Meta-analysis of Electron Cyclotron Resonance Absorption Features Detected in High-Mass X-ray Binaries. (arXiv:1905.05363v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Christodoulou_D/0/1/0/all/0/1">Dimitris M. Christodoulou</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Laycock_S/0/1/0/all/0/1">Silas G. T. Laycock</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kazanas_D/0/1/0/all/0/1">Demosthenes Kazanas</a>
Using recent compilations of detailed X-ray observations and spectral models
of exceptional quality, we record the electron cyclotron resonance absorption
(ECRA) features that have been detected in 45 pulsating high-mass X-ray
binaries (HMXBs) and ultraluminous X-ray (ULX) sources harboring neutron stars,
although seven of these detections are still questionable and another 21 are
single and/or not independently confirmed. From the comprehensive catalogs of
Jaisawal & Naik and Staubert et al. and from several additional recent
observations, we produce two lists of HMXB ECRA sources: a list of 17 sources
in which multiple ECRA lines or single very low-energy lines are seen, in which
we can reasonably assume that the lowest energy reveals the fundamental
cyclotron level for each source; and a `contaminated’ list of 38 sources
including the 21 detections of single ECRA lines that may (not) be higher-level
harmonics. Both lists confirm a previous result that we have obtained
independently by modeling the propeller lines of Magellanic HMXB pulsars: the
surface dipolar magnetic fields $B_*$ of HMXB neutron stars are segregated
around five distinct values with $B_* = 0.28pm 0.08, 0.55pm 0.11, 1.3pm
0.37, 3.0pm 0.68$, and $7.9pm 3.1$, in units of TG. An explanation of this
phenomenon is currently lacking. We have found no correlation between these
$B_*$ values and the corresponding observed spin periods, spin period
derivatives, orbital periods, maximum X-ray luminosities, neutron star masses,
or companion star masses.
Using recent compilations of detailed X-ray observations and spectral models
of exceptional quality, we record the electron cyclotron resonance absorption
(ECRA) features that have been detected in 45 pulsating high-mass X-ray
binaries (HMXBs) and ultraluminous X-ray (ULX) sources harboring neutron stars,
although seven of these detections are still questionable and another 21 are
single and/or not independently confirmed. From the comprehensive catalogs of
Jaisawal & Naik and Staubert et al. and from several additional recent
observations, we produce two lists of HMXB ECRA sources: a list of 17 sources
in which multiple ECRA lines or single very low-energy lines are seen, in which
we can reasonably assume that the lowest energy reveals the fundamental
cyclotron level for each source; and a `contaminated’ list of 38 sources
including the 21 detections of single ECRA lines that may (not) be higher-level
harmonics. Both lists confirm a previous result that we have obtained
independently by modeling the propeller lines of Magellanic HMXB pulsars: the
surface dipolar magnetic fields $B_*$ of HMXB neutron stars are segregated
around five distinct values with $B_* = 0.28pm 0.08, 0.55pm 0.11, 1.3pm
0.37, 3.0pm 0.68$, and $7.9pm 3.1$, in units of TG. An explanation of this
phenomenon is currently lacking. We have found no correlation between these
$B_*$ values and the corresponding observed spin periods, spin period
derivatives, orbital periods, maximum X-ray luminosities, neutron star masses,
or companion star masses.
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