Strasbourg
Interaction of a spiral galaxy with its environment • Gravitational interaction galaxy - cluster • Gravitational interaction galaxy - galaxy • Ram pressure galaxy ISM – intracluster medium (ICM) (Böhringer et al. 1994) (Kenney et al. 1995) (Kenney et al. 2004)
Interaction diagnostics for Virgo cluster spiral galaxies • Observations: HI (VLA, Effelsberg), CO(1-0) (IRAM 30m), radio continuum (VLA) • Simulations: non-collisional and collisional N-body code (sticky particles) including ram pressure • Comparison of the gas distribution and velocity field
The Virgo Cluster 3 Mpc NGC4522 (Cayatte et al. 1990)
Observational gas characteristics • Extraplanar, high surface brightness gas (NGC 4522, NGC 4438) • Extraplanar, very low surface brightness gas (NGC 4388) • Perturbed, low surface brightness arms (NGC 4548, NGC 4569, NGC 4654, NGC 4254)
3 Mpc NGC4522 (Cayatte et al. 1990)
NGC 4522 (nearly edge-on disk) Contours: PI (Vollmer et al. 2004) Greyscale: B band Contours: PI Greyscale: HI (Kenney et al. 2004)
NGC 4522 Observations Model Grey: HI Contours: 6cm PI Grey: gas Contours: stellar disk
3 Mpc NGC4522 (Cayatte et al. 1990)
NGC 4438 Color: optical B band Spectra: IRAM 30m CO(1-0) (Kenney et al. 1995) (Vollmer et al. 2004)
NGC 4438 Model Grey: gas Contours: stars Model spectra CO(1-0) spectra
Observational gas characteristics • Extraplanar, high surface brightness gas (NGC 4522, NGC 4438) • Extraplanar, very low surface brightness gas (NGC 4388) • Perturbed, low surface brightness arms (NGC 4548, NGC 4569, NGC 4654, NGC 4254)
3 Mpc NGC4522 (Cayatte et al. 1990)
NGC 4388 20 kpc
NGC 4388 model observations (Vollmer & Huchtmeier 2003)
Observational gas characteristics • Extraplanar, high surface brightness gas (NGC 4522, NGC 4438) • Extraplanar, very low surface brightness gas (NGC 4388) • Perturbed, low surface brightness arms (NGC 4548, NGC 4569, NGC 4654, NGC 4254)
3 Mpc NGC4522 (Cayatte et al. 1990)
NGC 4548 3D visualization Grey: HI Contours: CO(1-0) (Vollmer et al. 1999)
3 Mpc NGC4522 (Cayatte et al. 1990)
NGC 4569 (Vollmer et al. 2004) Contours: HI VLA C+D Greyscale: B band
NGC 4569 (Vollmer et al. 2004) HI observations active stripping past stripping
3 Mpc NGC4522 (Cayatte et al. 1990)
NGC 4654 NGC4639 NGC4654 HI gas distribution HI velocity field (Phookun & Mundy 1995)
NGC 4654 (Vollmer 2003) gas distribution velocity field model I: ram pressure model II: ram pressure + tidal interaction HI observations (Phookun & Mundy 1995)
3 Mpc NGC4522 (Cayatte et al. 1990)
NGC 4254 (Vollmer 2004) Model: gravitational only Model: gravitational + ram pressure + evaporation/ expansion HI observations (Phookun et al. 1993) Solid: model spectra Dashed: Effelsberg HI spectra
Towards a time sequence of ram pressure stripping NGC 4438 NGC 4569 model model model model NGC 4388 NGC 4522 NGC 4548
Evolution of the polarised radio continuum emission NGC4654 (3cm, Effelsberg 100m) (Chyzy et al.) NGC4522 Grey: model gas distribution Contours: Model distribution of polarised radio continuum emission (6cm, VLA) (Vollmer et al.) (Otmianowska- Mazur & Vollmer 2003) NGC4254 (3.6cm, VLA) (Chyzy et al.)
Polarized radio emission in NGC4654 – simulations versus observations Observations Simulations Effelsberg 3cm :Chyzy et al. in prep.) (Soida et al. in prep.)