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Search Results: 1 - 10 of 798 matches for " Masaru Hamabe "
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Clustering Properties of Galaxies at z~4 in the Subaru/XMM Deep Survey Field
Masami Ouchi,Kazuhiro Shimasaku,Sadanori Okamura,Mamoru Doi,Hisanori Furusawa,Masaru Hamabe,Masahiko Kimura,Yutaka Komiyama,Masayuki Miyazaki,Satoshi Miyazaki,Fumiaki Nakata,Maki Sekiguchi,Masafumi Yagi,Naoki Yasuda
Physics , 2001, DOI: 10.1086/323598
Abstract: We study the clustering properties of about 1200 z~4 Lyman Break Galaxy (LBG) candidates with i'<26 which are selected by color from deep BRi' imaging data of a 618 arcmin^2 area in the Subaru/XMM-Newton Deep Field taken with Subaru Prime Focus Camera. The contamination and completeness of our LBG sample are evaluated, on the basis of the Hubble Deep Field North (HDFN) objects, to be 17% and 45%, respectively. We derive the angular correlation function over theta = 2''-1000'', and find that it is fitted fairly well by a power law, omega(theta)=A_omega theta^{-0.8}, with A_omega = 0.71 +/- 0.26. We then calculate the correlation length r0 (in comoving units) of the two-point spatial correlation function xi(r) = (r/r0)^{-1.8} from A_omega using the redshift distribution of LBGs derived from the HDFN, and find r0=2.7 (+0.5/-0.6) h^{-1} Mpc in a Lambda-dominated universe (Omega_m=0.3 and Omega_Lambda=0.7). This is twice larger than the correlation length of the dark matter at z~4 predicted from an analytic model by Peacock & Dodds but about twice smaller than that of bright galaxies predicted by a semi-analytic model of Baugh et al. We find an excess of omega(theta) on small scales (theta < 5'') departing from the power law fit over 3 sigma significance levels. Interpreting this as due to galaxy mergers, we estimate the fraction of galaxies undergoing mergers in our LBG sample to be 3.0 +/- 0.9%, which is significantly smaller than those of galaxies at intermediate redshifts.
Statistical Properties of Lyman Break Galaxies at z~4
Masami Ouchi,Kazuhiro Shimasaku,Sadanori Okamura,Mamoru Doi,Hisanori Furusawa,Masaru Hamabe,Masahiko Kimura,Yutaka Komiyama,Masayuki Miyazaki,Satoshi Miyazaki,Fumiaki Nakata,Maki Sekiguchi,Masafumi Yagi,Naoki Yasuda
Physics , 2001,
Abstract: We study the luminosity function and the correlation function of about 1200 z~4 Lyman break galaxies (LBGs) with i'<26 that are photometrically selected from deep BRi' imaging data of a 618 arcmin^2 area in the Subaru/XMM-Newton Deep Field taken with Subaru Prime Focus Camera. The contamination and completeness of our LBG sample are evaluated, on the basis of the Hubble Deep Field-North (HDF-N) objects, to be 17% and 45%, respectively. We derive the UV (rest 1700A) luminosity functions (LFs) and find a large population of UV-luminous galaxies at z~4. The LFs of the red and blue subsamples imply that the bright LBGs are redder in the UV continuum than the average color of the LBGs. Then we calculate the correlation function over theta = 2''-1000'' and find that it is fitted fairly well by a power law, omega(theta)=A_omega theta^(-0.8), with A_omega=0.71 +/- 0.26. We estimate the correlation length r_0 (in comoving units) of the two-point spatial correlation function xi(r) = (r/r_0)^(-1.8) to be r_0=2.7 +0.5/-0.6 h^(-1) Mpc (Omega_m=0.3 and Omega_Lambda=0.7). The correlation function shows an excess of omega (theta) on small scales (theta < 5''), departing from the power-law fit at > 3 sigma significance level. Interpreting this as being due to galaxy mergers, we evaluate the fraction of galaxies undergoing mergers to be 3.0 +/- 0.9%, which is significantly smaller than those of galaxies at intermediate redshifts.
