Thermonuclear Burst Oscillations

Watts, Anna L.

doi:10.1146/annurev-astro-040312-132617

Cited by 188 publications

(254 citation statements)

References 190 publications

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“…This significantly reduces the minimum detectable amplitude A min of accretion powered X-ray pulsations emitted by NS in very-short period binaries (P orb < ∼ 1 h) 4 , but since the dependence of this effect on the pulsar spin frequency is only weak (A min ∝ ν 1/4 ), the resulting bias on the observed spin frequency distribution of accreting MSPs is small. On the other hand, the orbital motion does not affect the detection of nuclear MSPs at all because the burst oscillations are observed at X-ray fluxes > ∼ 100 times higher than accreting MSPs signals, and a detection is achieved in timeintervals of a few seconds (Watts 2012), which is much shorter than the orbital period of the binary. Pulse arrival-time delays induced by orbital motion and by propagation in the ionized interstellar medium also reduce the sensitivity to high-frequency signals in the radio band (Dewey et al 1985;Hessels et al 2007).…”

Section: Discussionmentioning

confidence: 99%

“…The accretion-driven spin up of an NS in an LMXB is demonstrated by the observation of coherent pulsations at a period of a few ms from 15 NSs (accreting millisecond pulsars, hereafter accreting MSPs; Wijnands & van der Klis 1998;Patruno & Watts 2012), and of quasi-coherent-oscillations observed from an additional ten sources exclusively during thermonuclear type I X-ray bursts (nuclear-powered millisecond pulsars, hereafter nuclear MSPs 1 ; Chakrabarty et al 2003;Watts 2012). The swings between rotation and accretionpowered behaviour recently observed from IGR J18245-2452 (Papitto et al 2013;Pallanca et al 2013;Ferrigno et al 2014;Linares et al 2014) PSR J1023+0038 (Archibald et al 2009;Stappers et al 2013;Patruno et al 2014), and XSS J12270-4859 (Bassa et al 2014;Papitto et al 2014;Roy et al 2014;Bogdanov et al 2014) demonstrated that NSs in some LMXBs alternate cyclically between rotation and accretion-powered states on short time-scales of a few years, or shorter.…”

Section: Introductionmentioning

confidence: 99%

“…Even though these two classes overlap (burst oscillations were also observed from eight accreting MSPs), we considered sources that showed oscillations only during bursts (nuclear MSPs) to form a distinct class, because so far they did not show evidence of possessing a magnetosphere able to channel the accreted mass close to the magnetic poles and yield coherent pulsations. Nuclear MSP bursts tend to be observed in brighter states that are characterized by a softer spectrum, while they occur even in the hard state in accreting MSPs (Galloway et al 2008;Watts et al 2009;Watts 2012), which possibly indicates that an important role is played 2 Available from http://astro.phys.wvu.edu/GalacticMSPs 3 Available from http://www.naic.edu/~pfreire/GCpsr.html by the magnetosphere in determining burst oscillation properties. The properties of the spin distribution of LMXB pulsars are summarized in Table 1 and are plotted in the bottom panel of Fig.…”

Section: Introductionmentioning

confidence: 99%

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Spin frequency distributions of binary millisecond pulsars

Papitto

Torres

Rea

et al. 2014

A&A

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Rotation-powered millisecond radio pulsars have been spun up to their present spin period by a 10 8 −10 9 yr long X-ray-bright phase of accretion of matter and angular momentum in a low-to-intermediate mass binary system. Recently, the discovery of transitional pulsars that alternate cyclically between accretion and rotation-powered states on time scales of a few years or shorter, has demonstrated this evolutionary scenario. Here, we present a thorough statistical analysis of the spin distributions of the various classes of millisecond pulsars to assess the evolution of their spin period between the different stages. Accreting sources that showed oscillations exclusively during thermonuclear type I X-ray bursts (nuclear-powered millisecond pulsars) are found to be significantly faster than rotationpowered sources, while accreting sources that possess a magnetosphere and show coherent pulsations (accreting millisecond pulsars) are not. On the other hand, if accreting millisecond pulsars and eclipsing rotation-powered millisecond pulsars form a common class of transitional pulsars, these are shown to have a spin distribution intermediate between the faster nuclear-powered millisecond pulsars and the slower non-eclipsing rotation-powered millisecond pulsars. We interpret these findings in terms of a spin-down due to the decreasing mass-accretion rate during the latest stages of the accretion phase, and in terms of the different orbital evolutionary channels mapped by the various classes of pulsars. We summarize possible instrumental selection effects, showing that even if an unbiased sample of pulsars is still lacking, their influence on the results of the presented analysis is reduced by recent improvements in instrumentation and searching techniques.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Spin frequency distributions of binary millisecond pulsars

