Abstract: Photometry collected using Sloan Digital Sky Survey ﬁlter systems shows that it is possible to photometrically separate low metallicity stars with 0.5 < g −r < 0.8 using ugri ﬁlters, and to separate stars with −0.2 < (g − r) < 0.25 by surface gravity using ugriz ﬁlters. This conﬁrms the result of Lenz et al. 1998, which predicted from Kurucz model atmospheres that for G/K stars there was a relationship between metallicity and the l-parameter, l = −0.436(u−g) 0.693(g−r) 0.574(r−i) 0.199; and for A stars there was a relationship between surface gravity and the v-parameter, v = 0.283(u−g)−0.354(g −r) 0.455(r− i) 0.766(i−z). Photometric metallicities are a rough guide to sort metallicities, but can give very incorrect metallicities for unusual stars such as carbon stars and X-ray sources. The photometric metallicity determinations may make it possible to study the statistics of Galactic populations without time-consuming spectroscopic analysis, thus leveraging our ability to study Galactic structure and abundance gradients in the Galactic halo and thick disk. Application of the l-parameter to tens of millions of Galactic stars in the SDSS catalogs will allow us to select low metallicity candidates for further spectroscopic analysis. This technique is already being used for target selection in SEGUE, which is part of SDSS II, the three year extension to the SDSS.
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Bongard's work focuses on understanding the general nature of cognition, regardless of whether it is found in humans, animals or robots. This unique approach focuses on the role that morphology and evolution plays in cognition. Addressing these questions has taken him into the fields of biology, psychology, engineering and computer science.
Danforth is an applied mathematician interested in modeling a variety of physical, biological, and social phenomenon. He has applied principles of chaos theory to improve weather forecasts as a member of the Mathematics and Climate Research Network, and developed a real-time remote sensor of global happiness using messages from Twitter: the Hedonometer. Danforth co-runs the Computational Story Lab with Peter Dodds, and helps run UVM's reading group on complexity.
Laurent studies the interaction of structure and dynamics. His research involves network theory, statistical physics and nonlinear dynamics along with their applications in epidemiology, ecology, biology, and sociology. Recent projects include comparing complex networks of different nature, the coevolution of human behavior and infectious diseases, understanding the role of forest shape in determining stability of tropical forests, as well as the impact of echo chambers in political discussions.
Hines' work broadly focuses on finding ways to make electric energy more reliable, more affordable, with less environmental impact. Particular topics of interest include understanding the mechanisms by which small problems in the power grid become large blackouts, identifying and mitigating the stresses caused by large amounts of electric vehicle charging, and quantifying the impact of high penetrations of wind/solar on electricity systems.
Bagrow's interests include: Complex Networks (community detection, social modeling and human dynamics, statistical phenomena, graph similarity and isomorphism), Statistical Physics (non-equilibrium methods, phase transitions, percolation, interacting particle systems, spin glasses), and Optimization(glassy techniques such as simulated/quantum annealing, (non-gradient) minimization of noisy objective functions).