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152. Spatial distribution of trapped holes in SiO2

Author

Khosru, Quazi Deen Mohd, Yasuda, Naoki, Taniguchi, Kenji, and Hamaguchi, Chihiro

Subjects
Metal oxide semiconductors -- Analysis, Silica -- Analysis, Physics
Abstract

Experimental studies using metal-oxide-semiconductor transistors with very thin oxide thicknesses help determine the spatial distribution of trapped holes and the position of charged centroids in the insulating layer of SiO2 films. Samples with extremely thin oxide films exhibit significant hole trapping and majority of the trapped holes lie between 2-6-nanometer from the Si/SiO2 surface. The trapped holes are distributed in an exponentially decaying manner with respect to distance from the Si/SiO2 interface. The charge centroid exists at 3.2 nanometers from the Si/SiO2 interface.

Published
1994

153. Prime Focus Spectrograph (PFS) for Subaru Telescope: progressing final steps to science operation

Author

Bryant, Julia J., Motohara, Kentaro, Vernet, Joël R. D., Tamura, Naoyuki, Yabe, Kiyoto, Koshida, Shintaro, Moritani, Yuki, Tanaka, Masayuki, Ishigaki, Miho N., Ishizuka, Yuki, Kamata, Yukiko, Allaoui, Ali, Arai, Akira, Arnouts, Stéphane, Barette, Rudy, Barkhouser, Robert H., Bergeron, Eddie, Blanchard, Patrick, Caplar, Neven, Carle, Michael, Chabaud, Pierre-Yves, Chang, Yin-Chang, Chen, Hsin-Yo, Chou, Richard C. Y., Cohen, Judith G., Costa, Ricardo, Crauchet, Thibaut, de Almeida, Rodorigo P., de Oliveira, Antonio C., de Oliveira, Ligia S., Dohlen, Kjetil, dos Santos, Leandro H., Dobos, László, Ellis, Richard S., Ertel, Steve, Fabricius, Maximilian, Ferreira, Décio, Furusawa, Hisanori, Gee, Wilfred T., Garciá-Carpio, Javier, Gerasimov, Roman, Golebiowski, Mirek, Gray, Aidan, Gunn, James E., Hahn, ChangHoon, Hamano, Satoshi, Hammond, Randolph P., Harding, Albert, Hattori, Takashi, Hayashi, Kota, He, Wanqiu, Heckman, Timothy M., Hope, Stephen C., Hsu, Shu-Fu, Huang, Pin-Jie, Jaquet, Marc, Jeschke, Eric, Jespersen, Christian K., Jing, Yipeng, Kackley, Russell, Karr, Jennifer L., Kawanomoto, Satoshi, Kimura, Masahiko, Kirby, Evan N., Koike, Michitaro, Komatsu, Eiichiro, Koyama, Yusei, Le Brun, Vincent, Le Fur, Arnaud, Le Mignant, David, Lemson, Gerald, Lin, Yen-Ting, Ling, Hung-Hsu, Loomis, Craig P., Lupton, Robert H., Madec, Fabrice, Marchesini, Danilo, Marrara, Lucas S., Medvedev, Dmitry, Mineo, Sogo, Mitschang, Arik, Miyazaki, Satoshi, Morihana, Kumiko, Morishima, Takahiro, Murayama, Hitoshi, Murray, Graham J., Okamoto, Sakurako, Okita, Hirofumi, Onodera, Masato, Passegger, Vera M., Peebles, Joshua, Price, Paul A., Pyo, Tae-Soo, Ramos, Lucio, Reiley, Daniel J., Reinecke, Martin, Roberts, Mitsuko, Rosa, Josemar A., Rousselle, Julien P., Rubio, Kody H., Schubert, Kiaina, Seiffert, Michael D., Siegel, Jared, Smee, Stephen A., Sodré, Laerte, Strauss, Michael A., Sunayama, Tomomi, Surace, Christian, Takada, Masahiro, Takagi, Yuhei, Tanaka, Ichi, Tanaka, Yoko, Thakar, Aniruddha R., Vibert, Didier, Wang, Shiang-Yu, Wen, Chih-Yi, Werner, Suzanne, Wung, Matthew, Yan, Chi-Hung, Yasuda, Naoki, and Yoshida, Hiroshige

Published
2024
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154. Immunogenicity and reactogenicity of Takeda acellular pertussis-component diphtheria-tetanus-pertussis vaccine in 2- and 3-month-old children in Japan

Author

Kamiya, Hitoshi, Nii, Ritsue, Matsuda, Tadashi, Yasuda, Naoki, Christenson, Peter D., and Cherry, James D.

Subjects
DPT vaccine -- Evaluation, Immunization of infants -- Methods, Family and marriage, Health
Abstract

* Objective.--To compare the reactogenicity and immune response to the Takeda acellular pertussis-component diphtheria-tetanus-pertussis (APDT) vaccine in children when immunization commenced at 2 months (group A) vs 3 months (group B) of age. Design.--Longitudinal, nonblinded, comparative study. Setting.--Pediatric well-child clinics. Participants.--Healthy 50- to 98-day-old infants. Results.--Good antibody responses to lymphocytosis-promoting factor, filamentous hemagglutinin, agglutinogens, and pertactin occurred in both age groups after both the third and fourth vaccine doses. Both young age and transplacentally acquired maternal antibody independently and together have a suppressive effect on the response to the four antigens in this APDT vaccine. However, these effects appear to be minor. Vaccine reactions were mild; group A children had slightly but not significantly higher rates than group B children. Conclusion.--The present US diphtheria and tetanus toxoids and pertussis vaccine immunization schedule should also be satisfactory with this acellular pertussis component vaccine. (AJDC 1992;146:1141-1147)

Published
1992

155. New carrier lifetime measurement method for fully depleted SOI MOSFET's

Author

Yasuda, Naoki, Taniguchi, Kenji, Hamaguchi, Chihiro, Yamaguchi, Yasuo, and Nishimura, Tadashi

Subjects
Silicon-on-isolator -- Research, Metal oxide semiconductor field effect transistors -- Research, Process control -- Research, Business, Electronics, Electronics and electrical industries
Abstract

A novel carrier measurement technique for depleted silicon on insulator metal oxide semiconductor field effect transistors (MOSFET) is presented. Capable of predicting generation and recombination lifetimes from transient drain current behavior analysis, it obtains the carrier lifetime from the transient inversioncharge density, accumulation charge concentration and the electric field. Experiments on MOSFET's made of SIMOX substrate verified the process's validity.

Published
1992

156. A Rapidly Declining Transient Discovered with the Subaru/Hyper Suprime-Cam

Author

Tominaga, Nozomu, primary, Morokuma, Tomoki, additional, Tanaka, Masaomi, additional, Yasuda, Naoki, additional, Furusawa, Hisanori, additional, Tanaka, Masayuki, additional, Jiang, Ji-an, additional, Tolstov, Alexey, additional, Blinnikov, Sergei, additional, Doi, Mamoru, additional, Iwata, Ikuru, additional, Kuncarayakti, Hanindyo, additional, Moriya, Takashi J., additional, Nagao, Tohru, additional, Nomoto, Ken’ichi, additional, Noumaru, Junichi, additional, and Takata, Tadafumi, additional

Published
2019
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157. HSC16aayt: A Slowly Evolving Interacting Transient Rising for More than 100 Days

Author

Moriya, Takashi J., primary, Tanaka, Masaomi, additional, Morokuma, Tomoki, additional, Pan, Yen-Chen, additional, Quimby, Robert M., additional, Jiang, Ji-an, additional, Kawana, Kojiro, additional, Maeda, Keiichi, additional, Nomoto, Ken’ichi, additional, Suzuki, Nao, additional, Takahashi, Ichiro, additional, Tanaka, Masayuki, additional, Tominaga, Nozomu, additional, Yamaguchi, Masaki, additional, Yasuda, Naoki, additional, Cooke, Jeff, additional, Curtin, Chris, additional, Galbany, Lluís, additional, González-Gaitán, Santiago, additional, Lee, Chien-Hsiu, additional, Pignata, Giuliano, additional, and Pritchard, Tyler, additional

Published
2019
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159. The Hyper Suprime-Cam SSP transient survey in COSMOS: Overview

Author

Yasuda, Naoki, primary, Tanaka, Masaomi, primary, Tominaga, Nozomu, primary, Jiang, Ji-an, primary, Moriya, Takashi J, primary, Morokuma, Tomoki, primary, Suzuki, Nao, primary, Takahashi, Ichiro, primary, Yamaguchi, Masaki S, primary, Maeda, Keiichi, primary, Sako, Masao, primary, Ikeda, Shiro, primary, Kimura, Akisato, primary, Morii, Mikio, primary, Ueda, Naonori, primary, Yoshida, Naoki, primary, Lee, Chien-Hsiu, primary, Suyu, Sherry H, primary, Komiyama, Yutaka, primary, Regnault, Nicolas, primary, and Rubin, David, primary

Published
2019
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160. The stellar halo of isolated central galaxies in the Hyper Suprime-Cam imaging survey

Author

Wang, Wenting, primary, Han, Jiaxin, additional, Sonnenfeld, Alessandro, additional, Yasuda, Naoki, additional, Li, Xiangchong, additional, Jing, Yipeng, additional, More, Surhud, additional, Price, Paul A, additional, Lupton, Robert, additional, Rykoff, Eli S, additional, Stark, David V, additional, Lan, Ting-Wen, additional, Takada, Masahiro, additional, Huang, Song, additional, Luo, Wentao, additional, Bahcall, Neta A, additional, and Komiyama, Yutaka, additional

Published
2019
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161. First Release of High-Redshift Superluminous Supernovae from the Subaru HIgh- Z SUpernova CAmpaign (SHIZUCA). I. Photometric Properties

