The high energy X-ray probe (HEX-P): Galactic PeVatrons, star clusters, superbubbles, microquasar jets, and gamma-ray binaries

Journal Article · 21 December 2023 · Frontiers in Astronomy and Space Sciences

DOI: https://doi.org/10.3389/fspas.2023.1303197 · OSTI ID:2426790

Mori, Kaya ^[1]; Reynolds, Stephen ^[2]; An, Hongjun ^[3]; Bamba, Aya ^[4]; Krivonos, Roman ^[5]; Tsuji, Naomi ^[6]; Abdelmaguid, Moaz ^[7]; Alford, Jason ^[7]; Bangale, Priyadarshini ^[8]; Celli, Silvia ^[9]; Diesing, Rebecca ^[10]; Eagle, Jordan ^[11]; Fryer, Chris L.  ^[12]; Gabici, Stefano ^[13]; Gelfand, Joseph ^[7]; Grefenstette, Brian ^[14]; Garcia, Javier ^[11]; Kim, Chanho ^[3]; Kumar, Sajan ^[15]; Kuznetsova, Ekaterina ^[5] ; Mac Intyre, Brydyn ^[16]; Madsen, Kristin ^[11]; Manconi, Silvia ^[17]; Motogami, Yugo ^[18]; Ohsumi, Hayato ^[18]; Olmi, Barbara ^[19]; Park, Jaegeun ^[3]; Ponti, Gabriele ^[20]; Sato, Toshiki ^[21]; Shang, Ruo-Yu ^[22]; Stern, Daniel ^[23]; Terada, Yukikatsu ^[24]; Woo, Jooyun ^[1]; Younes, George ^[25]; Zoglauer, Andreas ^[26]

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1. Columbia Univ., New York, NY (United States). Columbia Astrophysics Lab.
2. North Carolina State University, Raleigh, NC (United States)
3. Chungbuk National University, Cheongju (South Korea)
4. Univ. of Tokyo (Japan)
5. Russian Academy of Sciences (RAS), Moscow (Russia)
6. Kanagawa Univ., Yokohama, Kanagawa (Japan)
7. New York University (NYU), Abu Dhabi (United Arab Emirates)
8. Univ. of Delaware, Newark, DE (United States)
9. Sapienza University of Rome (Italy); Istituto Nazionale di Fisica Nucleare (INFN), Rome (Italy)
10. Univ. of Chicago, IL (United States); Institute for Advanced Study, Princeton, NJ (United States); Columbia Univ., New York, NY (United States). Columbia Astrophysics Lab.
11. NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States)
12. Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
13. Universite Paris Cite (France)
14. California Institute of Technology (CalTech), Pasadena, CA (United States). Space Radiation Laboratory
15. Univ. of Maryland, College Park, MD (United States)
16. Univ. of Manitoba, Winnipeg, MB (Canada)
17. Universite Savoie Mont Blanc, Annecy (France)
18. Saitama Univ. (Japan)
19. Istituto Nazionale di Astrofisica (INAF), Firenze (Italy). Osservatorio Astrofisico di Arcetri; Istituto Nazionale di Astrofisica (INAF), Palermo (Italy). Osservatorio Astronomico di Palermo
20. Istituto Nazionale di Astrofisica (INAF), Merate (Italy). Osservatorio Astrofisico di Brera; Max Planck Inst. fuer Extraterrestrische Physik, Garching (Germany)
21. Meiji University, Kawasaki (Japan)
22. Barnard College, New York, NY (United States)
23. California Institute of Technology (CalTech), Pasadena, CA (United States). Jet Propulsion Lab. (JPL)
24. Saitama Univ. (Japan); Japan Aerospace Exploration Agency (ISAS/JAXA), Sagamihara, Kanagawa (Japan). Institute of Space and Astronautical Science
25. NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States); George Washington Univ., Washington, DC (United States)
26. Univ. of California, Berkeley, CA (United States). Space Sciences Lab.

HEX-P is a probe-class mission concept that will combine high spatial resolution X-ray imaging (<10" FWHM) and broad spectral coverage (0.2–80 keV) with an effective area far superior to current facilities (including XMM-Newton and NuSTAR) to enable revolutionary new insights into a variety of important astrophysical problems. With the recent discoveries of over 40 ultra-high-energy gamma-ray sources (detected above 100 TeV) and neutrino emission in the Galactic Plane, we have entered a new era of multi-messenger astrophysics facing the exciting reality of Galactic PeVatrons. In the next decade, as more Galactic PeVatrons and TeV gamma-ray sources are expected to be discovered, the identification of their acceleration and emission mechanisms will be the most pressing issue in both particle and high-energy astrophysics. In this paper, along with its companion papers, we will present that HEX-P is uniquely suited to address important problems in various cosmic-ray accelerators, including Galactic PeVatrons, through investigating synchrotron X-ray emission of TeV–PeV electrons produced by both leptonic and hadronic processes. For Galactic PeVatron candidates and other TeV gamma-ray sources, HEX-P can fill in a large gap in the spectral-energy distributions (SEDs) of many objects observed in radio, soft X-rays, and gamma rays, constraining the maximum energies to which electrons can be accelerated, with implications for the nature of the Galactic PeVatrons and their contributions to the spectrum of Galactic cosmic rays beyond the knee at ~3 PeV. In particular, X-ray observation with HEX-P and TeV observation with CTAO will provide the most powerful multi-messenger diagnostics to identify Galactic PeVatrons and explore a variety of astrophysical shock mechanisms. We present simulations of each class of Galactic TeV–PeV sources, demonstrating the power of both the imaging and spectral capabilities of HEX-P to advance our knowledge of Galactic cosmic-ray accelerators. In addition, we discuss HEX-P’s unique and complementary roles to upcoming gamma-ray and neutrino observatories in the 2030s.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA). Office of Defense Programs (DP); JSPS KAKENHI
• Grant/Contract Number: 89233218CNA000001
• OSTI ID: 2426790
• Report Number(s): LA-UR--23-27394
• Journal Information: Frontiers in Astronomy and Space Sciences, Journal Name: Frontiers in Astronomy and Space Sciences Vol. 10; ISSN 2296-987X
• Publisher: Frontiers Research FoundationCopyright Statement
• Country of Publication: United States
• Language: English