Visiting Scholar (NIT, Hachinohe College)
I have broad interests in theories and observations related mostly to high energy astrophysics and plasma astrophysics. I am actively woking on astrophysical jets, accretion disks, and supermassive black holes (SMBHs) in active galactic nuclei (AGNs) with MHD theory and computation. Dynamics of galaxy cores and SMBHs, co-evolution of galaxies and SMBHs via AGN feedback process, and very high energy emission in AGN jets are especially interested.
I have been extensively working on the active radio galaxy M87, one of the most important targets to image a black hole shadow since 2010 in the Greenland Telescope (GLT) / Event Horizon telescope (EHT) project. On April 10th 2019, the EHT collaboration released the first image of a black hole in the center of M87. I have contributed the project in various ways such as proposal writing, numerical modeling of the M87 jet, and serving an internal reviewer of the GRMHD code comparison paper. Detailed comparison between the observed jet in VLBI scales and GRMHD simulations/analytical model suggests parabolic jets from the spinning black hole in M87 (Nakamura, Asada, Hada, et al. 2018, ApJ). This will be examined by future EHT observations including the GLT (2018-).
One of my research highlights is discovering the jet collimation break (JCB) in M87, collaborating with Dr. K. Asada (Asada & Nakamura 2012, ApJL). Together with the proper motion study (Asada, Nakamura, et al. 2014, ApJL), the jet acceleration and collimation zone (ACZ) is observationally confirmed for the first time in AGN jets where the black hole gravity plays a dynamical role inside the sphere of influence. Our study opens a new era of studying AGN jets toward the fundamental understanding how to make a relativist jet (e.g. Blandford, Meier, & Readhead 2019, ARAA; Perlman et al. 2019 [Astro2020 Decadal Survey of Astronomy & Astrophyics].