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73 results on '"Yan, Chi-Hung"'

51. The metrology cameras for Subaru PFS and FMOS

Author

Wang, Shiang-Yu, primary, Hu, Yen-Shan, additional, Yan, Chi-Hung, additional, Chang, Yin-Chang, additional, Tamura, Naoyuki, additional, Takato, Naruhisa, additional, Shimono, Atsushi, additional, Karr, Jennifer, additional, Ohyama, Youichi, additional, Chen, Hsin-Yo, additional, Ling, Hung-Hsu, additional, Karoji, Hiroshi, additional, Sugai, Hajime, additional, and Ueda, Akitoshi, additional

Published
2012
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52. Prime focus spectrograph: Subaru's future

Author

Sugai, Hajime, primary, Karoji, Hiroshi, additional, Takato, Naruhisa, additional, Tamura, Naoyuki, additional, Shimono, Atsushi, additional, Ohyama, Youichi, additional, Ueda, Akitoshi, additional, Ling, Hung-Hsu, additional, Vital de Arruda, Marcio, additional, Barkhouser, Robert H., additional, Bennett, Charles L., additional, Bickerton, Steve, additional, Braun, David F., additional, Bruno, Robin J., additional, Carr, Michael A., additional, Batista de Carvalho Oliveira, João, additional, Chang, Yin-Chang, additional, Chen, Hsin-Yo, additional, Dekany, Richard G., additional, Pereira Dominici, Tania, additional, Ellis, Richard S., additional, Fisher, Charles D., additional, Gunn, James E., additional, Heckman, Timothy, additional, Ho, Paul T. P., additional, Hu, Yen-Shan, additional, Jaquet, Marc, additional, Karr, Jennifer, additional, Kimura, Masahiko, additional, Le Fèvre, Olivier C., additional, Le Mignant, David, additional, Loomis, Craig, additional, Lupton, Robert H., additional, Madec, Fabrice, additional, Marrara, Lucas, additional, Martin, Laurent, additional, Murayama, Hitoshi, additional, Cesar de Oliveira, Antonio, additional, Mendes de Oliveira, Claudia, additional, Souza de Oliveira, Ligia, additional, Orndorff, Joseph D., additional, de Paiva Vilaça, Rodrigo M. P., additional, Macanhan, Vanessa B. d. P., additional, Prieto, Eric, additional, Bispo dos Santos, Jesulino, additional, Seiffert, Michael, additional, Smee, Stephen A., additional, Smith, Roger M., additional, Sodré, Laerte, additional, Spergel, David N., additional, Surace, Christian, additional, Vives, Sebastien, additional, Wang, Shiang-Yu, additional, and Yan, Chi-Hung, additional

Published
2012
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53. CLUSTERING PROPERTIES OF BzK-SELECTED GALAXIES IN GOODS-N: ENVIRONMENTAL QUENCHING AND TRIGGERING OF STAR FORMATION ATz∼ 2

Author

Lin, Lihwai, primary, Dickinson, Mark, additional, Jian, Hung-Yu, additional, Merson, A. I., additional, Baugh, C. M., additional, Scott, Douglas, additional, Foucaud, Sebastien, additional, Wang, Wei-Hao, additional, Yan, Chi-Hung, additional, Yan, Hao-Jing, additional, Cheng, Yi-Wen, additional, Guo, Yicheng, additional, Helly, John, additional, Kirsten, Franz, additional, Koo, David C., additional, Lagos, Claudia del P., additional, Meger, Nicole, additional, Messias, Hugo, additional, Pope, Alexandra, additional, Simard, Luc, additional, Grogin, Norman A., additional, and Wang, Shiang-Yu, additional

Published
2012
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54. IS FS Tau B DRIVING AN ASYMMETRIC JET?

