Keck Studies of M31's Stellar Halo

We present Keck 10-meter/LRIS spectra of candidate red giants in the halo of M31, located at a projected radius of R=19kpc on the minor axis. These spectroscopic targets have been selected using a combination of UBRI-based and morphological screening to eliminate background galaxies. Radial velocity measurements are used to separate M31 halo giants from foreground Milky Way dwarf stars, M31 disk stars, and residual background galaxies. The metallicity of each M31 halo giant is measured using standard photometric and spectroscopic techniques, the latter based on the strength of the CaII triplet. The various [Fe/H] estimates are in rough agreement with one another. The data reveal a large spread (>2dex) in [Fe/H] in M31's halo; there is no strong radial [Fe/H] gradient. LRIS and HIRES spectra are also presented for red giants in five dwarf spheroidal satellites of M31: AndI, AndIII, AndV, AndVI, and AndVII. There appears to be a significant metallicity spread in AndVI and possibly in AndI. The new radial velocity data on these outer dwarfs are used to constrain the total mass of M31: the best estimate is under 10^(12)Msun, somewhat less than the best estimate for the Milky Way.Comment: 12 pages, 7 figures, Proceedings of SPIE Conference: Discoveries and Research Prospects with 8-10 Meter Class Telescopes (Munich March 2000

Drug Use among a Sample of Federal Drug Crime Defendants: Implications for the Gateway Effect Hypothesis

This study investigated the association between marijuana first before other drugs and alcohol and later hard drug among a convenience sample of federal drug crime defendants from one federal court in the Mid-Atlantic region of the United States. Results from two binomial logistic regression models revealed statistically significant associations between first use of marijuana and regular drug use and hard drug use, respectively. Findings suggests a gateway effect for marijuana within this sample

Kinematics and Composition of the Galactic Bulge: Recent Progress

We present recent results from a Keck study of the composition of the Galactic bulge, as well as results from the bulge Bulge Radial Velocity Assay (BRAVA). Culminating a 10 year investigation, Fulbright, McWilliam, & Rich (2006, 2007) solved the problem of deriving the iron abundance in the Galactic bulge, and find enhanced alpha element abundances, consistent with the earlier work of McWilliam & Rich (1994). We also report on a radial velocity survey of {\sl 2MASS}-selected M giant stars in the Galactic bulge, observed with the CTIO 4m Hydra multi-object spectrograph. This program is to test dynamical models of the bulge and to search for and map any dynamically cold substructure in the Galactic bulge. We show initial results on fields at $-10^{\circ} < l <+10^{\circ}$ and $b=-4^{\circ}$. We construct a longitude-velocity plot for the bulge stars and the model data, and find that contrary to previous studies, the bulge does not rotate as a solid body; from $-5^{\circ}<l<+5^{\circ}$ the rotation curve has a slope of $\approx 100 km s^{-1}$ and flattens considerably at greater $l$ and reaches a maximum rotation of $45 {km s^{-1}}$ (heliocentric) or $\sim 70 {km s^{-1}}$ (Galactocentric). This rotation is slower than that predicted by the dynamical model of Zhao (1996).Comment: 6 pages, 6 figures, contributed paper at IAU Symposium 245 "Formation and Evolution of Galactic Bulges

The Bulge Radial Velocity Assay (BRAVA): I. Techniques and a Rotation Curve

We are undertaking a large scale radial velocity survey of the Galactic bulge which uses M giant stars selected from the 2MASS catalog as targets for the CTIO 4m Hydra multi-object spectrograph. The aim of this survey is to test dynamical models of the bulge and to quantify the importance, if any, of cold stellar streams in the bulge and its vicinity. Here we report on the kinematics of a strip of fields at -10 < l <+10 degres and b=-4 degres. We construct a longitude-velocity plot for the bulge stars and the model data, and find that contrary to previous studies, the bulge does not rotate as a solid body. From -5<l<+5 degrees the rotation curve has a slope of roughly 100 km/s/kpc and flattens considerably at greater l and reaches a maximum rotation of 45 km/s. We compare our rotation curve and velocity dispersion profile to both the self-consistent model of Zhao (1996) and to N-body models; neither fits both our observed rotation curve and velocity dispersion profile. The high precision of our radial velocities (3 km/s) yields an unexpected result: hints of cold kinematic features are seen in a number of the line of sight velocity distributions.Comment: Accepted to ApJ letters. This replacement updates the paper to the accepted versio