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SUMMARY:Accretion disc properties in Transition Millisecond pulsar: A case
  study of PSR J1023+0038 using XMM-Newton\, NuSTAR\, NICER\, Chandra\, and
  IXPE [Astrophysics Seminar]
DTSTART:20260326T100000Z
DTEND:20260326T110000Z
DTSTAMP:20260415T022400Z
UID:indico-event-424@events.iiap.res.in
CONTACT:colloqm@iiap.res.in
DESCRIPTION:Speakers: Mayukh Pahari (IIT Hyderabad)\n\nAbstract: Transiti
 onal millisecond pulsars (tMSPs) provide a unique laboratory to study the 
 interaction between an accretion disc and a rapidly rotating neutron star 
 magnetosphere. A key open question is whether\, during the X-ray high mode
 \, the accretion disc penetrates the magnetosphere and extends close to th
 e neutron star surface. This issue has important implications for the accr
 etion geometry\, pulsar emission mechanisms\, and the possibility of conti
 nuous gravitational wave emission. In this presentation\, I will discuss r
 esults from our investigation of the disc-magnetosphere configuration in t
 he prototypical tMSP PSR J1023+0038 using detailed X-ray spectral analysis
 . We isolate the X-ray high-mode intervals and analyse observations from m
 ultiple telescopes\, including XMM-Newton (EPIC-PN\, MOS1\, MOS2)\, NuSTAR
 \, NICER\, and Chandra X-ray Observatory. Combining the longest available 
 exposures\, we obtain about 202 ks of high-mode data from a total exposure
  of ~364 ks and perform a self-consistent spectral modelling. Our analysis
  constrains the inner disc radius to 16.8 ± 3.8 km with at least 3𝜎 si
 gnificance\, indicating that the accretion disc extends very close to the 
 neutron star. Consistent constraints are also obtained from independent NI
 CER observations and from joint XMM-Newton + NuSTAR data. Furthermore\, fi
 rst time\, we reported a Fe emission line at 6.45 keV from a tMSP in the C
 handra spectrum with 99% significance\, implying an upper limit on the inn
 er disc radius of ~21 𝑅𝑔. These results strongly suggest that\, duri
 ng the high mode\, the accretion disc in PSR J1023+0038 penetrates the mag
 netosphere and extends within the corotation radius\, supporting models of
  accretion-powered pulsations and a possible source for continuous gravita
 tional wave emission.\n\nhttps://events.iiap.res.in/event/424/
LOCATION:Auditorium
URL:https://events.iiap.res.in/event/424/
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