Observational constraints on the magnetic field of the bright transient Be/X-ray pulsar SXP 4.78. (arXiv:1907.06241v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Semena_A/0/1/0/all/0/1">Andrey N. Semena</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lutovinov_A/0/1/0/all/0/1">Alexander A. Lutovinov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mereminskiy_I/0/1/0/all/0/1">Ilya A. Mereminskiy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tsygankov_S/0/1/0/all/0/1">Sergey S. Tsygankov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shtykovsky_A/0/1/0/all/0/1">Andrey E. Shtykovsky</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Molkov_S/0/1/0/all/0/1">Sergey V. Molkov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Poutanen_J/0/1/0/all/0/1">Juri Poutanen</a>
We report results of the spectral and timing analysis of the Be/X-ray pulsar
SXP 4.78 using the data obtained during its recent outburst with NuSTAR, Swift,
Chandra and NICER observatories. Using an overall evolution of the system
luminosity, spectral analysis and variability power spectrum we obtain
constraints on the neutron star magnetic field strength. We found a rapid
evolution of the variability power spectrum during the rise of the outburst,
and absence of the significant changes during the flux decay. Several low
frequency quasi-periodic oscillation features are found to emerge on the
different stages of the outburst, but no clear clues on their origin were found
in the energy spectrum and overall flux behaviour. We use several indirect
methods to estimate the magnetic field strength on the neutron star surface and
found that most of them suggest magnetic field $B lesssim 2 times10^{12}$ G.
The strictest upper limit comes from the absence of the cyclotron absorption
features in the energy spectra and suggests relatively weak magnetic field $B <
6 times 10^{11}$ G.
We report results of the spectral and timing analysis of the Be/X-ray pulsar
SXP 4.78 using the data obtained during its recent outburst with NuSTAR, Swift,
Chandra and NICER observatories. Using an overall evolution of the system
luminosity, spectral analysis and variability power spectrum we obtain
constraints on the neutron star magnetic field strength. We found a rapid
evolution of the variability power spectrum during the rise of the outburst,
and absence of the significant changes during the flux decay. Several low
frequency quasi-periodic oscillation features are found to emerge on the
different stages of the outburst, but no clear clues on their origin were found
in the energy spectrum and overall flux behaviour. We use several indirect
methods to estimate the magnetic field strength on the neutron star surface and
found that most of them suggest magnetic field $B lesssim 2 times10^{12}$ G.
The strictest upper limit comes from the absence of the cyclotron absorption
features in the energy spectra and suggests relatively weak magnetic field $B <
6 times 10^{11}$ G.
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