Astrophysics, Relativity, and Cosmology Seminar - Fred Lamb (UIUC) "Determining the properties of cold ultra-dense matter using NICER"
- Sponsor
- Department of Physics
- Speaker
- Fred Lamb (UIUC)
- Contact
- Deanna Frye
- ddebord@illinois.edu
- Views
- 80
- Originating Calendar
- Physics - Astrophysics, Relativity, and Cosmology Seminar
What are the properties of cold matter at densities higher than those found in atomic nuclei? It cannot be produced in laboratories, but it exists in the cores of neutron stars. Fifteen years ago, a novel method was proposed that could accurately and reliably determine the properties of this matter using precise measurements of the thermal X-ray emission from a certain class of pulsars. Five years later the NICER instrument, which was designed to use this method, was placed on the International Space Station. I will describe some of the latest results that have been obtained using this method. In particular, I will describe new evidence that the estimates of the radius of the M ≈ 2.1 M⊙ PSR J0740+6620 made using NICER data are robust. I will also present the results of a careful analysis of the NICER data on PSR J0437−4715, which has the highest X-ray flux among non-accreting millisecond pulsars. I will then summarize the current constraints on the equation of state of matter in the cores of neutron stars provided by NICER and tidal deformability measurements and the high inferred masses of several pulsars, and describe the NICER data that has not yet been analyzed.