Magneto–Thermal Evolution of Neutron Stars with Emphasis to Radio Pulsars

Geppert, U.

doi:10.1007/s12036-017-9460-y

Cited by 24 publications

(22 citation statements)

References 84 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…. 5 × 10 6 K. Blackbody fits of thermal X-ray spectra provide radii Rpc of the emitting area, which is smaller by a factor ∼ 10 than the radius of the conventional polar cap R dip (see Table 1 in Geppert (2017)). Flux conservation arguments indicate that if R dip /Rpc ∼ 10, Bs ∼ 100B dip so that for a typical B dip ∼ 10 12 G Bs at the real polar cap is in the order of 10 14 G. Such field strengths cause a sufficiently high cohesive energy, in the cap surface layers, necessary for the creation of an electric potential gap sufficiently high to guarantee copious pair production.…”

Section: Introductionmentioning

confidence: 99%

Heating of the real polar cap of radio pulsars

Sznajder

Geppert

2020

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

The heating of the real polar cap surface of radio pulsars by the bombardment of ultrarelativistic charges is studied. The real polar cap is a significantly smaller area within or close by the conventional polar cap which is encircled by the last open field lines of the dipolar field B d . It is surrounded by those field lines of the small scale local surface field B s that join the last open field lines of B d in a height of ∼ 10 5 cm above the cap. As the ratio of radii of the conventional and real polar cap R dip /R pc ∼ 10, flux conservation requires B s /B d ∼ 100. For rotational periods P ∼ 0.5 s, B s ∼ 10 14 G creates a strong electric potential gap that forms the inner accelerating region (IAR) in which charges gain kinetic energies ∼ 3 × 10 14 eV. This sets an upper limit for the energy that back flowing charges can release as heat in the surface layers of the real polar cap. Within the IAR, which is flown through with a dense stream of extremely energetic charges, no stable atmosphere of hydrogen can survive. Therefore, we consider the polar cap as a solidified "naked" surface consisting of fully ionized iron ions. We discuss the physical situation at the real polar cap, calculate its surface temperatures T s as functions of B s and P , and compare the results with X-ray observations of radio pulsars.

show abstract

Section: Introductionmentioning

confidence: 99%

Heating of the real polar cap of radio pulsars

Sznajder

Geppert

2020

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…The presence of a strong multipolar magnetic field is often invoked to explain X-ray thermal emission from areas that are apparently smaller than the polar cap area for a dipolar surface magnetic field. Recent compilations of polar cap radii from X-ray observed non-recycled pulsars have been used as strong observational evidence for a multipolar surface magnetic field (Geppert 2017;Rigoselli & Mereghetti 2018). We revisit the literature listed in these compilations and assess the robustness of their thermal polar cap area measurements.…”

Section: Discussionmentioning

confidence: 99%

Evaluating the evidence of multipolar surface magnetic field in PSR J0108–1431

Arumugasamy

Mitra

2019

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

PSR J0108-1431 is an old pulsar where the X-ray emission is expected to have a thermal component from the polar cap and a non-thermal component from the magnetosphere. Although the phase-integrated spectra are fit best with a single non-thermal component modeled with a power-law (PL) of photon index Γ = 2.9, the X-ray pulse profiles do show the presence of phase-separated thermal and non-thermal components. The spectrum extracted from half the rotational phase away from the X-ray peak fits well with either a single blackbody (BB) or a neutron star atmosphere (NA) model, whereas, the spectrum from the rest of the phase range is dominated by a PL. From Bayesian analysis, the estimated BB area is smaller than the expected polar cap area for a dipolar magnetic field with a probability of 86% whereas the area estimate from the NA model is larger with a probability of 80%. Due to the ambiguity in the thermal emission model, the polar cap area cannot be reliably estimated and hence cannot be used to understand the nature of the surface magnetic field. Instead, we can infer the presence of multipolar magnetic field from the misalignment between the pulsar's thermal X-ray peak and the radio emission peak. For J0108-1431, we estimated a phase-offset ∆φ > 0.1 between the thermal polar cap emission peak and the radio emission peak and argue that this is best explained by the presence of a multipolar surface magnetic field.

show abstract

“…Fallback has also been invoked to explain the low magnetic field observed in central compact objects (CCOs), young neutron stars located near the centre of SN remnants. In this "hidden magnetic-field" scenario [238,239,240,241], the fallback material is able to bury the NS magnetic field explaining the observations of young NSs. In a longer timescale of 1 − 10 7 kyr, the magnetic field is able to re-emerge explaining magnetic fields in older objects [238,239,240].…”

Section: Iron Cores In Solar Metallicity Stars: Mass Dependence and Bmentioning

confidence: 99%

“…In this "hidden magnetic-field" scenario [238,239,240,241], the fallback material is able to bury the NS magnetic field explaining the observations of young NSs. In a longer timescale of 1 − 10 7 kyr, the magnetic field is able to re-emerge explaining magnetic fields in older objects [238,239,240]. Numerical simulations of the accretion of matter onto magnetised material have shown that this mechanism is indeed feasible [242,243,244,245,246,247].…”

Section: Iron Cores In Solar Metallicity Stars: Mass Dependence and Bmentioning

confidence: 99%

Neutron Stars Formation and Core Collapse Supernovae

Cerdá–Durán

Elias‐Rosa

2018

The Physics and Astrophysics of Neutron Stars

View full text Add to dashboard Cite

In the last decade there has been a remarkable increase in our knowledge about core-collapse supernovae (CC-SNe), and the birthplace of neutron stars, from both the observational and the theoretical point of view. Since the 1930's, with the first systematic supernova search, the techniques for discovering and studying extragalactic SNe have improved. Many SNe have been observed, and some of them, have been followed through efficiently and with detail. Furthermore, there has been a significant progress in the theoretical modelling of the scenario, boosted by the arrival of new generations of supercomputers that have allowed to perform multidimensional numerical simulations with unprecedented detail and realism. The joint work of observational and theoretical studies of individual SNe over the whole range of the electromagnetic spectrum has allowed to derive physical parameters, which constrain the nature of the progenitor, and the composition and structure of the star's envelope at the time of the explosion. The observed properties of a CC-SN are an imprint of the physical parameters of the explosion such as mass of the ejecta, kinetic energy of the explosion, the mass loss rate, or the structure of the star before the explosion. In this chapter, we review the current status of SNe observations and theoretical modelling, the connection with their progenitor stars, and the properties of the neutron stars left behind.

show abstract

Magneto–Thermal Evolution of Neutron Stars with Emphasis to Radio Pulsars

Cited by 24 publications

References 84 publications

Heating of the real polar cap of radio pulsars

Heating of the real polar cap of radio pulsars

Evaluating the evidence of multipolar surface magnetic field in PSR J0108–1431

Neutron Stars Formation and Core Collapse Supernovae

Contact Info

Product

Resources

About