Author

Moriya, Takashi J., primary, Tanaka, Masaomi, additional, Yasuda, Naoki, additional, Jiang, Ji-an, additional, Lee, Chien-Hsiu, additional, Maeda, Keiichi, additional, Morokuma, Tomoki, additional, Nomoto, Ken’ichi, additional, Quimby, Robert M., additional, Suzuki, Nao, additional, Takahashi, Ichiro, additional, Tanaka, Masayuki, additional, Tominaga, Nozomu, additional, Yamaguchi, Masaki, additional, Bernard, Stephanie R., additional, Cooke, Jeff, additional, Curtin, Chris, additional, Galbany, Lluís, additional, González-Gaitán, Santiago, additional, Pignata, Giuliano, additional, Pritchard, Tyler, additional, Komiyama, Yutaka, additional, and Lupton, Robert H., additional

Published
2019
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162. First Release of High-redshift Superluminous Supernovae from the Subaru HIgh-Z SUpernova CAmpaign (SHIZUCA). II. Spectroscopic Properties

Author

Curtin, Chris, primary, Cooke, Jeff, additional, Moriya, Takashi J., additional, Tanaka, Masayuki, additional, Quimby, Robert M., additional, Bernard, Stephanie R., additional, Galbany, Lluís, additional, Jiang, Ji-an, additional, Lee, Chien-Hsiu, additional, Maeda, Keiichi, additional, Morokuma, Tomoki, additional, Nomoto, Ken’ichi, additional, Pignata, Giuliano, additional, Pritchard, Tyler, additional, Suzuki, Nao, additional, Takahashi, Ichiro, additional, Tanaka, Masaomi, additional, Tominaga, Nozomu, additional, Yamaguchi, Masaki, additional, and Yasuda, Naoki, additional

Published
2019
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163. Can't See the Forest for the Trees?: Types of Related Experiences for Resource Utilization.

Author

Yasuda, Naoki

Abstract

Resource utilization is a crucial factor in gaining a competitive advantage. Research on organizational learning suggests that experience-based knowledge can promote utilization. However, an analysis regarding what specific type of experience is important remains unexplored due to the poor classification of organizational experience. This study proposes a novel classification of firm experiences consisting of three categories: (1) weakly-related experiences, (2) strongly-related experiences, and (3) direct experiences. Using this classification, our work examines how varying degrees of relatedness contribute to the effective utilization of newly introduced resources. Using data on newly introduced aircraft introduced between 1960 and 2019, this study first found that weakly- related experiences exert a greater positive influence on effective utilization than strongly-related experiences. Furthermore, this article uncovers that direct experiences are substitutes for the two types of related experiences. The presence of heterogeneous experiences also supplements the effects of related experiences. These findings contribute to the literature on organizational learning from relatedness, and resource utilization. [ABSTRACT FROM AUTHOR]

Published
2024
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165. Subaru Hyper Suprime-Cam Survey for an optical counterpart of GW170817

Author

80402759, 60622454, Tominaga, Nozomu, Tanaka, Masaomi, Morokuma, Tomoki, Utsumi, Yousuke, Yamaguchi, Masaki S, Yasuda, Naoki, Tanaka, Masayuki, Yoshida, Michitoshi, Fujiyoshi, Takuya, Furusawa, Hisanori, Kawabata, Koji S, Lee, Chien-Hsiu, Motohara, Kentaro, Ohsawa, Ryou, Ohta, Kouji, Terai, Tsuyoshi, Abe, Fumio, Aoki, Wako, Asakura, Yuichiro, Barway, Sudhanshu, Bond, Ian A, Fujisawa, Kenta, Honda, Satoshi, Ioka, Kunihito, Itoh, Youichi, Kawai, Nobuyuki, Kim, Ji Hoon, Koshimoto, Naoki, Matsubayashi, Kazuya, Miyazaki, Shota, Saito, Tomoki, Sekiguchi, Yuichiro, Sumi, Takahiro, Tristram, Paul J, 80402759, 60622454, Tominaga, Nozomu, Tanaka, Masaomi, Morokuma, Tomoki, Utsumi, Yousuke, Yamaguchi, Masaki S, Yasuda, Naoki, Tanaka, Masayuki, Yoshida, Michitoshi, Fujiyoshi, Takuya, Furusawa, Hisanori, Kawabata, Koji S, Lee, Chien-Hsiu, Motohara, Kentaro, Ohsawa, Ryou, Ohta, Kouji, Terai, Tsuyoshi, Abe, Fumio, Aoki, Wako, Asakura, Yuichiro, Barway, Sudhanshu, Bond, Ian A, Fujisawa, Kenta, Honda, Satoshi, Ioka, Kunihito, Itoh, Youichi, Kawai, Nobuyuki, Kim, Ji Hoon, Koshimoto, Naoki, Matsubayashi, Kazuya, Miyazaki, Shota, Saito, Tomoki, Sekiguchi, Yuichiro, Sumi, Takahiro, and Tristram, Paul J

Abstract

We perform a z-band survey for an optical counterpart of the binary neutron star coalescence GW170817 with Subaru/Hyper Suprime-Cam. Our untargeted transient search covers 23.6 deg² corresponding to the 56.6% credible region of GW170817 and reaches the 50% completeness magnitude of 20.6 mag on average. As a result, we find 60 candidate extragalactic transients, including J-GEM17btc (also known as SSS17a/DLT17ck). While J-GEM17btc is associated with NGC 4993, which is firmly located inside the 3D skymap of GW170817, the other 59 candidates do not have distance information in the GLADE v2 catalog or NASA/IPAC Extragalactic Database. Among 59 of the candidates, 58 are located at the center of extended objects in the Pan-STARRS1 catalog, while one candidate has an offset. We present location, z-band apparent magnitude, and time variability of the candidates and evaluate the probabilities that they are located within the 3D skymap of GW170817. The probability for J-GEM17btc is 64%, which is much higher than for the other 59 candidates (9.3 × 10⁻³–2.1 × 10⁻¹%). Furthermore, the possibility that at least one of the other 59 candidates is located within the 3D skymap is only 3.2%. Therefore, we conclude that J-GEM17btc is the most likely and distinguished candidate to be the optical counterpart of GW170817.

Published
2018

166. Isophote Shapes of Early-Type Galaxies in Massive Clusters at z ~ 1 and 0

Author

Mitsuda, Kazuma, Doi, Mamoru, Morokuma, Tomoki, Suzuki, Nao, Yasuda, Naoki, Perlmutter, Saul, Aldering, Greg, and Meyers, Joshua

Subjects
astro-ph.GA, Molecular, Astronomy & Astrophysics, Atomic, Physical Chemistry, cD, Particle and Plasma Physics, photometry [galaxies], structure [galaxies], clusters: general [galaxies], Nuclear, elliptical and lenticular [galaxies], evolution [galaxies], Astronomical and Space Sciences, Physical Chemistry (incl. Structural)
Abstract

© 2017. The American Astronomical Society. All rights reserved. We compare the isophote shape parameter a4 of early-type galaxies (ETGs) between z ∼ 1 and 0 as a proxy for dynamics to investigate the epoch at which the dynamical properties of ETGs are established, using cluster ETG samples with stellar masses of log(M∗/M⊙) ≥ 10.5 which have spectroscopic redshifts. We have 130 ETGs from the Hubble Space Telescope Cluster Supernova Survey for z ∼ 1 and 355 ETGs from the Sloan Digital Sky Survey for z ∼ 0. We have developed an isophote shape analysis method, which can be used for high-redshift galaxies and has been carefully compared with published results. We have applied the same method for both the z ∼ 1 and 0 samples. We find similar dependence of the a4 parameter on the mass and size at z ∼ 1 and 0; the main population of ETGs changes from disky to boxy at a critical stellar mass of log(M∗/M⊙) ∼ 11.5 with the massive end dominated by boxy. The disky ETG fraction decreases with increasing stellar mass both at z ∼ 1 and 0, and is consistent between these redshifts in all stellar mass bins when the Eddington bias is taken into account. Although uncertainties are large, the results suggest that the isophote shapes and probably dynamical properties of ETGs in massive clusters are already in place at z > 1 and do not significantly evolve in z < 1, despite significant size evolution in the same galaxy population. The constant disky fraction favors less violent processes than mergers as the main cause of the size and morphological evolution of intermediate mass ETGs in z < 1.

Published
2017
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167. Optical follow-up observation of Fast Radio Burst 151230

Author

Tominaga, Nozomu, primary, Niino, Yuu, additional, Totani, Tomonori, additional, Yasuda, Naoki, additional, Furusawa, Hisanori, additional, Tanaka, Masayuki, additional, Bhandari, Shivani, additional, Dodson, Richard, additional, Keane, Evan, additional, Morokuma, Tomoki, additional, Petroff, Emily, additional, and Possenti, Andrea, additional

Published
2018
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169. Prime Focus Spectrograph (PFS) for the Subaru telescope: ongoing integration and future plans

