Bayesian Analysis for Extracting Properties of the Nuclear Equation of State from Observational Data Including Tidal Deformability from GW170817

• Main Authors: Alexander Ayriyan, David Alvarez-Castillo, David Blaschke, Hovik Grigorian
• Format: Article
• Language: English
• Published: MDPI AG 2019-02-01
• Series: Universe
• Subjects: bayesian analysis; quark–hadron phase transition; pasta phases; hybrid compact stars; mass–radius relation; GW170817; tidal deformability
• Online Access: https://www.mdpi.com/2218-1997/5/2/61
• ISSN: 2218-1997

We develop a Bayesian analysis method for selecting the most probable equation of state under a set of constraints from compact star physics, which now include the tidal deformability from GW170817. We apply this method for the first time to a two-parameter family of hybrid equations of state that is based on realistic models for the hadronic phase (KVORcut02) and the quark matter phase (SFM<inline-formula> <math display="inline"> <semantics> <mi>&#945;</mi> </semantics> </math> </inline-formula>) which produce a third family of hybrid stars in the mass&#8315;radius diagram. One parameter (<inline-formula> <math display="inline"> <semantics> <mi>&#945;</mi> </semantics> </math> </inline-formula>) characterizes the screening of the string tension in the string-flip model of quark matter while the other (<inline-formula> <math display="inline"> <semantics> <msub> <mo>&#916;</mo> <mi>P</mi> </msub> </semantics> </math> </inline-formula>) belongs to the mixed phase construction that mimics the thermodynamics of pasta phases and includes the Maxwell construction as a limiting case for <inline-formula> <math display="inline"> <semantics> <mrow> <msub> <mo>&#916;</mo> <mi>P</mi> </msub> <mo>=</mo> <mn>0</mn> </mrow> </semantics> </math> </inline-formula>. We present the corresponding results for compact star properties like mass, radius and tidal deformabilities and use empirical data for them in the newly developed Bayesian analysis method to obtain the probabilities for the model parameters within their considered range.