Birth Events, Masses and the Maximum Mass of Compact Stars

Horvath, J. E.; Rocha, L. S.; Bernardo, A.; Avellar, Marcio G. B. de; Valentim, R.

doi:10.1142/9789811220944_0001

Cited by 3 publications

(7 citation statements)

References 26 publications

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“…At the present time, we can say that m max was studied using the current sample and turns out to be ∼2.5 M both by a simpler 3σ estimate of the second peak (Figure 2), and also by a Bayesian approach, both with and without an upper truncation mass introduced as an independent quantity [61]. [29,36]. The blue curve is the posterior mean of these synthetic samples and the black line is the maximum a posteriori distribution.…”

Section: Neutron Star Mass Distributionmentioning

confidence: 76%

“…where µ i and σ i are the mean and standard deviation of the i-th component N , and r i is its relative weight, satisfying the normalization condition ∑ n i r i = 1. As discussed in Horvath et al [36], the preferred figures for both Anderson-Darling and Kolmogorov-Smirnov frequentist tests are the ones appearing in Table 1. The p-values indicate a strong rejection of a "single mass" hypothesis (labeled as "Unimodal") and hence the confirmation of a structured mass distribution.…”

Section: Neutron Star Mass Distributionmentioning

confidence: 85%

“…In addition, new classes of NSs have been identified, and other properties such as masses and radii measured with increasing precision. We shall briefly point out the main features of each group, the expected demographics and the inferred physical quantities in the following (for a recent full review, see [36]).…”

Section: Neutron Starsmentioning

confidence: 99%

“…To visualize the form of the mass distribution, we have drawn 1000 posterior samples from the master sample discussed in [36], and taken their mean to compare with the maximum a posteriori distribution obtained. The result confirms the presence of two maxima as explained.…”

Section: Neutron Star Mass Distributionmentioning

confidence: 99%

“…Ongoing work on this issue [197,198] can now be taken both ways, as while in one hand an appropriate convection timescale can help explain the existence of the gap, a measure of the gap depth can help constrain the convection timescale. Other mechanisms for compact object production, such as AIC in WD binaries and accretion in "spider" binaries, have also been suggested to fill the gap to some extent [36], but the hypothesis of a partially filled gap has remained mostly speculative until recently.…”

Section: The Lower Mass Gapmentioning

confidence: 99%

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An Overview of Compact Star Populations and Some of Its Open Problems

et al. 2023

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The study of compact object populations has come a long way since the determination of the mass of the Hulse–Taylor pulsar, and we now count on more than 150 known Galactic neutron stars and black hole masses, as well as another 180 objects from binary mergers detected from gravitational-waves by the Ligo–Virgo–KAGRA Collaboration. With a growing understanding of the variety of systems that host these objects, their formation, evolution and frequency, we are now in a position to evaluate the statistical nature of these populations, their properties, parameter correlations and long-standing problems, such as the maximum mass of neutron stars and the black hole lower mass gap, to a reasonable level of statistical significance. Here, we give an overview of the evolution and current state of the field and point to some of its standing issues. We focus on Galactic black holes, and offer an updated catalog of 35 black hole masses and orbital parameters, as well as a standardized procedure for dealing with uncertainties.

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Section: Neutron Star Mass Distributionmentioning

confidence: 76%

Section: Neutron Star Mass Distributionmentioning

confidence: 85%

Section: Neutron Starsmentioning

confidence: 99%

Section: Neutron Star Mass Distributionmentioning

confidence: 99%

Section: The Lower Mass Gapmentioning

confidence: 99%

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An Overview of Compact Star Populations and Some of Its Open Problems

et al. 2023

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A light strange star in the remnant HESS J1731−347: Minimal consistency checks

Horvath

Rocha

et al. 2023

A&A

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Context. Recently, Doroshenko and collaborators reported a very low-mass compact star, a Central Compact Object named XMMU J173203.3-344518 inside the supernova remnant HESS J1731-347. Its tiny mass is at odds with all calculations of minimum masses of neutron stars generated by iron cores, therefore (and even if not compellingly) it has been suggested to be a "strange star". In addition to the mass, the radius and surface temperature were extracted from the data, and the whole body of information should ultimately reveal whether this object is truly consistent with an exotic composition. Aims. Our aim is to understand the status of the compact object XMMU J173203.3-344518 in HESS J1731-347 within the existing models of strange stars, including its prompt formation. Methods. The information obtained on the mass, radius and surface temperature are compared to theoretical calculations performed within usual theoretical models using General Relativity as the assumed theory of gravitation and a handful of cooling scenarios. A qualitative discussion showing the consistency of the strange-matter driven supernova scenario with a low-mass compact star is provided.Results. We found that the object HESS J1731-347 fits within the same quark star models recently employed to explain the masses and radii of the NICER objects PSR J040+6620 and PSR J0030+0451, in which both quantities were simultaneously determined. It is also remarkable to find that a simple cooling scenario devised 30 yr ago with superconducting quarks provides an overall good explanation of the surface temperature. Conclusions. We conclude that XMMU J173203.3-344518 in the remnant HESS J1731-347 fits into a strange star" scenario that is also consistent with heavier compact stars, which can also belong to the same class and constitute an homogeneous type of self-bound objects produced in Nature.

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Mass Distribution and Maximum Mass of Neutron Stars: Effects of Orbital Inclination Angle

Rocha,

Horvath,

de Sá

et al. 2023

Universe

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Matter at ultra-high densities finds a physical realization inside neutron stars. One key property is their maximum mass, which has far-reaching implications for astrophysics and the equation of state of ultra dense matter. In this work, we employ Bayesian analysis to scrutinize the mass distribution and maximum mass threshold of galactic neutron stars. We compare two distinct models to assess the impact of assuming a uniform distribution for the most important quantity, the cosine of orbital inclination angles (i), which has been a common practice in previous analyses. This prevailing assumption yields a maximum mass of 2.25 M⊙ (2.15–3.32 M⊙ within 90% confidence), with a strong peak around the maximum value. However, in the second model, which indirectly includes observational constraints of i, the analysis supports a mass limit of 2.56−0.58+0.87M⊙ (2σ uncertainty), a result that points in the same direction as some recent results gathered from gravitational wave observations, although their statistics are still limited. This work stresses the importance of an accurate treatment of orbital inclination angles, and contributes to the ongoing debate about the maximum neutron star mass, further emphasizing the critical role of uncertainties in the individual neutron star mass determinations.

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Birth Events, Masses and the Maximum Mass of Compact Stars

Cited by 3 publications

References 26 publications

An Overview of Compact Star Populations and Some of Its Open Problems

An Overview of Compact Star Populations and Some of Its Open Problems

A light strange star in the remnant HESS J1731−347: Minimal consistency checks

Mass Distribution and Maximum Mass of Neutron Stars: Effects of Orbital Inclination Angle

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