Author

Tamura, Naoyuki, primary, Chu, You-Hua, primary, Gunn, James E., primary, Strauss, Michael A., primary, Heckman, Timothy M., primary, Smee, Stephen A., primary, Le Fèvre, Olivier, primary, Le Mignant, David, primary, Aghazarian, Hrand, primary, Chabaud, Pierre-Yves, primary, Chang, Yin-Chang, primary, Chou, Chueh-Yi, primary, de Almeida, Rodorigo P., primary, de Oliveira, Antonio C., primary, Dekany, Richard G., primary, Dohlen, Kjetil, primary, dos Santos, Jesulino B., primary, dos Santos, Leandro H., primary, Karr, Jeniffer L., primary, Kimura, Masahiko, primary, King, Matthew E., primary, Koike, Michitaro, primary, Le Fur, Arnaud, primary, Ling, Hung-Hsu, primary, Le Brun, Vincent, primary, Loomis, Craig P., primary, Lupton, Robert H., primary, Madec, Fabrice, primary, Mao, Peter H., primary, Murayama, Hitoshi, primary, Takada, Masahiro, primary, Moritani, Yuki, primary, Yabe, Kiyoto, primary, Ishizuka, Yuki, primary, Takato, Naruhisa, primary, Ueda, Akitoshi, primary, Shimono, Atsushi, primary, Kamata, Yukiko, primary, Wang, Shiang-Yu, primary, Sodré Junior, Laerte, primary, de Oliveira, Lígia S., primary, Jing, Yipeng, primary, Cohen, Judith G., primary, Reiley, Daniel J., primary, Seiffert, Micheal D., primary, Schwochert, Mark A., primary, Komatsu, Eiichiro, primary, Ellis, Richard S., primary, Arnouts, Stephane, primary, Barkhouser, Robert H., primary, Balard, Philippe, primary, Barette, Rudy, primary, Belhadi, Mohamed, primary, Burnham, Jill A., primary, Caplar, Neven, primary, Garcia-Carpio, Javier, primary, Carr, Michael A., primary, Chen, Hsin-Yo, primary, Fabricius, Maximilian, primary, Ferreira, Decio, primary, Furusawa, Hisanori, primary, Golebiowski, Mirek, primary, Gross, Johannes, primary, Hammond, Randolph, primary, Harding, Albert, primary, Hart, Murdock, primary, Ho, Paul T., primary, Hope, Stephen C., primary, Hover, David J., primary, Hsu, Shu-Fu, primary, Hu, Yen-Shan, primary, Huang, Ping-Jie, primary, Jamal, Sara, primary, Jaquet, Marc, primary, Jeschke, Eric, primary, Kado-Fong, Erin, primary, Marchesini, Danilo, primary, Marrara, Lucas S., primary, Medvedev, Dmitry, primary, Mineo, Sogo, primary, Minowa, Yosuke, primary, Ohyama, Youichi, primary, Onodera, Masato, primary, Orndorff, Joseph, primary, Pascal, Sandrine, primary, Peebles, Josh, primary, Pernot, Guillaume, primary, Pourcelot, Raphael, primary, Reinecke, Martin, primary, Roberts, Mitsuko, primary, Rosa, Josimar A., primary, Rousselle, Julien, primary, Schmitt, Alain, primary, Siddiqui, Hassan, primary, Steinkraus, Aaron J., primary, Surace, Christian, primary, Tait, Philip J., primary, Tamura, Tomonori, primary, Tanaka, Masayuki, primary, Tanaka, Yoko, primary, Thakar, Aniruddha R., primary, Verducci, Orlando, primary, Vibert, Didier, primary, Wang, Zuo, primary, Wen, Chih-Yi, primary, Werner, Suzanne, primary, Yamada, Yoshihiko, primary, Yan, Chi-Hung, primary, Yasuda, Naoki, primary, Yoshida, Hiroshige, primary, Yoshida, Michitoshi, primary, and Murray, Graham J., primary

Published
2018
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170. Hyper Suprime-Cam: Filters

Author

Kawanomoto, Satoshi, primary, Uraguchi, Fumihiro, additional, Komiyama, Yutaka, additional, Miyazaki, Satoshi, additional, Furusawa, Hisanori, additional, Finet, François, additional, Hattori, Takashi, additional, Wang, Shiang-Yu, additional, Yasuda, Naoki, additional, and Suzuki, Naotaka, additional

Published
2018
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171. Degradation mechanism of HfAlOX/SiO2 stacked gate dielectrics studied by transient and steady-state leakage current analysis.

Author

Okada, Kenji, Mizubayashi, Wataru, Yasuda, Naoki, Ota, Hiroyuki, Tominaga, Koji, Iwamoto, Kunihiko, Horikawa, Tsuyoshi, Yamamoto, Katsuhiko, Hisamatsu, Hirokazu, Satake, Hideki, Nabatame, Toshihide, and Toriumi, Akira

Subjects
DIELECTRICS, EXCITON theory, SEMICONDUCTORS, CAPACITORS, LOW voltage systems, ELECTRIC currents
Abstract

Degradation mechanism of stacked high-k gate dielectrics has been studied with metal-oxide-semiconductor capacitors having HfAlOX/SiO2 films of various thickness combinations. A large leakage current with a peaked shape, named as the low-voltage peak current (LVPC), has been observed in the low-voltage region even in the initial current–voltage characteristics. It has been shown that a main part of LVPC is the transient current component controlled by the process of hole injection to traps in the vicinity of the HfAlOX/SiO2 interface through the interfacial SiO2 layer. By the electrical stress, both the transient and the steady-state current components monotonically increase with time having different rates. Steady-state component has significantly larger rate than the transient component, and the same rate with the stress-induced leakage current (SILC) observed in the high-voltage region, indicating that the steady-state component of LVPC should be regarded as the SILC in the higher-voltage region extending down to the lower gate voltage region where the LVPC is observed. [ABSTRACT FROM AUTHOR]

Published
2005
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172. The Union3 Supernova Ia Compilation

Author

Rubin, David, Aldering, Greg, Amanullah, Rahman, Ruiz-Lapuente, Pilar, Rykoff, Eli S., Saunders, Clare, Spadafora, Anthony L., Suzuki, Nao, Takanashi, Naohiro, and Yasuda, Naoki

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

David Rubin et al. ; 227th AAS Meeting Kissimmee, FL – January, 2016, High-redshift supernovae observed with the Hubble Space Telescope (HST) are crucial for constraining any time variation in dark energy. In a forthcoming paper (Rubin+, in prep), we will present a cosmological analysis incorporating existing supernovae with improved calibrations, and new HST-observed supernovae (six above z=1). We combine these data with current literature data, and fit them using SALT2-4 to create the Union3 Supernova compilation. We build on the Unified Inference for Type Ia cosmologY (UNITY) framework (Rubin+ 2015b), incorporating non-linear light-curve width and color relations, a model for unexplained dispersion, an outlier model, and a redshift-dependent host-mass correction.

Published
2016

173. Early Science Result from the Japanese Virtual Observatory: AGN and Galaxy Clustering atz= 0.3 to 3.0

Author

Shirasaki, Yuji, Tanaka, Masahiro, Ohishi, Masatoshi, Mizumoto, Yoshihiko, Yasuda, Naoki, and Takata, Tadafumi

Subjects
Physics, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Virtual observatory, Redshift, Galaxy, Space and Planetary Science, Cluster analysis, Astrophysics::Galaxy Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

We present the result of projected cross correlation analysis of AGNs and galaxies at redshifts from 0.3 to 3.0. The Japanese Virtual Observatory (JVO) was used to obtain the Subaru Suprime-Cam images and UKIDSS catalog data around AGNs. We investigated 1,809 AGNs, which is about ten times larger a sample than that used in previous studies on AGN-galaxy clustering at redshifts larger than 0.6. 90% of the AGN samples are optically-selected AGN from the SDSS and 2dF catalogs. The galaxy samples at low redshift includes many redder objects from UKIDSS survey, while at higher redshift they are mainly blue galaxies from Suprime-Cam. We found significant excess of galaxies around the AGNs at redshifts from 0.3 to 1.8. For the low redshift samples ($z, Comment: accepted to PASJ, 36 pages, 21 figures, this is an accepted version

Published
2011

174. Degradation mechanism of HfAlO(sub x)/SiO(sub 2) stacked gate dielectrics studied by transient and steady-state leakage current analysis

Author

Okada, Kenji, Nabatame, Toshihide, Iwamoto, Kunihiko, Mizubayashi, Wataru, Toriumi, Akira, Horikawa, Tsuyoshi, Yasuda, Naoki, Yamamoto, Katsuhiko, Ota, Hiroyuki, Hisamatsu, Hirokazu, Tominaga, Koji, and Satake, Hideki

Subjects
Dielectric films -- Research, Thin films -- Research, Silicon compounds -- Optical properties, Silicon compounds -- Electric properties, Aluminum compounds -- Optical properties, Aluminum compounds -- Electric properties, Hafnium -- Optical properties, Hafnium -- Electric properties, Physics
Abstract

Degradation mechanism of stacked high-k gate dielectrics is studied with metal-oxide-semiconductor capacitors having HfAlO(sub x)/SiO(sub 2) films of various thickness combinations. A large leakage current with a peaked shape, named as the low-voltage peak current (LVPC), is observed in the low-voltage region even in the initial current-voltage characteristics.

Published
2005

175. Kilonova from post-merger ejecta as an optical and near-Infrared counterpart of GW170817

Author

Tanaka, Masaomi, primary, Utsumi, Yousuke, additional, Mazzali, Paolo A., additional, Tominaga, Nozomu, additional, Yoshida, Michitoshi, additional, Sekiguchi, Yuichiro, additional, Morokuma, Tomoki, additional, Motohara, Kentaro, additional, Ohta, Kouji, additional, Kawabata, Koji S., additional, Abe, Fumio, additional, Aoki, Kentaro, additional, Asakura, Yuichiro, additional, Baar, Stefan, additional, Barway, Sudhanshu, additional, Bond, Ian A., additional, Doi, Mamoru, additional, Fujiyoshi, Takuya, additional, Furusawa, Hisanori, additional, Honda, Satoshi, additional, Itoh, Yoichi, additional, Kawabata, Miho, additional, Kawai, Nobuyuki, additional, Kim, Ji Hoon, additional, Lee, Chien-Hsiu, additional, Miyazaki, Shota, additional, Morihana, Kumiko, additional, Nagashima, Hiroki, additional, Nagayama, Takahiro, additional, Nakaoka, Tatsuya, additional, Nakata, Fumiaki, additional, Ohsawa, Ryou, additional, Ohshima, Tomohito, additional, Okita, Hirofumi, additional, Saito, Tomoki, additional, Sumi, Takahiro, additional, Tajitsu, Akito, additional, Takahashi, Jun, additional, Takayama, Masaki, additional, Tamura, Yoichi, additional, Tanaka, Ichi, additional, Terai, Tsuyoshi, additional, Tristram, Paul J., additional, Yasuda, Naoki, additional, and Zenko, Tetsuya, additional

