ALPACA is a wide-field telescope designed to survey large areas of sky. By observing these regions night after night, it will be able to detect moving or variable objects. These range from nearby asteroids, potentially hazardous to life on Earth, to stars exploding in distant galaxies. Over several years of operation, it is expected to make major contributions in many areas. These include:
Cosmology: ALPACA will obtain well-sampled multiband light curves to R ~ 24.5 each night and discover ~ 50,000 type Ia supernovae and ~ 12,000 type II supernovae each year to a redshift z ~ 0.8. This will provide a sensitive probe of dark energy.
Weak lensing: ALPACA will observe 800 square degrees to a limiting magnitude r ~ 28, obtaining multiband images and photometric redshifts for approximately 1 billion galaxies.
Clustering and large scale structure: ALPACA will survey more than 3 cubic gigaparsecs of space. It is expected to detect about 70,000 galaxy clusters, achieving the same richness as the SDSS cluster catalog, but at three times the distance, obtaining multiband images of galaxies and photometric redshifts for about 10 million galaxies.
Astrophysics: ALPACA will amass the largest ever sample of stellar photometry. This will form the basis for studies ranging from stellar structure, composition, and variability to the structure of our galaxy.
Planets: ALPACA will observe the bulge of our galaxy every night for half of each year searching for variability in the brightness of stars. It is expected to find over 10,000 microlensing events each year, many of which will be due to extrasolar planets.
Solar system: ALPACA will observe near the ecliptic a significant proportion of the time. It should detect about 50 Kuiper Belt objects each night.
Asteroids: ALPACA will be able to detect 50 m diameter near-Earth asteroids at 1 AU and 1 km diameter asteroids as far away as Jupiter.