<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Vasilopoulos, G.</style></author><author><style face="normal" font="default" size="100%">Lander, S. K.</style></author><author><style face="normal" font="default" size="100%">Koliopanos, F.</style></author><author><style face="normal" font="default" size="100%">Bailyn, C. D.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">M51 ULX-7: superorbital periodicity and constraints on the neutron star magnetic field</style></title><short-title><style face="normal" font="default" size="100%">Monthly Notices of the Royal Astronomical Society</style></short-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Astrophysics - High Energy Astrophysical Phenomena</style></keyword><keyword><style  face="normal" font="default" size="100%">galaxies: individual: M51</style></keyword><keyword><style  face="normal" font="default" size="100%">pulsars: individual: M51 ULX-7</style></keyword><keyword><style  face="normal" font="default" size="100%">stars: neutron</style></keyword><keyword><style  face="normal" font="default" size="100%">X-rays: binaries</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2020</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2020/02/1</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://ui.adsabs.harvard.edu/abs/2020MNRAS.491.4949V</style></url></web-urls></urls><publisher><style face="normal" font="default" size="100%">OUP</style></publisher><volume><style face="normal" font="default" size="100%">491</style></volume><pages><style face="normal" font="default" size="100%">4949 - 4959</style></pages><isbn><style face="normal" font="default" size="100%">0035-8711</style></isbn><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">In this work, we explore the applicability of standard theoretical models of accretion to the observed properties of M51 ULX-7. The spin-up rate and observed X-ray luminosity are evidence of a neutron star with a surface magnetic field of 2-7 × 10&lt;SUP&gt;13&lt;/SUP&gt; G, rotating near equilibrium. Analysis of the X-ray light curve of the system (Swift/XRT data) reveals the presence of a ∼39 d superorbital period. We argue that the superorbital periodicity is due to disc precession, and that material is accreted on to the neutron star at a constant rate throughout it. Moreover, by attributing this modulation to the free precession of the neutron star we estimate a surface magnetic field strength of 3-4 × 10&lt;SUP&gt;13&lt;/SUP&gt; G. The agreement of these two independent estimates provide strong constraints on the surface polar magnetic field strength of the NS.</style></abstract></record></records></xml>