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We present intermediate-resolution (R$\sim$1000) spectra in the $\sim$3500-10,000 A range of 14 globular clusters in the magellanic irregular galaxy NGC 4449 acquired with the Multi Object Double Spectrograph on the Large Binocular Telescope. We derived Lick indices in the optical and the CaII-triplet index in the near-infrared in order to infer the clusters' stellar population properties. The inferred cluster ages are typically older than $\sim$9 Gyr, although ages are derived with large uncertainties. The clusters exhibit intermediate metallicities, in the range $-1.2\lesssim$[Fe/H]$\lesssim-0.7$, and typically sub-solar [$\alpha/Fe$] ratios, with a peak at $\sim-0.4$. These properties suggest that i) during the first few Gyrs NGC 4449 formed stars slowly and inefficiently, with galactic winds having possibly contributed to the expulsion of the $\alpha$-elements, and ii) globular clusters in NGC 4449 formed relatively "late", from a medium already enriched in the products of type Ia supernovae. The majority of clusters appear also under-abundant in CN compared to Milky Way halo globular clusters, perhaps because of the lack of a conspicuous N-enriched, second-generation of stars like that observed in Galactic globular clusters. Using the cluster velocities, we infer the dynamical mass of NGC 4449 inside 2.88 kpc to be M($, Comment: Accepted for publication in MNRAS; corrected typo in author list

We present high-precision multi-band photometry for the globular cluster (GC) M2. We combine the analysis of the photometric data obtained from the Hubble Space Telescope UV Legacy Survey of Galactic GCs GO-13297, with chemical abundances by Yong et al.(2014), and compare the photometry with models in order to analyze the multiple stellar sequences we identified in the color-magnitude diagram (CMD). We find three main stellar components, composed of metal-poor, metal-intermediate, and metal-rich stars (hereafter referred to as population A, B, and C, respectively). The components A and B include stars with different $s$-process element abundances. They host six sub-populations with different light-element abundances, and exhibit an internal variation in helium up to Delta Y~0.07 dex. In contrast with M22, another cluster characterized by the presence of populations with different metallicities, M2 contains a third stellar component, C, which shows neither evidence for sub-populations nor an internal spread in light-elements. Population C does not exhibit the typical photometric signatures that are associated with abundance variations of light elements produced by hydrogen burning at hot temperatures. We compare M2 with other GCs with intrinsic heavy-element variations and conclude that M2 resembles M22, but it includes an additional stellar component that makes it more similar to the central region of the Sagittarius galaxy, which hosts a GC (M54) and the nucleus of the Sagittarius galaxy itself., 12 pages, 7 figures, accepted for publication in MNRAS

We present dynamical models of the nearby compact elliptical galaxy M32, using high quality kinematical measurements, obtained with the integral-field spectrograph SAURON mounted on the William Herschel Telescope on La Palma. We also include STIS data obtained by Joseph et al. We find a best-fit black hole mass of (2.5 +/- 0.5) million solar masses and a stellar I-band mass-to-light ratio of (1.85 +/- 0.15) in solar units. For the first time, we are also able to constrain the inclination along which M32 is observed to (70 +/- 5) degrees. Combined with an averaged observed flattening of 0.73, this corresponds to an intrinsic flattening of approximately 0.68 +/- 0.03. These tight constraints are mainly caused by the use of integral-field data. We show this quantitatively by comparing with models that are constrained by multiple slits only. We show the phase-space distribution and intrinsic velocity structure of the best-fit model and investigate the effect of regularisation on the orbit distribution., 10 pages, 9 figures, accepted for publication by MNRAS; version with full resolution Fig.1 available at http://www.strw.leidenuniv.nl/~verolme/papers.html

The contour integral method of Hunter & Qian is applied to axisymmetric galaxy models in which the distribution function (DF) is of the form f=f(E,L_z), where E and L_z are the classical integrals of motion in an axisymmetric potential. A practical way to construct the unique even part of the DF for such systems is presented. It is applied to models, both oblate and prolate, in which the mass density is stratified on similar concentric spheroids. The spheroids with scale-free densities are discussed in detail. These provide useful approximations to the behaviour of more realistic models in the limit of small and large radii. The self-consistent case is treated, as well as the case in which there are additional contributions to the potential from a central black hole or dark halo. The range of axis ratios and density profile slopes is determined for which spheroidal power--law cusps with a central black hole have a physical two--integral DF. More generally, the f(E,L_z) DFs are discussed for a set of spheroidal `(alpha,beta)-models', characterized by a power-law density cusp with slope alpha at small radii, and a power-law density fall-off with slope [alpha + 2 beta] at large radii. As an application, the DF is constructed for the (alpha,beta) model with a 1.8 x 10^6 solar mass black hole used by van der Marel et al. to interpret their high spatial resolution spectroscopic data for M32. The results confirm that the model fits the observed line-of-sight velocity profiles remarkably well. The model is used to calculate predictions for future spectroscopic observations with the HST.

The Jeans equations are used to study the galactic halo. Relations are derived between the axial ratio q of the metal-poor halo, the axial ratio p of the dark halo, and the local velocity ellipsoid of metal-poor halo stars. Comparison with observational data implies that (1) neither models in which the principal axes of the velocity ellipsoid align with cylindrical coordinate axes, nor models in which they align with spherical coordinate axes can ruled out by the presently avaible observational data, (2) if the principal axes of the velocity ellipsoid align with cylindrical coordinate axes, then q 0.53 and (4) the axial ratio of the dark halo must satisfy p > 0.34.