Zobrazeno 1 - 10
of 74
pro vyhledávání: '"Yutaka, Hirai"'
Autor:
Yutaka Hirai, Evan N. Kirby, Masashi Chiba, Kohei Hayashi, Borja Anguiano, Takayuki R. Saitoh, Miho N. Ishigaki, Timothy C. Beers
Publikováno v:
The Astrophysical Journal, Vol 970, Iss 2, p 105 (2024)
The chemical abundances of Milky Way’s (MW's) satellites reflect their star formation histories (SFHs), yet, due to the difficulty of determining the ages of old stars, the SFHs of most satellites are poorly measured. Ongoing and upcoming surveys w
Externí odkaz:
https://doaj.org/article/b834e425161a4551863e4d31d34c6cd2
Autor:
Jihye Hong, Timothy C. Beers, Young Sun Lee, Yang Huang, Yutaka Hirai, Jonathan Cabrera Garcia, Derek Shank, Shuai Xu, Haibo Yuan, Mohammad K. Mardini, Thomas Catapano, Gang Zhao, Zhou Fan, Jie Zheng, Wei Wang, Kefeng Tan, Jingkun Zhao, Chun Li
Publikováno v:
The Astrophysical Journal Supplement Series, Vol 273, Iss 1, p 12 (2024)
Photometric stellar surveys now cover a large fraction of the sky, probe to fainter magnitudes than large-scale spectroscopic surveys, and are relatively free from the target selection biases often associated with such studies. Photometric-metallicit
Externí odkaz:
https://doaj.org/article/59f813e9f7da436c9480c01d24f83f27
Autor:
Yi Xu, Masami Ouchi, Yuki Isobe, Kimihiko Nakajima, Shinobu Ozaki, Nicolas F. Bouché, John H. Wise, Eric Emsellem, Haruka Kusakabe, Takashi Hattori, Tohru Nagao, Gen Chiaki, Hajime Fukushima, Yuichi Harikane, Kohei Hayashi, Yutaka Hirai, Ji Hoon Kim, Michael V. Maseda, Kentaro Nagamine, Takatoshi Shibuya, Yuma Sugahara, Hidenobu Yajima, Shohei Aoyama, Seiji Fujimoto, Keita Fukushima, Shun Hatano, Akio K. Inoue, Tsuyoshi Ishigaki, Masahiro Kawasaki, Takashi Kojima, Yutaka Komiyama, Shuhei Koyama, Yusei Koyama, Chien-Hsiu Lee, Akinori Matsumoto, Ken Mawatari, Takashi J. Moriya, Kentaro Motohara, Kai Murai, Moka Nishigaki, Masato Onodera, Yoshiaki Ono, Michael Rauch, Tomoki Saito, Rin Sasaki, Akihiro Suzuki, Tsutomu T. Takeuchi, Hiroya Umeda, Masayuki Umemura, Kuria Watanabe, Kiyoto Yabe, Yechi Zhang
Publikováno v:
The Astrophysical Journal, Vol 961, Iss 1, p 49 (2024)
We present the demography of the dynamics and gas mass fraction of 33 extremely metal-poor galaxies (EMPGs) with metallicities of 0.015–0.195 Z _⊙ and low stellar masses of 10 ^4 –10 ^8 M _⊙ in the local universe. We conduct deep optical inte
Externí odkaz:
https://doaj.org/article/676be6f7cd2249aeae362e439f3fe5f9
Autor:
Doris Arzoumanian, Sota Arakawa, Masato I. N. Kobayashi, Kazunari Iwasaki, Kohei Fukuda, Shoji Mori, Yutaka Hirai, Masanobu Kunitomo, M. S. Nanda Kumar, Eiichiro Kokubo
Publikováno v:
The Astrophysical Journal Letters, Vol 947, Iss 2, p L29 (2023)
Cylindrical molecular filaments are observed to be the main sites of Sunlike star formation, while massive stars form in dense hubs at the junction of multiple filaments. The role of hub–filament configurations has not been discussed yet in relatio
Externí odkaz:
https://doaj.org/article/c4765dda7b4042aa8f8d2d4f64d4db52
Publikováno v:
The Astrophysical Journal, Vol 953, Iss 2, p 185 (2023)
Elucidating dark matter density profiles in Galactic dwarf satellites is essential to understanding not only the quintessence of dark matter, but also the evolution of the satellites themselves. In this work, we present the current constraints on dar
