Transient and explosive phenomena in the heavens have been a cause of astonishment and a source of enlightenment, from Cepheid variables and pulsars to supernovae, explosive X-ray sources and gamma-ray bursts. Thus, Cepheid variables showed that the Universe was much larger than had been imagined, supernovae revealed the buildup of elements in the Universe, pulsars touch on the physics of strong gravity and the densest matter, and gamma-ray bursts serve as beacons to the young Universe. Technological innovations now make it practical and timely to search the optical heavens for transients, and this project, the Palomar Transient Factory (PTF), is optimized for a systematic and very high throughput survey for transients and variables to the 21st magnitude level.
The PTF program will yield guaranteed science in certain known areas, such as ultra-high energy cosmic rays, energetic neutrinos, tera-electron-volt photons, and gravitational wave sources. The localization of these sources is currently very poor, but PTF will be able to respond because of its large field of view, as well as measuring the rates of background and foreground events. PTF will also explore the unexpected or ill-defined transient sky, including hypothesized objects brighter than novae but fainter than supernovae. Such systematic charting of the sky every few days will reveal around seven hundred thermonuclear supernovae and several hundred core-collapse supernovae, whose follow-on will require more than just this project's resources, considerable as they are.
The impact of cosmic transient objects is indicated by the excitement caused by reports of items like the farthest gamma-ray burst, the most brilliant supernova, and the fastest pulsar. This project will continue to offer early career (student and postdoctoral) researchers hands-on experience with cutting edge research. The planned public archive with built-in easy access will not only benefit the scientific community but also expose the public to science in action, and contribute to the education of college and talented high school students.
