5 results on '"Chiba, Takeshi"'
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2. Spontaneous Scalarization in Scalar-Tensor Theories with Conformal Symmetry as an Attractor
- Author
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Chiba, Takeshi
- Subjects
High Energy Physics - Theory ,High Energy Physics - Theory (hep-th) ,FOS: Physical sciences ,General Relativity and Quantum Cosmology (gr-qc) ,General Relativity and Quantum Cosmology - Abstract
Motivated by constant-G theory, we introduce a one-parameter family of scalar-tensor theories as an extension of constant-G theory in which the conformal symmetry is a cosmological attractor. Since the model has the coupling function of negative curvature, we expect spontaneous scalarization occurs and the parameter is constrained by pulsar-timing measurements. Modeling neutron stars with realistic equation of states, we study the structure of neutron stars and calculate the effective scalar coupling with the neutron star in these theories. We find that within the parameter region where the observational constraints are satisfied, the effective scalar coupling almost coincides with that derived using the quadratic model with the same curvature. This indicates that the constraints obtained by the quadratic model will be used to limit the curvature of the coupling function universally in the future., Comment: 15 pages, 7 figures, updated to match the published version
- Published
- 2021
- Full Text
- View/download PDF
3. DECIGO pathfinder
- Author
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Ando, Masaki, Kawamura, Seiji, Nakamura, Takashi, Tsubono, Kimio, Tanaka, Takahiro, Funaki, Ikkoh, Seto, Naoki, Numata, Kenji, Sato, Shuichi, Ioka, Kunihito, Kanda, Nobuyuki, Takashima, Takeshi, Agatsuma, Kazuhiro, Akutsu, Tomotada, Akutsu, Tomomi, Aoyanagi, Koh-suke, Arai, Koji, Arase, Yuta, Araya, Akito, Asada, Hideki, Aso, Yoichi, Chiba, Takeshi, Ebisuzaki, Toshikazu, Enoki, Motohiro, Eriguchi, Yoshiharu, Fujimoto, Masa-Katsu, Fujita, Ryuichi, Fukushima, Mitsuhiro, Futamase, Toshifumi, Ganzu, Katsuhiko, Harada, Tomohiro, Hashimoto, Tatsuaki, Hayama, Kazuhiro, Hikida, Wataru, Himemoto, Yoshiaki, Hirabayashi, Hisashi, Hiramatsu, Takashi, Hong, Feng-Lei, Horisawa, Hideyuki, Hosokawa, Mizuhiko, Ichiki, Kiyotomo, Ikegami, Takashi, Inoue, Kaiki T., Ishidoshiro, Koji, Ishihara, Hideki, Ishikawa, Takehiko, Ishizaki, Hideharu, Ito, Hiroyuki, Itoh, Yousuke, Kamagasako, Shogo, Kawashima, Nobuki, Kawazoe, Fumiko, Kirihara, Hiroyuki, Kishimoto, Naoko, Kiuchi, Kenta, Kobayashi, Shiho, Kohri, Kazunori, Koizumi, Hiroyuki, Kojima, Yasufumi, Kokeyama, Keiko, Kokuyama, Wataru, Kotake, Kei, Kozai, Yoshihide, Kudoh, Hideaki, Kunimori, Hiroo, Kuninaka, Hitoshi, Kuroda, Kazuaki, Maeda, Kei-ichi, Matsuhara, Hideo, Mino, Yasushi, Miyakawa, Osamu, Miyoki, Shinji, Morimoto, Mutsuko