1. CDM cusps in LSB galaxies by means of stellar kinematics A.Pizzella, E.M.Corsini, F. Bertola Università di Padova And J. Magorrian, M. Sarzi University of Oxford

2.  Introduction  Observational results  Long-slit spectroscopy (FORS2)  IFU-VIMOS  Dynamical modeling  Does gas move in circular orbits in the inner regions ?  Cursy or not cuspy DM profiles ? Summary

3. Introduction LSB  μ B,0 > 22.6 mag/””  They are believed to be dark matter dominated  Test the prediction of cosmological simulations (Navarro et al. 1997, ApJ, 490, 493).  gas velocity curves. However this approach turned out to give ambiguous results.  stellar disk and the dark halo produce rotation curves very similar in shape;  it is never very clear up to which point the disk is responsible for the inner part of the rotation curve (de Blok, McGaugh & Rubin, 2001, AJ 122, 2396).

4. Additional osservational problems are: Centering of the slit; Non circular motion of the ionized gas; A way to solve this problems is: 2-D spectroscopy of the nuclear region Use the stellar kinematics:  Stellar and gaseous kinematics of major and minor axes (+ IFU for 2D gas kinematics).

5. Data for 11 galaxies: LSB with a bulge

6. ESO 234 –13 V=4703km/s Sbc 2.5’x2.5’

7. FORS2 Spectroscopy (~2h integration)

8. Dynamical models of the stellar kinematics Galaxy is assumed to be axisymmetric (biggest assumption in the whole process) Stellar light distribution by deprojecting the galaxy image. Constant M/L of the stellar component DM halo  r  Velocity ellipsoid shape/orientation free parameter. Jeans equations give kinematics Fit parameter using Metropolis algorithm NOTE: no use of gas kinematics

9. ESO 186 –55 V=4640km/s Sa 2.5’x2.5’

11. minor axis Major axis Dynamical model for ESO 186-55

12. Total Mass density (model) Deprojected Light The density radial profile seeing Last data point

13. Ionized gas Circular velocities predicted from model

14. ESO 186-55 IFU-VIMOS Velocity field H  flux [NII] flux  field continuum Velocity field

15. Circular modelResidual Ionized gas turbulent motion

16. Summary 1.Gas kinematics: non circular motions are significative in the ionized gas kinematics when studying the inner regions. Evidence from a.long-slit minor axis b.IFU velocity field c.Comparision with stellar kinematics mass models 2.Stellar kinematics (2 models untill now): in the inner region a.mass follows light b.DM is not cuspy

17. The End

18. end

19. We present the results of the spectroscopic observations of LSB. 11 objects (may have a bulge - Beijersbergen et al 1999) Stellar and gaseous kinematics of major and minor axes. VIMOS+IFU of the inner region R, z-band imaging

21. ESO 446-17 V=4193km/s Sb 1’=16kpc

23. ESO 534 -20 2’x2’ V=17320km/s Sa

25. Major axis minor axis

26. model Deprojected Light

27. Ionized gas Circular velocities from dynamical model

28. ESO 514 -10 (IC4538) V=2875km/s Sc

29. ESO 514 –10 Major Gas and Stars