Frontiers in Astronomy and Space Sciences (Mar 2024)
The high energy X-ray probe (HEX-P): bringing the cosmic X-ray background into focus
- F. Civano,
- X. Zhao,
- P. G. Boorman,
- S. Marchesi,
- S. Marchesi,
- T. Ananna,
- S. Creech,
- S. Creech,
- C.-T. Chen,
- C.-T. Chen,
- R. C. Hickox,
- D. Stern,
- K. Madsen,
- J. A. García,
- R. Silver,
- R. Silver,
- J. Aird,
- D. M. Alexander,
- M. Baloković,
- M. Baloković,
- W. N. Brandt,
- W. N. Brandt,
- W. N. Brandt,
- J. Buchner,
- P. Gandhi,
- E. Kammoun,
- E. Kammoun,
- S. LaMassa,
- G. Lanzuisi,
- A. Merloni,
- A. Moretti,
- K. Nandra,
- E. Nardini,
- A. Pizzetti,
- S. Puccetti,
- R. W. Pfeifle,
- R. W. Pfeifle,
- C. Ricci,
- C. Ricci,
- D. Spiga,
- N. Torres-Albà
Affiliations
- F. Civano
- NASA Goddard Space Flight Center, Greenbelt, MD, United States
- X. Zhao
- Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, United States
- P. G. Boorman
- Cahill Center for Astrophysics, California Institute of Technology, Pasadena, CA, United States
- S. Marchesi
- INAF—Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Bologna, Italy
- S. Marchesi
- Department of Physics and Astronomy, Kinard Lab of Physics, Clemson University, Clemson, SC, United States
- T. Ananna
- Department of Physics and Astronomy, Wayne State University, Detroit, MI, United States
- S. Creech
- Department of Physics and Astronomy, University of Utah, Salt Lake City, UT, United States
- S. Creech
- Astrophysics Science Division, SURA/GSFC/CRESST II, Greenbelt, MD, United States
- C.-T. Chen
- Science and Technology Institute, Universities Space Research Association, Huntsville, AL, United States
- C.-T. Chen
- 0Astrophysics Office, NASA Marshall Space Flight Center, Huntsville, AL, United States
- R. C. Hickox
- 1Department of Physics and Astronomy, Dartmouth College, Hanover, NH, United States
- D. Stern
- 2Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States
- K. Madsen
- NASA Goddard Space Flight Center, Greenbelt, MD, United States
- J. A. García
- NASA Goddard Space Flight Center, Greenbelt, MD, United States
- R. Silver
- NASA Goddard Space Flight Center, Greenbelt, MD, United States
- R. Silver
- 3NASA NPP Program, Oak Ridge Associated Universities, Oak Ridge, TN, United States
- J. Aird
- 4Institute for Astronomy, Royal Observatory, University of Edinburgh, Edinburgh, United Kingdom
- D. M. Alexander
- 5Department of Physics, Centre for Extragalactic Astronomy, Durham University, Durham, United Kingdom
- M. Baloković
- 6Yale Center for Astronomy and Astrophysics, New Haven, CT, United States
- M. Baloković
- 7Department of Physics, Yale University, New Haven, CT, United States
- W. N. Brandt
- 8Department of Astronomy & Astrophysics, The Pennsylvania State University, University Park, PA, United States
- W. N. Brandt
- 9Institute for Gravitation and the Cosmos, The Pennsylvania State University, University Park, PA, United States
- W. N. Brandt
- 0Department of Physics, The Pennsylvania State University, University Park, PA, United States
- J. Buchner
- 1Max-Planck-Institut für Extraterrestrische Physik, Garching, Germany
- P. Gandhi
- 2Department of Physics and Astronomy, Faculty of Physical Sciences and Engineering, University of Southampton, Southampton, United Kingdom
- E. Kammoun
- 3INAF–Osservatorio Astrofisico di Arcetri, Florence, Italy
- E. Kammoun
- 4Dipartimento di Matematica e Fisica, Università Roma Tre, Rome, Italy
- S. LaMassa
- 5Space Telescope Science Institute, Baltimore, MD, United States
- G. Lanzuisi
- INAF—Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Bologna, Italy
- A. Merloni
- 1Max-Planck-Institut für Extraterrestrische Physik, Garching, Germany
- A. Moretti
- 6INAF, Osservatorio Astronomico di Brera, Milano, Italy
- K. Nandra
- 1Max-Planck-Institut für Extraterrestrische Physik, Garching, Germany
- E. Nardini
- 3INAF–Osservatorio Astrofisico di Arcetri, Florence, Italy
- A. Pizzetti
- Department of Physics and Astronomy, Kinard Lab of Physics, Clemson University, Clemson, SC, United States
- S. Puccetti
- 7ASI—Agenzia Spaziale Italiana, Rome, Italy
- R. W. Pfeifle
- NASA Goddard Space Flight Center, Greenbelt, MD, United States
- R. W. Pfeifle
- 3NASA NPP Program, Oak Ridge Associated Universities, Oak Ridge, TN, United States
- C. Ricci
- 8Núcleo de Astronom ía de la Facultad de Ingeniería, Universidad Diego Portales, Santiago, Chile
- C. Ricci
- 9Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing, China
- D. Spiga
- 0INAF, Osservatorio Astronomico di Brera, Merate, Italy
- N. Torres-Albà
- Department of Physics and Astronomy, Kinard Lab of Physics, Clemson University, Clemson, SC, United States
- DOI
- https://doi.org/10.3389/fspas.2024.1340719
- Journal volume & issue
-
Vol. 11
Abstract
Since the discovery of the cosmic X-ray background (CXB), astronomers have strived to understand the accreting supermassive black holes (SMBHs) contributing to its peak in the 10–40 keV band. Existing soft X-ray telescopes could study this population up to only 10 keV, and, while NuSTAR (focusing on 3–24 keV) made great progress, it also left significant uncertainties in characterizing the hard X-ray population, crucial for calibrating current population synthesis models. This paper presents an in-depth analysis of simulations of two extragalactic surveys (deep and wide) with the High-Energy X-ray Probe (HEX-P), each observed for 2 Ms. Applying established source detection techniques, we show that HEX-P surveys will reach a flux of ∼10−15 erg s−1 cm−2 in the 10–40 keV band, an order of magnitude fainter than current NuSTAR surveys. With the large sample of new hard X-ray detected sources (∼2000), we showcase HEX-P’s ability to resolve more than 80% of the CXB up to 40 keV into individual sources. The expected precision of HEX-P’s resolved background measurement will allow us to distinguish between population synthesis models of SMBH growth. HEX-P will leverage accurate broadband (0.5–40 keV) spectral analysis and the combination of soft and hard X-ray colors to provide obscuration constraints even for the fainter sources, with the overall objective of measuring the Compton-thick fraction. With unprecedented sensitivity in the 10–40 keV band, HEX-P will explore the hard X-ray emission from AGN to flux limits never reached before, thus expanding the parameter space for serendipitous discoveries. Consequently, it is plausible that new models will be needed to capture the population HEX-P will unveil.
Keywords