Author

Liu, Chun-Fan, primary, Shang, Hsien, additional, Pyo, Tae-Soo, additional, Takami, Michihiro, additional, Walter, Frederick M., additional, Yan, Chi-Hung, additional, Wang, Shiang-Yu, additional, Ohashi, Nagayoshi, additional, and Hayashi, Masahiko, additional

Published
2012
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58. A MOLECULAR HYDROGEN NEBULA IN THE CENTRAL cD GALAXY OF THE PERSEUS CLUSTER

Author

Youichi Ohyama, Jeremy Lim, Wang Shiang-Yu, Dinh-V-Trung, and Yan Chi-Hung

Subjects
Physics, Nebula, Astrophysics::High Energy Astrophysical Phenomena, Astronomy, Astronomy and Astrophysics, Type-cD galaxy, Extragalactic astronomy, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Radius, Galaxy, Luminosity, Space and Planetary Science, Astrophysics::Galaxy Astrophysics, Galaxy cluster, Line (formation)
Abstract

We report narrowband imaging of the 1–0S(1) ro-vibrational transition of molecular hydrogen (H2) from NGC 1275, the central cD galaxy of the Perseus Cluster. We find that the H2 gas has a spatial morphology identical to the optical emission-line nebula associated with this galaxy, a total luminosity in H2 1–0 S(1) only an order of magnitude less than in Hα, and if the line-emitting gas is thermalized a mass (at ∼2000 K) that is over two orders of magnitude smaller than that of the optical emission-line nebula (at ∼10,000 K). The ratio in H2 1–0 S(1) to Hα +[ Nii] line intensities spans a characteristic range of ∼0.02–0.08 throughout the nebula; the brighter inner nebula exhibits patches with (nearly) constant line ratios unrelated to individual filaments. Recent models proposed to explain the peculiar nebular spectrum from the optical to infrared invoke thermalized along with non-thermalized injection of energy from ionizing particles. The energy density of highly relativistic electrons inferred to cause inverse-Compton scattering of hard X-ray emission from the core of the Perseus Cluster decreases steeply beyond a central radius of ∼20 kpc, yet we do not find any changes in the average or range spanned by the H2 1–0 S(1) to Hα +[ Nii] line ratio between the inner (20 kpc) and outer (∼20–50 kpc) nebulae. On the other hand, saturated conduction from the surrounding X-ray gas produces, in the absence of magnetic fields, a heat flux that is approximately constant throughout the nebula: the change in the line ratio with position would then reflect the ability of the X-ray gas to penetrate presumably magnetically threaded filaments at different locations.

Published
2011

59. Development of a highly accurate OCR system by neural network approach

Author

Gary M. T. Man, Joe C. H. Poon, and Yan Chi Hung

Subjects
Artificial neural network, business.industry, Computer science, Feature extraction, Normalization (image processing), Pattern recognition, Optical character recognition, Image segmentation, computer.software_genre, Machine learning, Backpropagation, Segmentation, Artificial intelligence, business, Gradient descent, computer
Abstract

We have developed an application software system for font and size invariant optical character recognition (OCR). A preliminary front-end process, which handles gray scale normalization, noise elimination, line finding, and character block segmentation, has been included in our system. But the main characteristic of our system is that we adopt a Fourier descriptors (FDs) based feature extraction approach and a multicategory back-propagation neural network classifier for the recognition. Instead of using one set of FDs to represent the image object as in conventional FDs approach, we use three sets of FDs to represent different portions of the object. We find this approach can solve the intrinsic problem of FDs caused by their rotational and reflectional invariance properties. Thus, our existing method can correctly classify ambiguous characters like 5, 2, p, q, etc. Our system will become a primitive building block for later more complex OCR systems. In general, the back propagation provides a gradient descent optimization in training. Without prior knowledge of the mathematical relation between the input and output, the network is highly efficient to map a large variety set of input patterns to an arbitrary set of output patterns after successful training. Thus, the system is not only capable of understanding printed English text and isolated cursive scripts, but also can be extended to read other symbols at the expense of additional training time. At present, a 99.8 percent rate of recognition accuracy has already been achieved for trained English samples in our experiment.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Published
1993

