Significant progress has been achieved in developing the science case for building a Large Synoptic Survey Telescope and in deriving the scientific requirements for the facility from the science case.
A single set of LSST observations will support a wide range of scientific programs. Members of the LSST collaboration have identified four broad topics that drive different aspects of the requirements:
- Nature of Dark Energy
- Requires excellent image quality (FWHM < 0.7arcsec in two of five bands), control of PSF shape, and deep summed images. Many short exposures (15 sec) are required to control systematics and to obtain a sufficient depth in the summed images (29th AB per square arcsec, in 5 bands). The PSF must be mapped on each CCD for each exposure. Photometric redshifts require better than 1% photometric precision. The tracking of image quality and rapid response to changing observing conditions requires simultaneous data reduction, with latency not longer than a few minutes.
- Solar System
- Requires accurate absolute astrometry to link motion vectors. The same exposures used for dark energy can be organized in a cadence that allows robust and efficient linking of moving objects.
- Optical Transients
- Data processing must enable real time alerts (with latency not longer than a few minutes). The same exposures used for dark energy can be organized in a cadence that minimizes aliasing.
- Galactic Structure
- The separation of stellar populations also drives the requirements on photometric precision (1% internal, 2% absolute); proper motions and parallax measurements drive the requirements on relative astrometry.
Our overview paper has more details. The community has presented posters on LSST science in several events such as the American Astronomical Society's meetings. Visit our events page for a listing and links to presentation posters.