Population synthesis of young neutron stars

AbstractWe investigate the fortune of young neutron stars (NS) in the whole volume of the Milky Way with new code for population synthesis. We start our modeling from the birth of massive OB stars and follow their motion in the Galaxy up to the Supernova explosion. Next we integrate the equations of motion of NS in the averaged gravitational potential of the Galaxy. We estimate the mean kick velocities from a comparison the model Z and R-distributions of radio emitting NS with that for galactic NS accordingly ATNF pulsar catalog. We follow the history of the rotational velocity and the surface magnetic field of NS taking into account the significant magnetic field decay during the first million year of a neutron star's life. The derived value for the mean time of ohmic decay is 2.3ċ105 years. We model the subsample of galactic radio pulsars which can be detected with available radio telescopes, using a radio beaming model with inhomogeneous distribution of the radio emission in the cone. The distributions functions of the pulsar periods P, period derivatives Ṗ and surface magnetic fields B appear to be in a close agreement with those obtained from an ensemble of neutron stars in the ATNF catalogue.

Download Full-text

Population synthesis studies of isolated neutron stars with magnetic field decay

Monthly Notices of the Royal Astronomical Society ◽

10.1111/j.1365-2966.2009.15850.x ◽

2010 ◽

Vol 401 (4) ◽

pp. 2675-2686 ◽

Cited By ~ 84

Author(s):

S. B. Popov ◽

J. A. Pons ◽

J. A. Miralles ◽

P. A. Boldin ◽

B. Posselt

Keyword(s):

Magnetic Field ◽

Neutron Stars ◽

Population Synthesis ◽

Field Decay

Download Full-text

Secondary Components of Binary Pulsars & Magnetic Field Decay in Neutron Stars

Symposium - International Astronomical Union ◽

10.1017/s0074180900161029 ◽

1987 ◽

Vol 125 ◽

pp. 407-407

Author(s):

Shrinivas R. Kulkarni

Keyword(s):

Magnetic Field ◽

Neutron Star ◽

Field Strength ◽

Neutron Stars ◽

White Dwarf ◽

Optical Counterpart ◽

Surface Magnetic Field ◽

Binary Pulsars ◽

Field Decay

We report the discovery of white dwarf secondaries in 0655+64 and 0820+02 systems. In the 2303+46 system, we do not find any optical counterpart suggesting that the companion is another neutron star. The existence of a cool and therefore old white dwarf in the 0655+64 system implies that the surface magnetic field of neutron stars stops decaying beyond some value(s) of field strength.

Download Full-text

Neutron stars: history of the magnetic field decay

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312024301 ◽

2012 ◽

Vol 8 (S291) ◽

pp. 408-410

Author(s):

Andrei P. Igoshev ◽

Alexander F. Kholtygin

Keyword(s):

Magnetic Field ◽

Neutron Stars ◽

Birth Rate ◽

Initial Period ◽

Universal Function ◽

Initial Surface ◽

Surface Magnetic Field ◽

History Of ◽

Field Decay ◽

The Magnetic Field

AbstractUsing the data of the ATNF pulsar catalog we study the relation connected the real age t of young neutron stars (NS) and their spin-down age τ. We suppose that this relation is independent from both initial period of the NS and its initial surface magnetic field, and that the laws of the surface magnetic field decay are similar for all NSs in the Milky Way. We further assume that the birth-rate of pulsars was constant during at least last 200 million years. With these assumptions we were able to restore the history of the magnetic field decay for the galactic NSs. We reconstruct the universal function f(t) = B(t)/B0, where B0 is the initial magnetic field and B(t) is the magnetic field of NS at the age t. The function f(t) can be fitted by a power law with power index α = −1.17.

Download Full-text

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.

Download Full-text

Evidence for Heating of Neutron Stars by Magnetic-Field Decay

Physical Review Letters ◽

10.1103/physrevlett.98.071101 ◽

2007 ◽

Vol 98 (7) ◽

Cited By ~ 56

Author(s):

José A. Pons ◽

Bennett Link ◽

Juan A. Miralles ◽

Ulrich Geppert

Keyword(s):

Magnetic Field ◽

Neutron Stars ◽

Field Decay

Download Full-text

Mutual influence of magnetic field decay and thermal evolution of rotational neutron stars

Proceedings of the International Astronomical Union ◽

10.1017/s1743921313000045 ◽

2012 ◽

Vol 8 (S291) ◽

pp. 586-588

Author(s):

Xia Zhou ◽

Miao Kang ◽

Na Wang

Keyword(s):

Magnetic Field ◽

Neutron Stars ◽

Mutual Influence ◽

Thermal Evolution ◽

Chemical Heating ◽

Field Decay ◽

The Magnetic Field

AbstractThe effect of magnetic field decay on the chemical heating and thermal evolution of neutron stars is discussed. Our main goal is to study how chemical heating mechanisms and thermal evolution are changed by field decay and how magnetic field decay is modified by the thermal evolution. We show that the effect of chemical heating is suppressed by the star spin-down through decaying magnetic field at a later stage; magnetic field decay is delayed significantly relative to stars cooling without heating mechanisms; compared to typical chemical heating, the decay of the magnetic field can even cause the temperature to turn down at a later stage.

Download Full-text

Population Synthesis of Old Neutron Stars in the Galaxy

Symposium - International Astronomical Union ◽

10.1017/s0074180900162916 ◽

2000 ◽

Vol 195 ◽

pp. 181-188

Author(s):

S. B. Popov ◽

M. Colpi ◽

A. Treves ◽

R. Turolla ◽

V. M. Lipunov ◽

...

Keyword(s):

Neutron Stars ◽

Ambient Medium ◽

Dynamical Evolution ◽

Low Velocity ◽

Mean Velocity ◽

Secular Evolution ◽

Sky Survey ◽

The Galaxy ◽

The Mean ◽

Statistical Sample

The paucity of old, isolated accreting neutron stars in ROSAT observations is used to derive a lower limit on the mean velocity of neutron stars at birth. The secular evolution of the population is simulated following the paths of a statistical sample of stars for different values of the initial kick velocity, drawn from an isotropic, Gaussian distribution with mean velocity 0 ≤ 〈V〉 ≤ 550 km s−1. The spin-down, induced by dipole losses and the interaction with the ambient medium, is tracked together with the dynamical evolution in the Galactic potential, allowing for the determination of the fraction of stars which are, at present, in each of the four possible stages: Ejector, Propeller, Accretor, and Georotator. Taking from the ROSAT All-Sky Survey an upper limit of ~ 10 accreting neutron stars within ~ 140 pc from the Sun, we infer a lower bound for the mean kick velocity, 〈V〉 ≳ 200–300 km s−1. The same conclusion is reached for both a constant (B ~ 1012 G) and an exponentially decaying magnetic field with a timescale ~ 109 yr. Present results, moreover, constrain the fraction of low-velocity stars which could have escaped pulsar statistics to ≲ 1%.

Download Full-text