Published September 23, 2021 | Version v1
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Is a number of strongly magnetised OB stars enough to produce all known magnetars?

Description

According to stellar evolution models, massive OB stars form neutron stars after the end of their life. But does the initial magnetic field of a neutron star depend on the magnetic field of a predecessor star? Some pulsar population synthesis (e.g. Gullón et al. 2015) which included thermally emitting neutron stars showed that magnetars (and for example the group of young cooling neutron stars called "the Magnificent Seven") could originate from a peculiar subpopulation of massive stars. Moreover, we can see that massive stars also can be divided into two groups: magnetic stars with average magnetic fields from several hundreds of Gauss to tens of kilogauss (only 5-7% of all) and nonmagnetic or weakly magnetic stars whose magnetic fields can not yet be measured accurately. Therefore, we want to check the hypothesis if magnetic OB stars in the Milky Way could be progenitors of magnetars. We also aim to explain how the magnetic fields depend on the stellar radii, binarity, and other parameters using modern observational data for various values (NARVAL measurements, Magnetar Outburst Online Catalog, Gaia DR2, etc). To do so, we study the distribution of magnetic fields of massive stars using the maximum likelihood technique and run a new pulsar population synthesis code. As a result of our analysis, we can claim that normal pulsars seem to be plausible descendants of the weakly magnetic OB stars and the precursors of magnetars are magnetic OB stars.

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Ekaterina Makarenko - ct_makarenko.mp4

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