The Carnegie-Spitzer-IMACS Redshift Survey

The Carnegie-Spitzer-IMACS (CSI) survey, currently underway at the Magellan-Baade 6.5m telescope in Chile, has been specifically designed to characterize normal galaxies and their environments to z=1.5.

The survey selection is done using 3.6μm observations of Spitzer Legacy fields, providing as close a selection by stellar mass as possible.

Using a low-dispersion prism in IMACS, the survey goal is to study galaxies down to 21.0 AB mag in the 3.6μm band over a 15 degs². This area is defined by our goal of reducing cosmic variance in the density of massive galaxies at z>1 to 10% in redshift bins of Δz=0.1. By doing so we will be able to accurately trace the evolution of the galaxy mass function to a time with the universe was a third of its current age. Over this area, down to the magnitude limit of the survey, we expect to obtain low-dispersion spectra for over 200,000 galaxies.

We combine the flux-calibrated spectroscopy with broadband optical-near IR colors, and use SED fitting to measure redshifts. In direct comparisons with previously published high resolution redshifts from the VVDS, our redshift accuracy is σ_z/(1+z)=1% for galaxies brighter than i'=23 mag and σ_z/(1+z)=2.5% for fainter galaxies. With this level of accuracy, CSI will be able to assemble a picture of how galaxies have evolved as functions of both mass and environment.

Principal Investigator: Daniel D. Kelson

Co-Investigators: Rik J. Williams, Alan Dressler, Patrick J. McCarthy, Stephen A. Shectman, John S. Mulchaey, Ryan F. Quadri

For a brief discussion of the motivation and selection of galaxies in CSI, please see this Introduction.

CSI papers that have been submitted are available here.