XRISM Spectroscopy of the Fe Kα Emission Line in the Seyfert Active Galactic Nucleus NGC 4151 Reveals the Disk, Broad-line Region, and Torus

Journal article

M. Audard, H. Awaki, R. Ballhausen, A. Bamba, E. Behar, R. Boissay-Malaquin, L. Brenneman, G. V. Brown, L. Corrales, E. Costantini, R. Cumbee, M. Díaz Trigo, C. Done, T. Dotani, K. Ebisawa, M. Eckart, Dominique Eckert, T. Enoto, Satoshi Eguchi, Y. Ezoe, A. Foster, R. Fujimoto, Yutaka Fujita, Y. Fukazawa, K. Fukushima, A. Furuzawa, L. Gallo, Javier A. García, L. Gu, M. Guainazzi, Kouichi Hagino, Kenji Hamaguchi, I. Hatsukade, K. Hayashi, T. Hayashi, N. Hell, E. Hodges-Kluck, A. Hornschemeier, Y. Ichinohe, Manabu Ishida, K. Ishikawa, Y. Ishisaki, J. Kaastra, T. Kallman, E. Kara, S. Katsuda, Y. Kanemaru, Rich Kelley, C. Kilbourne, S. Kitamoto, S. Kobayashi, T. Kohmura, A. Kubota, M. Leutenegger, M. Loewenstein, Y. Maeda, M. Markevitch, Hironori Matsumoto, K. Matsushita, D. McCammon, Brian McNamara, F. Mernier, Eric D. Miller, Jon M. Miller, I. Mitsuishi, M. Mizumoto, T. Mizuno, K. Mori, Koji Mukai, Hiroshi Murakami, R. Mushotzky, H. Nakajima, K. Nakazawa, J. Ness, K. Nobukawa, M. Nobukawa, Hirofumi Noda, H. Odaka, S. Ogawa, A. Ogorzałek, T. Okajima, Naomi Ota, S. Paltani, R. Petre, P. Plucinsky, F. Porter, K. Pottschmidt, Kosuke Sato, Toshiki Sato, M. Sawada, H. Seta, M. Shidatsu, A. Simionescu, Randall K. Smith, Hiromasa Suzuki, A. Szymkowiak, H. Takahashi, M. Takeo, T. Tamagawa, Keisuke Tamura, Takaaki Tanaka, A. Tanimoto, M. Tashiro, Y. Terada, Y. Terashima, Y. Tsuboi, M. Tsujimoto, H. Tsunemi, T. Tsuru, H. Uchida, N. Uchida, Y. Uchida, H. Uchiyama, Y. Ueda, S. Uno, J. Vink, S. Watanabe, Brian J. Williams, S. Yamada, S. Yamada, H. Yamaguchi, K. Yamaoka, N. Yamasaki, M. Yamauchi, S. Yamauchi, T. Yaqoob, T. Yoneyama, Tessei Yoshida, M. Yukita, I. Zhuravleva, Xin Xiang, T. Minezaki, M. Buhariwalla, D. Gerolymatou, S. Hagen
Astrophysical Journal Letters, 2024

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APA Click to copy
Audard, M., Awaki, H., Ballhausen, R., Bamba, A., Behar, E., Boissay-Malaquin, R., … Hagen, S. (2024). XRISM Spectroscopy of the Fe Kα Emission Line in the Seyfert Active Galactic Nucleus NGC 4151 Reveals the Disk, Broad-line Region, and Torus. Astrophysical Journal Letters.

Chicago/Turabian Click to copy
Audard, M., H. Awaki, R. Ballhausen, A. Bamba, E. Behar, R. Boissay-Malaquin, L. Brenneman, et al. “XRISM Spectroscopy of the Fe Kα Emission Line in the Seyfert Active Galactic Nucleus NGC 4151 Reveals the Disk, Broad-Line Region, and Torus.” Astrophysical Journal Letters (2024).

MLA Click to copy
Audard, M., et al. “XRISM Spectroscopy of the Fe Kα Emission Line in the Seyfert Active Galactic Nucleus NGC 4151 Reveals the Disk, Broad-Line Region, and Torus.” Astrophysical Journal Letters, 2024.

