Rapid cooling of Cassiopeia A as a phase transition in dense QCD

Sedrakian, Armen

doi:10.1051/0004-6361/201321541

Cited by 60 publications

(59 citation statements)

References 40 publications

(64 reference statements)

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“…In this Section we summarize the results of the studies of cooling of hybrid compact stars carried out in Refs. [12][13][14]. As part of this program, the rapid cooling of the compact star in Cassiopea A (hereafter Cas A) was modelled as a phase transition within the QCD phase diagram [13].…”

Section: Cooling Of Compact Starsmentioning

confidence: 99%

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Exploring phases of dense QCD with compact stars

Sedrakian

2017

EPJ Web Conf.

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Abstract. I review a number of recent developments in the physics of compact stars containing deconfined quark matter, including (a) their cooling with possible phase transition from a fully gapped to a gapless phase of QCD at low temperatures and large isospin; (b) the transport coefficients of the 2SC phase and the role played by the Aharonov-Bohm interactions between flux-tubes and unpaired fermions; (c) rapidly rotating compact stars and spin-down and spin-up induced phase transition between hadronic and QCD matter as well as between different phases of QCD.

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Section: Cooling Of Compact Starsmentioning

confidence: 99%

“…[12][13][14]. As part of this program, the rapid cooling of the compact star in Cassiopea A (hereafter Cas A) was modelled as a phase transition within the QCD phase diagram [13]. The latest updated data [15] that covers the 10 year period from 2003 to 2013 was fitted in Ref.…”

Section: Cooling Of Compact Starsmentioning

confidence: 99%

Exploring phases of dense QCD with compact stars

Sedrakian

2017

EPJ Web Conf.

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“…Refs. [65,56] demonstrated that Cas A data could be explained within the hybrid star scenario exploiting stiff hadronic EoS.…”

Section: Introductionmentioning

confidence: 99%

Influence of the stiffness of the equation of state and in-medium effects on the cooling of compact stars

2016

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Abstract. Measurements of the low masses for the pulsar PSR J0737-3039B, for the companion of PSR J1756-2251 and for the companion of PSR J0453+1559 on the one hand and of the high masses for the pulsars PSR J1614-2230 and PSR J0348-0432 on the other demonstrate the existence of compact stars with masses in a broad range from 1.2 to 2 M . The most massive of these objects might be hybrid stars. To fulfill the constraint Mmax > 2 M with a reserve we exploit the stiff DD2 hadronic equation of state (EoS) without and with excluded volume (DD2vex) correction, which produce maximum neutron star masses of Mmax = 2.43 M and 2.70 M , respectively. We show that the stiffness of the EoS does not preclude an explanation of the whole set of cooling data within "nuclear medium cooling" scenario for compact stars by a variation of the star masses. We select appropriate proton gap profiles from those exploited in the literature and allow for a variation of the effective pion gap controlling the efficiency of the medium modified Urca process. However, we suppress the possibility of pion condensation. In general, the stiffer the EoS the steeper a decrease with density of the effective pion gap is required. Results are compared with previously obtained ones for the HDD EoS for which Mmax = 2.06 M . The cooling of the compact star in the supernova remnant Cassiopeia A (Cas A) is explained mainly by an efficient medium modified Urca process. To explain a > ∼ 2.5% decline of the cooling curve for Cas A, as motivated by an analysis of the ACIS-S instrument data, together with other cooling data exploiting the DD2 EoS a large proton gap at densities n < ∼ 2n0 is required vanishing for n > ∼ 2.5 n0, where n0 is the saturation nuclear density. A smaller decline, as it follows from an analysis of the HRC-S instrument data, is explained with many choices of parameters. With the DD2vex EoS and using an effective pion gap steeper decreasing with the density and/or a proton gap shifted to smaller densities we are also able to reproduce both a strong decline compatible with ACIS-S data and HRC-S instrument data. The mass of Cas A is estimated as 1.6 − 1.9 M , above the value 1.5 M , which we have evaluated with the softer HDD equation of state. Different mass choices for the hottest object XMMU J173203.3-344518 are discussed. We make general remarks also on hybrid star cooling and on its dependence on the stiffness of the hadronic EoS.PACS. 97.60.Jd Neutron stars -95.30.Cq Elementary particle processes -26.60-c Nuclear matter aspects of neutron stars

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“…Moreover, recent discovery with the aid of the NASA's Chandra X-Ray Observatory of unusually fast cooling of supernova remnant in Cassiopeia A (Cas A), which is the youngest known neutron star (NS) in the Milky Way Galaxy, has attracted great attention (see, e.g., [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] and references therein). Several authors [18][19][20][21][22][23] explain such rapid cooling of NS in Cas A during last years (since August 1999, when Chandra found point x-ray source in the Cas A, up to 2014) due to the existence of spin-triplet superfluidity of neutrons inside high-density liquid outer core of this NS.…”

Section: Introductionmentioning

confidence: 99%

“…Several authors [18][19][20][21][22][23] explain such rapid cooling of NS in Cas A during last years (since August 1999, when Chandra found point x-ray source in the Cas A, up to 2014) due to the existence of spin-triplet superfluidity of neutrons inside high-density liquid outer core of this NS. But alternative explanations for the observed rapid cooling of Cas A have also been proposed (see, e.g., [24][25][26][27][28][29] and the discussion of [24] in [20,21]). This NS in Cas A is the first one whose cooling has been observed in the real time.…”

Section: Introductionmentioning

confidence: 99%

Analytical solutions of equation for the order parameter of dense superfluid neutron matter with anisotropic spin-triplet p-wave pairing at finite temperatures

Tarasov

2016

Low Temperature Physics

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The previously derived equations for the components of the order parameter (OP) of dense superfluid neutron matter (SNM) with anisotropic spin-triplet p-wave pairing and with taking into account the effects of magnetic field and finite temperatures are reduced to the single equation for the one-component OP in the limit of zero magnetic field. Here this equation is solved analytically for arbitrary parametrization of the effective Skyrme interaction in neutron matter and as the main results the energy gap (in the energy spectrum of neutrons in SNM) is obtained as nonlinear function of temperature T and density n in two limiting cases: for low temperatures near T = 0 and in the vicinity of phase transition temperature T c0 (n) for dense neutron matter from normal to superfluid state. These solutions for the energy gap are specified for generalized BSk21 and BSk24 parametrizations of the Skyrme forces (with additional terms dependent on density n) and figures are plotted on the interval 0.1n 0 < n <2.0n 0 , where n 0 = 0.17 fm -3 is nuclear density.

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Rapid cooling of Cassiopeia A as a phase transition in dense QCD

Cited by 60 publications

References 40 publications

Exploring phases of dense QCD with compact stars

Exploring phases of dense QCD with compact stars

Influence of the stiffness of the equation of state and in-medium effects on the cooling of compact stars

Analytical solutions of equation for the order parameter of dense superfluid neutron matter with anisotropic spin-triplet p-wave pairing at finite temperatures

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