Our paper on the contribution of radio galaxies to the cosmic gamma-ray background radiation is accepted by ApJ.

Title: High energy emission component, population, and contribution to the extragalactic gamma-ray background of gamma-ray emitting radio galaxies. Authors: Yasushi Fukazawa, Hiroto Matake, Taishu Kayanoki, Yoshiyuki Inoue, Justin Finke In this study, we systematically studied the X-ray to GeV gamma-ray spectra of 61 {\it Fermi} Large Area Telescope (LAT) detected radio galaxies. We found an anticorrelation between peak frequency and peak luminosity in the high-energy spectral component of radio galaxies, similar to blazars. [続きを読む]

Our paper on a fundamental plane in X-ray binary activity of external galaxies is accepted by PASJ.

Title: A fundamental plane in X-ray binary activity of external galaxies. Authors: Yoshiyuki Inoue, Kiyoto Yabe, Yoshihiro Ueda We construct a new catalog of extragalactic X-ray binaries (XRBs) by matching the latest Chandra source catalog with local galaxy catalogs. Our XRB catalog contains 4430 XRBs hosted by 237 galaxies within $\sim130$ Mpc. As XRBs dominate the X-ray activity in galaxies, the catalog enables us to study the correlations between the total X-ray luminosity of a galaxy, star formation rate, and stellar mass. [続きを読む]

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]

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]