Y., Morioka, Tomoko, Morisawa, Toshiyuki, Moriwaki, Shigenori, Mukohyama, Shinji, Musha, Mitsuru, Nagano, Shigeo, Naito, Isao, Nakagawa, Noriyasu, Nakamura, Kouji, Nakano, Hiroyuki, Nakao, Kenichi, Nakasuka, Shinichi, Nakayama, Yoshinori, Nishida, Erina, Nishiyama, Kazutaka, Nishizawa, Atsushi, Niwa, Yoshito, Ohashi, Masatake, Ohishi, Naoko, Ohkawa, Masashi, Okutomi, Akira, Onozato, Kouji, Oohara, Kenichi, Sago, Norichika, Saijo, Motoyuki, Sakagami, Masaaki, Sakai, Shin-ichiro, Sakata, Shihori, Sasaki, Misao, Sato, Takashi, Shibata, Masaru, Shinkai, Hisaaki, Somiya, Kentaro, Sotani, Hajime, Sugiyama, Naoshi, Suwa, Yudai, Tagoshi, Hideyuki, Takahashi, Kakeru, Takahashi, Keitaro, Takahashi, Tadayuki, Takahashi, Hirotaka, Takahashi, Ryuichi, Takahashi, Ryutaro, Takamori, Akiteru, Takano, Tadashi, Taniguchi, Keisuke, Taruya, Atsushi, Tashiro, Hiroyuki, Tokuda, Mitsuru, Tokunari, Masao, Toyoshima, Morio, Tsujikawa, Shinji, Tsunesada, Yoshiki, Ueda, Ken-ichi, Utashima, Masayoshi, Yamakawa, Hiroshi, Yamamoto, Kazuhiro, Yamazaki, Toshitaka, Yokoyama, Jun'ichi, Yoo, Chul-Moon, Yoshida, Shijun, and Yoshino, Taizoh
- Subjects
History ,Computer Science Applications ,Education - Abstract
DECIGO pathfinder (DPF) is a milestone satellite mission for DECIGO (DECi-hertz Interferometer Gravitational wave Observatory) which is a future space gravitational wave antenna. DECIGO is expected to provide us fruitful insights into the universe, in particular about dark energy, a formation mechanism of supermassive black holes, and the inflation of the universe. Since DECIGO will be an extremely large mission which will formed by three drag-free spacecraft with 1000m separation, it is significant to gain the technical feasibility of DECIGO before its planned launch in 2024. Thus, we are planning to launch two milestone missions: DPF and pre-DECIGO. The conceptual design and current status of the first milestone mission, DPF, are reviewed in this article.
- Published
- 2008
4. Weak Lensing of Galaxy Clusters in MOND
- Author
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Takahashi, Ryuichi and Chiba, Takeshi
- Subjects
High Energy Physics - Phenomenology ,High Energy Physics - Phenomenology (hep-ph) ,Astrophysics (astro-ph) ,FOS: Physical sciences ,Astrophysics::Cosmology and Extragalactic Astrophysics ,General Relativity and Quantum Cosmology (gr-qc) ,Astrophysics ,General Relativity and Quantum Cosmology ,Astrophysics::Galaxy Astrophysics - Abstract
We study weak gravitational lensing of galaxy clusters in terms of the MOND (MOdified Newtonian Dynamics) theory. We calculate shears and convergences of background galaxies for three clusters (A1689, CL0024+1654, CL1358+6245) and the mean profile of 42 SDSS (Sloan Digital Sky Survey) clusters and compare them with observational data. The mass profile is modeled as a sum of X-ray gas, galaxies and dark halo. For the shear as a function of the angular radius, MOND predicts a shallower slope than the data irrespective of the critical acceleration parameter $g_0$. The dark halo is necessary to explain the data for any $g_0$ and for three interpolation functions. If the dark halo is composed of massive neutrinos, its mass should be heavier than 2 eV. However the constraint still depends on the dark halo model and there are systematic uncertainties, and hence the more careful study is necessary to put a stringent constraint., Comment: 12 pages, 7 figures, references added, minor changes, accepted for publication in ApJ
