BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Interstellar scintillation – near and far - Barney Rickett (Univ
 ersity of California\, San Diego\, USA)
DTSTART:20160223T140000Z
DTEND:20160223T150000Z
UID:TALK63879@talks.cam.ac.uk
CONTACT:Greg Willatt
DESCRIPTION:Interstellar (ISS) causes variation in flux density at radio w
 avelengths of compact radio sources on time scales from minutes to weeks t
 o years\, which must be distinguished from intrinsic variability.  ISS of 
 pulsars is a nuisance but has allowed us to probe the turbulent interstell
 ar plasma in our galaxy.  Far away bright sources such as compact AGN jets
  also suffer from ISS\, which is seen as intraday variability at cm wavele
 ngths and probes their angular structure down to 10 micro-arcsec.  Their I
 SS is observed to decrease for sources beyond z=2\, which is consistent wi
 th cosmological expansion and emission from peak brightness temperatures n
 ear 1E11K.  ISS studies of pulsars have discovered localised condensations
  of plasma\, whose origin remains a mystery.  I will outline a possible ex
 planation in terms of reflection rather than refraction in the interstella
 r plasma.\n
LOCATION:Martin Ryle Seminar Room\, Kavli Institute
END:VEVENT
END:VCALENDAR