Externí odkaz:
https://doaj.org/article/8eae361df8094c3f9fa1fb00b2175888
Autor:
Moka Nishigaki, Masami Ouchi, Kimihiko Nakajima, Yoshiaki Ono, Michael Rauch, Yuki Isobe, Yuichi Harikane, Kanako Narita, Fakhri Zahedy, Yi Xu, Hidenobu Yajima, Hajime Fukushima, Yutaka Hirai, Ji Hoon Kim, Shigeki Inoue, Haruka Kusakabe, Chien-Hsiu Lee, Tohru Nagao, Masato Onodera
Publikováno v:
The Astrophysical Journal, Vol 952, Iss 1, p 11 (2023)
We search for local extremely metal-poor galaxies (EMPGs), selecting photometric candidates by broadband color excess and machine-learning techniques with the SDSS photometric data. After removing stellar contaminants by shallow spectroscopy with Sei
Externí odkaz:
https://doaj.org/article/5629754457f54d329a7f8145f8a7eda3
Autor:
Yuki Isobe, Masami Ouchi, Kimihiko Nakajima, Shinobu Ozaki, Nicolas F. Bouché, John H. Wise, Yi Xu, Eric Emsellem, Haruka Kusakabe, Takashi Hattori, Tohru Nagao, Gen Chiaki, Hajime Fukushima, Yuichi Harikane, Kohei Hayashi, Yutaka Hirai, Ji Hoon Kim, Michael V. Maseda, Kentaro Nagamine, Takatoshi Shibuya, Yuma Sugahara, Hidenobu Yajima, Shohei Aoyama, Seiji Fujimoto, Keita Fukushima, Shun Hatano, Akio K. Inoue, Tsuyoshi Ishigaki, Masahiro Kawasaki, Takashi Kojima, Yutaka Komiyama, Shuhei Koyama, Yusei Koyama, Chien-Hsiu Lee, Akinori Matsumoto, Ken Mawatari, Takashi J. Moriya, Kentaro Motohara, Kai Murai, Moka Nishigaki, Masato Onodera, Yoshiaki Ono, Michael Rauch, Tomoki Saito, Rin Sasaki, Akihiro Suzuki, Tsutomu T. Takeuchi, Hiroya Umeda, Masayuki Umemura, Kuria Watanabe, Kiyoto Yabe, Yechi Zhang
Publikováno v:
The Astrophysical Journal, Vol 951, Iss 2, p 102 (2023)
We present kinematics of six local extremely metal-poor galaxies (EMPGs) with low metallicities (0.016–0.098 Z _⊙ ) and low stellar masses (10 ^4.7 –10 ^7.6 M _⊙ ). Taking deep medium/high-resolution ( R ∼ 7500) integral-field spectra with
Externí odkaz:
https://doaj.org/article/ecaf49e39cde4e3b8fd3e73fb1e4c8c2
Autor:
Andrés E. Piatti, Yutaka Hirai
Publikováno v:
The Astronomical Journal, Vol 165, Iss 5, p 213 (2023)
The ancient Large Magellanic Cloud (LMC) globular cluster NGC 2005 has recently been reported to have an ex situ origin, thus, setting precedents that the LMC could have partially formed from smaller merged dwarf galaxies. We here provide additional
Externí odkaz:
https://doaj.org/article/0a0e596883ae4345b917655048c32034
Autor:
Joseph Zepeda, Timothy C. Beers, Vinicius M. Placco, Derek Shank, Dmitrii Gudin, Yutaka Hirai, Mohammad Mardini, Colin Pifer, Thomas Catapano, Sean Calagna
Publikováno v:
The Astrophysical Journal, Vol 947, Iss 1, p 23 (2023)
We construct a sample of 644 carbon-enhanced metal-poor (CEMP) stars with abundance analyses based on moderate- to high-resolution spectroscopic studies. Dynamical parameters for these stars are estimated based on radial velocities, Bayesian parallax
Externí odkaz:
https://doaj.org/article/d95119e8943b48dd9370e567ac404c53
Autor:
Shraddha Gupta, Haruki Tanaka, Kentaro Fuku, Kaiji Uchida, Hiroaki Iguchi, Ryota Sakamoto, Hiroaki Kobayashi, Yoshiyuki Gambe, Itaru Honma, Yutaka Hirai, Shinya Hayami, Shinya Takaishi
Publikováno v:
Inorganic Chemistry. 62:6306-6313
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::54d8bbc0a690f1c333c928e83532048a
https://doi.org/10.1021/acs.inorgchem.2c04313
https://doi.org/10.1021/acs.inorgchem.2c04313