Published
2017
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176. The Hyper Suprime-Cam software pipeline

Author

Bosch, James, primary, Armstrong, Robert, additional, Bickerton, Steven, additional, Furusawa, Hisanori, additional, Ikeda, Hiroyuki, additional, Koike, Michitaro, additional, Lupton, Robert, additional, Mineo, Sogo, additional, Price, Paul, additional, Takata, Tadafumi, additional, Tanaka, Masayuki, additional, Yasuda, Naoki, additional, AlSayyad, Yusra, additional, Becker, Andrew C, additional, Coulton, William, additional, Coupon, Jean, additional, Garmilla, Jose, additional, Huang, Song, additional, Krughoff, K Simon, additional, Lang, Dustin, additional, Leauthaud, Alexie, additional, Lim, Kian-Tat, additional, Lust, Nate B, additional, MacArthur, Lauren A, additional, Mandelbaum, Rachel, additional, Miyatake, Hironao, additional, Miyazaki, Satoshi, additional, Murata, Ryoma, additional, More, Surhud, additional, Okura, Yuki, additional, Owen, Russell, additional, Swinbank, John D, additional, Strauss, Michael A, additional, Yamada, Yoshihiko, additional, and Yamanoi, Hitomi, additional

Published
2017
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177. First data release of the Hyper Suprime-Cam Subaru Strategic Program

Author

Aihara, Hiroaki, primary, Armstrong, Robert, additional, Bickerton, Steven, additional, Bosch, James, additional, Coupon, Jean, additional, Furusawa, Hisanori, additional, Hayashi, Yusuke, additional, Ikeda, Hiroyuki, additional, Kamata, Yukiko, additional, Karoji, Hiroshi, additional, Kawanomoto, Satoshi, additional, Koike, Michitaro, additional, Komiyama, Yutaka, additional, Lang, Dustin, additional, Lupton, Robert H, additional, Mineo, Sogo, additional, Miyatake, Hironao, additional, Miyazaki, Satoshi, additional, Morokuma, Tomoki, additional, Obuchi, Yoshiyuki, additional, Oishi, Yukie, additional, Okura, Yuki, additional, Price, Paul A, additional, Takata, Tadafumi, additional, Tanaka, Manobu M, additional, Tanaka, Masayuki, additional, Tanaka, Yoko, additional, Uchida, Tomohisa, additional, Uraguchi, Fumihiro, additional, Utsumi, Yousuke, additional, Wang, Shiang-Yu, additional, Yamada, Yoshihiko, additional, Yamanoi, Hitomi, additional, Yasuda, Naoki, additional, Arimoto, Nobuo, additional, Chiba, Masashi, additional, Finet, Francois, additional, Fujimori, Hiroki, additional, Fujimoto, Seiji, additional, Furusawa, Junko, additional, Goto, Tomotsugu, additional, Goulding, Andy, additional, Gunn, James E, additional, Harikane, Yuichi, additional, Hattori, Takashi, additional, Hayashi, Masao, additional, Hełminiak, Krzysztof G, additional, Higuchi, Ryo, additional, Hikage, Chiaki, additional, Ho, Paul T P, additional, Hsieh, Bau-Ching, additional, Huang, Kuiyun, additional, Huang, Song, additional, Imanishi, Masatoshi, additional, Iwata, Ikuru, additional, Jaelani, Anton T, additional, Jian, Hung-Yu, additional, Kashikawa, Nobunari, additional, Katayama, Nobuhiko, additional, Kojima, Takashi, additional, Konno, Akira, additional, Koshida, Shintaro, additional, Kusakabe, Haruka, additional, Leauthaud, Alexie, additional, Lee, Chien-Hsiu, additional, Lin, Lihwai, additional, Lin, Yen-Ting, additional, Mandelbaum, Rachel, additional, Matsuoka, Yoshiki, additional, Medezinski, Elinor, additional, Miyama, Shoken, additional, Momose, Rieko, additional, More, Anupreeta, additional, More, Surhud, additional, Mukae, Shiro, additional, Murata, Ryoma, additional, Murayama, Hitoshi, additional, Nagao, Tohru, additional, Nakata, Fumiaki, additional, Niida, Mana, additional, Niikura, Hiroko, additional, Nishizawa, Atsushi J, additional, Oguri, Masamune, additional, Okabe, Nobuhiro, additional, Ono, Yoshiaki, additional, Onodera, Masato, additional, Onoue, Masafusa, additional, Ouchi, Masami, additional, Pyo, Tae-Soo, additional, Shibuya, Takatoshi, additional, Shimasaku, Kazuhiro, additional, Simet, Melanie, additional, Speagle, Joshua, additional, Spergel, David N, additional, Strauss, Michael A, additional, Sugahara, Yuma, additional, Sugiyama, Naoshi, additional, Suto, Yasushi, additional, Suzuki, Nao, additional, Tait, Philip J, additional, Takada, Masahiro, additional, Terai, Tsuyoshi, additional, Toba, Yoshiki, additional, Turner, Edwin L, additional, Uchiyama, Hisakazu, additional, Umetsu, Keiichi, additional, Urata, Yuji, additional, Usuda, Tomonori, additional, Yeh, Sherry, additional, and Yuma, Suraphong, additional

Published
2017
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178. A hybrid type Ia supernova with an early flash triggered by helium-shell detonation

Author

Jiang, Ji-an, primary, Doi, Mamoru, additional, Maeda, Keiichi, additional, Shigeyama, Toshikazu, additional, Nomoto, Ken’ichi, additional, Yasuda, Naoki, additional, Jha, Saurabh W., additional, Tanaka, Masaomi, additional, Morokuma, Tomoki, additional, Tominaga, Nozomu, additional, Ivezić, Željko, additional, Ruiz-Lapuente, Pilar, additional, Stritzinger, Maximilian D., additional, Mazzali, Paolo A., additional, Ashall, Christopher, additional, Mould, Jeremy, additional, Baade, Dietrich, additional, Suzuki, Nao, additional, Connolly, Andrew J., additional, Patat, Ferdinando, additional, Wang, Lifan, additional, Yoachim, Peter, additional, Jones, David, additional, Furusawa, Hisanori, additional, and Miyazaki, Satoshi, additional

Published
2017
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179. The on-site quality-assurance system for Hyper Suprime-Cam: OSQAH†

Author

Furusawa, Hisanori, primary, Koike, Michitaro, additional, Takata, Tadafumi, additional, Okura, Yuki, additional, Miyatake, Hironao, additional, Lupton, Robert H, additional, Bickerton, Steven, additional, Price, Paul A, additional, Bosch, James, additional, Yasuda, Naoki, additional, Mineo, Sogo, additional, Yamada, Yoshihiko, additional, Miyazaki, Satoshi, additional, Nakata, Fumiaki, additional, Koshida, Shintaro, additional, Komiyama, Yutaka, additional, Utsumi, Yousuke, additional, Kawanomoto, Satoshi, additional, Jeschke, Eric, additional, Noumaru, Junichi, additional, Schubert, Kiaina, additional, Iwata, Ikuru, additional, Finet, Francois, additional, Fujiyoshi, Takuya, additional, Tajitsu, Akito, additional, Terai, Tsuyoshi, additional, and Lee, Chien-Hsiu, additional

Published
2017
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180. Hyper Suprime-Cam: System design and verification of image quality

Author

Miyazaki, Satoshi, primary, Komiyama, Yutaka, additional, Kawanomoto, Satoshi, additional, Doi, Yoshiyuki, additional, Furusawa, Hisanori, additional, Hamana, Takashi, additional, Hayashi, Yusuke, additional, Ikeda, Hiroyuki, additional, Kamata, Yukiko, additional, Karoji, Hiroshi, additional, Koike, Michitaro, additional, Kurakami, Tomio, additional, Miyama, Shoken, additional, Morokuma, Tomoki, additional, Nakata, Fumiaki, additional, Namikawa, Kazuhito, additional, Nakaya, Hidehiko, additional, Nariai, Kyoji, additional, Obuchi, Yoshiyuki, additional, Oishi, Yukie, additional, Okada, Norio, additional, Okura, Yuki, additional, Tait, Philip, additional, Takata, Tadafumi, additional, Tanaka, Yoko, additional, Tanaka, Masayuki, additional, Terai, Tsuyoshi, additional, Tomono, Daigo, additional, Uraguchi, Fumihiro, additional, Usuda, Tomonori, additional, Utsumi, Yousuke, additional, Yamada, Yoshihiko, additional, Yamanoi, Hitomi, additional, Aihara, Hiroaki, additional, Fujimori, Hiroki, additional, Mineo, Sogo, additional, Miyatake, Hironao, additional, Oguri, Masamune, additional, Uchida, Tomohisa, additional, Tanaka, Manobu M, additional, Yasuda, Naoki, additional, Takada, Masahiro, additional, Murayama, Hitoshi, additional, Nishizawa, Atsushi J, additional, Sugiyama, Naoshi, additional, Chiba, Masashi, additional, Futamase, Toshifumi, additional, Wang, Shiang-Yu, additional, Chen, Hsin-Yo, additional, Ho, Paul T P, additional, Liaw, Eric J Y, additional, Chiu, Chi-Fang, additional, Ho, Cheng-Lin, additional, Lai, Tsang-Chih, additional, Lee, Yao-Cheng, additional, Jeng, Dun-Zen, additional, Iwamura, Satoru, additional, Armstrong, Robert, additional, Bickerton, Steve, additional, Bosch, James, additional, Gunn, James E, additional, Lupton, Robert H, additional, Loomis, Craig, additional, Price, Paul, additional, Smith, Steward, additional, Strauss, Michael A, additional, Turner, Edwin L, additional, Suzuki, Hisanori, additional, Miyazaki, Yasuhito, additional, Muramatsu, Masaharu, additional, Yamamoto, Koei, additional, Endo, Makoto, additional, Ezaki, Yutaka, additional, Ito, Noboru, additional, Kawaguchi, Noboru, additional, Sofuku, Satoshi, additional, Taniike, Tomoaki, additional, Akutsu, Kotaro, additional, Dojo, Naoto, additional, Kasumi, Kazuyuki, additional, Matsuda, Toru, additional, Imoto, Kohei, additional, Miwa, Yoshinori, additional, Suzuki, Masayuki, additional, Takeshi, Kunio, additional, and Yokota, Hideo, additional

