Neutron Stars—Thermal Emitters

Potekhin, A. Y.; Luca, A. De; Pons, José A.

doi:10.1007/s11214-014-0102-2

Cited by 51 publications

(42 citation statements)

References 183 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…With our approach and the increasing samples of INSs with gravitational redshift measurements, the mass distribution of such objects can be reconstructed and their evolutionary paths will be better understood. For example, a constructed mass distribution can help to unify the apparent diversity of the classes of INSs (Viganò et al 2013;Potekhin et al 2015), or help to determine the minimum mass forming an NS (Suwa et al 2018); and the initial mass function may be used to check the theoretical expectations for remnant masses produced by electron-capture versus Fe-core collapse SNe (Podsiadlowski et al 2004;Kiziltan et al 2013). Please note that our investigations are based on the assumption of the absence of phase transition.…”

Section: Discussion and Summarymentioning

confidence: 99%

The Masses of Isolated Neutron Stars Inferred from the Gravitational Redshift Measurements

Tang

Jiang

Gao

et al. 2020

ApJ

View full text Add to dashboard Cite

For some neutron stars (NSs) in the binary systems, the masses have been accurately measured. While for the isolated neutron stars (INSs), no mass measurement has been reported yet. The situation will change soon thanks to the successful performance of the Neutron Star Interior Composition Explorer (NICER), with which the radius and mass of the isolated PSR J0030+0451 can be simultaneously measured. For most INSs, no mass measurements are possible for NICER because of observational limitations. Benefiting from recent significant progress made on constraining the equation of state of NSs, in this work we propose a way to estimate the masses of the INSs with the measured gravitational redshifts. We apply our method to RX J1856.5-3754, RX J0720.4-3125, and RBS 1223, three members of "The Magnificent Seven" (M7), and estimate their masses to be 1.24 +0.29 −0.29 M , 1.23 +0.10 −0.05 M , and 1.08 +0.20 −0.11 M , respectively. These masses are consistent with that of binary NS systems, suggesting no evidence for experiencing significant accretion of these isolated objects.

show abstract

Section: Discussion and Summarymentioning

confidence: 99%

The Masses of Isolated Neutron Stars Inferred from the Gravitational Redshift Measurements

Tang

Jiang

Gao

et al. 2020

ApJ

View full text Add to dashboard Cite

show abstract

“…Thermal emission from INSs is expected to originate immediately at the surface, with the bulk of the energy flux peaking in the soft X-ray band. In principle, by confronting the observed spectra and light curves with theoretical models for neutron star thermal radiation, it should be possible to derive the surface temperature, magnetic field, gravitational acceleration and chemical composition: if distances are known, then the stellar mass, radius and the equation of state of neutron star interior could be constrained as well (see Potekhin et al 2015;Özel & Freire 2016, for recent reviews on neutron star atmosphere models and upto-date astrophysical constraints on the equation of state of nuclear matter). Since their discovery in the All-Sky Survey of the ROSAT satellite (Voges et al 1999), the M7 have been regarded as the closest-to-perfect candidates for testing neutron star emission models, due to a combination of bright thermal emission, proximity, independent distance estimates 10 , and a lack of significant magnetospheric or accretion activity.…”

Section: The Energy Distributionmentioning

confidence: 99%

A deep XMM-Newton look on the thermally emitting isolated neutron star RX J1605.3+3249

