89 citations · 320 across the 23 of their papers we have counts for
24 papers · 1 filter
A differentiable hydrodynamical approach to the Milky Way bar pattern speed with CO longitude--velocity data
Junichi Baba, Kohei Hattori
We present a differentiable hydrodynamical framework for modeling barred gas flow in the Milky Way and constraining broad low-loss regions in bar-pattern-speed parameter space from…
Dynamical clock of the Helmi stream -- Analysis of the clumping of stars in the orbital frequency-space
Kohei Hattori
Reconstructing the assembly history of the Milky Way requires precise constraints on the dynamical age of its merger remnants -- the time elapsed since a progenitor satellite was d…
HR-GO II: chemical abundances of low- retrograde dynamically-tagged-groups: Revealing Thamnos as a very metal-poor substructure
Renjing Xie, Zhen Yuan, Haining Li +12
Milky Way halo substructures identified in dynamical space are known to suffer from contamination from the Milky Way in-situ stars, which makes their accreted origins uncertain. We…
Discovery of WINERED-HVS1: A metal-rich hyper-velocity star candidate ejected from the Galactic center
Kohei Hattori, Daisuke Taniguchi, Takuji Tsujimoto +4
We report the discovery of a metal-rich red giant star, WINERED-HVS1, which is a candidate for a hyper-velocity star (HVS). Its past trajectory suggests that this star may have bee…
Minimum-entropy constraints on galactic potentials
Leandro Beraldo e Silva, Monica Valluri, Eugene Vasiliev +3
A tracer sample in a gravitational potential, starting from a generic initial condition, phase-mixes towards a stationary state. This evolution is accompanied by an entropy increas…
Metallicity and -abundance for 48 million stars in low-extinction regions in the Milky Way
Kohei Hattori
We estimate ([M/H], [/M]) for 48 million giants and dwarfs in low-dust extinction regions from the Gaia DR3 XP spectra by using tree-based machine-learning models trained on APO…