Hello. I am an associate professor at Osaka University, interested in understanding the nature of black holes. As an astronomer, I have been working on both theoretical and observational astrophysics.

Our paper on spatial variations of magnetic field along active galactic nuclei jets on sub-pc to Mpc scales is accepted by ApJ.

Title: Spatial variations of magnetic field along active galactic nuclei jets on sub-pc to Mpc scales. Authors: Soichiro Ito, Yoshiyuki Inoue, Jun Kataoka We report the systematic analysis of knots, hotspots, and lobes in 57 active galactic nuclei (AGNs) to investigate the variation of the magnetic field along with the jet from the sub-pc base to the terminus in kpc-to-Mpc scales. Expanding the number of radio/X-ray samples in \citet{2005ApJ…622..797K}, we analyzed the data in 12 FR~I and 30 FR~II radio galaxies, 12 quasars, and 3 BL Lacs that contained 76 knots, 42 hotspots, and 29 radio lobes. [続きを読む]

Our paper on cross-match between the latest Swift-BAT and Fermi-LAT catalogs is accepted by ApJ.

Title: Cross-match between the latest Swift-BAT and Fermi-LAT catalogs. Authors: Naomi Tsuji, Hiroki Yoneda, Yoshiyuki Inoue, Tsuguo Aramaki, Georgia Karagiorgi, Reshmi Mukherjee, Hirokazu Odaka We report the results of a cross-match study between the hard X-ray and GeV gamma-ray catalogs, by making use of the latest 105-month Swift-BAT and 10-yr Fermi-LAT catalogs, respectively. The spatial cross-matching between the two catalogs results in the matching of 132 point-like sources, including ~5% of false-match sources. [続きを読む]

Our review article on the high energy aspect of AGN coronae is accepted by Galaxies.

Title: Gamma-ray and Neutrino Signals from Accretion Disk Coronae of Active Galactic Nuclei. Authors: Yoshiyuki Inoue, Dmitry Khangulyan, Akihiro Doi To explain X-ray spectra of active galactic nuclei (AGN), non-thermal activity in AGN coronae such as pair cascade models has been extensively discussed in the past literature. Although X-ray and gamma-ray observations in the 1990s disfavored such pair cascade models, recent millimeter-wave observations of nearby Seyferts establish the existence of weak non-thermal coronal activity. [続きを読む]

Bachelor Thesis Presentation Day

We are pleasure to hear that our excellent undergraduate student defended his bachelor thesis presentation. Kaoru Yanagisawa worked on new PBH constraint method using AGN torus. Congratulations!


Our paper on the PBH abundance using Leo T is accepted by ApJL.

Title: Constraining Primordial Black Holes with Dwarf Galaxy Heating. Authors: Philip Lu, Volodymyr Takhistov, Graciela B. Gelmini, Kohei Hayashi, Yoshiyuki Inoue, Alexander Kusenko Black holes formed in the early universe, prior to the formation of stars, can exist as dark matter and also contribute to the black hole merger events observed in gravitational waves. We set a new limit on the abundance of primordial black holes (PBHs) by considering interactions of PBHs with the interstellar medium, which result in the heating of gas. [続きを読む]

Our paper on the origin of Galactic spurs is accepted by ApJ.

Title: Origin of Galactic Spurs: New Insight from Radio/X-ray All-sky Maps. Authors: Jun Kataoka, Marino Yamamoto, Yuki Nakamura, Soichiro Ito, Yoshiaki Sofue, Yoshiyuki Inoue, Takeshi Nakamori, Tomonori Totani In this study, we analyze giant Galactic spurs seen in both radio and X-ray all-sky maps to reveal their origins. We discuss two types of giant spurs: one is the brightest diffuse emission near the map’s center, which is likely to be related to Fermi bubbles (NPSs/SPSs, north/south polar spurs, respectively), and the other is weaker spurs that coincide positionally with local spiral arms in our Galaxy (LAS, local arm spur). [続きを読む]

Our paper on the optical follow-up of TXS 0506+056 is accepted by PASJ.

Title: Follow-up Observations for IceCube-170922A: Detection of Rapid Near-Infrared Variability and Intensive Monitoring of TXS 0506+056. Authors: Tomoki Morokuma, Yousuke Utsumi, Kouji Ohta, Masayuki Yamanaka, Koji S. Kawabata, Yoshiyuki Inoue, Masaomi Tanaka, Michitoshi Yoshida, Ryosuke Itoh, Mahito Sasada, Nozomu Tominaga, Hiroki Mori, Miho Kawabata, Tatsuya Nakaoka, Maiko Chogi, Taisei Abe, Ruochen Huang, Naoki Kawahara, Hiroki Kimura, Hiroki Nagashima, Kengo Takagi, Yuina Yamazaki, Wei Liu, Ryou Ohsawa, Shigeyuki Sako, Katsuhiro L. Murata, Kumiko Morihana, Christina K. [続きを読む]

Postdoctoral Researcher Position at Osaka University

Now I am seeking a postdoctoral researcher at Osaka University. The candidate will work on the study of AGN coronal emission using theory, X-ray data, and radio (ALMA) data.

The position is posted here: https://jobregister.aas.org/ad/c9248b30

Application Deadline: Friday, November 13, 2020

活動銀河核コロナの研究に関する特任研究員(理論 and/or 観測)を一名、公募しております。 応募締切は令和2年11月13日(金) 日本時間 15:00必着です。 国立天文台で雇用され、大阪大学(豊中キャンパス)に派遣される形になります。

詳しくはこちらをご参照ください。 https://jobregister.nao.ac.jp/ja-JP/jobVacancyList https://www.nao.ac.jp/contents/job-vacancy/job-20201012-alma-osaka.pdf