The <i>N</i> <sub>H</sub> Distribution of Hard X-Ray Selected Active Galactic Nuclei in the NEP Field
Abstract X-ray surveys are one of the most unbiased methods for detecting Compton-thick (CT; N H ≥ 10 24 cm −2 ) active galactic nuclei (AGN), which are thought to comprise up to 60% of AGN within z ≲ 1.0. These CT AGN are often difficult to detect with current instruments, but the X-ray data within the JWST-North Ecliptic Pole (NEP) Time Domain Field present a unique opportunity to study faint and obscured AGN. The NEP contains the deepest NuSTAR survey to date, and X. Zhao et al. detected 60 hard X-ray sources from the combined exposure of NuSTAR’s Cycle 5 and 6 observations. In this work, we utilize the NuSTAR Cycle 5+6+8+9 data and simultaneous XMM-Newton observations in order to perform the first spectroscopic analysis of the 60 source catalog. We present this analysis and measure the N H distribution of the sample. We measure an observed CT fraction of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>0.1</mml:mn> <mml:msubsup> <mml:mrow> <mml:mn>3</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.04</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.15</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> down to an observed 8–24 keV flux of 6.0 × 10 −14 erg s cm −2 , and we correct our analysis for absorption bias to estimate an underlying CT fraction of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>0.3</mml:mn> <mml:msubsup> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.08</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.23</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> . The derived obscuration distribution and CT fraction are consistent with population synthesis models and previous surveys.
Authors
- R. Silver (ORCID: https://orcid.org/0000-0001-6564-0517)
- F. Civano (ORCID: https://orcid.org/0000-0002-2115-1137)
- Rogier A. Windhorst (ORCID: https://orcid.org/0000-0001-8156-6281)
- Rolf A. Jansen (ORCID: https://orcid.org/0000-0003-1268-5230)
- Norman A. Grogin (ORCID: https://orcid.org/0000-0001-9440-8872)
- Anton M. Koekemoer (ORCID: https://orcid.org/0000-0002-6610-2048)
- Samantha Creech (ORCID: https://orcid.org/0000-0002-9041-7437)
- X. Zhao (ORCID: https://orcid.org/0000-0002-7791-3671)
- Daniel R. Wik (ORCID: https://orcid.org/0000-0001-9110-2245)
- Christopher N. A. Willmer (ORCID: https://orcid.org/0000-0001-9262-9997)
- Tonima Tasnim Ananna (ORCID: https://orcid.org/0000-0001-8211-3807)
- Rafael Ortiz (ORCID: https://orcid.org/0000-0002-6150-833X)
Institutions
- California Institute of Technology (US)
- Space Telescope Science Institute (US)
- Goddard Space Flight Center (US)
- University of Arizona (US)
- University of Illinois Urbana-Champaign (US)
- Wayne State University (US)
- University of Utah (US)
- Université Bourgogne Franche-Comté (FR)
- Arizona State University (US)
Publication Details
- Journal
- The Astrophysical Journal
- Published
- 2025-12-17
- DOI
- https://doi.org/10.3847/1538-4357/ae196a
- Primary Topic
- Astrophysical Phenomena and Observations
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Science Foundation
- U.S. Department of Energy
- National Aeronautics and Space Administration
- Gordon and Betty Moore Foundation
- California Institute of Technology
- University of Arizona
- Nuclear Safety and Security Commission
- Ministerio de Ciencia e Innovación
- Commissariat à l'Énergie Atomique et aux Énergies Alternatives
- Office of Science
- Jet Propulsion Laboratory
- Goddard Space Flight Center
- Science and Technology Facilities Council
- Division of Astronomical Sciences
- Lawrence Berkeley National Laboratory