Relativistic Shapiro delay measurements of an extremely massive millisecond pulsar

Despite its importance to our understanding of physics at supranuclear densities, the equation of state (EoS) of matter deep within neutron stars remains poorly understood. Millisecond pulsars (MSPs) are among the most useful astrophysical objects in the Universe for testing fundamental physics, and place some of the most stringent constraints on this high-density EoS. Pulsar timing-the process of accounting for every rotation of a pulsar over long time periods-can precisely measure a wide variety of physical phenomena, including those that allow the measurement of the masses of the components of a pulsar binary system1. One of these, called relativistic Shapiro delay2, can yield precise masses for both an MSP and its companion; however, it is only easily observed in a small subset of high-precision, highly inclined (nearly edge-on) binary pulsar systems. By combining data from the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) 12.5-yr data set with recent orbitalphase-specific observations using the Green Bank Telescope, we have measured the mass of the MSP J0740+6620 to be 2:14thorn0:10 similar to 0:09 I M. (68.3% credibility interval; the 95.4% credibility interval is 2:14thorn0:20 similar to 0:18 I M.). It is highly likely to be the most massive neutron star yet observed, and serves as a strong constraint on the neutron star interior EoS.

Title	Relativistic Shapiro delay measurements of an extremely massive millisecond pulsar
Creator	Blumer, H.
	Garver-Daniels, N.
	Demorest, P. B.
	Lynch, R. S.
	McLaughlin, M. A.
	Ferdman, R. D.
	Arzoumanian, Z.
	Stovall, K.
	Swiggum, J. K.
	Brook, P. R.
	Lorimer, D. R.
	Cromartie, H. T.
	Stairs, I. H.
	Ferrara, E. C.
	Gentile, P. A.
	Ng, C.
	Fonseca, E.
	Ransom, S. M.
	Ellis, J. A.
	DeCesar, M. E.
	Zhu, W. W.
	Jones, M. L.
	Nice, David J.
	Lam, M. T.
	Dolch, T.
	Spiewak, R.
	Pennucci, T. T.
Publisher	Nature Astronomy
Academic Department	Physics
Division	Natural Sciences
Organization	Lafayette College
Date Issued	January 2020
Date Available	2020-03-09
Type	Article
Language	English
Bibliographic Citation	Cromartie, H. T., et al. (2020 Jan) "Relativistic Shapiro delay measurements of an extremely massive millisecond pulsar." Nature Astronomy 41 (2): 72-6.
Standard Identifier	Handle 10385/nc580n19p
Standard Identifier	DOI 10.1038/s41550-019-0880-2
Permalink	http://hdl.handle.net/10385/nc580n19p
Rights Statement	In Copyright
Rights Holders	The Authors