The high energy X-ray probe ( HEX-P ): studying extreme accretion with ultraluminous X-ray sources

Bachetti, Matteo; Middleton, Matthew J.; Pinto, Ciro; Gúrpide, Andrés; Walton, Dominic J.; Brightman, Murray; Lehmer, Bret; Roberts, Timothy P.; Vasilopoulos, Georgios; Alford, Jason; Amato, Roberta; Ambrosi, Elena; Dai, Lixin; Earnshaw, Hannah P.; El Byad, Hamza; García, Javier A.; Luca Israel, Gian; Jaodand, Amruta; Madsen, Kristin; Maitra, Chandreyee; Mandel, Shifra; Mori, Kaya; Pintore, Fabio; Ohsuga, Ken; Pilia, Maura; Stern, Daniel; Younes, George; Wolter, Anna

doi:10.3389/fspas.2023.1289432

The high energy X-ray probe ( HEX-P ): studying extreme accretion with ultraluminous X-ray sources

Bachetti, Matteo; Middleton, Matthew J.; Pinto, Ciro; Gúrpide, Andrés; Walton, Dominic J.; Brightman, Murray; Lehmer, Bret; Roberts, Timothy P.; Vasilopoulos, Georgios; Alford, Jason; Amato, Roberta; Ambrosi, Elena; Dai, Lixin; Earnshaw, Hannah P.; El Byad, Hamza; García, Javier A.; Luca Israel, Gian; Jaodand, Amruta; Madsen, Kristin; Maitra, Chandreyee; Mandel, Shifra; Mori, Kaya; Pintore, Fabio; Ohsuga, Ken; Pilia, Maura; Stern, Daniel; Younes, George; Wolter, Anna

Authors

Matteo Bachetti

Matthew J. Middleton

Ciro Pinto

Andrés Gúrpide

Dominic J. Walton

Murray Brightman

Bret Lehmer

Professor Tim Roberts t.p.roberts@durham.ac.uk
Professor

Georgios Vasilopoulos

Jason Alford

Roberta Amato

Elena Ambrosi

Lixin Dai

Hannah P. Earnshaw

Hamza El Byad

Javier A. García

Gian Luca Israel

Amruta Jaodand

Kristin Madsen

Chandreyee Maitra

Shifra Mandel

Kaya Mori

Fabio Pintore

Ken Ohsuga

Maura Pilia

Daniel Stern

George Younes

Anna Wolter

Abstract

Introduction: Ultraluminous X-ray sources (ULXs) represent an extreme class of accreting compact objects: from the identification of some of the accretors as neutron stars to the detection of powerful winds travelling at 0.1–0.2 c, the increasing evidence points towards ULXs harbouring stellar-mass compact objects undergoing highly super-Eddington accretion. Measuring their intrinsic properties, such as the accretion rate onto the compact object, the outflow rate, the masses of accretor/companion-hence their progenitors, lifetimes, and future evolution-is challenging due to ULXs being mostly extragalactic and in crowded fields. Yet ULXs represent our best opportunity to understand super-Eddington accretion physics and the paths through binary evolution to eventual double compact object binaries and gravitational-wave sources. Methods: Through a combination of end-to-end and single-source simulations, we investigate the ability of HEX-P to study ULXs in the context of their host galaxies and compare it to XMM-Newton and NuSTAR, the current instruments with the most similar capabilities. Results: HEX-P’s higher sensitivity, which is driven by its narrow point-spread function and low background, allows it to detect pulsations and broad spectral features from ULXs better than XMM-Newton and NuSTAR. Discussion: We describe the value of HEX-P in understanding ULXs and their associated key physics, through a combination of broadband sensitivity, timing resolution, and angular resolution, which make the mission ideal for pulsation detection and low-background, broadband spectral studies.

Citation

Bachetti, M., Middleton, M. J., Pinto, C., Gúrpide, A., Walton, D. J., Brightman, M., …Wolter, A. (2023). The high energy X-ray probe ( HEX-P ): studying extreme accretion with ultraluminous X-ray sources. Frontiers in Astronomy and Space Sciences, 10, Article 1289432. https://doi.org/10.3389/fspas.2023.1289432

Journal Article Type	Article
Acceptance Date	Oct 26, 2023
Online Publication Date	Nov 27, 2023
Publication Date	Nov 27, 2023
Deposit Date	Feb 21, 2024
Publicly Available Date	Feb 21, 2024
Journal	Frontiers in Astronomy and Space Sciences
Publisher	Frontiers Media
Peer Reviewed	Peer Reviewed
Volume	10
Article Number	1289432
DOI	https://doi.org/10.3389/fspas.2023.1289432
Keywords	accretion, spectra, black holes, HEX-P, pulsars, ultraluminous X-ray sources
Public URL	https://durham-repository.worktribe.com/output/2120256

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Copyright Statement
© 2023 Bachetti, Middleton, Pinto, Gúrpide, Walton, Brightman, Lehmer, Roberts, Vasilopoulos, Alford, Amato, Ambrosi, Dai, Earnshaw, El Byad, García, Luca Israel, Jaodand, Madsen, Maitra,
Mandel, Mori, Pintore, Ohsuga, Pilia, Stern, Younes and Wolter. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the
original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.