S. B. Popov

Population synthesis studies of isolated neutron stars with magnetic field decay

We perform population synthesis studies of different types of neutron stars (NSs) (thermally emitting isolated NSs, normal radio pulsars, magnetars) taking into account the magnetic field decay and using results from the most recent advances in NS cooling theory. For the first time, we confront our results with observations using simultaneously the log N-log S distribution for nearby isolated NSs, the log N-log L distribution for magnetars, and the distribution of radio pulsars in the P-P diagram. For this purpose, we fix a baseline NS model (all microphysics input), and other relevant parameters to standard values (velocity distribution, mass spectrum, birth rates, etc.), allowing us to vary the initial magnetic field strength. We find that our theoretical model is consistent with all sets of data if the initial magnetic field distribution function follows a lognormal law with (log (B 0 /G)〉 ∼ 13.25 and σ log B 0 ∼ 0.6. The typical scenario includes about 10 per cent of NSs born as magnetars, significant magnetic field decay during the first million years of a NS life (only about a factor of 2 for low-field NSs but more than an order of magnitude for magnetars), and a mass distribution function dominated by low-mass objects. This model explains satisfactorily all known populations. Evolutionary links between different subclasses may exist, although robust conclusions are not yet possible.

Be–X-ray binaries and candidates

We present a compilative catalogue of Be–X-ray binaries and candidates in the Galaxy and in the Large and Small Magellanic Clouds. This catalogue contains 130 sources and provides information on names and spectral types of optical components, distances, on spin characteristics of neutron stars and on orbital and X-ray properties of binary systems. We give brief comments on each object and provide necessary references to original data.

Fast radio bursts as giant pulses from young rapidly rotating pulsars

We discuss possible association of fast radio bursts (FRBs) with supergiant pulses emitted by young pulsars (ages

A tale of two populations: rotating radio transients and X-ray dim isolated neutron stars

\sim

The Magnificent Seven in the dusty prairie - the role of interstellar absorption on the observed neutron star population

tens to hundreds of years) born with regular magnetic field but very short -- few milliseconds -- spin periods. FRBs are extra-Galactic events coming from distances

Population synthesis in astrophysics

d \lesssim 100

Soft gamma repeaters outside the Local Group

Mpc. Most of the dispersion measure (DM) comes from the material in the freshly ejected SNR shell; for a given burst the DM should decrease with time. FRBs are not expected to be seen below

The needle in the haystack: where to look for more isolated cooling neutron stars

\sim 300

LOG N - LOG S DISTRIBUTIONS OF ACCRETING AND COOLING ISOLATED NEUTRON STARS

MHz due to free-free absorption in the expanding ejecta. A supernova might have been detected years before the burst; FRBs are mostly associated with star forming galaxies. The model requires that some pulsars are born with very fast spins, of the order of few milliseconds. The observed distribution of spin-down powers

Progenitors with enhanced rotation and the origin of magnetars

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