J-GLOBAL         Last updated: Nov 12, 2018 at 23:13
Toyo University
Faculty of Literature Department of English Communication
Research funding number


2006-2015 National Astronomical Observatory of Japan
2004-2006 National Astronomical Observatory of Japan, Postdoctoral fellow
2002-2004 ASTRON/Westerbork Observatory, Postdoctoral fellow
1999-2002 Max-Planck-Institute for radio astronomy, Postdoctoral fellow

Research Areas


Academic & Professional Experience

Apr 2018
Professor, Faculty of Letters, Dept. of International Culture and Communication Studies, Toyo University
Apr 2015
Mar 2018
Associate Professor, Faculty of Letters, Toyo University
Apr 2007
Mar 2015
Assistant Professor, Mizusawa VLBI Observatory (Mitaka Office), National Astronomical Observatory of Japan
Nov 2006
Mar 2007
Assistant Professor, Space VLBI Project Office, National Astronomical Observatory of Japan
Oct 2004
Oct 2006
Postdoctoral fellow, Space VLBI Project Office, National Astronomical Observatory of Japan
May 2002
Sep 2004
Postdoctoral fellow, ASTRON, Westerbork Observatory
Apr 1999
Apr 2002
Postdoctoral fellow, VLBI group, Max-Planck Institute for radio astronomy


Apr 1995
Mar 1999
Astronomical Science, Graduate University for Advanced Studies
Apr 1993
Mar 1995
Nagoya University