Papitto

Torres

Rea

et al. 2014

A&A

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“…So far the spin frequencies of a number of such stars have been measured (e.g., Watts (2012); Patruno & Watts (2012); Smedley et al (2014)). Some of these sources are binary millisecond radio pulsars, and the masses of a fraction of them have been relatively precisely measured (e.g., Smedley et al (2014)).…”

Section: Introductionmentioning

confidence: 99%

Fast spinning strange stars: possible ways to constrain interacting quark matter parameters

Bhattacharyya

Bombaci

Logoteta

et al. 2016

Mon. Not. R. Astron. Soc.

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For a set of equation of state (EoS) models involving interacting strange quark matter, characterized by an effective bag constant (B eff ) and a perturbative QCD corrections term (a 4 ), we construct fully general relativistic equilibrium sequences of rapidly spinning strange stars for the first time. Computation of such sequences is important to study millisecond pulsars and other fast spinning compact stars. Our EoS models can support a gravitational mass (M G ) and a spin frequency (ν) at least up to ≈ 3.0M ⊙ and ≈ 1250 Hz respectively, and hence are fully consistent with measured M G and ν values. This paper reports the effects of B eff and a 4 on measurable compact star properties, which could be useful to find possible ways to constrain these fundamental quark matter parameters, within the ambit of our EoS models. We confirm that a lower B eff allows a higher mass. Besides, for known M G and ν, measurable parameters, such as stellar radius, radius-to-mass ratio and moment of inertia, increase with the decrease of B eff . Our calculations also show that a 4 significantly affects the stellar rest mass and the total stellar binding energy. As a result, a 4 can have signatures in evolutions of both accreting and non-accreting compact stars, and the observed distribution of stellar mass and spin and other source parameters. Finally, we compute the parameter values of two important pulsars, PSR J1614-2230 and PSR J1748-2446ad, which may have implications to probe their evolutionary histories, and for constraining EoS models.

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“…The best-fit spin frequency, 0.8±0.2 kHz, is lower than the break-up spin frequency, 1-2 kHz, of a NS [1] and the error region overlaps with the spin frequencies measured for other burst sources, 11-620 Hz [6]. The emergence of the spectral feature may be naturally explained by the change of the ionization degree of the burst products from fully ionized state to H/He-like state.…”

Section: Discussionmentioning

confidence: 51%

Observational Constraints on the Surface Gravitational Redshift of a Neutron Star

Iwai¹,

Dotani²,

Maeda³

et al. 2017

Proceedings of the 14th International Symposium on Nuclei in the Cosmos (NIC2016)

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A neutron star (NS) is a natural laboratory to probe the nature of the ultra-dense matter. Its observational parameters, e.g., mass and radius, may constrain the equation of state of the supranuclear matter. Here, we analyzed the thermonuclear X-ray burst from GRS 1747−312 observed with Suzaku to constrain the mass-radius relation of a NS. The burst had a long duration with the photospheric radius expansion. We detected for the first time a broad absorption edge like feature above 6 keV in the energy spectrum during the decay phase of the burst. The feature was most plausibly explained by the absorption edges of hydrogen-like Fe and Zn ions, which were smeared by the rapid NS spin. Assuming those ions are responsible for the feature, the surface gravitational redshift is estimated as 1 + z = 1.56 ± 0.03. This value may be feasible if the NS is as heavy as 2M ⊙ .

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Thermonuclear Burst Oscillations

Cited by 188 publications

References 190 publications

Spin frequency distributions of binary millisecond pulsars

Spin frequency distributions of binary millisecond pulsars

Fast spinning strange stars: possible ways to constrain interacting quark matter parameters

Observational Constraints on the Surface Gravitational Redshift of a Neutron Star

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