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SUMMARY:The Extremes of Accretion: Ultraluminous X-ray Sources and Super-E
 ddington Pulsars - Dr. Dom Walton\, University of Hertfordshire
DTSTART:20230216T160000Z
DTEND:20230216T170000Z
UID:TALK196867@talks.cam.ac.uk
CONTACT:107123
DESCRIPTION:Ultraluminous X-ray sources (ULXs) are off-nuclear X-ray sourc
 es with luminosities that exceed the Eddington limit for stellar remnant b
 lack holes. This implies either the presence of larger\, 'intermediate mas
 s' black holes\, or systems that have managed to violate their Eddington l
 imits. Prior to the NuSTAR era\, black hole accretors were widely assumed\
 , even in the latter scenario. However\, in 2014 NuSTAR made the remarkabl
 e discovery that one of these systems\, M82 X-2\, is in fact powered by an
  accreting\, pulsating neutron star (i.e.\, a pulsar)\, firmly demonstrati
 ng that this is a source radiating at ~100 times Eddington. Much about the
 se systems remains shrouded in mystery: it is not clear how significantly 
 neutron star accretors contribute to the demographics of the overall ULX p
 opulation\, and it is also not understood how these sources are able to ra
 diate at such extreme levels. As of today\, roughly half a dozen neutron s
 tar ULXs are known\, including systems radiating up to 500 times the Eddin
 gton limit. I will discuss the current state of this rapidly evolving fiel
 d.\n
LOCATION:Hoyle Lecture Theatre - Details will be sent by email
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