Understanding the Neutron Star Population with the SKA

Tauris, T. M.; Kaspi, V. M.; Breton, R.; Deller, Adam; Keane, E. F.; Krämer, M.; Lorimer, D. R.; McLaughlin, Maura; Possenti, A.; Ray, Paul S.; Stappers, B. W.; Weltevrede, P.

doi:10.22323/1.215.0039

Cited by 18 publications

(12 citation statements)

References 150 publications

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“…The continuous observation, as well as theoretical analysis and comparison of the radio emission of rotating radio transients (RRATS), high-B pulsars, SGRs/AXPs, and ordinary radio pulsars will allow us to understand the NS properties leading to the differences and similarities of the radio emission of these sources. New observational capabilities such as the ones of the Square Kilometer Array (SKA) expect to give also important contributions in this direction (Tauris et al 2015).…”

Section: Possible Additional Evidencementioning

confidence: 99%

The rotation-powered nature of some soft gamma-ray repeaters and anomalous X-ray pulsars

Coelho

Cáceres

Lima

et al. 2017

A&A

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Context. Soft gamma repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are slow rotating isolated pulsars whose energy reservoir is still matter of debate. Adopting neutron star (NS) fiducial parameters; mass M = 1.4M , radius R = 10 km, and moment of inertia, I = 10 45 g cm 2 , the rotational energy loss,Ė rot , is lower than the observed luminosity (dominated by the X-rays) L X for many of the sources. Aims. We investigate the possibility that some members of this family could be canonical rotation-powered pulsars using realistic NS structure parameters instead of fiducial values. Methods. We compute the NS mass, radius, moment of inertia and angular momentum from numerical integration of the axisymmetric general relativistic equations of equilibrium. We then compute the entire range of allowed values of the rotational energy loss,Ė rot , for the observed values of rotation period P and spin-down rateṖ. We also estimate the surface magnetic field using a general relativistic model of a rotating magnetic dipole. Results. We show that realistic NS parameters lowers the estimated value of the magnetic field and radiation efficiency, L X /Ė rot , with respect to estimates based on fiducial NS parameters. We show that nine SGRs/AXPs can be described as canonical pulsars driven by the NS rotational energy, for L X computed in the soft (2-10 keV) X-ray band. We compute the range of NS masses for which L X /Ė rot < 1. We discuss the observed hard X-ray emission in three sources of the group of nine potentially rotation-powered NSs. This additional hard X-ray component dominates over the soft one leading to L X /Ė rot > 1 in two of them. Conclusions. We show that 9 SGRs/AXPs can be rotation-powered NSs if we analyze their X-ray luminosity in the soft 2-10 keV band. Interestingly, four of them show radio emission and six have been associated with supernova remnants (including Swift J1834.9-0846 the first SGR observed with a surrounding wind nebula). These observations give additional support to our results of a natural explanation of these sources in terms of ordinary pulsars. Including the hard X-ray emission observed in three sources of the group of potential rotation-powered NSs, this number of sources with L X /Ė rot < 1 becomes seven. It remains open to verification 1) the accuracy of the estimated distances and 2) the possible contribution of the associated supernova remnants to the hard X-ray emission.

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Section: Possible Additional Evidencementioning

confidence: 99%

The rotation-powered nature of some soft gamma-ray repeaters and anomalous X-ray pulsars

Coelho

Cáceres

Lima

et al. 2017

A&A

View full text Add to dashboard Cite

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“…Mapping the NS mass distribution (Tauris et al 2015) is important for understanding the astrophysics of NS formation in core-collapse supernovae (EOS dependent) and subsequent 'recycling' in a binary system (Alpar et al 1982). The lowest mass NS are also potentially extremely interesting.…”

Section: Importance Of Large Surveys To Sample Populationsmentioning

confidence: 99%

Probing the neutron star interior and the Equation of State of cold dense matter with the SKA

Watts¹,

Espinoza²,

Xu³

et al. 2015

Proceedings of Advancing Astrophysics With the Square Kilometre Array — PoS(AASKA14)

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With an average density higher than the nuclear density, neutron stars (NS) provide a unique testground for nuclear physics, quantum chromodynamics (QCD), and nuclear superfluidity. Determination of the fundamental interactions that govern matter under such extreme conditions is one of the major unsolved problems of modern physics, and -since it is impossible to replicate these conditions on Earth -a major scientific motivation for SKA. The most stringent observational constraints come from measurements of NS bulk properties: each model for the microscopic behaviour of matter predicts a specific density-pressure relation (its 'Equation of state', EOS). This generates a unique mass-radius relation which predicts a characteristic radius for a large range of masses and a maximum mass above which NS collapse to black holes. It also uniquely predicts other bulk quantities, like maximum spin frequency and moment of inertia. The SKA, in Phase 2 and particularly in Phase 2 will, thanks to the exquisite timing precision enabled by its raw sensitivity, and surveys that dramatically increase the number of sources: 1) Provide many more precise NS mass measurements (high mass NS measurements are particularly important for ruling out EOS models); 2) Allow the measurement of the NS moment of inertia in highly relativistic binaries such as the Double Pulsar; 3) Greatly increase the number of fast-spinning NS, with the potential discovery of spin frequencies above those allowed by some EOS models; 4) Improve our knowledge of new classes of binary pulsars such as black widows and redbacks (which may be massive as a class) through sensitive broad-band radio observations; and 5) Improve our understanding of dense matter superfluidity and the state of matter in the interior through the study of rotational glitches, provided that an ad-hoc campaign is developed.Advancing Astrophysics with the Square Kilometer Array

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“…These studies present a challenge to degenerate matter physics, including the recent discovery of a neutron star of 2.01(4) M , violating substantially the Chandrasekar limit (Tauris et al 2015).…”

Section: Pulsars and Gravitymentioning

confidence: 99%

Square Kilometre Array key science: a progressive retrospective

Carilli¹

2015

Proceedings of Advancing Astrophysics With the Square Kilometre Array — PoS(AASKA14)

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I summarize the science drivers presented at the workshop for Phase I of the Square Kilometre Array: 'Advancing Astrophysics with the Square Kilometre Array'. I build from the historical perspective of the original Key Science programs: 'Science with a Square Kilometre Array', and consider progress in astrophysics since 2004. I then present my 'score card' of the primary science drivers proposed by the Science Working Groups, and further developed in the white papers and presentations at the meeting, assuming a conservative high frequency of 3GHz. The science case for the SKA phase I is compelling, with the right mix of killer applications (eg. pulsars and gravity, 21cm cosmology), foundational radio astronomy (eg. cosmic magnetism, baryon cycle, high energy phenomena), and high risk-high return 'game-changing' programs (eg. fast radio bursts, BAO intensity mapping, SETI). A strong case was made at the conference for band 5 (4 to 15GHz), in particular in the area of planet formation and exobiology. Such a capability engages the rapidly growing exoplanet community, and enables fundamental break-throughs in most of the key science areas. The case for real-time data spigots that allow for commensal observing is also strong. Ultimately, the greatest discoveries that will come from the SKA are likely even richer still, and beyond prognostication.

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Understanding the Neutron Star Population with the SKA

Cited by 18 publications

References 150 publications

The rotation-powered nature of some soft gamma-ray repeaters and anomalous X-ray pulsars

The rotation-powered nature of some soft gamma-ray repeaters and anomalous X-ray pulsars

Probing the neutron star interior and the Equation of State of cold dense matter with the SKA

Square Kilometre Array key science: a progressive retrospective

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