Published
2017
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181. The Hyper Suprime-Cam SSP Survey: Overview and survey design

Author

Aihara, Hiroaki, primary, Arimoto, Nobuo, additional, Armstrong, Robert, additional, Arnouts, Stéphane, additional, Bahcall, Neta A, additional, Bickerton, Steven, additional, Bosch, James, additional, Bundy, Kevin, additional, Capak, Peter L, additional, Chan, James H H, additional, Chiba, Masashi, additional, Coupon, Jean, additional, Egami, Eiichi, additional, Enoki, Motohiro, additional, Finet, Francois, additional, Fujimori, Hiroki, additional, Fujimoto, Seiji, additional, Furusawa, Hisanori, additional, Furusawa, Junko, additional, Goto, Tomotsugu, additional, Goulding, Andy, additional, Greco, Johnny P, additional, Greene, Jenny E, additional, Gunn, James E, additional, Hamana, Takashi, additional, Harikane, Yuichi, additional, Hashimoto, Yasuhiro, additional, Hattori, Takashi, additional, Hayashi, Masao, additional, Hayashi, Yusuke, additional, Hełminiak, Krzysztof G, additional, Higuchi, Ryo, additional, Hikage, Chiaki, additional, Ho, Paul T P, additional, Hsieh, Bau-Ching, additional, Huang, Kuiyun, additional, Huang, Song, additional, Ikeda, Hiroyuki, additional, Imanishi, Masatoshi, additional, Inoue, Akio K, additional, Iwasawa, Kazushi, additional, Iwata, Ikuru, additional, Jaelani, Anton T, additional, Jian, Hung-Yu, additional, Kamata, Yukiko, additional, Karoji, Hiroshi, additional, Kashikawa, Nobunari, additional, Katayama, Nobuhiko, additional, Kawanomoto, Satoshi, additional, Kayo, Issha, additional, Koda, Jin, additional, Koike, Michitaro, additional, Kojima, Takashi, additional, Komiyama, Yutaka, additional, Konno, Akira, additional, Koshida, Shintaro, additional, Koyama, Yusei, additional, Kusakabe, Haruka, additional, Leauthaud, Alexie, additional, Lee, Chien-Hsiu, additional, Lin, Lihwai, additional, Lin, Yen-Ting, additional, Lupton, Robert H, additional, Mandelbaum, Rachel, additional, Matsuoka, Yoshiki, additional, Medezinski, Elinor, additional, Mineo, Sogo, additional, Miyama, Shoken, additional, Miyatake, Hironao, additional, Miyazaki, Satoshi, additional, Momose, Rieko, additional, More, Anupreeta, additional, More, Surhud, additional, Moritani, Yuki, additional, Moriya, Takashi J, additional, Morokuma, Tomoki, additional, Mukae, Shiro, additional, Murata, Ryoma, additional, Murayama, Hitoshi, additional, Nagao, Tohru, additional, Nakata, Fumiaki, additional, Niida, Mana, additional, Niikura, Hiroko, additional, Nishizawa, Atsushi J, additional, Obuchi, Yoshiyuki, additional, Oguri, Masamune, additional, Oishi, Yukie, additional, Okabe, Nobuhiro, additional, Okamoto, Sakurako, additional, Okura, Yuki, additional, Ono, Yoshiaki, additional, Onodera, Masato, additional, Onoue, Masafusa, additional, Osato, Ken, additional, Ouchi, Masami, additional, Price, Paul A, additional, Pyo, Tae-Soo, additional, Sako, Masao, additional, Sawicki, Marcin, additional, Shibuya, Takatoshi, additional, Shimasaku, Kazuhiro, additional, Shimono, Atsushi, additional, Shirasaki, Masato, additional, Silverman, John D, additional, Simet, Melanie, additional, Speagle, Joshua, additional, Spergel, David N, additional, Strauss, Michael A, additional, Sugahara, Yuma, additional, Sugiyama, Naoshi, additional, Suto, Yasushi, additional, Suyu, Sherry H, additional, Suzuki, Nao, additional, Tait, Philip J, additional, Takada, Masahiro, additional, Takata, Tadafumi, additional, Tamura, Naoyuki, additional, Tanaka, Manobu M, additional, Tanaka, Masaomi, additional, Tanaka, Masayuki, additional, Tanaka, Yoko, additional, Terai, Tsuyoshi, additional, Terashima, Yuichi, additional, Toba, Yoshiki, additional, Tominaga, Nozomu, additional, Toshikawa, Jun, additional, Turner, Edwin L, additional, Uchida, Tomohisa, additional, Uchiyama, Hisakazu, additional, Umetsu, Keiichi, additional, Uraguchi, Fumihiro, additional, Urata, Yuji, additional, Usuda, Tomonori, additional, Utsumi, Yousuke, additional, Wang, Shiang-Yu, additional, Wang, Wei-Hao, additional, Wong, Kenneth C, additional, Yabe, Kiyoto, additional, Yamada, Yoshihiko, additional, Yamanoi, Hitomi, additional, Yasuda, Naoki, additional, Yeh, Sherry, additional, Yonehara, Atsunori, additional, and Yuma, Suraphong, additional

Published
2017
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186. J-GEM follow-up observations of the gravitational wave source GW151226*

Author

Yoshida, Michitoshi, primary, Utsumi, Yousuke, additional, Tominaga, Nozomu, additional, Morokuma, Tomoki, additional, Tanaka, Masaomi, additional, Asakura, Yuichiro, additional, Matsubayashi, Kazuya, additional, Ohta, Kouji, additional, Abe, Fumio, additional, Chimasu, Sho, additional, Furusawa, Hisanori, additional, Itoh, Ryosuke, additional, Itoh, Yoichi, additional, Kanda, Yuka, additional, Kawabata, Koji S., additional, Kawabata, Miho, additional, Koshida, Shintaro, additional, Koshimoto, Naoki, additional, Kuroda, Daisuke, additional, Moritani, Yuki, additional, Motohara, Kentaro, additional, Murata, Katsuhiro L., additional, Nagayama, Takahiro, additional, Nakaoka, Tatsuya, additional, Nakata, Fumiaki, additional, Nishioka, Tsubasa, additional, Saito, Yoshihiko, additional, Terai, Tsuyoshi, additional, Tristram, Paul J., additional, Yanagisawa, Kenshi, additional, Yasuda, Naoki, additional, Doi, Mamoru, additional, Fujisawa, Kenta, additional, Kawachi, Akiko, additional, Kawai, Nobuyuki, additional, Tamura, Yoichi, additional, Uemura, Makoto, additional, and Yatsu, Yoichi, additional

Published
2016
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187. stellar halo of isolated central galaxies in the Hyper Suprime-Cam imaging survey.

Author

Wang, Wenting, Han, Jiaxin, Sonnenfeld, Alessandro, Yasuda, Naoki, Li, Xiangchong, Jing, Yipeng, More, Surhud, Price, Paul A, Lupton, Robert, Rykoff, Eli S, Stark, David V, Lan, Ting-Wen, Takada, Masahiro, Huang, Song, Luo, Wentao, Bahcall, Neta A, and Komiyama, Yutaka

Subjects
GALAXIES, STELLAR mass, SURFACE brightness (Astronomy)
Abstract

We study the faint stellar halo of isolated central galaxies, by stacking galaxy images in the HSC survey and accounting for the residual sky background sampled with random points. The surface brightness profiles in HSC r band are measured for a wide range of galaxy stellar masses (9.2 < log10 M ∗/M⊙ < 11.4) and out to 120 kpc. Failing to account for the stellar halo below the noise level of individual images will lead to underestimates of the total luminosity by ≤15%. Splitting galaxies according to the concentration parameter of their light distributions, we find that the surface brightness profiles of low-concentration galaxies drop faster between 20 and 100 kpc than those of high-concentration galaxies. Albeit the large galaxy-to-galaxy scatter, we find a strong self-similarity of the stellar halo profiles. They show unified forms once the projected distance is scaled by the halo virial radius. The colour of galaxies is redder in the centre and bluer outside, with high-concentration galaxies having redder and more flattened colour profiles. There are indications of a colour minimum, beyond which the colour of the outer stellar halo turns red again. This colour minimum, however, is very sensitive to the completeness in masking satellite galaxies. We also examine the effect of the extended PSF in the measurement of the stellar halo, which is particularly important for low-mass or low-concentration galaxies. The PSF-corrected surface brightness profile can be measured down to ∼31  |$\mathrm{mag}\, \mathrm{arcsec}^{-2}$| at 3σ significance. PSF also slightly flattens the measured colour profiles. [ABSTRACT FROM AUTHOR]

Published
2019
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188. Generation and relaxation phenomena of positive charge and interface trap in a metal-oxide-semiconductor structure.

Author

Khosru, Quazi Deen Mohd, Yasuda, Naoki, Taniguchi, Kenji, and Hamaguchi, Chihiro

Subjects
*HOLES (Electron deficiencies), *METAL oxide semiconductors, *INTERFACES (Physical sciences)
Abstract

Deals with a study which investigated the positive charge and interface trap generation during substrate hot-hole injection into the insulating layer of a metal-oxide semiconductor structure. Preparation of the sample; Measurement and injection of hot-hole; Calculation of trapped hole density and injection fluence.

