2021/02/16 by G. Vasilopoulos, Georgios Vasilopoulos, Filippos Koliopanos +11 · 22 citations
Earth and Planetary Sciences · Physics and Astronomy · #Astrophysical Phenomena and Observations #Binary number #Binary pulsar #Earth Systems and Cosmic Evolution #Flux (metallurgy) #Light curve #Neutron star #Orbital period #Orbital plane #Propeller #Pulsar #Pulsars and Gravitational Waves Research #astro-ph.HE
paper · pdf · doi:10.3847/1538-4357/abda49
published in The Astrophysical Journal 909(1), 50 (IOP Publishing) · 11 pages, 5 figures, Accepted to APJ
arxiv created 2021/02/16 · openalex created_date 2021/03/01 · openalex publication_date 2021/03/01 · arxiv updated 2021/03/10 · openalex updated_date 2026/08/05
Abstract We report on the temporal properties of the ultraluminous X-ray (ULX) pulsar M51 ULX-7 inferred from the analysis of the 2018–2020 Swift/X-ray Telescope monitoring data and archival Chandra data obtained over a period of 33 days in 2012. We find an extended low flux state, which might be indicative of propeller transition, lending further support to the interpretation that the neutron star is rotating near equilibrium. Alternatively, this off-state could be related to a variable superorbital period. Moreover, we report the discovery of periodic dips in the X-ray light curve that are associated with the binary orbital period. The presence of the dips implies a configuration where the orbital plane of the binary is closer to an edge-on orientation, and thus demonstrates that favorable geometries are not necessary in order to observe ULX pulsars. These characteristics are similar to those seen in prototypical X-ray pulsars such as Her X-1 and SMC X-1 or other ULX pulsars such as NGC 5907 ULX1.