PSR J0030+0451 Mass and Radius from NICER Data and Implications for the Properties of Neutron Star Matter

Journal Article · 11 December 2019 · The Astrophysical Journal. Letters (Online)

DOI: https://doi.org/10.3847/2041-8213/ab50c5 · OSTI ID:1800655

Miller, M. C.  ^[1]; Lamb, F. K.  ^[2]; Dittmann, A. J.  ^[3]; Bogdanov, S.  ^[4]; Arzoumanian, Z. ^[5]; Gendreau, K. C. ^[5]; Guillot, S.  ^[6]; Harding, A. K.  ^[7]; Ho, W. C. G.  ^[8]; Lattimer, J. M.  ^[9]; Ludlam, R. M.  ^[10]; Mahmoodifar, S.  ^[11]; Morsink, S. M.  ^[12]; Ray, P. S.  ^[13]; Strohmayer, T. E.  ^[14]; Wood, K. S.  ^[15]; Enoto, T.  ^[16]; Foster, R.  ^[17]; Okajima, T. ^[5]; Prigozhin, G. ^[17] ; Soong, Y. ^[5]

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1. Univ. of Maryland, College Park, MD (United States). Dept. of Astronomy and Joint Space-Science Institute; University of Maryland
2. Univ. of Illinois at Urbana-Champaign, Urbana, IL (United States). Center for Theoretical Astrophysics and Dept. of Physics; Univ. of Illinois at Urbana-Champaign, Urbana, IL (United States). Dept. of Astronomy
3. Univ. of Maryland, College Park, MD (United States). Dept. of Astronomy and Joint Space-Science Institute
4. Columbia Univ., New York, NY (United States). Columbia Astrophysics Lab
5. NASA Goddard Space Flight Center, Greenbelt, MD (United States). X-Ray Astrophysics Lab
6. Centre National de la Recherche Scientifique (CNRS) (France); Univ. of Toulouse (France)
7. NASA Goddard Space Flight Center, Greenbelt, MD (United States). Astrophysics Science Div.
8. Haverford College, Haverford, PA (United States). Dept. of Physics and Astronomy; Univ. of Southampton (United Kingdom)
9. Stony Brook University, Stony Brook, NY (United States). Dept. of Physics and Astronomy
10. California Institute of Technology, Pasadena, CA (United States). Cahill Center for Astronomy and Astrophysics
11. Univ. of Maryland, College Park, MD (United States). Dept. of Astronomy and Joint Space-Science Institute; NASA Goddard Space Flight Center, Greenbelt, MD (United States). Astrophysics Science Div.
12. Univ. of Alberta, Edmonton, AB (Canada)
13. U.S. Naval Research Laboratory, Washington, DC (United States). Space Science Div.
14. NASA Goddard Space Flight Center, Greenbelt, MD (United States). Astrophysics Science Division and Joint Space-Science Institute
15. Naval Research Lab. (NRL), Washington, DC (United States)
16. Kyoto Univ. (Japan)
17. Massachusetts Institute of Technology, Cambridge, MA (United States). MIT Kavli Institute for Astrophysics and Space Research

Neutron stars are not only of astrophysical interest, but are also of great interest to nuclear physicists because their attributes can be used to determine the properties of the dense matter in their cores. One of the most informative approaches for determining the equation of state (EoS) of this dense matter is to measure both a star's equatorial circumferential radius R_e and its gravitational mass M. Here we report estimates of the mass and radius of the isolated 205.53 Hz millisecond pulsar PSR J0030+0451 obtained using a Bayesian inference approach to analyze its energy-dependent thermal X-ray waveform, which was observed using the Neutron Star Interior Composition Explorer (NICER). This approach is thought to be less subject to systematic errors than other approaches for estimating neutron star radii. We explored a variety of emission patterns on the stellar surface. In this work, our best-fit model has three oval, uniform-temperature emitting spots and provides an excellent description of the pulse waveform observed using NICER. The radius and mass estimates given by this model are $${R}_{e}={13.02}_{-1.06}^{+1.24}$$ km and $$M={1.44}_{-0.14}^{+0.15}\,{M}_{\odot }$$ (68%). The independent analysis reported in the companion paper by Riley et al. explores different emitting spot models, but finds spot shapes and locations and estimates of R_e and M that are consistent with those found in this work. We show that our measurements of R_e and M for PSR J0030+0451 improve the astrophysical constraints on the EoS of cold, catalyzed matter above nuclear saturation density.

• Research Organization: Research Foundation of New York, NY (United States); State Univ. of New York (SUNY), Albany, NY (United States)
• Sponsoring Organization: National Aeronautics and Space Administration (NASA); National Science Foundation (NSF); USDOE Office of Science (SC); USDOE Office of Science (SC), Nuclear Physics (NP)
• Grant/Contract Number: FG02-87ER40317
• OSTI ID: 1800655
• Journal Information: The Astrophysical Journal. Letters (Online), Journal Name: The Astrophysical Journal. Letters (Online) Journal Issue: 1 Vol. 887; ISSN 2041-8213
• Publisher: IOP PublishingCopyright Statement
• Country of Publication: United States
• Language: English