Identifying the Baryons in a Multiphase Intergalactic Medium
Abstract
In this white paper, we summarize current observations of the baryon census at low redshift (Shull, Smith, & Danforth 2012). Measurements of Lya, O-VI, and broad Lya absorbers, together with more careful corrections for metallicity and ionization fraction, can now account for approximately 60% of the baryons in the intergalactic medium (IGM). An additional 5 +/- 3% may reside in the circumgalactic medium (CGM), 7 +/- 2% in galaxies, and 4 +/- 1.5% in clusters. This still leaves a substantial fraction, 29 +/- 13%, unaccounted for. We suggest improvements in measuring the baryons in major components of the IGM and CGM with future Ultraviolet and X-ray spectrographs. These missions could find and map the missing baryons, the fuel for the formation and chemical evolution of galaxies.
Keywords
Cite
@article{arxiv.1208.3249,
title = {Identifying the Baryons in a Multiphase Intergalactic Medium},
author = {J. Michael Shull and Charles W. Danforth},
journal= {arXiv preprint arXiv:1208.3249},
year = {2012}
}
Comments
6 pages, 2 figures, submitted to NASA-RFI for "Science Objectives and Requirements for the Next NASA UV/Visible Astrophysics Mission Concepts"