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The impact of precession on the observed population of ULXs

Khan, N.; Middleton, M.J.; Wiktorowicz, G.; Dauser, T.; Roberts, T.P.; Wilms, J.

The impact of precession on the observed population of ULXs Thumbnail


N. Khan

M.J. Middleton

G. Wiktorowicz

T. Dauser

J. Wilms


The discovery of neutron stars (NSs) powering several ultraluminous X-ray sources (ULXs) raises important questions about the nature of the underlying population. In this paper, we build on previous work studying simulated populations by incorporating a model where the emission originates from a precessing, geometrically beamed wind-cone, created by a supercritical inflow. We obtain estimates – independent of the prescription for the precession period of the wind – for the relative number of ULXs that are potentially visible (persistent or transient) for a range of underlying factors such as the relative abundance of black holes or NSs within the population, maximum precessional angle, and low-mass X-ray binary duty cycle. We make initial comparisons to existing data using a catalogue compiled from XMM–Newton. Finally, based on estimates for the precession period, we determine how the eROSITA all-sky survey (eRASS) will be able to constrain the underlying demographic.


Khan, N., Middleton, M., Wiktorowicz, G., Dauser, T., Roberts, T., & Wilms, J. (2022). The impact of precession on the observed population of ULXs. Monthly Notices of the Royal Astronomical Society, 509(2), 2493-2506.

Journal Article Type Article
Acceptance Date Oct 15, 2021
Online Publication Date Oct 23, 2021
Publication Date 2022-01
Deposit Date Nov 1, 2021
Publicly Available Date Mar 18, 2022
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 509
Issue 2
Pages 2493-2506
Related Public URLs


Published Journal Article (3.8 Mb)

Copyright Statement
This article has been accepted for publication in Monthly Notices of the Royal astronomical Society ©: 2021, The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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