NOAO >   Observing Info >   Approved Programs >   2004A-0133

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Proposal Information for 2004A-0133


PI: Joshua Simon, University of California at Berkeley, jsimon@astro.berkeley.edu
Address: Astronomy Department, 601 Campbell Hall, Berkeley, CA 94720, USA

CoI: Adam Leroy, University of California at Berkeley
CoI: Alberto Bolatto, University of California at Berkeley
CoI: Leo Blitz, University of California at Berkeley
CoI: Elinor Gates, Lick Observatory

Title: Cusps vs. Cores: The Distribution of Dwarf Galaxy Density Profile Slopes

Abstract: We propose to follow up our previous rotation-curve studies of nearby dwarf galaxies with integral field optical spectroscopy of a larger sample of galaxies at the WIYN telescope. Our work to date has shown a wide range of dark matter density profiles in nearby dwarfs, contrary to the predictions of the Cold Dark Matter (CDM) model. With this new study, we will address the following questions: 1) What is the distribution of density profile slopes?, 2) Is the density profile slope correlated with any global parameters of galaxies (e.g., mass, color, Hubble type)?, 3) How common are the noncircular motions that we have found in two other galaxies?, 4) What causes such noncircular motions? We will use the DensePak fiber array to map the \ha emission in 10 additional galaxies. These observations will enable us to study the internal kinematics of our targets with 4\arcsec (60-200 pc) angular resolution and ~1 km/s velocity uncertainties. The DensePak data represent a dramatic improvement over most previous work; the spatial resolution, the spectral resolution, and the number of independent velocity data points will be up to an order of magnitude better, allowing us to carry out a crucial test of CDM with unprecedented precision.


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NOAO >   Observing Info >   Approved Programs >   2004A-0133

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