2013/10/31 by Gregory Dobler, C. D. Fassnacht, Christopher Fassnacht +9 · 1 citation
Physics and Astronomy · #Adaptive optics and wavefront sensing #Astronomy and Astrophysical Research #Astrophysics #Computer science #Cosmology #Data mining #Galaxies: Formation, Evolution, Phenomena #Galaxy #Large Synoptic Survey Telescope #Lens (geology) #Measure (data warehouse) #Optics #Physics #Plug-in #Quasar #Set (abstract data type) #Telescope #Through-the-lens metering #astro-ph.CO #astro-ph.IM
paper · pdf · doi:10.1088/0004-637x/799/2/168
published as 2015, ApJ, 799, 168 · referee's comments incorporated, to appear in ApJ; challenge data and instructions can be accessed at http://timedelaychallenge.org
arxiv created 2014/12/15 · openalex publication_date 2015/01/27 · arxiv updated 2015/02/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The time delays between point-like images in gravitational lens systems can be used to measure cosmological parameters. The number of lenses with measured time delays is growing rapidly; the upcoming Large Synoptic Survey Telescope (LSST) will monitor ∼10 3 strongly lensed quasars. In an effort to assess the present capabilities of the community, to accurately measure the time delays, and to provide input to dedicated monitoring campaigns and future LSST cosmology feasibility studies, we have invited the community to take part in a "Time Delay Challenge" (TDC). The challenge is organized as a set of "ladders," each containing a group of simulated data sets to be analyzed blindly by participating teams. Each rung on a ladder consists of a set of realistic mock observed lensed quasar light curves, with the rungs' data sets increasing in complexity and realism. The initial challenge described here has two ladders, TDC0 and TDC1. TDC0 has a small number of data sets, and is designed to be used as a practice set by the participating teams. The (non-mandatory) deadline for completion of TDC0 was the TDC1 launch date, 2013 December 1. The TDC1 deadline was 2014 July 1. Here we give an overview of the challenge, we introduce a set of metrics that will be used to quantify the goodness of fit, efficiency, precision, and accuracy of the algorithms, and we present the results of TDC0. Thirteen teams participated in TDC0 using 47 different methods. Seven of those teams qualified for TDC1, which is described in the companion paper.