On the diversity of compact objects within supernova remnants – I. A parametric model for magnetic field evolution

ABSTRACT Central Compact Objects (CCOs) are X-ray sources with luminosity ranging between 1032 and 1034 erg s−1, located at the centres of supernova remnants. Some of them have been confirmed to be neutron stars. Timing observations have allowed the estimation of their dipole magnetic field, placing them in the range ∼1010–1011 G. The decay of their weak dipole fields, mediated by the Hall effect and Ohmic dissipation, cannot provide sufficient thermal energy to power their X-ray luminosity, as opposed to magnetars whose X-ray luminosities are comparable. Motivated by the question of producing high X-ray power through magnetic field decay while maintaining a weak dipole field, we explore the evolution of a crustal magnetic field that does not consist of an ordered axisymmetric structure, but rather comprises a tangled configuration. This can be the outcome of a non-self-excited dynamo, buried inside the crust by fallback material following the supernova explosion. We find that such initial conditions lead to the emergence of the magnetic field from the surface of the star and the formation of a dipolar magnetic field component. An internal tangled magnetic field of the order of 1014 G can provide sufficient Ohmic heating to the crust and power CCOs, while the dipole field it forms is approximately 1010 G, as observed in CCOs.

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Resolving dichotomy in compact objects through continuous gravitational waves observation

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab2625 ◽

2021 ◽

Vol 508 (1) ◽

pp. 842-851

Author(s):

Surajit Kalita ◽

Tushar Mondal ◽

Christopher A Tout ◽

Tomasz Bulik ◽

Banibrata Mukhopadhyay

Keyword(s):

Magnetic Field ◽

Gravitational Wave ◽

Supernova Remnants ◽

Laser Interferometer ◽

Gamma Ray ◽

Signal To Noise Ratio ◽

Big Bang ◽

Compact Objects ◽

One Year ◽

The Masses

ABSTRACT More than two dozen soft gamma-ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs) have been detected so far. These are isolated compact objects. Many of them are either found to be associated with supernova remnants or their surface magnetic fields are directly measured, confirming that they are neutron stars (NSs). However, it has been argued that some SGRs and AXPs are highly magnetized white dwarfs (WDs). Meanwhile, the existence of super-Chandrasekhar WDs has remained to be a puzzle. However, not even a single such massive WD has been observed directly. Moreover, some WD pulsars are detected in electromagnetic surveys and some of their masses are still not confirmed. Here, we calculate the signal-to-noise ratio for all these objects, considering different magnetic field configurations and thereby estimate the required time for their detection by various gravitational wave (GW) detectors. For SGRs and AXPs, we show that, if these are NSs, they can hardly be detected by any of the GW detectors, while if they are WDs, big bang Observer (BBO), DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) and Advanced Laser Interferometer Antenna (ALIA) would be able to detect them within a few days to a year of integration, depending on the magnetic field strength and its configuration. Similarly, if a super-Chandrasekhar WD has a dominant toroidal field, we show that even Laser Interferometer Space Antenna (LISA) and TianQin would be able to detect it within one year of integration. We also discuss how GWs can confirm the masses of the WD pulsars.

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Magnetic Field Evolution in Merging Clusters of Galaxies

The Astrophysical Journal ◽

10.1086/307298 ◽

1999 ◽

Vol 518 (2) ◽

pp. 594-602 ◽

Cited By ~ 121

Author(s):

Kurt Roettiger ◽

James M. Stone ◽

Jack O. Burns

Keyword(s):

Magnetic Field ◽

Clusters Of Galaxies ◽

Field Evolution

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High magnetic-field evolution of the in-plane angular magnetoresistance of electron-doped Sr1−xLaxCuO2 in the normal state

Physical Review B ◽

10.1103/physrevb.103.014520 ◽

2021 ◽

Vol 103 (1) ◽

Author(s):

V. P. Jovanović ◽

H. Raffy ◽

Z. Z. Li ◽

G. Reményi ◽

P. Monceau

Keyword(s):

