BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Quiescent black holes in globular clusters: the nature of low-lumi
 nosity accretion - James Miller-Jones (Curtin University)
DTSTART:20140325T163000Z
DTEND:20140325T173000Z
UID:TALK51704@talks.cam.ac.uk
CONTACT:Roderick Johnstone
DESCRIPTION:Black holes spend the majority of their lives in a low-luminos
 ity\, quiescent state whose intrinsic faintness makes it relatively inacce
 ssible to study.  While the accretion flow in this state is extremely radi
 atively inefficient\, the distribution of accretion power between radiatio
 n\, mechanical power and black hole growth is not well understood.  I will
  review our current understanding of low-luminosity accretion\, and then o
 utline one promising avenue for making progress\, via deep radio surveys o
 f globular clusters.  Although several hundred stellar-mass black holes ar
 e believed to form from the deaths of the most massive stars early in the 
 lifetime of a globular cluser\, it was thought that they would then mass s
 egregate to the cluster centre\, causing most of them to be ejected via mu
 tual gravitational interactions.  Using deep radio continuum observations\
 , we have recently found the first strong evidence for stellar-mass black 
 holes in galactic globular clusters\, challenging this theoretical expecta
 tion.  I will present our initial results\, and outline ongoing follow-up 
 campaigns to verify the black hole nature of these sources\, as well as a 
 major radio survey to determine the demographics of this newly-discovered 
 population of candidate black holes\, which provide new laboratories for s
 tudying quiescent accretion.  The known distances to globular clusters can
  provide more accurate estimates of the physical parameters of these black
  holes than exist for typical field sources\, and the additional formation
  channels available in a dense cluster should provide a less biased estima
 te of the black hole mass function than the handful of known systems elsew
 here in the galaxy.
LOCATION:Sackler Lecture Theatre\, IoA (tea at 4.00 pm)
END:VEVENT
END:VCALENDAR