Thursday, May 11, 2006, Pratt Conference Room at 12:30 pm
Mapping Matter in the Universe
with 2MASS and SFI++
Dr. Karen Masters (CfA)
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The peculiar velocities of galaxies directly trace the underlying
gravitational field of the universe, providing a powerful tool to
study the amount and distribution of mass independent of the
complicated details of galaxy and star formation. Techniques which
attempt to exploit this property have had varying success in the past,
struggling with large errors on peculiar velocity measurements, poor
statistics and uneven sky coverage.
The SFI++ sample is the largest currently available homogeneous sample of peculiar velocities, being at least a factor of two larger than previous samples. I will describe early results on the local velocity field seen by SFI++. I will describe a 2MASS selected all-sky peculiar velocity survey which has been started at CfA. This survey will provide significant improvements over the SFI++ and other currently available peculiar velocity samples, both in statistics and sky coverage. Together with the 2MASS redshift survey a 2MASS peculiar velocity survey will settle the debate about the nature and size of the bias between galaxies and dark matter, and map the velocity and density fields in the local universe at unprecedented spatial resolution. |
