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CELT Science Case. CELT Science Justification Process. Put together a Science Working Group Bolte, Chuck Steidel, Andrea Ghez, Mike Brown, Judy Cohen, Mike Jura, Richard Ellis, Wal Sargent Identified areas and solicited work from various members of the UC/CIT community
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CELT Science Justification Process • Put together a Science Working Group • Bolte, Chuck Steidel, Andrea Ghez, Mike Brown, Judy Cohen, Mike Jura, Richard Ellis, Wal Sargent • Identified areas and solicited work from various members of the UC/CIT community • Made a presentation at a workshop in Feb 2001 and gathered useful feedback. • Final result is Chapter 2 of the CELT Conceptual Design `Greenbook’
SWG Goals • Answer questions: • Is it worthwhile building a next generation large telescope based on science drivers? • What is the minimum size for `breakthrough’ capability • Where does a 30m O/IR telescope fit into the ALMA/NGST/multiple 8m picture • Make the science case • Guide conceptual design of telescope and proposed 1st generation instruments and the site
Emphasize capabilities, rather than specific science projects. • Lesson from Keck is that it is difficult to anticipate the most exciting science areas a decade in advance. • Developing workhorse capabilities in general areas pays large scientific dividends. • Anticipated Science Areas: • The development and evolution of structure in the universe • The emergence of the first galaxies • The physics of star formation • The formation and evolution of planetary systems • Physical processes in the Solar System • The star formation and chemical evolution history of galaxies in the local universe. • New discovery space
Greenbook Examples • Spectral studies of Solar System objects • Extra-solar planets • Extend searches to lower L/M • Spectroscopic studies of ESP atmospheres • Direct detection • Star formation • Chemical Evolution/star formation histories of galaxies to 20Mpc • Black hole demographics • Evolution of galaxies and the IGM from z=1-5
Seeing-Limited Observations • One illustrative example: Sloan Digital Sky Survey survey at a lookback time of 10 billion years (z~2.5) • 20 arc minute seeing limited field of view: equivalent at z=2.5 to a 3.4 degree field at the mean redshift of the SDSS– CELT is a wide-field telescope for the distant universe. • There are 50,000 galaxies (in the z=2-3.5 range) per square degree accessible to low-resolution optical spectroscopy with CELT (R=26.5) • The CELT aperture allows one to use the brightest high redshift galaxies, rather than rare quasars, as background sources that can be used to perform tomography on the diffuse intergalactic medium. • Surface density of objects for which R>5000 spectra could be obtained increases by 2 orders of magnitude • Detailed physics, chemistry of baryonic material, relative distribution of galaxies, diffuse hydrogen, and metals in the young universe.
Example: Baryonic Structure at High Redshift The 3-D Structure of the diffuse IGM can be probed using “tomography” via multiple sightlines through the survey volume Keck/HIRES hydrogen carbon
Where to next? • Database of night-sky emission and detector characteristics • Develop a simulator • Identify few key science questions and do a detailed evaluation of 30m capability (assist in tradeoff discussions) • Expand the science baseline of ideas for 30m science - e.g. astrometry