A Multi-Resolution 3D Map of the Intergalactic Medium via the Lyman-Alpha Forest

• Activity Number: 83 - Your Invited Poster Evening Entertainment: No Longer Board
• Type: Invited
• Date/Time: Sunday, July 30, 2017 : 8:30 PM to 10:30 PM
• Sponsor: Astrostatistics Special Interest Group
• Author(s): Collin Eubanks* and Jessi Cisewski and Rupert Croft and Doug Nychka and Larry Wasserman
• Companies: Carnegie Mellon University and Yale University and Carnegie Mellon University and National Center for Atmospheric Research and Carnegie Mellon
• Keywords: intergalactic medium ; quasar ; Lyman-alpha forest ; Gaussian random field

Abstract

The objective of this work is to use the quasar Lyman-alpha forest data of twelfth data release of the Baryon Oscillation Spectroscopic Survey to produce a three-dimensional map of the H I density fluctuations in the intergalactic medium (IGM) in the redshift range 1.94 < z < 3 with a total sky coverage of 12,300 deg^2. Specifically, we utilize a multi-resolution Gaussian random field model. With this methodology we are able to reproduce the complex multi-scale structure of the IGM while still maintaining the computational parsimony necessary for a problem of this magnitude. Furthermore, given the irregular spacing of the observations dictated by line of sight (LOS) sampling and the locations of quasars, a key feature of this methodology is that no assumptions are made about the sampling scheme. Moreover, the resolution of the predicted map inherently adapts to the number of locally available LOSs and the measurement variance of the observations so as to extract as much signal from the data as possible. The map can be viewed on the WorldWide Telescope and downloaded from my personal webpage.