Published
1995
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189. Morphological Classification of Galaxies Using Photometric Parameters: The Concentration Index versus the Coarseness Parameter

Author

Nakamura, Osamu, Yamauchi, Chisato, Ichikawa, Shin-ichi, Doi, Mamoru, Yasuda, Naoki, Yagi, Masafumi, Fukugita, Masataka, Okamura, Sadanori, Sekiguchi, Maki, and Goto, Tomotsugu

Subjects
Physics, Index (economics), Spiral galaxy, Texture (cosmology), Aperture, media_common.quotation_subject, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Galaxy, Space and Planetary Science, Sky, Data release, Astrophysics::Galaxy Astrophysics, media_common
Abstract

We devise improved photometric parameters for the morphological classification of galaxies using a bright sample from the First Data Release of the Sloan Digital Sky Survey. In addition to using an elliptical aperture concentration index for classification, we introduce a new texture parameter, coarseness, which quantifies deviations from smooth galaxy isophotes. The elliptical aperture concentration index produces morphological classifications that are in appreciably better agreement with visual classifications than those based on circular apertures. With the addition of the coarseness parameter,the success rate of classifying galaxies into early and late types increases to \~88% with respect to the reference visual classification. A reasonably high success rate ~68% is also attained in classifying galaxies into three types, early-type galaxies (E+S0), early- (Sa+Sb) and late- (Sc+Sdm+Im) type spiral galaxies., Comment: 13 pages, 16 figures, accepted by the Astronomical Journal

Published
2005

190. Machine-learning selection of optical transients in the Subaru/Hyper Suprime-Cam survey

Author

Morii, Mikio, Ikeda, Shiro, Tominaga, Nozomu, Tanaka, Masaomi, Morokuma, Tomoki, Ishiguro, Katsuhiko, Yamato, Junji, Ueda, Naonori, Suzuki, Naotaka, Yasuda, Naoki, and Yoshida, Naoki

Abstract

We present an application of machine-learning (ML) techniques to source selection in the optical transient survey data with the Hyper Suprime-Cam (HSC) on the Subaru telescope. Our goal is to select real transient events accurately and in a timely manner out of a large number of false candidates, obtained by the standard difference-imaging method. We have developed the transient selector, which is based on majority voting of the three ML machines of AUC Boosting, Random Forest, and Deep Neural Networks. We applied it to our observing runs of Subaru-HSC in 2015 May and August, and proved it to be efficient in selecting optical transients. The false positive rate was 1.0% at the true positive rate of 90% in the magnitude range of 22.0–25.0 mag for the May data. For the August run, we successfully detected and reported 10 supernovae candidates within the same day as the observation. From these runs, we learned the following lessons: (1) training using artificial objects is effective in filtering false candidates out, especially for faint objects, and (2) a combination of ML by majority voting is advantageous.

Published
2024
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191. Isophote Shapes of Early-Type Galaxies in Massive Clusters at $z\sim1$ and 0

Author

Mitsuda, Kazuma, Doi, Mamoru, Morokuma, Tomoki, Suzuki, Nao, Yasuda, Naoki, Perlmutter, Saul, Aldering, Greg, Meyers, Joshua, Mitsuda, Kazuma, Doi, Mamoru, Morokuma, Tomoki, Suzuki, Nao, Yasuda, Naoki, Perlmutter, Saul, Aldering, Greg, and Meyers, Joshua

Abstract

We compare the isophote shape parameter $a_{4}$ of early-type galaxies (ETGs) between $z\sim1$ and 0 as a proxy for dynamics to investigate the epoch at which the dynamical properties of ETGs are established, using cluster ETG samples with stellar masses of $\log(M_{*}/M_{\odot})\geq10.5$ which have spectroscopic redshifts. We have 130 ETGs from the Hubble Space Telescope Cluster Supernova Survey for $z\sim1$ and 355 ETGs from the Sloan Digital Sky Survey for $z\sim0$. We have developed an isophote shape analysis method which can be used for high-redshift galaxies and has been carefully compared with published results. We have applied the same method for both the $z\sim1$ and $0$ samples. We find similar dependence of the $a_{4}$ parameter on the mass and size at $z\sim1$ and 0; the main population of ETGs changes from disky to boxy at a critical stellar mass of $\log(M_{*}/M_{\odot})\sim11.5$ with the massive end dominated by boxy. The disky ETG fraction decreases with increasing stellar mass both at $z\sim1$ and $0$, and is consistent between these redshifts in all stellar mass bins when the Eddington bias is taken into account. Although uncertainties are large, the results suggest that the isophote shapes and probably dynamical properties of ETGs in massive clusters are already in place at $z>1$ and do not significantly evolve in $z<1$, despite significant size evolution in the same galaxy population. The constant disky fraction favors less violent processes than mergers as a main cause of the size and morphological evolution of intermediate mass ETGs in $z<1$., Comment: 22 pages, 21 figures. Accepted for publication in ApJ

Published
2016
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192. Machine-learning Selection of Optical Transients in Subaru/Hyper Suprime-Cam Survey

Author

Morii, Mikio, Ikeda, Shiro, Tominaga, Nozomu, Tanaka, Masaomi, Morokuma, Tomoki, Ishiguro, Katsuhiko, Yamato, Junji, Ueda, Naonori, Suzuki, Naotaka, Yasuda, Naoki, Yoshida, Naoki, Morii, Mikio, Ikeda, Shiro, Tominaga, Nozomu, Tanaka, Masaomi, Morokuma, Tomoki, Ishiguro, Katsuhiko, Yamato, Junji, Ueda, Naonori, Suzuki, Naotaka, Yasuda, Naoki, and Yoshida, Naoki

Abstract

We present an application of machine-learning (ML) techniques to source selection in the optical transient survey data with Hyper Suprime-Cam (HSC) on the Subaru telescope. Our goal is to select real transient events accurately and in a timely manner out of a large number of false candidates, obtained with the standard difference-imaging method. We have developed the transient selector which is based on majority voting of three ML machines of AUC Boosting, Random Forest, and Deep Neural Network. We applied it to our observing runs of Subaru-HSC in 2015 May and August, and proved it to be efficient in selecting optical transients. The false positive rate was 1.0% at the true positive rate of 90% in the magnitude range of 22.0--25.0 mag for the former data. For the latter run, we successfully detected and reported ten candidates of supernovae within the same day as the observation. From these runs, we learned the following lessons: (1) the training using artificial objects is effective in filtering out false candidates, especially for faint objects, and (2) combination of ML by majority voting is advantageous., Comment: 9 pages, 6 figures. Accepted for publication in PASJ

Published
2016
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193. J-GEM Follow-Up Observations of The Gravitational Wave Source GW151226

Author

Yoshida, Michitoshi, Utsumi, Yousuke, Tominaga, Nozomu, Morokuma, Tomoki, Tanaka, Masaomi, Asakura, Yuichiro, Matsubayashi, Kazuya, Ohta, Kouji, Abe, Fumio, Chimasu, Sho, Furusawa, Hisanori, Itoh, Ryosuke, Itoh, Yoichi, Kanda, Yuka, Kawabata, Koji S., Kawabata, Miho, Koshida, Shintaro, Koshimoto, Naoki, Kuroda, Daisuke, Moritani, Yuki, Motohara, Kentaro, Murata, Katsuhiro L., Nagayama, Takahiro, Nakaoka, Tatsuya, Nakata, Fumiaki, Nishioka, Tsubasa, Saito, Yoshihiko, Terai, Tsuyoshi, Tristram, Paul J., Yanagisawa, Kenshi, Yasuda, Naoki, Doi, Mamoru, Fujisawa, Kenta, Kawachi, Akiko, Kawai, Nobuyuki, Tamura, Yoichi, Uemura, Makoto, Yatsu, Yoichi, Yoshida, Michitoshi, Utsumi, Yousuke, Tominaga, Nozomu, Morokuma, Tomoki, Tanaka, Masaomi, Asakura, Yuichiro, Matsubayashi, Kazuya, Ohta, Kouji, Abe, Fumio, Chimasu, Sho, Furusawa, Hisanori, Itoh, Ryosuke, Itoh, Yoichi, Kanda, Yuka, Kawabata, Koji S., Kawabata, Miho, Koshida, Shintaro, Koshimoto, Naoki, Kuroda, Daisuke, Moritani, Yuki, Motohara, Kentaro, Murata, Katsuhiro L., Nagayama, Takahiro, Nakaoka, Tatsuya, Nakata, Fumiaki, Nishioka, Tsubasa, Saito, Yoshihiko, Terai, Tsuyoshi, Tristram, Paul J., Yanagisawa, Kenshi, Yasuda, Naoki, Doi, Mamoru, Fujisawa, Kenta, Kawachi, Akiko, Kawai, Nobuyuki, Tamura, Yoichi, Uemura, Makoto, and Yatsu, Yoichi

Abstract

We report the results of optical--infrared follow-up observations of the gravitational wave (GW) event GW151226 detected by the Advanced LIGO in the framework of J-GEM (Japanese collaboration for Gravitational wave ElectroMagnetic follow-up). We performed wide-field optical imaging surveys with Kiso Wide Field Camera (KWFC), Hyper Suprime-Cam (HSC), and MOA-cam3. The KWFC survey started at 2.26 days after the GW event and covered 778 deg$^2$ centered at the high Galactic region of the skymap of GW151226. We started the HSC follow-up observations from 12 days after the event and covered an area of 63.5 deg$^2$ of the highest probability region of the northern sky with the limiting magnitudes of 24.6 and 23.8 for i band and z band, respectively. MOA-cam3 covered 145 deg$^2$ of the skymap with MOA-red filter 2.5 months after the GW alert. Total area covered by the wide-field surveys was 986.5 deg$^2$. The integrated detection probability of all the observed area was $\sim$29%. We also performed galaxy-targeted observations with six optical and near-infrared telescopes from 1.61 days after the event. Total of 238 nearby (<100 Mpc) galaxies were observed with the typical I band limiting magnitude of $\sim$19.5. We detected 13 supernova candidates with the KWFC survey, and 60 extragalactic transients with the HSC survey. Two third of the HSC transients were likely supernovae and the remaining one third were possible active galactic nuclei. With our observational campaign, we found no transients that are likely to be associated with GW151226., Comment: 12 pages, 6 figures, 4 tables, accepted for publication in PASJ

