1. Hitomi Observation of Radio Galaxy NGC 1275: The First X-ray Microcalorimeter Spectroscopy of Fe-K�� Line Emission from an Active Galactic Nucleus
- Author
-
Hitomi Collaboration, Aharonian, Felix, Akamatsu, Hiroki, Akimoto, Fumie, Allen, Steven W., Angelini, Lorella, Audard, Marc, Awaki, Hisamitsu, Axelsson, Magnus, Bamba, Aya, Bautz, Marshall W., Blandford, Roger, Brenneman, Laura W., Brown, Gregory V., Bulbul, Esra, Cackett, Edward M., Chernyakova, Maria, Chiao, Meng P., Coppi, Paolo S., Costantini, Elisa, de Plaa, Jelle, de Vries, Cor P., Herder, Jan-Willem den, Done, Chris, Dotani, Tadayasu, Ebisawa, Ken, Eckart, Megan E., Enoto, Teruaki, Ezoe, Yuichiro, Fabian, Andrew C., Ferrigno, Carlo, Foster, Adam R., Fujimoto, Ryuichi, Fukazawa, Yasushi, Furuzawa, Akihiro, Galeazzi, Massimiliano, Gallo, Luigi C., Gandhi, Poshak, Giustini, Margherita, Goldwurm, Andrea, Gu, Liyi, Guainazzi, Matteo, Haba, Yoshito, Hagino, Kouichi, Hamaguchi, Kenji, Harrus, Ilana M., Hatsukade, Isamu, Hayashi, Katsuhiro, Hayashi, Takayuki, Hayashida, Kiyoshi, Hiraga, Junko S., Hornschemeier, Ann, Hoshino, Akio, Hughes, John P., Ichinohe, Yuto, Iizuka, Ryo, Inoue, Hajime, Inoue, Yoshiyuki, Ishida, Manabu, Ishikawa, Kumi, Ishisaki, Yoshitaka, Iwai, Masachika, Kaastra, Jelle, Kallman, Tim, Kamae, Tsuneyoshi, Kataoka, Jun, Katsuda, Satoru, Kawai, Nobuyuki, Kelley, Richard L., Kilbourne, Caroline A., Kitaguchi, Takao, Kitamoto, Shunji, Kitayama, Tetsu, Kohmura, Takayoshi, Kokubun, Motohide, Koyama, Katsuji, Koyama, Shu, Kretschmar, Peter, Krimm, Hans A., Kubota, Aya, Kunieda, Hideyo, Laurent, Philippe, Lee, Shiu-Hang, Leutenegger, Maurice A., Limousin, Olivier O., Loewenstein, Michael, Long, Knox S., Lumb, David, Madejski, Greg, Maeda, Yoshitomo, Maier, Daniel, Makishima, Kazuo, Markevitch, Maxim, Matsumoto, Hironori, Matsushita, Kyoko, McCammon, Dan, McNamara, Brian R., Mehdipour, Missagh, Miller, Eric D., Miller, Jon M., Mineshige, Shin, Mitsuda, Kazuhisa, Mitsuishi, Ikuyuki, Miyazawa, Takuya, Mizuno, Tsunefumi, Mori, Hideyuki, Mori, Koji, Mukai, Koji, Murakami, Hiroshi, Mushotzky, Richard F., Nakagawa, Takao, Nakajima, Hiroshi, Nakamori, Takeshi, Nakashima, Shinya, Nakazawa, Kazuhiro, Nobukawa, Kumiko K., Nobukawa, Masayoshi, Noda, Hirofumi, Odaka, Hirokazu, Ohashi, Takaya, Ohno, Masanori, Okajima, Takashi, Ota, Naomi, Ozaki, Masanobu, Paerels, Frits, Paltani, St��phane, Petre, Robert, Pinto, Ciro, Porter, Frederick S., Pottschmidt, Katja, Reynolds, Christopher S., Safi-Harb, Samar, Saito, Shinya, Sakai, Kazuhiro, Sasaki, Toru, Sato, Goro, Sato, Kosuke, Sato, Rie, Sawada, Makoto, Schartel, Norbert, Serlemitsos, Peter J., Seta, Hiromi, Shidatsu, Megumi, Simionescu, Aurora, Smith, Randall K., Soong, Yang, Stawarz, ��ukasz, Sugawara, Yasuharu, Sugita, Satoshi, Szymkowiak, Andrew, Tajima, Hiroyasu, Takahashi, Hiromitsu, Takahashi, Tadayuki, Takeda, Shin'ichiro, Takei, Yoh, Tamagawa, Toru, Tamura, Takayuki, Tanaka, Takaaki, Tanaka, Yasuo, Tanaka, Yasuyuki T., Tashiro, Makoto S., Tawara, Yuzuru, Terada, Yukikatsu, Terashima, Yuichi, Tombesi, Francesco, Tomida, Hiroshi, Tsuboi, Yohko, Tsujimoto, Masahiro, Tsunemi, Hiroshi, Tsuru, Takeshi Go, Uchida, Hiroyuki, Uchiyama, Hideki, Uchiyama, Yasunobu, Ueda, Shutaro, Ueda, Yoshihiro, Uno, Shin'ichiro, Urry, C. Megan, Ursino, Eugenio, Watanabe, Shin, Werner, Norbert, Wilkins, Dan R., Williams, Brian J., Yamada, Shinya, Yamaguchi, Hiroya, Yamaoka, Kazutaka, Yamasaki, Noriko Y., Yamauchi, Makoto, Yamauchi, Shigeo, Yaqoob, Tahir, Yatsu, Yoichi, Yonetoku, Daisuke, Zhuravleva, Irina, Zoghbi, Abderahmen, and Kawamuro, Taiki
- Subjects
High Energy Astrophysical Phenomena (astro-ph.HE) ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
The origin of the narrow Fe-K�� fluorescence line at 6.4 keV from active galactic nuclei has long been under debate; some of the possible sites are the outer accretion disk, the broad line region, a molecular torus, or interstellar/intracluster media. In February-March 2016, we performed the first X-ray microcalorimeter spectroscopy with the Soft X-ray Spectrometer (SXS) onboard the Hitomi satellite of the Fanaroff-Riley type I radio galaxy NGC 1275 at the center of the Perseus cluster of galaxies. With the high energy resolution of ~5 eV at 6 keV achieved by Hitomi/SXS, we detected the Fe-K�� line with ~5.4 �� significance. The velocity width is constrained to be 500-1600 km s$^{-1}$ (FWHM for Gaussian models) at 90% confidence. The SXS also constrains the continuum level from the NGC 1275 nucleus up to ~20 keV, giving an equivalent width ~20 eV of the 6.4 keV line. Because the velocity width is narrower than that of broad H�� line of ~2750 km s$^{-1}$, we can exclude a large contribution to the line flux from the accretion disk and the broad line region. Furthermore, we performed pixel map analyses on the Hitomi/SXS data and image analyses on the Chandra archival data, and revealed that the Fe-K�� line comes from a region within ~1.6 kpc from the NGC 1275 core, where an active galactic nucleus emission dominates, rather than that from intracluster media. Therefore, we suggest that the source of the Fe-K�� line from NGC 1275 is likely a low-covering fraction molecular torus or a rotating molecular disk which probably extends from a pc to hundreds pc scale in the active galactic nucleus system., 20 pages, 8 figures, 6 tables, accepted for publication in PASJ
- Published
- 2017
- Full Text
- View/download PDF