61. The Nature of FaintSpitzer‐selected Dust‐obscured Galaxies

Author

Pope, Alexandra, primary, Bussmann, R. Shane, additional, Dey, Arjun, additional, Meger, Nicole, additional, Alexander, David M., additional, Brodwin, Mark, additional, Chary, Ranga‐Ram, additional, Dickinson, Mark E., additional, Frayer, David T., additional, Greve, Thomas R., additional, Huynh, Minh, additional, Lin, Lihwai, additional, Morrison, Glenn, additional, Scott, Douglas, additional, and Yan, Chi‐Hung, additional

Published
2008
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64. A search for interstellar pyrimidine

Author

Kuan, Yi-Jehng, primary, Yan, Chi-Hung, additional, Charnley, Steven B., additional, Kisiel, Zbigniew, additional, Ehrenfreund, Pascale, additional, and Huang, Hui-Chun, additional

Published
2003
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65. Prime Focus Spectrograph (PFS) for the Subaru telescope: overview, recent progress, and future perspectives

Author

Evans, Christopher J., Simard, Luc, Takami, Hideki, Tamura, Naoyuki, Takato, Naruhisa, Shimono, Atsushi, Moritani, Yuki, Yabe, Kiyoto, Ishizuka, Yuki, Ueda, Akitoshi, Kamata, Yukiko, Aghazarian, Hrand, Arnouts, Stéphane, 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, de Almeida, Rodrigo P., de Oliveira, Antonio C., de Oliveira, Ligia S., Dekany, Richard G., Dohlen, Kjetil, dos Santos, Jesulino B., dos Santos, Leandro H., Ellis, Richard, Fabricius, Maximilian, Ferrand, Didier, Ferreira, Décio, 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, Le Brun, Vincent, Le Fèvre, Olivier, Le Fur, Arnaud, Le Mignant, David, Ling, Hung-Hsu, Loomis, Craig P., Lupton, Robert H., Madec, Fabrice, Mao, Peter, Marrara, Lucas S., Mendes de Oliveira, Claudia, Minowa, Yosuke, Morantz, Chaz, Murayama, Hitoshi, Murray, Graham J., Ohyama, Youichi, Orndorff, Joseph, Pascal, Sandrine, Pereira, Jefferson M., Reiley, Daniel, Reinecke, Martin, Ritter, Andreas, Roberts, Mitsuko, Schwochert, Mark A., Seiffert, Michael D., Smee, Stephen A., Sodre, 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, Orlando, Vibert, Didier, Vidal, Clement, Wang, Shiang-Yu, Wen, Chih-Yi, Yan, Chi-Hung, and Yasuda, Naoki

Published
2016
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66. TIME MONITORING OF RADIO JETS AND MAGNETOSPHERES IN THE NEARBY YOUNG STELLAR CLUSTER R CORONAE AUSTRALIS.

Author

Liu, Hauyu Baobab, Galván-Madrid, Roberto, Forbrich, Jan, Rodríguez, Luis F., Takami, Michihiro, Costigan, Gráinne, Manara, Carlo Felice, Yan, Chi-Hung, Karr, Jennifer, Chou, Mei-Yin, Ho, Paul T.-P., and Zhang, Qizhou

Subjects
CIRCUMSTELLAR matter, STAR formation, STELLAR magnetic fields, STAR observations, ACCRETION (Astrophysics), PROTOPLANETARY disks
Abstract

