scholarly journals Magnetic field decay in young radio pulsars

Author(s):  
Andrei P. Igoshev ◽  
Sergei B. Popov
2000 ◽  
Vol 177 ◽  
pp. 699-702 ◽  
Author(s):  
E. V. Gotthelf ◽  
G. Vasisht

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.


2004 ◽  
Vol 13 (09) ◽  
pp. 1805-1815 ◽  
Author(s):  
OKTAY H. GUSEINOV ◽  
AŞKIN ANKAY ◽  
SEVINÇ O. TAGIEVA

In this work we have analysed various data on radio pulsars and we have shown that magnetic field decay of a factor about 10–20 is necessary to explain their evolution, in particular to remove the discrepancy between the characteristic and the real ages. The character of the field decay is exponential with a characteristic time of about 3×106 year. Observational data on single X-ray pulsars which radiate due to cooling also support this result.


1992 ◽  
Vol 128 ◽  
pp. 26-34
Author(s):  
Dipankar Bhattacharya

AbstractThe evolution of the magnetic field strength plays a major role in the life history of a neutron star. In this article the observational evidence of field evolution, in particular that of field decay and magnetic alignment, are critically examined. It is concluded that the observed decay of the spindown torque on radio pulsars cannot be caused by a secular evolution of the “obliqueness” of the neutron star, as suggested by some authors. Recent observations provide a strong indication that the decay of the magnetic field strength of a neutron star may be closely related to its evolution in a binary system. Theoretical models for such an evolution are discussed.


2015 ◽  
Vol 336 (8-9) ◽  
pp. 831-834 ◽  
Author(s):  
A.P. Igoshev ◽  
S.B. Popov

2012 ◽  
Vol 8 (S291) ◽  
pp. 115-115
Author(s):  
Simone Dall'Osso

AbstractMagnetic field decay in neutron stars has been a long debated subject, since the early realization that radio pulsars were likely spinning neutron stars endowed with a 1E12 G magnetic dipole. This problem has however eluded all attempts of solution so far, mostly due to the scarcity of observational indications. Here I discuss the observational evidence for decay of the dipole magnetic field in magnetar candidates (Soft Gamma Repeaters and Anomalous X-ray Pulsars) and present a quantitative study of its main properties. I show that the decaying dipole does not have enough energy to power the persistent X-ray emission of magnetars. The latter must thus directly reveal the decay of an additional, stronger field component, presumably hidden in the interior of these neutron stars. Using existing models it is possible to characterize the salient properties of this internal field component and their implications for magnetar astrophysics. Finally, I sketch preliminary considerations on evolutionary links between magnetars and other classes of neutron stars with strong dipole field that do not show magnetar-like activity.


1992 ◽  
Vol 128 ◽  
pp. 86-89
Author(s):  
W. Kundt

AbstractControversial interpretations of the functioning and evolution of (radio) pulsars are discussed and confronted with the constraints. It is argued that (i) polarized e± bunches are ejected from near the polar caps at high Lorentz factors γ ≳ 102, that (ii) coherent radio pulses are emitted by them during transit to the outer magnetosphere via curvature radiation, (iii) in the shape of (transverse) fan beams, that (iv) there is no indication of magnetic field decay (or buildup), and that (v) pulsars die either by alignment or by interstellar quenching.The so-called “millisecond” pulsars (outside globular clusters) are likely to be an abundant, young population of fast-born pulsars.


2020 ◽  
Vol 499 (2) ◽  
pp. 2826-2835 ◽  
Author(s):  
Andrei P Igoshev ◽  
Sergei B Popov

ABSTRACT Recently, Parthsarathy et al. analysed long-term timing observations of 85 young radio pulsars. They found that 15 objects have absolute values of braking indices ranging ∼10–3000, far from the classical value n = 3. They also noted a mild correlation between measured value of n and characteristic age of a radio pulsar. In this article, we systematically analyse possible physical origin of large braking indices. We find that a small fraction of these measurements could be caused by gravitational acceleration from an unseen ultra-wide companion of a pulsar or by precession. Remaining braking indices cannot be explained neither by pulsar obliquity angle evolution, nor by complex high-order multipole structure of the poloidal magnetic field. The most plausible explanation is a decay of the poloidal dipole magnetic field which operates on a time-scale ∼104−105 yr in some young objects, but has significantly longer time-scale in other radio pulsars. This decay can explain both amplitude of measured n and some correlation between n and characteristic age. The decay can be caused by either enhanced crystal impurities in the crust of some isolated radio pulsars or, more likely, by enhanced resistivity related to electron scattering off phonons due to slow cooling of low-mass neutron stars. If this effect is indeed the main cause of the rapid magnetic field decay manifesting as large braking indices, we predict that pulsars with large braking indices are hotter in comparison to those with n ≈ 3.


1997 ◽  
Vol 489 (2) ◽  
pp. 928-940 ◽  
Author(s):  
Soma Mukherjee ◽  
Ajit Kembhavi

2007 ◽  
Vol 98 (7) ◽  
Author(s):  
José A. Pons ◽  
Bennett Link ◽  
Juan A. Miralles ◽  
Ulrich Geppert

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