Published Papers

Hagiwara Yoshiaki, Doi Akihiro, Hachisuka Kazuya, Horiuchi Shinji
Yoshiaki Hagiwara, Shinji Horiuchi, Akihiro Doi, Makoto Miyoshi, Philip G. Edwards
The Astrophysical Journal      Apr 2016   [Refereed]
We present further results of a search for extragalactic submillimeter H2O
masers using the Atacama Large Millimeter/Submillimeter Array (ALMA). The
detection of a 321 GHz H2O maser in the nearby Type 2 Seyfert galaxy, the
Circinus galaxy, has pre...
Extragalactic Astronomical Masers I - A tool for exploring the innermost part of active galactic nuclei
dialogos   69(16) 71-80   Mar 2016
Water Vapour Maser Emission in the Type 2 Seyfert galaxy NGC 1068
Journal of Toyo University, Natural Science   (60) 67-75   Mar 2016
Yoshiaki Hagiwara, Philip G. Edwards
The Astrophysical Journal, Volume 815, 124 (6 pp), 2015 December 20   815(2) 124   Feb 2016   [Refereed]
We present the results of observations of 22GHz H2O maser emission in NGC 6240 and M51 made with the Karl G. Jansky Very Large Array. Two major H2O maser features and several minor features are detected toward the southern nucleus of NGC 6240. The...
Kazuhiro Hada, Motoki Kino, Akihiro Doi, Hiroshi Nagai, Mareki Honma, Kazunori Akiyama, Fumie Tazaki, Rocco Lico, Marcello Giroletti, Gabriele Giovannini, Monica Orienti, Yoshiaki Hagiwara
   Dec 2015   [Refereed]
We report on results from new high-sensitivity, high-resolution 86GHz (3.5 millimeter) observations of the jet base in the nearby radio galaxy M87, obtained by the Very Long Baseline Array in conjunction with the Green Bank Telescope. The resultin...
Toshiki Saito, Daisuke Iono, Min S. Yun, Junko Ueda, Kouichiro Nakanishi, Hajime Sugai, Daniel Espada, Masatoshi Imanishi, Kentaro Motohara, Yoshiaki Hagiwara, Ken Tateuchi, Minju Lee, Ryohei Kawabe
   Jan 2015   [Refereed]
We present ALMA cycle 0 observations of the molecular gas and dust in the IR-bright mid-stage merger VV114 obtained at 160 - 800 pc resolution. The main aim of this study is to investigate the distribution and kinematics of the cold/warm gas and t...
Kotaro Niinuma, Sang-Sung Lee, Motoki Kino, Bong Won Sohn, Kazunori Akiyama, Guang-Yao Zhao, Satoko Sawada-Satoh, Sascha Trippe, Kazuhiro Hada, Taehyun Jung, Yoshiaki Hagiwara, et al.
   Jun 2014   [Refereed]
The Korean very-long-baseline interferometry (VLBI) network (KVN) and VLBI Exploration of Radio Astrometry (VERA) Array (KaVA) is the first international VLBI array dedicated to high-frequency (23 and 43 GHz bands) observations in East Asia. Here,...
Kazuhiro Hada, Motoki Kino, Akihiro Doi, Hiroshi Nagai, Mareki Honma, Yoshiaki Hagiwara, Marcello Giroletti, Gabriele Giovannini, Noriyuki Kawaguchi
   Aug 2013   [Refereed]
We investigated the detailed inner jet structure of M87 using the Very Long Baseline Array data at 2, 5, 8.4, 15, 23.8, 43, and 86 GHz, especially focusing on the multi-frequency properties of the radio core at the jet base. First, we measured a s...
Yoshiaki Hagiwara, Makoto Miyoshi, Akihiro Doi, Shinji Horiuchi
2013, The Astrophysical Journal, 768, L38      May 2013   [Refereed]
We present the first detection of extragalactic submillimeter H2O maser in the 321 GHz transition toward the center of Circinus galaxy, the nearby Type 2 Seyfert using the Atacama Large Millimeter/Submillimeter Array. We find that Doppler features...
Search for Extragalactic H2O Maser Toward Active Galaxies
Hagiwara Yoshiaki, Doi Akihiro, Hachisuka Kazuya
Kazuhiro Hada, Motoki Kino, Hiroshi Nagai, Akihiro Doi, Yoshiaki Hagiwara, Mareki Honma, Marcello Giroletti, Gabriele Giovannini, Noriyuki Kawaguchi
The Astrophysical Journal      Oct 2012   [Refereed]
We report on the detailed radio status of the M87 jet during the Very-High-Energy (VHE) gamma-ray flaring event in April 2010, obtained from high-resolution, multi-frequency, phase-referencing VLBA observations. We especially focus on the properti...
Yoshiaki Hagiwara
The Astronomical Journal 140, 1905-1910, 2010      Nov 2010   [Refereed]
Studies of 22GHz H2O maser emission from the merging galaxy NGC 6240 with double nuclei are presented. Two epochs of Very Large Array (VLA) observations in the A-configuration in spectral-line mode were carried out at 0.1 arcsec resolution by cove...
Yoshiaki Hagiwara
Astron.J.133:1176-1186,2007      Feb 2007   [Refereed]
Sub-arcsecond observations using the Very Large Array (VLA) are presented for low-luminosity water maser in M82, M51, and NGC4051. New maser features have been detected within the M82 starburst complex. They are largely associated with star-formin...
Willem A. Baan, Yoshiaki Hagiwara, Peter Hofner
Astrophys.J.661:173-184,2007      Feb 2007   [Refereed]
VLA observations of large-scale HI and OH absorption in the merging galaxy of NGC6240 are presented with 1 arcsec resolution. HI absorption is found across large areas of the extended radio continuum structure with a strong concentration towards t...
Yoshiaki Hagiwara, Philip J Diamond, Makoto Miyoshi, Emmanouel Rovilos, Willem Baan
Mon.Not.Roy.Astron.Soc.344:L53,2003      Sep 2003   [Refereed]
Water vapor maser emission in the 6_{16}-5_{23} transition towards the narrow-line Seyfert 1 (NLS1) galaxy NGC 4051 has been discovered during an ongoing single-dish extragalactic water maser survey. The Doppler-shifted maser components appear to ...
Yoshiaki Hagiwara, Philip J. Diamond, Makoto Miyoshi
Astron.Astrophys. 400 (2003) 457-464      Feb 2003   [Refereed]
We performed VLA observations of the 22 GHz H2O maser emission in the merging galaxy NGC6240, which hosts the well-known double active nuclei. In a previous paper, we reported on the first solid detection of the H2O maser emission in 2001. After t...
Yoshiaki Hagiwara, Christian Henkel, Karl. M. Menten, Naomasa Nakai
   Sep 2001   [Refereed]
22 GHz water vapor `kilomaser' emission is reported from the central region of the Whirlpool galaxy M 51 (NGC 5194). The red-shifted spectral features (Vlsr ~ 560 km/s), flaring during most of the year 2000, originate from a spatially unresolved m...
Yoshiaki Hagiwara, Philip J. Diamond, Naomasa Nakai, Ryohei Kawabe
   Jul 2001   [Refereed]
We present the first result of VLBI observations of the blueshifted water maser emission from the type 2 Seyfert galaxy NGC5793, which we combine with new and previous VLBI observations of continuum emission at 1.7, 5.0, 8.4, 15, and 22 GHz. Maser...
Heino Falcke, Christian Henkel, Alison B. Peck, Yoshiaki Hagiwara, M. Almudena Prieto, Jack F. Gallimore
   Apr 2000   [Refereed]
We report the detection of a new H_2O megamaser in the Seyfert 2 galaxy Mrk 348 with the MPIfR 100 m telescope in Effelsberg. With an apparent isotropic luminosity of L_H2O ~ 420 L_sun the maser is the third most luminous maser discovered so far. ...


萩原喜昭, 河野祐介, 鈴木駿策, 秦和弘, 小山友明, 宇賀裕哉, 松枝知佳, 藤澤健太, 新沼浩太郎, 嶺重慎, 米倉覚則, 笹田真人
日本天文学会年会講演予稿集   2018 191   Aug 2018
小山友明, 河野祐介, 鈴木駿策, 松枝知佳, 宇賀裕哉, KIM Jeong‐Sook, 永山匠, 寺家孝明, 萩原喜昭
日本天文学会年会講演予稿集   2017 206   Aug 2017
林隆之, 林隆之, 今西昌俊, 萩原喜昭
日本天文学会年会講演予稿集   2017 179   Aug 2017
萩原喜昭, 堀内真司, 土居明広, 三好真
日本天文学会年会講演予稿集   2015 192   Aug 2015
秦和弘, 紀基樹, 永井洋, 本間希樹, 秋山和徳, 田崎文得, 萩原喜昭, 土居明広, GIOVANNINI G., GIROLETTI M.
日本天文学会年会講演予稿集   2015 199   Feb 2015