Published
2016
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194. Prime Focus Spectrograph (PFS) for the Subaru Telescope: Overview, recent progress, and future perspectives

Author

Tamura, Naoyuki, Takato, Naruhisa, Shimono, Atsushi, Moritani, Yuki, Yabe, Kiyoto, Ishizuka, Yuki, Ueda, Akitoshi, Kamata, Yukiko, Aghazarian, Hrand, Arnouts, Stephane, Barban, Gabriel, Barkhouser, Robert H., Borges, Renato C., Braun, David F., Carr, Michael A., Chabaud, Pierre-Yves, Chang, Yin-Chang, Chen, Hsin-Yo, Chiba, Masashi, Chou, Richard C. Y., Chu, You-Hua, Cohen, Judith G., de Almeida, Rodrigo P., de Oliveira, Antonio C., de Oliveira, Ligia S., Dekany, Richard G., Dohlen, Kjetil, Santos, Jesulino B. dos, Santos, Leandro H. dos, Ellis, Richard S., Fabricius, Maximilian, Ferrand, Didier, Ferreira, Decio, Golebiowski, Mirek, Greene, Jenny E., Gross, Johannes, Gunn, James E., Hammond, Randolph, Harding, Albert, Hart, Murdock, Heckman, Timothy M., Hirata, Christopher M., Ho, Paul, Hope, Stephen C., Hovland, Larry, Hsu, Shu-Fu, Hu, Yen-Shan, Huang, Ping-Jie, Jaquet, Marc, Jing, Yipeng, Karr, Jennifer, Kimura, Masahiko, King, Matthew E., Komatsu, Eiichiro, Brun, Vincent Le, Fevre, Olivier Le, Fur, Arnaud Le, Mignant, David Le, Ling, Hung-Hsu, Loomis, Craig P., Lupton, Robert H., Madec, Fabrice, Mao, Peter, Marrara, Lucas S., de Oliveira, Claudia Mendes, Minowa, Yosuke, Morantz, Chaz N., Murayama, Hitoshi, Murray, Graham J., Ohyama, Youichi, Orndorff, Joseph, Pascal, Sandrine, Pereira, Jefferson M., Reiley, Daniel J., Reinecke, Martin, Ritter, Andreas, Roberts, Mitsuko, Schwochert, Mark A., Seiffert, Michael D., Smee, Stephen A., Sodre Jr., Laerte, Spergel, David N., Steinkraus, Aaron J., Strauss, Michael A., Surace, Christian, Suto, Yasushi, Suzuki, Nao, Swinbank, John, Tait, Philip J., Takada, Masahiro, Tamura, Tomonori, Tanaka, Yoko, Tresse, Laurence, Verducci Jr., Orlando, Vibert, Didier, Vidal, Clement, Wang, Shiang-Yu, Wen, Chih-Yi, Yan, Chi-Hung, Yasuda, Naoki, Tamura, Naoyuki, Takato, Naruhisa, Shimono, Atsushi, Moritani, Yuki, Yabe, Kiyoto, Ishizuka, Yuki, Ueda, Akitoshi, Kamata, Yukiko, Aghazarian, Hrand, Arnouts, Stephane, Barban, Gabriel, Barkhouser, Robert H., Borges, Renato C., Braun, David F., Carr, Michael A., Chabaud, Pierre-Yves, Chang, Yin-Chang, Chen, Hsin-Yo, Chiba, Masashi, Chou, Richard C. Y., Chu, You-Hua, Cohen, Judith G., de Almeida, Rodrigo P., de Oliveira, Antonio C., de Oliveira, Ligia S., Dekany, Richard G., Dohlen, Kjetil, Santos, Jesulino B. dos, Santos, Leandro H. dos, Ellis, Richard S., Fabricius, Maximilian, Ferrand, Didier, Ferreira, Decio, Golebiowski, Mirek, Greene, Jenny E., Gross, Johannes, Gunn, James E., Hammond, Randolph, Harding, Albert, Hart, Murdock, Heckman, Timothy M., Hirata, Christopher M., Ho, Paul, Hope, Stephen C., Hovland, Larry, Hsu, Shu-Fu, Hu, Yen-Shan, Huang, Ping-Jie, Jaquet, Marc, Jing, Yipeng, Karr, Jennifer, Kimura, Masahiko, King, Matthew E., Komatsu, Eiichiro, Brun, Vincent Le, Fevre, Olivier Le, Fur, Arnaud Le, Mignant, David Le, Ling, Hung-Hsu, Loomis, Craig P., Lupton, Robert H., Madec, Fabrice, Mao, Peter, Marrara, Lucas S., de Oliveira, Claudia Mendes, Minowa, Yosuke, Morantz, Chaz N., Murayama, Hitoshi, Murray, Graham J., Ohyama, Youichi, Orndorff, Joseph, Pascal, Sandrine, Pereira, Jefferson M., Reiley, Daniel J., Reinecke, Martin, Ritter, Andreas, Roberts, Mitsuko, Schwochert, Mark A., Seiffert, Michael D., Smee, Stephen A., Sodre Jr., Laerte, Spergel, David N., Steinkraus, Aaron J., Strauss, Michael A., Surace, Christian, Suto, Yasushi, Suzuki, Nao, Swinbank, John, Tait, Philip J., Takada, Masahiro, Tamura, Tomonori, Tanaka, Yoko, Tresse, Laurence, Verducci Jr., Orlando, Vibert, Didier, Vidal, Clement, Wang, Shiang-Yu, Wen, Chih-Yi, Yan, Chi-Hung, and Yasuda, Naoki

Abstract

PFS (Prime Focus Spectrograph), a next generation facility instrument on the 8.2-meter Subaru Telescope, is a very wide-field, massively multiplexed, optical and near-infrared spectrograph. Exploiting the Subaru prime focus, 2394 reconfigurable fibers will be distributed over the 1.3 deg field of view. The spectrograph has been designed with 3 arms of blue, red, and near-infrared cameras to simultaneously observe spectra from 380nm to 1260nm in one exposure at a resolution of ~1.6-2.7A. An international collaboration is developing this instrument under the initiative of Kavli IPMU. The project is now going into the construction phase aiming at undertaking system integration in 2017-2018 and subsequently carrying out engineering operations in 2018-2019. This article gives an overview of the instrument, current project status and future paths forward., Comment: 17 pages, 10 figures. Proceeding of SPIE Astronomical Telescopes and Instrumentation 2016

Published
2016
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195. Photometric properties of intermediate redshift Type Ia Supernovae observed by SDSS-II Supernova Survey

Author

Takanashi, Naohiro, Doi, Mamoru, Yasuda, Naoki, Kuncarayakti, Hanindyo, Konishi, Kohki, Schneider, Donald P., Cinabro, David, Marriner, John, Takanashi, Naohiro, Doi, Mamoru, Yasuda, Naoki, Kuncarayakti, Hanindyo, Konishi, Kohki, Schneider, Donald P., Cinabro, David, and Marriner, John

Abstract

We have analyzed multi-band light curves of 328 intermediate redshift (0.05 <= z < 0.24) type Ia supernovae (SNe Ia) observed by the Sloan Digital Sky Survey-II Supernova Survey (SDSS-II SN Survey). The multi-band light curves were parameterized by using the Multi-band Stretch Method, which can simply parameterize light curve shapes and peak brightness without dust extinction models. We found that most of the SNe Ia which appeared in red host galaxies (u - r > 2.5) don't have a broad light curve width and the SNe Ia which appeared in blue host galaxies (u - r < 2.0) have a variety of light curve widths. The Kolmogorov-Smirnov test shows that the colour distribution of SNe Ia appeared in red / blue host galaxies is different (significance level of 99.9%). We also investigate the extinction law of host galaxy dust. As a result, we find the value of Rv derived from SNe Ia with medium light curve width is consistent with the standard Galactic value. On the other hand, the value of Rv derived from SNe Ia that appeared in red host galaxies becomes significantly smaller. These results indicate that there may be two types of SNe Ia with different intrinsic colours, and they are obscured by host galaxy dust with two different properties., Comment: 21 pages, 15 figures, accepted for publication in MNRAS

Published
2016
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196. A new quadruple gravitational lens from the Hyper Suprime-Cam Survey: the puzzle of HSC~J115252+004733

Author

More, Anupreeta, Lee, Chien-Hsiu, Oguri, Masamune, Ono, Yoshiaki, Suyu, Sherry H., Chan, James H. H., Silverman, John D., More, Surhud, Schulze, Andreas, Komiyama, Yutaka, Matsuoka, Yoshiki, Miyazaki, Satoshi, Nagao, Tohru, Ouchi, Masami, Tait, Philip J., Tanaka, Manobu M., Tanaka, Masayuki, Usuda, Tomonori, Yasuda, Naoki, More, Anupreeta, Lee, Chien-Hsiu, Oguri, Masamune, Ono, Yoshiaki, Suyu, Sherry H., Chan, James H. H., Silverman, John D., More, Surhud, Schulze, Andreas, Komiyama, Yutaka, Matsuoka, Yoshiki, Miyazaki, Satoshi, Nagao, Tohru, Ouchi, Masami, Tait, Philip J., Tanaka, Manobu M., Tanaka, Masayuki, Usuda, Tomonori, and Yasuda, Naoki