We report Karl G. Jansky Very Large Array 8-10 GHz (λ = 3.0-3.7 cm) monitoring observations toward the young stellar object (YSO) cluster R Coronae Australis (R CrA), taken from 2012 March 15 to 2012 September 12. These observations were planned to measure the radio flux variabilities in timescales from 0.5 hr to several days, to tens of days, and up to ∼200 days. We found that among the YSOs detectable in individual epochs, in general, the most reddened objects in the Spitzer observations show the highest mean 3.5 cm Stokes I emission, and the lowest fractional variabilities on <200 day timescales. The brightest radio flux emitters in our observations are the two reddest sources IRS7W and IRS7E. In addition, by comparing our observations with observations taken from 1996 to 1998 and 2005, we found that the radio fluxes of these two sources have increased by a factor of ∼1.5. The mean 3.5 cm fluxes of the three Class I/II sources, IRSI, IRS2, and IRS6, appear to be correlated with their accretion rates derived by a previous near-infrared line survey. The weakly accreting Class I/II YSOs, or those in later evolutionary stages, present radio flux variability on <0.5 hr timescales. Some YSOs were detected only during occasional flaring events. The source R CrA went below our detection limit during a few fading events. [ABSTRACT FROM AUTHOR]

Published
2014
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67. A MOLECULAR HYDROGEN NEBULA IN THE CENTRAL cD GALAXY OF THE PERSEUS CLUSTER.

Author

Lim, Jeremy, Ohyama, Youichi, Yan Chi-Hung, Dinh-V-Trung, and Wang Shiang-Yu

Subjects
GALAXY clusters, NEBULAE, X-ray astronomy, X-ray spectroscopy, MAGNETIC fields
Abstract

We report narrowband imaging of the 1-0 S(1) ro-vibrational transition of molecular hydrogen (H2) from NGC 1275, the central cD galaxy of the Perseus Cluster. We find that the H2 gas has a spatial morphology identical to the optical emission-line nebula associated with this galaxy, a total luminosity in H2 1-0 S(1) only an order of magnitude less than in Hα, and if the line-emitting gas is thermalized a mass (at ~2000 K) that is over two orders of magnitude smaller than that of the optical emission-line nebula (at ~ 10,000 K). The ratio in H2 1-0 S(1) to Hα + [N II] line intensities spans a characteristic range of ~0.02-0.08 throughout the nebula; the brighter inner nebula exhibits patches with (nearly) constant line ratios unrelated to individual filaments. Recent models proposed to explain the peculiar nebular spectrum from the optical to infrared invoke thermalized along with non-thermalized injection of energy from ionizing particles. The energy density of highly relativistic electrons inferred to cause inverse-Compton scattering of hard X-ray emission from the core of the Perseus Cluster decreases steeply beyond a central radius of ~20 kpc, yet we do not find any changes in the average or range spanned by the H2 1-0 S(1) to Hα + [N II] line ratio between the inner (≲20 kpc) and outer (~20-50 kpc) nebulae. On the other hand, saturated conduction from the surrounding X-ray gas produces, in the absence of magnetic fields, a heat flux that is approximately constant throughout the nebula: the change in the line ratio with position would then reflect the ability of the X-ray gas to penetrate presumably magnetically threaded filaments at different locations. [ABSTRACT FROM AUTHOR]

Published
2012
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68. Prime Focus Spectrograph (PFS) for the Subaru Telescope: its start of the last development phase

