Download Presentation
## dSph Masses

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -

**dSph Masses**Matthew Walker – IoA, Cambridge with Mario Mateo - U. Michigan Edward Olszewski - U. Arizona Jorge Peñarrubia - IoA Wyn Evans - IoA Gerry Gilmore - IoA --Stay tuned for Joe Wolf’s talk too-- Extreme Star Formation in Dwarf Galaxies Ann Arbor, 28 July, 2009**Velocity Dispersion Profiles**Walker etal (arXiv:0906.0341)**Kinematics with the Jeans Equation**1) Jeans Eq. (spherical) 2) Solution in terms of observables 3) Adopt Hernquist Halo Model Free Parameters V_max, r_scale, alpha, gamma, beta=constant --> Core --> NFW Cusp**Fornax: Vmax = 20 +/- 4 km/s**arXiv:0906.0341**M(rhalf) for 8 “classical” dSphs**• Robust to large ranges for r0, alpha, gamma, beta arXiv:0906.0341**Simple Mass Estimator**Jeans Eq. Isotropy, flat vdisp profile -->**Simple Mass Estimator**c.f. Strigari et al. 2008**Data for 28 Satellites**arXiv:0906.0341**A Universal Mass Profile?**arXiv:0906.0341**Velocity Dispersion vs. Size**arXiv:0906.0341**Universal Mass Profile?**arXiv:0906.0341**Scatter wrt Universal Profile and M300**arXiv:0906.0341