Information about DOI 10.17909/T9CC7G

Million, Chase
Fleming, Scott

2016-11-20 05:00:00 Z

A Time-Tagged Database Of Every GALEX Photon Event ("gPhoton")

View data for doi:10.17909/T9CC7G

The Galaxy Evolution Explorer (GALEX) mission surveyed the sky in the ultraviolet for approximately ten years between April 2003 and June 2013. Its two microchannel plate (MCP) detectors recorded the position and time-of-arrival of incident photons ("photon events") with a time resolution of 5 thousandths of a second. Due to storage space and processing limitations, however, these data have previously been released and archived almost exclusively as integrated images (with visit- and coadd-level depths of minutes or more). The gPhoton database and associated software tools now give researchers the means to use photon-level GALEX data up through General Release (GR) 6/7. The corpus of GR 6/7 photon data is composed of more than 79 billion FUV and over a trillion NUV photon events. On disk, the gPhoton database is approximately 130 TB. The gPhoton command line tools permit users to search for coverage within this database and create calibrated light curves, images, or movies (image cubes), with the flexibility to set time and spatial ranges or cuts across the entire mission. This enables studies of variability at timescales shorter than the GALEX visit files, customization or refinement of the calibration, and simplifies the fusion of data across mission phases, surveys and modes. When imported as Python modules, gPhoton permits even more detailed work with the data, including analysis at the level of individual photons.