Author

Evans, Christopher J., Bryant, Julia J., Motohara, Kentaro, Tamura, Naoyuki, Moritani, Yuki, Yabe, Kiyoto, Ishizuka, Yuki, Kamata, Yukiko, Allaoui, Ali, Arai, Akira, Arnouts, Stéphane, Barkhouser, Robert H., Barette, Rudy, Blanchard, Patrick, Bergeron, Eddie, Caplar, Neven, Chabaud, Pierre-Yves, Chang, Yin-Chang, Chen, Hsin-Yo, Chou, Chueh-Yi, Chu, You-Hua, Cohen, Judith G., da Costa, Richardo L., Crauchet, Thibaut, de Almeida, Rodrigo P., de Oliveira, Antonio C., de Oliveira, Ligia S., Dohlen, Kjetil, dos Santos, Leandro H., Ellis, Richard S., Fabricius, Maximilian, Ferreira, Décio, Furusawa, Hisanori, Givans, Jahmour J., Garciá-Carpio, Javier, Golebiowski, Mirek, Gray, Aidan, Gunn, James E., Hamano, Satoshi, Hammond, Randolph P., Harding, Albert, Hayashi, Kota, He, Wanqiu, Heckman, Timothy M., Hope, Stephen C., Hsu, Shu-Fu, Hu, Yen-Shan, Huang, Pin Jie, Ishigaki, Miho N., Jeschke, Eric, Jing, Yipeng, Kado-Fong, Erin, Karr, Jennifer L., Kawanomoto, Satoshi, Kimura, Masahiko, Koike, Michitaro, Komatsu, Eiichiro, Koshida, Shintaro, Le Brun, Vincent, Le Fur, Arnaud, Le Mignant, David, Lhoussaine, Romain, Lin, Yen-Ting, Ling, Hung-Hsu, Loomis, Craig P., Lupton, Robert H., Madec, Fabrice, Marchesini, Danilo, Marguerite, Edouard, Marrara, Lucas S., Medvedev, Dmitry, Mineo, Sogo, Miyazaki, Satoshi, Morishima, Takahiro, Murata, Kazumi, Murayama, Hitoshi, Murray, Graham J., Okita, Hirofumi, Onodera, Masato, Peebles, Joshua, Price, Paul, Pyo, Tae-Soo, Ramos, Lucio, Reiley, Daniel J., Reinecke, Martin, Roberts, Mitsuko, Rosa, Josimar A., Rousselle, Julien P., Sarkis, Mira, Seiffert, Michael D., Schubert, Kiaina, Siddiqui, Hassan, Smee, Stephen A., Sodré, Laerte, Strauss, Michael A., Surace, Christian, Taghizadeh Popp, Manuchehr, Tait, Philip J., Takada, Masahiro, Takagi, Yuhei, Tanaka, Masayuki, Tanaka, Yoko, Thakar, Aniruddha R., Vibert, Didier, Wang, Shiang-Yu, Wen, Chih-Yi, Werner, Suzanne, Wung, Matthew, Lemson, Gerald, Mitschang, Arik, Yasuda, Naoki, Yoshida, Hiroshige, Yan, Chi-Hung, Yoshida, Michitoshi, and Yamashita, Takuji

Published
2022
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69. Metrology camera system of prime focus spectrograph for Subaru telescope

Author

Ramsay, Suzanne K., McLean, Ian S., Takami, Hideki, Wang, Shiang-Yu, Chou, Chueh-Yi, Chang, Yin-Chang, Huang, Pin-Jie, Hu, Yen-Sang, Chen, Hsin-Yo, Tamura, Naoyuki, Takato, Naruhisa, Ling, Hung-Hsu, Gunn, James E., Karr, Jennifer, Yan, Chi-Hung, Mao, Peter, Ohyama, Youichi, Karoji, Hiroshi, Sugai, Hajime, and Shimono, Atsushi

Published
2014
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70. Progress with the Prime Focus Spectrograph for the Subaru Telescope: a massively multiplexed optical and near-infrared fiber spectrograph

