Characterizing the missing baryons in the Universe: Prospects for ALMA
by
Jesper Rasmussen(DARK Cosmology Centre)
→
Europe/Stockholm
FC 61
FC 61
Description
Observations reveal a shortfall of baryons in the nearby Universe when
compared to results obtained at high redshift. Most of these nearby
"missing baryons" are believed to reside outside galaxies in a
warm-hot gaseous phase, tracing the large-scale structure of the
Universe. This material should be observable in emission or absorption
using ultra-sensitive X-ray observations, but such observations are
pushing current X-ray instrumentation to its limits, and only
tentative and disputed claims of detection have been made. An
alternative approach to mapping these baryons is to search for the
faint hyperfine structure lines they emit at millimetre wavelengths.
With the advent of ALMA, this may now have become feasible. I will
describe the background for this, and discuss some of the prospects
for using ALMA to detect these missing baryons and to characterize
their role in galaxy formation and evolution.