- Published
- 2007
- Full Text
- View/download PDF
5. The Japanese space gravitational wave antenna: DECIGO
- Author
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Chen, Dan, Hong, Feng-Lei, Ichiki, Kiyotomo, Ikegami, Takeshi, Inoue, Kaiki T., Ishidoshiro, Koji, Ishihara, Hideki, Ishizaki, Hideharu, Ito, Hiroyuki, Itoh, Yousuke, Izumi, Kiwamu, Kawashima, Nobuki, Kawazoe, Fumiko, Kishimoto, Naoko, Kiuchi, Kenta, Kobayashi, Shiho, Kohri, Kazunori, Kojima, Yasufumi, Kokeyama, Keiko, Kokuyama, Wataru, Kotake, Kei, Kozai, Yoshihide, Kunimori, Hiroo, Kuroda, Kazuaki, Kuroyanagi, Sachiko, Maeda, Kei-ichi, Matsumoto, Nobuyuki, Michimura, Yuta, Miyakawa, Osamu, Miyamoto, Umpei, Miyoki, Shinji, Morisawa, Toshiyuki, Moriwaki, Shigenori, Mukohyama, Shinji, Musha, Mitsuru, Nagano, Shigeo, Naito, Isao, Nakamura, Kouji, Nakano, Hiroyuki, Nakao, Kenichi, Nakasuka, Shinichi, Nakayama, Yoshinori, Nakazawa, Kazuhiro, Nishida, Erina, Nishizawa, Atsushi, Niwa, Yoshito, Noumi, Taiga, Obuchi, Yoshiyuki, Ohashi, Masatake, Ohishi, Naoko, Ohkawa, Masashi, Okada, Kenshi, Okada, Norio, Oohara, Kenichi, Sago, Norichika, Saijo, Motoyuki, Saito, Ryo, Sakagami, Masaaki, Sakata, Shihori, Sasaki, Misao, Sato, Takashi, Shibata, Masaru, Shinkai, Hisaaki, Shoda, Ayaka, Somiya, Kentaro, Sotani, Hajime, Sugiyama, Naoshi, Suwa, Yudai, Suzuki, Rieko, Tagoshi, Hideyuki, Takahashi, Fuminobu, Takahashi, Kakeru, Takahashi, Keitaro, Takahashi, Ryutaro, Takahashi, Ryuichi, Takahashi, Hirotaka, Akiteru, Takamori, Takano, Tadashi, Tanaka, Nobuyuki, Taniguchi, Keisuke, Taruya, Atsushi, Tashiro, Hiroyuki, Torii, Yasuo, Toyoshima, Morio, Tsujikawa, Shinji, Tsunesada, Yoshiki, Ueda, Akitoshi, Ueda, Ken-ichi, Wakabayashi, Yaka, Yagi, Kent, Yamakawa, Hiroshi, Yamamoto, Kazuhiro, Yamazaki, Toshitaka, Yoo, Chul-Moon, Yoshida, Shijun, Yoshino, Taizoh, Sun, Ke-Xun, Kawamura, Seiji, Ando, Masaki, Seto, Naoki, Sato, Shuichi, Nakamura, Takashi, Tsubono, Kimio, Kanda, Nobuyuki, Tanaka, Takahiro, Yokoyama, Jun'ichi, Funaki, Ikkoh, Numata, Kenji, Ioka, Kunihito, Takashima, Takeshi, Agatsuma, Kazuhiro, Akutsu, Tomotada, Aoyanagi, Koh-suke, Arai, Koji, Araya, Akito, Asada, Hideki, Aso, Yoichi, Chiba, Takeshi, Ebisuzaki, Toshikazu, Ejiri, Yumiko, Enoki, Motohiro, Eriguchi, Yoshiharu, Fujimoto, Masa-Katsu, Fujita, Ryuichi, Fukushima, Mitsuhiro, Futamase, Toshifumi, Harada, Tomohiro, Hashimoto, Tatsuaki, Hayama, Kazuhiro, Hikida, Wataru, Himemoto, Yoshiaki, Hirabayashi, Hisashi, Hiramatsu, Takashi, Horisawa, Hideyuki, Hosokawa, Mizuhiko, Ishikawa, Takehiko, Kawano, Isao, Koizumi, Hiroyuki, Kuninaka, Hitoshi, Matsuhara, Hideo, Morimoto, Mutsuko Y., Nishiyama, Kazutaka, Sakai, Shin-ichiro, Takahashi, Tadayuki, and Utashima, Masayoshi
- Subjects
Physics ,Optics ,Physics and Astronomy (miscellaneous) ,Gravitational wave ,business.industry ,Big Bang Observer ,Antenna (radio) ,Space (mathematics) ,business - Abstract
著者人数: 145名, 資料番号: SA1002921000
- Published
- 2011
- Full Text
- View/download PDF
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