Deep Sky Astronomical Image Database

Key Challenges: Develop, store, analyze, and make available an astronomical image database of unprecedented depth, temporal breadth, and sky coverage, consisting of images from the seven-year span of the Palomar-Quest and Near-Earth Astroid Tracking (NEAT) transient surveys and the current Palomar Transient Factory (PTF). The database currently has over 13 million images stored on the NERSC Global Filesystem but data from the PTF are accumulating at the rate of about 105TB per year. The challenge is not only archiving the data but processing it in near-real time to observe rare and fleeting cosmic events as they happen so that experimental astronomers can be alerted.

Why it Matters: The PTF will probe gaps in the transient phase space and search for theoretically predicted, but not yet detected, phenomena such as fallback supernovae, macronovae, Ia supernovae or the orphan afterglows of gamma-ray bursts. PTF will also discover many new members of known source classes, from cataclysmic variables in their various avatars to supernovae and active galactic nuclei. It will provide important insights into galactic dynamics, the solar system, asteroids and other near-earth objects. The lessons learned from PTF will be essential for the preparation of future large synoptic sky surveys such as DES, JDEM and LSST. The DeepSky data portal will afford efficient, streamlined access to massive amounts of data for a broad user community.

Accomplishments: NERSC staff have developed automated software for astrometric & photometric analysis and real-time classification of transients. PTF has been in full operation since 2009 and has proven incredibly efficient at discovering young supernovae. Using the new software and the NERSC-based data analysis pipeline has enabled discovery of 817 new astrophysical transients, including supernovae, novae, new active galaxies and even three new classes of objects. On average, a new cosmic event is uncovered every 12 minutes! Of particular interest to DOE is the discovery of over 500 SNe Ia during the first 18 months of the survey, all spectroscopically classified with a variety of follow-up spectroscopic resources. These supernovae will be used to anchor the low-redshift portion of the Hubble diagram.

NERSC provides the primary data processing pipeline for the PTF.

NERSC Science Gateway: The Deep Sky data portal is available to instantly serve high-resolution cosmic reference and data images. See http://deepskyproject.org/

Investigators: Peter Nugent, Cecilia Aragon (LBNL)

More Information: See, for example,

• "Rapidly Decaying Supernova 2010x: a Candidate ".ia" Explosion," The Astrophysical Journal Letters 723 (2010) L98;
• "Core-Collapse Supernovae from the Palomar Transient Factory: Indications for a Different Population in Dwarf Galaxies," The Astrophysical Journal Volume 721 Number 1;
• and the PTF web site.