1. Dynamic and Spatial Properties of Satellites in Isolated Galactic Systems Abel B. Diaz

2. Presentation Outline Rotation Curves: Probing the mass distribution The Problem Rotation Curves of Isolated Galaxy Systems Stellar properties of Satellites The Holmberg effect 2D Rotation Curve

3. Rotation Curves: Probing the mass distribution Within Galaxy –Well known External to Galaxy –Not well known Fritz Zwicky (1933) Babcock (1939)&Vera Rubin (1970)

4. The Problem How does the mass distribution of galaxies change with distance beyond the disk of the galaxy?

5. What would this tell us? Learning more about the mass distribution of isolated galaxies may provide insight into galaxy –formation –evolution –LSS

6. So how can this be done? Rotation Curves of Isolated Galaxy Systems –Dominate source of gravitation The center-of-mass of the system is located at center of “primary” galaxy –Satellites relatively small compared to primary Maintains center-of-mass located at the center of primary

7. Limits on Isolated Galaxies 1.Small number of detectable satellites 2.Line-of-sight velocity 3.Projected distance

8. Isolated Galaxy Ensembles

9. Interlopers Observed redshift = cosmological redshift + Doppler redshift The peculiar velocities of the satellites can be on the order of 400km/s Uncertainty of distance along the line-of-sight

10. Velocity Dispersions McKay (2002), Prada et al (2003), and Brainerd (2004)

11. The Data Sample New York University Value-Added Galaxy Catalog (NYU-VAGC) –Lowz (Sub Sample of ~50,000 galaxies)

12. Ensembles

13. Robust Analysis

14. Velocity Dispersion Curve Prada et al (2003), and Brainerd (2004)

15. Galaxies Types

16. Early vs. Late Early type galaxies have larger halos than late type galaxies Conroy et al. (2007)

17. What These Results Tell Us Rotation curve (consistent with NFW) –Supports hierarchical scenario Halo sizes –Larger primordial dark matter halos for early type galaxies than for late type galaxies

18. Stellar Properties How does the satellite stellar properties change as a function of distance from the primary? –Star formation from self gravity or tidal effects from primary

19. Stellar properties of Satellites

20. What Does This Mean Primaries cause "tidal" effects on their satellites –Kosh and Grebal (2006) More pronounced in satellites with primaries that have a larger mass (halo) Different distribution in Systems at larger z (longer ago)

21. The Holmberg Effect Holmberg (1969)

22. Modeling Check for Isotropy –polar fraction ~0.70 –Mean  = 45 degrees Interloper check –P/T >> 0.5

23. Results for Primary tilt < 30 o No Holmberg found in my data Kolmogorov-Smirnov (KS) test

24. Results for Varying tilts angle No Holmberg found in my data

25. Binned Results for Primary tilt < 30 o Brainerd (2005) Sales & Lambas (2004), Koch & Grebel (2006) Zaritsky et al. (1997)

26. Binned Results for Primary tilt > 60 o

27. What does this tell us? Dark Matter halo –Spherical Puts constraints on models –Infall through fillaments

28. 2D Velocity Dispersions Velocity Distribution –Isotropic about primary DM halo –Spherical

29. Conclusion The Dynamic Properties –Dark Matter Halos Different sizes for different type of galaxies Consistent with NFW (hierarchical scenario) The Spatial Properties –Satellites are isotropically distributed, and have isotropic velocity distribution Spherical Dark Matter Halo –Star formation depends on distance from their primary Primaries effect their satellites