The evolution of isolated neutron stars until accretion: the role of the initial magnetic field

Abstract

We study the evolution of isolated neutron stars on long time‐scales and calculate the distribution of these sources in the main evolutionary stages: ejector, propeller, accretor and georotator. We make comparisons among different initial magnetic field distributions taking into account the possibility of magnetic field decay, and include in our calculations the stage of subsonic propeller. It is shown that though the subsonic propeller stage can be relatively long, initially highly magnetized neutron stars (B0≳ 1013 G) reach the accretion regime within the Galactic lifetime if their kick velocities are not too large. The fact that in previous studies made >10 yr ago such objects were not considered results in a slight increase of the accretor fraction in comparison with earlier conclusions. Most of the neutron stars similar to the Magnificent Seven are expected to become accreting from the interstellar medium after a few billion years of their evolution. They are the main predecessors of accreting isolated neutron stars.

Detecting axion dark matter with radio lines from neutron star populations

“…We use population models such as [18,19], which have been tuned to observable pulsar data, to describe the distributions of initial NS magnetic field strengths and spin periods. We then evolve the NSs to the present day using spin-down and magnetic field decay models [18][19][20][21][22][23][24], though there are uncertainties on these processes which we describe. To date we have detected more than 2000 rotationpowered pulsars, but this only makes up a very small fraction of the total NS population.…”

Settling accretion on to isolated neutron stars from interstellar medium

“…If we neglect interstellar absorption (which may be well justified for small distances around 100 pc), then the limiting distance to AINS reduces to ∼ 15 pc. With a local density of AINS of ∼ 10 −4 pc −3 (Boldin & Popov 2010) only a few sources can be found within this volume. The rate of possible flares short flares (with a duration of tinst ∼ a few hours) can be rather high, but the rate of longer bursts caused by magnetic reconnection is difficult to estimate.…”

“…Then the expected X-ray luminosity of AINS Lx ∼ 10 27 erg s −1 suggests a limiting distance of 30 pc. According to Boldin & Popov (2010), only ∼ 10 very dim candidates can be found in this volume, which are very difficult to identify.…”

Isolated neutron stars in the galaxy: from magnetars to antimagnetars

“…Here we briefly present the results published in [4]. We update the approach by [5] using a more detailed description of evolutionary stages [6] and applying the magnetic field distribution from [2].…”