Dark matter in massive galaxies

The spatial distributions of luminous and dark matter in massive early-type galaxies reflect the formation processes which shaped these systems. This article reviews the predictions of cosmological simulations for the dark and baryonic components of ETGs, and the observational constraints from lensing, hydrostatic X-ray gas athmospheres, and outer halo stellar dynamics.Comment: Invited review, 10 pages, 1 figure, LaTeX. To appear in Proc. of IAU Symposium 295 held in Beijing, China, August 2012, eds. D. Thomas, A. Pasquali and I. Ferreras, Cambridge Univ. Pres

Formation Models of the Galactic Bulge

The Galactic bulge is now considered to be the inner three-dimensional part of the Milky Way's bar. It has a peanut shape and is characterized by cylindrical rotation. In N-body simulations, box/peanut bulges arise from disks through bar and buckling instabilities. Models of this kind explain much of the structure and kinematics of the Galactic bulge and, in principle, also its vertical metallicity gradient. Cosmological disk galaxy formation models with high resolution and improved feedback models are now able to generate late-type disk galaxies with disk-like or barred bulges. These bulges often contain an early collapse stellar population and a population driven by later disk instabilities. Due to the inside-out disk formation, these bulges can be predominantly old, similar to the Milky Way bulge.Comment: Invited talk, 5pp. To be published in "Resolved Stellar Populations in the Bulge and the Magellanic Clouds", a conference to celebrate the 50th anniversary of CTIO, May 2013, eds. Points, S. and Kunder, A. (ASP Conference Series, Astronomical Society of the Pacific

Planetary Nebulae Surveys Beyond the Local Group

Distant planetary nebulae (PNe) are used to measure distances through the PN luminosity function, as kinematic tracers in determining the mass distribution in elliptical galaxies, and most recently, for measuring the kinematics of the diffuse stellar population in galaxy clusters. This article reviews the photometric and spectroscopic survey techniques that have been used to detect PNe beyond the Local Group, out to the Coma cluster at 100 Mpc distance. Contaminations by other emission sources and ways to overcome them will be discussed as well as some science highlights and future perspectives.Comment: Invited Review, nine pages, three figures. In 'Planetary Nebulae in our Galaxy and Beyond', eds. Michael J. Barlow and Roberto H. Mende

The barred inner Milky Way: dynamical models from surveys

The Milky Way is a barred galaxy whose central bulge has a box/peanut shape and consists of multiple stellar populations with different orbit distributions. This review describes dynamical and chemo-dynamical equilibrium models for the Bulge, Bar, and inner Disk based on recent survey data. Some of the highlighted results include (i) stellar mass determinations for the different Galactic components, (ii) the need for a core in the dark matter distribution, (iii) a revised pattern speed putting corotation at ~6 kpc, (iv) the strongly barred distribution of the metal-rich stars, and (v) the radially varying dynamics of the metal-poor stars which is that of a thick disk-bar outside ~1 kpc, but changes into an inner centrally concentrated component with several possible origins. On-going and future surveys will refine this picture, making the Milky Way a unique case for studying how similar galaxies form and evolve.Comment: Invited review, 9pp, 7 figures, to be published in Proceedings of IAU Symposium 334, eds. C. Chiappini, I. Minchev, E. Starkenburg & M. Valentini, Cambridge Univ Pres