Abstract

We report the serendipitous discovery of a quadruply lensed source at $z_{\rm s}=3.76$, HSC~J115252+004733, from the Hyper Suprime-Cam (HSC) Survey. The source is lensed by an early-type galaxy at $z_{\rm l}=0.466$ and a satellite galaxy. Here, we investigate the properties of the source by studying its size and luminosity from the imaging and the luminosity and velocity width of the Ly-$\alpha$ line from the spectrum. Our analyses suggest that the source is most probably a low-luminosity active galactic nucleus (LLAGN) but the possibility of it being a compact bright galaxy (e.g., a Lyman-$\alpha$ emitter or Lyman Break Galaxy) cannot be excluded. The brighter pair of lensed images appears point-like except in the HSC $i$-band (with a seeing $\sim0.5"$). The extended emission in the $i$-band image could be due to the host galaxy underneath the AGN, or alternatively, due to a highly compact lensed galaxy (without AGN) which appears point-like in all bands except in $i$-band. We also find that the flux ratio of the brighter pair of images is different in the Ks-band compared to optical wavelengths. Phenomena such as differential extinction and intrinsic variability cannot explain this chromatic variation. While microlensing from stars in the foreground galaxy is less likely to be the cause, it cannot be ruled out completely. If the galaxy hosts an AGN, then this represents the highest redshift quadruply imaged AGN known to date, enabling study of a distant LLAGN. Discovery of this unusually compact and faint source demonstrates the potential of the HSC survey., Comment: 9 pages, 7 figures, 3 Tables, MNRAS accepted, text reduced

Published
2016
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197. The survey operation software system development for Prime Focus Spectrograph (PFS) on Subaru Telescope

Author

Shimono, Atsushi, Tamura, Naoyuki, Takato, Naruhisa, Yasuda, Naoki, Suzuki, Nao, Loomis, Craig P., Lupton, Robert H., Moritani, Yuki, Yabe, Kiyoto, Shimono, Atsushi, Tamura, Naoyuki, Takato, Naruhisa, Yasuda, Naoki, Suzuki, Nao, Loomis, Craig P., Lupton, Robert H., Moritani, Yuki, and Yabe, Kiyoto

Abstract

The Prime Focus Spectrograph (PFS) is a wide-field, multi-object spectrograph accommodating 2394 fibers to observe the sky at the prime focus of the Subaru telescope. The software system to operate a spectroscopic survey is structured by the four packages: Instrument control software, exposure targeting software, data reduction pipeline, and survey planning and tracking software. In addition, we operate a database system where various information such as properties of target objects, instrument configurations, and observation conditions is stored and is organized via a standardized data model for future references to update survey plans and to scientific researches. In this article, we present an overview of the software system and describe the workflows that need to be performed in the PFS operation, with some highlights on the database that organizes various information from sub-processes in the survey operation, and on the process of fiber configuration from the software perspectives., Comment: 9 pages, 5 figures; SPIE (2016) 9913-88

Published
2016
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198. An Effective Selection Method for Low-Mass Active Black Holes and First Spectroscopic Identification

Author

Morokuma, Tomoki, Tominaga, Nozomu, Tanaka, Masaomi, Yasuda, Naoki, Furusawa, Hisanori, Taniguchi, Yuki, Kato, Takahiro, Jiang, Ji-an, Nagao, Tohru, Kuncarayakti, Hanindyo, Morokuma-Matsui, Kana, Ikeda, Hiroyuki, Blinnikov, Sergei, Nomoto, Ken'ichi, Kokubo, Mitsuru, Doi, Mamoru, Morokuma, Tomoki, Tominaga, Nozomu, Tanaka, Masaomi, Yasuda, Naoki, Furusawa, Hisanori, Taniguchi, Yuki, Kato, Takahiro, Jiang, Ji-an, Nagao, Tohru, Kuncarayakti, Hanindyo, Morokuma-Matsui, Kana, Ikeda, Hiroyuki, Blinnikov, Sergei, Nomoto, Ken'ichi, Kokubo, Mitsuru, and Doi, Mamoru

Abstract

We present a new method to effectively select objects which may be low-mass active black holes (BHs) at galaxy centers using high-cadence optical imaging data, and our first spectroscopic identification of an active 2.7x10^6 Msun BH at z=0.164. This active BH was originally selected due to its rapid optical variability, from a few hours to a day, based on Subaru Hyper Suprime-Cam~(HSC) g-band imaging data taken with 1-hour cadence. Broad and narrow H-alpha and many other emission lines are detected in our optical spectra taken with Subaru FOCAS, and the BH mass is measured via the broad H-alpha emission line width (1,880 km s^{-1}) and luminosity (4.2x10^{40} erg s^{-1}) after careful correction for the atmospheric absorption around 7,580-7,720A. We measure the Eddington ratio to be as low as 0.05, considerably smaller than those in a previous SDSS sample with similar BH mass and redshift, which indicates one of the strong potentials of our Subaru survey. The g-r color and morphology of the extended component indicate that the host galaxy is a star-forming galaxy. We also show effectiveness of our variability selection for low-mass active BHs., Comment: 11 pages, 5 figures, 2 tables. accepted for publication in PASJ

Published
2016
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199. A New Constraint on the Ly$\alpha$ Fraction of UV Very Bright Galaxies at Redshift 7

Author

Furusawa, Hisanori, Kashikawa, Nobunari, Kobayashi, Masakazu A. R., Dunlop, James S., Shimasaku, Kazuhiro, Takata, Tadafumi, Sekiguchi, Kazuhiro, Naito, Yoshiaki, Furusawa, Junko, Ouchi, Masami, Nakata, Fumiaki, Yasuda, Naoki, Okura, Yuki, Taniguchi, Yoshiaki, Yamada, Toru, Kajisawa, Masaru, Fynbo, Johan P. U., Fevre, Olivier Le, Furusawa, Hisanori, Kashikawa, Nobunari, Kobayashi, Masakazu A. R., Dunlop, James S., Shimasaku, Kazuhiro, Takata, Tadafumi, Sekiguchi, Kazuhiro, Naito, Yoshiaki, Furusawa, Junko, Ouchi, Masami, Nakata, Fumiaki, Yasuda, Naoki, Okura, Yuki, Taniguchi, Yoshiaki, Yamada, Toru, Kajisawa, Masaru, Fynbo, Johan P. U., and Fevre, Olivier Le

Abstract

We study the extent to which very bright (-23.0 < MUV < -21.75) Lyman-break selected galaxies at redshifts z~7 display detectable Lya emission. To explore this issue, we have obtained follow-up optical spectroscopy of 9 z~7 galaxies from a parent sample of 24 z~7 galaxy candidates selected from the 1.65 sq.deg COSMOS-UltraVISTA and SXDS-UDS survey fields using the latest near-infrared public survey data, and new ultra-deep Subaru z'-band imaging (which we also present and describe in this paper). Our spectroscopy has yielded only one possible detection of Lya at z=7.168 with a rest-frame equivalent width EW_0 = 3.7 (+1.7/-1.1) Angstrom. The relative weakness of this line, combined with our failure to detect Lya emission from the other spectroscopic targets allows us to place a new upper limit on the prevalence of strong Lya emission at these redshifts. For conservative calculation and to facilitate comparison with previous studies at lower redshifts, we derive a 1-sigma upper limit on the fraction of UV bright galaxies at z~7 that display EW_0 > 50 Angstrom, which we estimate to be < 0.23. This result may indicate a weak trend where the fraction of strong Lya emitters ceases to rise, and possibly falls between z~6 and z~7. Our results also leave open the possibility that strong Lya may still be more prevalent in the brightest galaxies in the reionization era than their fainter counterparts. A larger spectroscopic sample of galaxies is required to derive a more reliable constraint on the neutral hydrogen fraction at z~7 based on the Lya fraction in the bright galaxies., Comment: 20 pages, 7 figures, accepted for publication in ApJ

Published
2016
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200. Rapidly Rising Transients from Subaru Hyper Suprime-Cam Transient Survey

Author

Tanaka, Masaomi, Tominaga, Nozomu, Morokuma, Tomoki, Yasuda, Naoki, Furusawa, Hisanori, Baklanov, Petr V., Blinnikov, Sergei I., Moriya, Takashi J., Doi, Mamoru, Jiang, Ji-an, Kato, Takahiro, Kikuchi, Yuki, Kuncarayakti, Hanindyo, Nagao, Tohru, Nomoto, Ken'ichi, Taniguchi, Yuki, Tanaka, Masaomi, Tominaga, Nozomu, Morokuma, Tomoki, Yasuda, Naoki, Furusawa, Hisanori, Baklanov, Petr V., Blinnikov, Sergei I., Moriya, Takashi J., Doi, Mamoru, Jiang, Ji-an, Kato, Takahiro, Kikuchi, Yuki, Kuncarayakti, Hanindyo, Nagao, Tohru, Nomoto, Ken'ichi, and Taniguchi, Yuki

Abstract

We present rapidly rising transients discovered by a high-cadence transient survey with Subaru telescope and Hyper Suprime-Cam. We discovered five transients at z=0.384-0.821 showing the rising rate faster than 1 mag per 1 day in the restframe near-ultraviolet wavelengths. The fast rising rate and brightness are the most similar to SN 2010aq and PS1-13arp, for which the ultraviolet emission within a few days after the shock breakout was detected. The lower limit of the event rate of rapidly rising transients is ~9 % of core-collapse supernova rates, assuming a duration of rapid rise to be 1 day. We show that the light curves of the three faint objects agree with the cooling envelope emission from the explosion of red supergiants. The other two luminous objects are, however, brighter and faster than the cooling envelope emission. We interpret these two objects to be the shock breakout from dense wind with the mass loss rate of ~10^{-3} Msun yr^{-1}, as also proposed for PS1-13arp. This mass loss rate is higher than that typically observed for red supergiants. The event rate of these luminous objects is >~1 % of core-collapse supernova rate, and thus, our study implies that more than ~1 % of massive stars can experience an intensive mass loss at a few years before the explosion., Comment: 15 pages, 11 figures, accepted for publication in ApJ

Published
2016
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