The High Energy X-ray Probe: Resolved X-ray Populations in Extragalactic Environments

Authors

Bret D. Lehmer, University of Arkansas, FayettevilleFollow
Kristen Garofali, NASA Goddard Space Flight Center
Breanna A. Binder, California State Polytechnic University - Pomona
Francesca Fornasini, Stonehill College
Neven Vulic, Eureka Scientific, Inc.
Andreas Zezas, University of Crete
Ann Hornschemeier, NASA Goddard Space Flight Center
Margaret Lazzarini, California State University, Los Angeles
Hannah Moon, University of Utah
Toni Venters, NASA Goddard Space Flight Center
Daniel Wik, University of Utah
Mihoko Yukita, The Johns Hopkins University
Matteo Bachetti, INAF - Osservatorio Astronomico di Cagliari
Javier A. Garcia, NASA Goddard Space Flight Center
Brian Grefenstette, California Institute of Technology
Kristin Madsen, NASA Goddard Space Flight Center
Kaya Mori, Columbia University
Daniel Stern, California Institute of Technology

Document Type

Article

Publication Date

11-2023

Keywords

early-type galaxies; star formation; starburst galaxies; X-ray binary stars; X-ray astronomy; compact objects

Abstract

We construct simulated galaxy data sets based on the High Energy X-ray Probe (HEX-P) mission concept to demonstrate the significant advances in galaxy science that will be yielded by the HEX-P observatory. The combination of high spatial resolution imaging (<20 arcsec FWHM), broad spectral coverage (0.2–80 keV), and sensitivity superior to current facilities (e.g., XMM-Newton and NuSTAR) will enable HEX-P to detect hard (4–25 keV) X-ray emission from resolved point-source populations within ∼800 galaxies and integrated emission from ∼6,000 galaxies out to 100 Mpc. These galaxies cover wide ranges of galaxy types (e.g., normal, starburst, and passive galaxies) and properties (e.g., metallicities and star-formation histories). In such galaxies, HEX-P will: 1) provide unique information about X-ray binary populations, including accretor demographics (black hole and neutron stars), distributions of accretion states and state transition cadences; 2) place order-of-magnitude more stringent constraints on inverse Compton emission associated with particle acceleration in starburst environments; and 3) put into clear context the contributions from X-ray emitting populations to both ionizing the surrounding interstellar medium in low-metallicity galaxies and heating the intergalactic medium in the z > 8 Universe.

Citation

Lehmer, B. D., Garofali, K., Binder, B. A., Fornasini, F., Vulic, N., Zezas, A., Hornschemeier, A., Lazzarini, M., Moon, H., Venters, T., Wik, D., Yukita, M., Bachetti, M., Garcia, J. A., Grefenstette, B., Madsen, K., Mori, K., & Stern, D. (2023). The High Energy X-ray Probe: Resolved X-ray Populations in Extragalactic Environments. Frontiers in Astronomy and Space Sciences, 10, 1293918. https://doi.org/10.3389/fspas.2023.1293918

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