Author

Ramsay, Suzanne K., McLean, Ian S., Takami, Hideki, Sugai, Hajime, Tamura, Naoyuki, Karoji, Hiroshi, Shimono, Atsushi, Takato, Naruhisa, Kimura, Masahiko, Ohyama, Youichi, Ueda, Akitoshi, Aghazarian, Hrand, de Arruda, Marcio V., Barkhouser, Robert H., Bennett, Charles L., Bickerton, Steve, Bozier, Alexandre, Braun, David F., Bui, Khanh, Capocasale, Christopher M., Carr, Michael A., Castilho, Bruno, Chang, Yin-Chang, Chen, Hsin-Yo, Chou, Richard C. Y., Dawson, Olivia R., Dekany, Richard G., Ek, Eric M., Ellis, Richard S., English, Robin J., Ferrand, Didier, Ferreira, Décio, Fisher, Charles D., Golebiowski, Mirek, Gunn, James E., Hart, Murdock, Heckman, Timothy M., Ho, Paul T. P., Hope, Stephen, Hovland, Larry E., Hsu, Shu-Fu, Hu, Yen-Sang, Huang, Pin Jie, Jaquet, Marc, Karr, Jennifer E., Kempenaar, Jason G., King, Matthew E., Le Fèvre, Olivier, Le Mignant, David, Ling, Hung-Hsu, Loomis, Craig, Lupton, Robert H., Madec, Fabrice, Mao, Peter, Marrara, Lucas S., Ménard, Brice, Morantz, Chaz, Murayama, Hitoshi, Murray, Graham J., de Oliveira, Antonio Cesar, de Oliveira, Claudia M., de Oliveira, Ligia S., Orndorff, Joe D., de Paiva Vilaça, Rodrigo, Partos, Eamon J., Pascal, Sandrine, Pegot-Ogier, Thomas, Reiley, Daniel J., Riddle, Reed, Santos, Leandro, dos Santos, Jesulino B., Schwochert, Mark A., Seiffert, Michael D., Smee, Stephen A., Smith, Roger M., Steinkraus, Ronald E., Sodré, Laerte, Spergel, David N., Surace, Christian, Tresse, Laurence, Vidal, Clément, Vives, Sebastien, Wang, Shiang-Yu, Wen, Chih-Yi, Wu, Amy C., Wyse, Rosie, and Yan, Chi-Hung

Published
2014
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73. CLUSTERING PROPERTIES OF BzK-SELECTED GALAXIES IN GOODS-N: ENVIRONMENTAL QUENCHING AND TRIGGERING OF STAR FORMATION AT z ∼ 2.

Author

Lin, Lihwai, Dickinson, Mark, Jian, Hung-Yu, Merson, A. I., Baugh, C. M., Scott, Douglas, Foucaud, Sebastien, Wang, Wei-Hao, Yan, Chi-Hung, Yan, Hao-Jing, Cheng, Yi-Wen, Guo, Yicheng, Helly, John, Kirsten, Franz, Koo, David C., Lagos, Claudia del P., Meger, Nicole, Messias, Hugo, Pope, Alexandra, and Simard, Luc

Subjects
GALAXIES, STAR formation, STELLAR mass, METAPHYSICAL cosmology, GALACTIC halos
Abstract

Using a sample of BzK-selected galaxies at z ∼ 2 identified from the CFHT/WIRCAM near-infrared survey of GOODS-North, we discuss the relation between star formation rate (SFR), specific star formation rate (SSFR), and stellar mass (M*), and the clustering of galaxies as a function of these parameters. For star-forming galaxies (sBzKs), the UV-based SFR, corrected for extinction, scales with the stellar mass as SFR∝Mα* with α = 0.74 ± 0.20 down to M* ∼ 109M☼, indicating a weak dependence on the stellar mass of the SFR efficiency, namely, SSFR. We also measure the angular correlation function and hence infer the correlation length for sBzK galaxies as a function of M*, SFR, and SSFR, as well as K-band apparent magnitude. We show that passive galaxies (pBzKs) are more strongly clustered than sBzK galaxies at a given stellar mass, mirroring the color-density relation seen at lower redshifts. We also find that the correlation length of sBzK galaxies ranges from 4 to 20 h–1 Mpc, being a strong function of MK, M*, and SFR. On the other hand, the clustering dependence on SSFR changes abruptly at 2 × 10–9 yr–1, which is the typical value for “main-sequence” star-forming galaxies at z ∼ 2. We show that the correlation length reaches a minimum at this characteristic value, and is larger for galaxies with both smaller and larger SSFRs; a dichotomy that is only marginally implied from the predictions of the semi-analytical models. Our results suggest that there are two types of environmental effects at work at z ∼ 2. Stronger clustering for relatively quiescent galaxies implies that the environment has started to play a role in quenching star formation. At the same time, stronger clustering for galaxies with elevated SSFRs (“starbursts”) might be attributed to an increased efficiency for galaxy interactions and mergers in dense environments. [ABSTRACT FROM AUTHOR]

Published
2012
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