Magnetic Field ◽

High Magnetic Field ◽

Normal State ◽

Field Evolution

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A New View on Young Pulsars in Supernova Remnants: Slow, Radio-quiet & X-ray Bright

International Astronomical Union Colloquium ◽

10.1017/s0252921100061017 ◽

2000 ◽

Vol 177 ◽

pp. 699-702 ◽

Cited By ~ 2

Author(s):

E. V. Gotthelf ◽

G. Vasisht

Keyword(s):

Magnetic Field ◽

Neutron Stars ◽

Supernova Remnants ◽

Simple Explanation ◽

Crab Pulsar ◽

Radio Pulsars ◽

Substantial Fraction ◽

Subsequent Evolution ◽

X Ray ◽

Field Decay

AbstractWe propose a simple explanation for the apparent dearth of radio pulsars associated with young supernova remnants (SNRs). Recent X-ray observations of young remnants have revealed slowly rotating (P∼ 10s) central pulsars with pulsed emission above 2 keV, lacking in detectable radio emission. Some of these objects apparently have enormous magnetic fields, evolving in a manner distinct from the Crab pulsar. We argue that these X-ray pulsars can account for a substantial fraction of the long sought after neutron stars in SNRs and that Crab-like pulsars are perhaps the rarer, but more highly visible example of these stellar embers. Magnetic field decay likely accounts for their high X-ray luminosity, which cannot be explained as rotational energy loss, as for the Crab-like pulsars. We suggest that the natal magnetic field strength of these objects control their subsequent evolution. There are currently almost a dozen slow X-ray pulsars associated with young SNRs. Remarkably, these objects, taken together, represent at least half of the confirmed pulsars in supernova remnants. This being the case, these pulsars must be the progenitors of a vast population of previously unrecognized neutron stars.

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Constraining the coherence scale of the interstellar magnetic field using TeV gamma-ray observations of supernova remnants

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa1678 ◽

2020 ◽

Vol 496 (2) ◽

pp. 2448-2461 ◽

Cited By ~ 2

Author(s):

Matteo Pais ◽

Christoph Pfrommer ◽

Kristian Ehlert ◽

Maria Werhahn ◽

Georg Winner

Keyword(s):

Magnetic Field ◽

Interstellar Medium ◽

Supernova Remnants ◽

Gamma Ray ◽

Galactic Cosmic Rays ◽

Shock Acceleration ◽

Interstellar Gas ◽

Narrow Angle ◽

Magnetohydrodynamic Simulations ◽

Tev Gamma Rays

ABSTRACT Galactic cosmic rays (CRs) are believed to be accelerated at supernova remnant (SNR) shocks. In the hadronic scenario, the TeV gamma-ray emission from SNRs originates from decaying pions that are produced in collisions of the interstellar gas and CRs. Using CR-magnetohydrodynamic simulations, we show that magnetic obliquity-dependent shock acceleration is able to reproduce the observed TeV gamma-ray morphology of SNRs such as Vela Jr and SN1006 solely by varying the magnetic morphology. This implies that gamma-ray bright regions result from quasi-parallel shocks (i.e. when the shock propagates at a narrow angle to the upstream magnetic field), which are known to efficiently accelerate CR protons, and that gamma-ray dark regions point to quasi-perpendicular shock configurations. Comparison of the simulated gamma-ray morphology to observations allows us to constrain the magnetic coherence scale λB around Vela Jr and SN1006 to $\lambda _B \simeq 13_{-4.3}^{+13}$ pc and $\lambda _B \gt 200_{-40}^{+50}$ pc, respectively, where the ambient magnetic field of SN1006 is consistent with being largely homogeneous. We find consistent pure hadronic and mixed hadronic-leptonic models that both reproduce the multifrequency spectra from the radio to TeV gamma-rays and match the observed gamma-ray morphology. Finally, to capture the propagation of an SNR shock in a clumpy interstellar medium, we study the interaction of a shock with a dense cloud with numerical simulations and analytics. We construct an analytical gamma-ray model for a core collapse SNR propagating through a structured interstellar medium, and show that the gamma-ray luminosity is only biased by 30 per cent for realistic parameters.

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