2021/05/31 by B. Biswas, Bhaskar Biswas · 77 citations
Earth and Planetary Sciences · Physics and Astronomy · #Algorithm #Computer science #Gamma-ray bursts and supernovae #Geophysics and Gravity Measurements #Physics #Pulsars and Gravitational Waves Research #astro-ph.HE #gr-qc #nucl-th
paper · pdf · doi:10.3847/1538-4357/ac1c72
published in The Astrophysical Journal 921(1), 63 (IOP Publishing)
openalex created_date 2021/05/24 · arxiv created 2021/07/14 · openalex publication_date 2021/11/01 · arxiv updated 2021/11/17 · openalex updated_date 2026/08/05
Abstract In this paper, we discuss the impact of the following laboratory experiments and astrophysical observation of neutron stars (NSs) on their equation of state (EoS): (a) the new measurement of neutron skin thickness of 208 Pb, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mi>R</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>skin</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>208</mml:mn> </mml:mrow> </mml:msubsup> <mml:mo>=</mml:mo> <mml:mn>0.29</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.07</mml:mn> </mml:math> fm by the PREX-II experiment; (b) the mass measurement of PSR J0740+6620 has been slightly revised down by including additional ∼1.5 yr of pulsar timing data. As well as the radius measurement of PSR J0740+6620 by joint NICER/XMM-Newton collaboration, which has a similar size to PSR J0030+0451. We combine this information using Bayesian statistics along with the previous LIGO/Virgo and NICER observations of NS using a hybrid nuclear+piecewise-polytrope EoS parameterization. Our findings are as follows. (a). Adding PREX-II result yields the value of empirical parameter <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>L</mml:mi> <mml:mo>=</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>69</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>19</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>21</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> MeV, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mi>R</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>skin</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>208</mml:mn> </mml:mrow> </mml:msubsup> <mml:mo>=</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>0.20</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.05</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.05</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> fm, and radius of a 1.4 M ⊙ ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>R</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>1.4</mml:mn> </mml:mrow> </mml:msub> <mml:mo stretchy="false">)</mml:mo> <mml:mo>=</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>12.75</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.54</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.42</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> km at 1 σ confidence interval. We find these inferred values are mostly dominated by the combined astrophysical observations as the measurement uncertainty in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mi>R</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>skin</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>208</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> by PREX-II is much broader. Also, a better measurement of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mi>R</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>skin</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>208</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> might have a small effect on the radius of low-mass NSs but, for the high masses, there will be almost no effect. (b) After adding the revised mass and radius measurement of PSR J0740+6620, we find the inferred radii of NSs are slightly pushed toward the larger values and the uncertainty on the radius of a 2.08 M ⊙ NS is moderately improved.