8–13 Sept 2025
Integrated Innovation Building (IIB), RIKEN Kobe Campus
Asia/Tokyo timezone
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An update to the neutron star mass and radius measurements from NICER data

11 Sept 2025, 09:50
30m
Auditorium (8F) (Integrated Innovation Building (IIB), RIKEN Kobe Campus)

Auditorium (8F)

Integrated Innovation Building (IIB), RIKEN Kobe Campus

Minatojima-minamimachi 6-7-1, Kobe, Japan
7. Astrophysical multi-messenger observations and nucleosynthesis NuSym Scientific Session

Speaker

Sebastien Guillot (IRAP / U. Toulouse)

Description

Since 2017, The Neutron Star Interior Composition Explorer (NICER) on the International Space Station has been in collecting observational data from millisecond pulsars. This old and stable neutron stars are ideal objects to constrain dense nuclear matter. Their hot ($10^6$ K) surface emission, located at the base of the magnetic field, emit X-rays that are seen as X-ray pulsations by the observer as the neutron star rotates. Furthermore, the effects of special and general relativity affect the shape of these X-ray pulsations (light-bending and Doppler are the dominant effects). Therefore by modelling the X-ray pulsations, one can deduce the intensity of the gravitational field, and therefore the compactness of the neutron star. We have been applying this technique to NICER data and obtained measurements from five neutron stars, and a few more analyses are in progress. In this talk, I will summarise all results, emphasising on the most recent ones, their possible caveats, as well as the implications for the equation of state of dense matter. The talk will also include a discussion of expected constraints from future observatories.

Presentation Style Invited Speaker

Author

Sebastien Guillot (IRAP / U. Toulouse)

Presentation materials