Dark Matter Discussion Group: Lincoln Greenhill, Harvard-Smithsonian Center for Astrophysics, “A surprising chill before cosmic dawn (?)”

Event time: 
Wednesday, May 2, 2018 - 3:30pm to 5:00pm
Wright Lab (WL), 216 See map
272 Whitney Avenue
New Haven, CT 06511
Event description: 

The spin temperature of the atomic hydrogen 21cm transition has long been anticipated to be unique tracer of gas temperature in the diffuse pre-galactic medium when widespread star formation began, at redshifts of very approximately 20. Bowman et al. have recently claimed the first detection and inferred a gas temperature below what can be accommodated by adiabatic cooling following global recombination. This has been interpreted by Barkana as evidence of non-gravitational baryon-dark matter scattering. I will review this work and discuss two crash efforts by other groups to confirm or disconfirm the conclusions.

Post-talk discussion: After the talk, we will discuss the recent result from the EDGES collaboration by Bowman et al. 2018 (https://www.nature.com/articles/nature25792) and interpretation by Barkana (https://www.nature.com/articles/nature25791).

The Dark Matter Discussion Group (DMDG) meetings are open to everyone interested in understanding dark matter, and we hope that graduate students, post-docs and faculty will all attend with enthusiasm.