BibTeX Click to copy

@article{m2024a,
  title = {XRISM Spectroscopy of the Fe Kα Emission Line in the Seyfert Active Galactic Nucleus NGC 4151 Reveals the Disk, Broad-line Region, and Torus},
  year = {2024},
  journal = {Astrophysical Journal Letters},
  author = {Audard, M. and Awaki, H. and Ballhausen, R. and Bamba, A. and Behar, E. and Boissay-Malaquin, R. and Brenneman, L. and Brown, G. V. and Corrales, L. and Costantini, E. and Cumbee, R. and Trigo, M. Díaz and Done, C. and Dotani, T. and Ebisawa, K. and Eckart, M. and Eckert, Dominique and Enoto, T. and Eguchi, Satoshi and Ezoe, Y. and Foster, A. and Fujimoto, R. and Fujita, Yutaka and Fukazawa, Y. and Fukushima, K. and Furuzawa, A. and Gallo, L. and García, Javier A. and Gu, L. and Guainazzi, M. and Hagino, Kouichi and Hamaguchi, Kenji and Hatsukade, I. and Hayashi, K. and Hayashi, T. and Hell, N. and Hodges-Kluck, E. and Hornschemeier, A. and Ichinohe, Y. and Ishida, Manabu and Ishikawa, K. and Ishisaki, Y. and Kaastra, J. and Kallman, T. and Kara, E. and Katsuda, S. and Kanemaru, Y. and Kelley, Rich and Kilbourne, C. and Kitamoto, S. and Kobayashi, S. and Kohmura, T. and Kubota, A. and Leutenegger, M. and Loewenstein, M. and Maeda, Y. and Markevitch, M. and Matsumoto, Hironori and Matsushita, K. and McCammon, D. and McNamara, Brian and Mernier, F. and Miller, Eric D. and Miller, Jon M. and Mitsuishi, I. and Mizumoto, M. and Mizuno, T. and Mori, K. and Mukai, Koji and Murakami, Hiroshi and Mushotzky, R. and Nakajima, H. and Nakazawa, K. and Ness, J. and Nobukawa, K. and Nobukawa, M. and Noda, Hirofumi and Odaka, H. and Ogawa, S. and Ogorzałek, A. and Okajima, T. and Ota, Naomi and Paltani, S. and Petre, R. and Plucinsky, P. and Porter, F. and Pottschmidt, K. and Sato, Kosuke and Sato, Toshiki and Sawada, M. and Seta, H. and Shidatsu, M. and Simionescu, A. and Smith, Randall K. and Suzuki, Hiromasa and Szymkowiak, A. and Takahashi, H. and Takeo, M. and Tamagawa, T. and Tamura, Keisuke and Tanaka, Takaaki and Tanimoto, A. and Tashiro, M. and Terada, Y. and Terashima, Y. and Tsuboi, Y. and Tsujimoto, M. and Tsunemi, H. and Tsuru, T. and Uchida, H. and Uchida, N. and Uchida, Y. and Uchiyama, H. and Ueda, Y. and Uno, S. and Vink, J. and Watanabe, S. and Williams, Brian J. and Yamada, S. and Yamada, S. and Yamaguchi, H. and Yamaoka, K. and Yamasaki, N. and Yamauchi, M. and Yamauchi, S. and Yaqoob, T. and Yoneyama, T. and Yoshida, Tessei and Yukita, M. and Zhuravleva, I. and Xiang, Xin and Minezaki, T. and Buhariwalla, M. and Gerolymatou, D. and Hagen, S.}
}

Abstract

We present an analysis of the first two XRISM/Resolve spectra of the well-known Seyfert-1.5 active galactic nucleus (AGN) in NGC 4151, obtained in 2023 December. Our work focuses on the nature of the narrow Fe K α emission line at 6.4 keV, the strongest and most common X-ray line observed in AGN. The total line is found to consist of three components. Even the narrowest component of the line is resolved with evident Fe K α,1 (6.404 keV) and K α,2 (6.391 keV) contributions in a 2:1 flux ratio, fully consistent with neutral gas with negligible bulk velocity. Subject to the limitations of our models, the narrowest and intermediate-width components are consistent with emission from optically thin gas, suggesting that they arise in a disk atmosphere and/or wind. Modeling the three line components in terms of Keplerian broadening, they are readily associated with (1) the inner wall of the “torus,” (2) the innermost optical “broad-line region” (or “X-ray BLR”), and (3) a region with a radius of r ≃ 100 GM/c 2 that may signal a warp in the accretion disk. Viable alternative explanations of the broadest component include a fast-wind component and/or scattering; however, we find evidence of variability in the narrow Fe K α line complex on timescales consistent with small radii. The best-fit models are statistically superior to simple Voigt functions, but when fit with Voigt profiles the time-averaged lines are consistent with a projected velocity broadening of FWHM =1600−200+400kms−1 . Overall, the resolution and sensitivity of XRISM show that the narrow Fe K line in AGN is an effective probe of all key parts of the accretion flow, as it is currently understood. We discuss the implications of these findings for our understanding of AGN accretion, future studies with XRISM, and X-ray-based black hole mass measurements.