Galaxy Population in a Cluster of Galaxies around the Radio Galaxy 3C 324 at z=1.2
Fumiaki Nakata,Masaru Kajisawa,Toru Yamada,Tadayuki Kodama,Kazuhiro Shimasaku,Ichi Tanaka,Mamoru Doi,Hisanori Furusawa,Masaru Hamabe,Masanori Iye,Masahiko Kimura,Yutaka Komiyama,Satoshi Miyazaki,Sadanori Okamura,Masami Ouchi,Toshiyuki Sasaki,Maki Sekiguchi,Masafumi Yagi,Naoki Yasuda
Physics , 2001, DOI: 10.1093/pasj/53.6.1139
Abstract: We discuss the properties of galaxies around the radio galaxy 3C 324 at z=1.2 based on BVRIK' multi-band imaging data. We have applied a photometric-redshift technique to objects in the 3C 324 field, and identified 35 objects as plausible cluster members. We have found that red and luminous members are concentrated in a small region enclosed by a circle of 40" radius (0.33 Mpc at z=1.2 for \Omega_0=0.3, \lambda_0=0.7, H_0=70km/s/Mpc cosmology) from the 3C 324 galaxy. The 3C 324 cluster is probably much more compact in size compared with the local clusters. We constructed a K'-band luminosity function of the cluster members and fit a Schechter function, and found the characteristic magnitude to be K*_{AB}=20.2+-0.6. This value is consistent with the extrapolation of the pure passive evolution seen for z<1 clusters. We have identified eight bright galaxies which form a red color-magnitude sequence. The slope of the sequence is consistent with the passive evolution model down to K'_{AB}<22; we also found that there is no clear age variation in these bright red galaxies. However, seven out of these eight galaxies exhibit a significant excess in the rest UV light with respect to the passive evolution model. This may suggest that the massive early-type galaxies in this high-redshift cluster are still forming stars to some extent. We have confirmed a truncation of the color-magnitude sequence at K'_{AB}\sim22; faint passively-evolving galaxies may not yet be present in this cluster at z\sim1.2. The overall color distribution of the cluster members, selected by the photometric redshift technique, is found to be very broad. We derived the fraction of blue galaxies in this cluster following a
Subaru Prime Focus Camera -- Suprime-Cam --
Satoshi Miyazaki,Yutaka Komiyama,Maki Sekiguchi,Sadanori Okamura,Mamoru Doi,Hisanori Furusawa,Masaru Hamabe,Katsumi Imi,Masahiki Kimura,Fumiaki Nakata,Norio Okada,Masami Ouchi,Kazuhiro Shimasaku,Masafumi Yagi,Naoki Yasuda
Physics , 2002, DOI: 10.1093/pasj/54.6.833
Abstract: We have built an 80-mega pixels (10240 X 8192) mosaic CCD camera, called Suprime-Cam, for the wide-field prime focus of the 8.2 m Subaru telescope. Suprime-Cam covers a field of view 34' X 27', a unique facility among the the 8-10 m class telescopes, with a resolution of 0.''202 per pixel. The focal plane consists of ten high-resistivity 2k X 4k CCDs developed by MIT Lincoln Laboratory, which are cooled by a large stirling-cycle cooler. The CCD readout electronics was designed to be scalable, which allows the multiple read-out of tens of CCDs. It takes 50 seconds to readout entire arrays. We designed a filter-exchange mechanism of the jukebox type that can hold up to ten large filters (205 X 170 X 15 mm^3). The wide-field corrector is basically a three-lens Wynne-type, but has a new type of atmospheric dispersion corrector. The corrector provides a flat focal plane and an un-vignetted field of view of 30' in diameter. The achieved co-planarity of the focal array mosaic is smaller than 30 micron peak-to-peak, which realizes mostly the seeing limited image over the entire field. The median seeing in the Ic-band, measured over one year and a half, is 0.''61. The PSF anisotropy in Suprime-Cam images, estimated by stellar ellipticities, is about 2% under this median seeing condition. At the time of commissioning, Suprime-Cam had the largest survey speed, which is defined as the field of view multiplied by the primary mirror area of the telescope, among those cameras built for sub-arcsecond imaging.
Discovery of Very Extended Emission-Line Region around the Seyfert 2 Galaxy NGC 4388
Michitoshi Yoshida,Masafumi Yagi,Sadanori Okamura,Kentaro Aoki,Youichi Ohyama,Yutaka Komiyama,Naoki Yasuda,Masanori Iye,Nobunari Kashikawa,Mamoru Doi,Hisanori Furusawa,Masaru Hamabe,Masahiko Kimura,Masayuki Miyazaki,Satoshi Miyazaki,Fumiaki Nakata,Masami Ouchi,Maki Sekiguchi,Kazuhiro Shimasaku,Hiroshi Ohtani
Physics , 2001, DOI: 10.1086/338353
Abstract: We found a very large, 35 kpc, emission-line region around the Seyfert type 2 galaxy NGC 4388, using deep narrow-band imaging with the prime focus camera (Suprime-Cam) of the Subaru telescope. This region consists of many faint gas clouds or filaments, and extends northeastwards from the galaxy. The typical H-alpha luminosity L(H-alpha) of the clouds is 10^37 erg s^-1, and the total L(H-alpha) of the region within 10 kpc from the nucleus is 2 x 10^38 erg s^-1, which corresponds to an ionized gas mass of 10^5 M_solar. The map of the emission-line intensity ratio I([OIII])/I(H-alpha) indicates that the inner (r < 12 kpc) region of the VEELR may be excited by nuclear ionizing radiation. The excitation mechanism of the outer (r > 12 kpc) region is unclear, but it is likely that the nuclear radiation is also a dominant source of its ionization. We discuss the origin of the ionized gas. Two plausible origins of the gas in the VEELR are (i) the tidal debris resulting from a past interaction with a gas-rich dwarf galaxy, i.e., a minor merger, or (ii) the interstellar medium of NGC 4388, stripped by the ram pressure of the hot intracluster medium of the Virgo cluster.
