1. Euro3D Kick-off Meeting, IAC July 2002 Studying Galaxy Clusters with IFUs Studying Clusters of Galaxies with IFUs Marco Scodeggio, Bianca Garilli, Dario Maccagni, Micol Bolzonella, Paolo Franzetti, Alessandra Zanichelli * IASF - CNR, Milano, Italy *IRA - CNR, Bologna, Italy

2. Euro3D Kick-off Meeting, IAC July 2002 Why study clusters of galaxies 1. for themselves, as tracers of the large-scale distribution of matter in the Universe 2. for the galaxies they "contain", to study the processes of galaxy formation and evolution

3. Euro3D Kick-off Meeting, IAC July 2002 2dF Galaxies (Peacock et al. 2001) REFLEX Clusters (Guzzo 2002)

4. Despite the different density of objects, galaxies and clusters trace the same 3D structures, with clusters covering (potentially) larger volumes (Guzzo 2002) Notice how the best fitting model is just one, the same for galaxies and for clusters, scaled to the different "mass" of these objects Euro3D Kick-off Meeting, IAC July 2002

5. Evolution of cluster abundance with redshift (Bahcall & Fan 1997) No evolution for a low  0 Universe Strong evolution for a high  0 Universe

6. Euro3D Kick-off Meeting, IAC July 2002 Galaxy properties: the Fundamental Plane From the Virial theorem we have : GM/ = k E /2 The observed quantities can be related to the physical ones via R e = k R ;  2 = k V ; L = k L R e 2  And one derives the relation: R e = k FP  2  -1 (M/L) -1 To be compared with the observed one: Log R e = a Log  + b Log  with coefficients a Y 1.5 and b Y - 0.85

7. Euro3D Kick-off Meeting, IAC July 2002 Local Universe High -z Universe (Scodeggio et al. 1997) (Kelson et al. 1997)

8. Euro3D Kick-off Meeting, IAC July 2002 (van Dokkum 2001) Evolution of the M/L ratio with redshift, and implications on the formation epoch of cluster elliptical galaxies

9. Euro3D Kick-off Meeting, IAC July 2002 How to study clusters of galaxies 1. from a survey, build a candidates sample 2. confirm spectroscopically the candidates (and get a measure of the cluster redshift) 3. study in detail the cluster and its galaxies (obtain spectra for many cluster galaxies)

10. Euro3D Kick-off Meeting, IAC July 2002 The spectroscopic work is trivial at low redshift (z < 0.1) but becomes very difficult at medium / high redshift (z > 0.5) (Dickinson 1997)

11. Euro3D Kick-off Meeting, IAC July 2002 Targetting cluster galaxies: the MOS case

12. Euro3D Kick-off Meeting, IAC July 2002 Targetting cluster galaxies: the IFU case

13. Euro3D Kick-off Meeting, IAC July 2002 IFU dominates over MOS for clusters work Same limiting magnitude Same exposure time

14. Euro3D Kick-off Meeting, IAC July 2002 Conclusions 1. MOS observations are not well suited for studying medium/ high redshift clusters (z > 0.5), as they not even always provide enough redshifts to confirm the cluster presence 2. IFU observations, on the contrary, always provide enough data to confirm the cluster presence, and most of the time also enough data to study the cluster properties and build a significant sample of cluster galaxies 3. The number of target cluster galaxies in deep IFU observations depends very mildly on the cluster redshift

15. Euro3D Kick-off Meeting, IAC July 2002 To be continued....