Exploring the Transient Optical Sky
Time domain science will greatly benefit from unique LSST capability to simultaneously provide large area coverage, dense temporal coverage, accurate color information, good image quality , and rapid data reduction and classification. Since LSST extends time-volume space a thousand times over current surveys, the most interesting science may well be the discovery of new classes of objects. There are many known applications for LSST data products:
- Studies of dwarf novae, including their use as probes of stellar populations and structure in the Local Group.
- Gamma Ray Burst afterglows and transients to high redshift.
- Gravitational micro-lensing in the local group and beyond. Studies of SNe populations and parametrization of light curves.
- A deep search for dolichonovae (slow) and macronovae populations (newly discovered subclasses).
- Search for stellar tidal disruptions by nuclear supermassive black holes.
- Accretion of nuclear gas clouds or large-scale accretion-disk instabilities.
- Optical bursters (varying faster than 1 mag/hr) to r~25 mag: new phenomena.
- Optical identifications for transients detected at other wavelengths, from gamma-rays to radio.
- A study of quasar variability using 2% accurate, multicolor light curves for 2 million low-redshift (z<2) quasars: constraints on the accretion physics.
- The superb continuum light curves will enable economical "piggyback" reverberation-mapping efforts using emission lines. These results will greatly broaden the luminosity-redshift plane of reverberation-mapped AGNs, upon which the whole industry of AGN black-hole mass estimates relies. For LSST data alone, the inter-band continuum lags will give useful structural information.
- LSST should provide a dramatic increase in the number of known AGNs at the end of the dark ages, z~6.5-7.5 (about 1000).
- By pushing substantially further down the luminosity function over a very large solid angle, will lead to a much clearer understanding of black-hole growth during the first Gyr.
- LSST data will allow good constraints on AGN lifetimes.