Pires

Schwope

Haberl

et al. 2019

A&A

View full text Add to dashboard Cite

Previous XMM-Newton observations of the thermally emitting isolated neutron star RX J1605.3+3249 provided a candidate for a shallow periodic signal and evidence of a fast spin down, which suggested a high dipolar magnetic field and an evolution from a magnetar. We obtained a large programme with XMM-Newtonto confirm its candidate timing solution, understand the energydependent amplitude of the modulation, and investigate the spectral features of the source. We performed extensive high-resolution and broadband periodicity searches in the new observations, using the combined photons of the three EPIC cameras and allowing for moderate changes of pulsed fraction and the optimal energy range for detection. We also investigated the EPIC and RGS spectra of the source with unprecedented statistics and detail. A deep 4σ upper limit of 1.33(6)% for modulations in the relevant frequency range conservatively rules out the candidate period previously reported. Blind searches revealed no other periodic signal above the 1.5% level (3σ; P > 0.15 s; 0.3 − 1.35 keV) in any of the four new observations. While theoretical models fall short at physically describing the complex energy distribution of the source, best-fit X-ray spectral parameters are obtained for a fully or partially ionized neutron star hydrogen atmosphere model with B = 10 13 G, modified by a broad Gaussian absorption line at energy = 385 ± 10 eV. The deep limits from the timing analysis disfavour equally well-fit double temperature blackbody models where both the neutron star surface and small hotspots contribute to the X-ray flux of the source. We identified a low significance (1σ) temporal trend on the parameters of the source in the analysis of RGS data dating back to 2002, which may be explained by unaccounted calibration issues and spectral model uncertainties. The new dataset also shows no evidence of the previously reported narrow absorption feature at ∼ 570 eV, whose possible transient nature disfavours an atmospheric origin.

show abstract

“…The magnetars are young objects as implied by their characteristic ages τ c ∼ 10 4 years and about half of them being associated with SNRs. X-ray dim isolated neutron stars (XDINSs), or sometimes called "magnificent seven", are the 7 nearby neutron stars identified through their thermal X-ray emission (Özel 2013;Potekhin et al 2015;Mereghetti 2011) with luminosities of order L X ∼ 10 30 − 10 32 erg s −1 (see Haberl 2007;Kaplan 2008;Turolla 2009, for reviews). They have a period range similar to the AXP/SGR family (Hambaryan et al 2017), but are typically older, with characteristic ages τ c ∼ 10 5 − 10 6 years and kinematic ages of a few 10 6 years (Tetzlaff et al 2010(Tetzlaff et al , 2011(Tetzlaff et al , 2012.…”

Section: Introductionmentioning

confidence: 99%

Classification of pulsars with Dirichlet process Gaussian mixture model

İnce

Kamasak

et al. 2020

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

Young isolated neutron stars (INS) most commonly manifest themselves as rotationally powered pulsars (RPPs) which involve conventional radio pulsars as well as gammaray pulsars (GRPs) and rotating radio transients (RRATs). Some other young INS families manifest themselves as anomalous X-ray pulsars (AXPs) and soft gammaray repeaters (SGRs) which are commonly accepted as magnetars, i.e. magnetically powered neutron stars with decaying super-strong fields. Yet some other young INS are identified as central compact objects (CCOs) and X-ray dim isolated neutron stars (XDINSs) which are cooling objects powered by their thermal energy. Older pulsars, as a result of a previous long episode of accretion from a companion, manifest themselves as millisecond pulsars and more commonly appear in binary systems. We use Dirichlet process Gaussian mixture model (DPGMM), an unsupervised machine learning algorithm, for analyzing the distribution of these pulsar families in the parameter space of period and period derivative. We compare the average values of the characteristic age, magnetic dipole field strength, surface temperature and transverse velocity of all discovered clusters. We verify that DPGMM is robust and provides hints for inferring relations between different classes of pulsars. We discuss the implications of our findings for the magneto-thermal spin evolution models and fallback discs.

show abstract

Neutron Stars—Thermal Emitters

Cited by 51 publications

References 183 publications

The Masses of Isolated Neutron Stars Inferred from the Gravitational Redshift Measurements

The Masses of Isolated Neutron Stars Inferred from the Gravitational Redshift Measurements

A deep XMM-Newton look on the thermally emitting isolated neutron star RX J1605.3+3249

Classification of pulsars with Dirichlet process Gaussian mixture model

Contact Info

Product

Resources

About