BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Axion Cosmology and the Lightest DM Candidate - David Marsh (KCL)
DTSTART:20170227T130000Z
DTEND:20170227T140000Z
UID:TALK70189@talks.cam.ac.uk
CONTACT:47984
DESCRIPTION:If axions are particularly light\, and compose a significant f
 raction of the dark matter then there are interesting and potentially obse
 rvable effects on the acoustic peaks and gravitational lensing of the CMB 
 power spectrum\, and on galaxy formation. These effects can be used to sea
 rch for axions in cosmological and astrophysical data. Current constraints
  from Planck limit axions over eight orders of magnitude in mass to compos
 e less than a few percent of the total dark matter. Upcoming "CMB Stage IV
 " lensing data will probe ten orders of magnitude in mass and could detect
  a percent level presence of axion dark matter at high statistical signifi
 cance . This represents sub-percent level tests of the single-component st
 andard cold DM model. Constraints from high redshift structure formation w
 ith axion DM place the current best lower bound on DM particle mass\, m>1e
 -22 eV\, which may be relevant to certain issues with the standard cold DM
  model in dwarf galaxies. This lower bound could be improved by up to four
  orders of magnitude using futuristic 21cm surveys. Given time\, I will di
 scuss the ideas and challenges to detect axion DM in this mass window\, th
 e possibility of forming black holes from the collapse of "axion stars"\, 
 and the origins of light axions in models of the string landscape.
LOCATION:CMS\, Pav. B\, CTC Common Room (B1.19) [Potter Room]
END:VEVENT
END:VCALENDAR