Palomar Transient Factory
PTF • Missions & Center • Operational
The Palomar Transient Factory (PTF) is a fully-automated, wide-field optical synoptic survey aimed at a systematic exploration of the transient and time-variable sky.
The project utilizes a 12Kx8K, 7.8 square degree CCD camera mounted on the 48-inch Oschin Telescope at Palomar Observatory. Observations of roughly 1000 square degrees per night are made at g- and R-band. An additional set of H-alpha filters have enabled an all-sky H-alpha survey. With an exposure time per image of 60s the survey reaches an approximate depth of m(R)=20.5 and m(g')=21. Photometric followup is undertaken by the automated Palomar 60-inch telescope and other facilities provided by consortium members. Spectroscopic followup is routinely acquired from the Palomar 200-inch.
During the first five years of operations strong emphasis was placed on transient discovery (primarily SNe), with a 5-day cadence supernova search and an exotic transient search with cadences between 90 seconds and 1 day. Emphasis later evolved towards variable stars and other time-variable phenomena. Since 2013 the science program (now dubbed "iPTF") has shifted to intensely focused science campaigns on specific topics, for example transient monitoring of the galactic plane.
Data is processed in realtime with image subtraction and transient detection including machine vetting. For solar system objects, tracklets (orbital segments) are constructed. Data is also reprocessed on a nightly basis with an emphasis on high precision. Data are also coadded into deeper reference images of the static sky. Data is available through an IPAC developed GUI and a VO-compliant program API. 10% of the data was released publicly in 2014. A full data release of all data from 2009-2012 will occur in 2015, and all data to-date will be released in 2016.
The original 5-year PTF program was a collaboration of Caltech, LBNL, IPAC, Berkeley, LCOGT, Oxford, Columbia and the Weizmann Institute. The current program (iPTF) is a collaboration of Caltech, Los Alamos National Laboratory, the University of Wisconsin-Milwaukee, the Oskar Klein Centre in Sweden, the Weizmann Institute of Science in Israel, the TANGO Program of the University System of Taiwan, and the Kavli Institute for the Physics and Mathematics of the Universe in Japan.
In late 2016 the existing camera will be decommissioned and replaced with a new 50 square degree camera, the largest in the world by area. By mid-2017 the Zwicky Transient Facility will reach operational status, including a public data release component and transient alerts.
IPAC is responsible for the data processing and archiving for PTF.