A Search for Lyman alpha Emitters at Redshift 3.7
Shinobu S. Fujita,Masaru Ajiki,Yasuhiro Shioya,Tohru Nagao,Takashi Murayama,Yoshiaki Taniguchi,Sadanori Okamura,Masami Ouchi,Kazuhiro Shimasaku,Mamoru Doi,Hisanori Furusawa,Masaru Hamabe,Masahiko Kimura,Yutaka Komiyama,Masayuki Miyazaki,Satoshi Miyazaki,Fumiaki Nakata,Maki Sekiguchi,Masafumi Yagi,Naoki Yasuda,Yuichi Matsuda,Hajime Tamura,Tomoki Hayashino,Keiichi Kodaira,Hiroshi Karoji,Toru Yamada,Kouji Ohta,Masayuki Umemura
Physics , 2002, DOI: 10.1086/344806
Abstract: We present the results of a survey for emission-line objects based on optical intermediate-band ($\lambda_{\rm c}$ = 5736 \AA ~ and $\Delta\lambda$ = 280 \AA) and broad-band ($B$, $V$, $R$, and $i^\prime$) observations of the Subaru/XMM-Newton Deep Field on the 8.2 m Subaru telescope with the Subaru Prime Focus Camera, Suprime-Cam. All the data were obtained during the guaranteed time observations of the Suprime-Cam instrument. The intermediate-band image covered a sky area with 10\minpoint62 $\times 12\minpoint40 \approx 132$ arcmin$^2$ in the Subaru/XMM-Newton Deep Field (Ouchi et al.). Using this image, we have found 23 emission-line sources whose observed emission-line equivalent widths are greater than 250 \AA. Their optical multicolor properties indicate that six emission-line sources are Ly$\alpha$ emitters at $z \approx$ 3.7 ($\Delta z \approx 0.22$). They are either intense starburst galaxies or active galactic nuclei like quasars at $z \approx$ 3.7. Two more emission-line sources may also be Ly$\alpha$ emitters at $z \approx$ 3.7 although their multicolor properties are marginal. Among the remaining 15 emission-line objects, eight objects appear strong emission-line galaxies at lower redshift; e.g., [O {\sc ii}] $\lambda$3727 emitters at $z \approx 0.54$, H$\beta$ at $z \approx 0.18$, or [O {\sc iii}]$\lambda$5007 emitters at $z \approx 0.15$. The remaining seven objects are unclassified because they are too faint to be detected in broad-band images. We discuss observational properties of these strong emission-line sources. In particular, our data allow us to estimate the star formation density at $z \approx 3.7$ for the first time.
How Do Foreign and Domestic Demand Affect Exports Performance? An Econometric Investigation of Indonesia’s Exports  [PDF]
Rudy Rahmaddi, Masaru Ichihashi
Modern Economy (ME) , 2012, DOI: 10.4236/me.2012.31005
Abstract: This paper explores the impacts of foreign and domestic demand on Indonesia’s exports within demand and supply frameworks using aggregate data of 1971 - 2007. In contrast to many previous studies employing a single equation model, the paper investigates such relationship by dealing with plausible simultaneity between quantity and price within demand and supply of exports using a simultaneous equation framework, which also enables one to distinct between pull (foreign demand) and push (cost) factors of exports. To capture effects of secular and cyclical movements on exports, we dissect income variables into trend and business cycle as proxies of productive capacity and capacity utilization rate, respectively. Our results suggest that both demandand supply-price elasticity are elastic, and secular and cyclical movements may have contrast effects on exports. The production capacity is positively attributed to exports performance, while the capacity utilization negatively affects exports, which confirms the customary version of domestic-demand pressure hypothesis. Some economic shocks and policies also play roles in determining exports performance. All estimated coefficients are statistically stable over the period under study. The findings draw policy implications namely the importance of price-based policy, provision of adequate and sound infrastructures, and further development of human capital-based industrialization.
Recent advances in choledochal cysts  [PDF]
Hiroyuki Tadokoro, Masaru Takase
Open Journal of Gastroenterology (OJGas) , 2012, DOI: 10.4236/ojgas.2012.24029
Abstract: Choledochal cysts are a congenital anomaly, and they show dilatation of the intra- or extrahepatic biliary tree. These cysts are uncommon in Western countries, but are not rare in Asian countries. Choledochal cysts are classified into five groups based on location or shape of the cysts. Types I and IV-A cysts are the most common types, which are associated with anomalous pancreaticobiliary junction (APBJ), but other cysts are not associated with APBJ. Types I and IV-A cysts appear to belong to a different category from other cysts embryologically. Type I and IV-A cysts accompany anomalies of the pancreas. Type I and IV-A cysts might occur when left ventral anlage persists, and with disturbed recanalization of the common bile duct. Endoscopic retrograde cholangiopancreatography is the gold standard for detecting APBJ, but it is an invasive procedure. Magnetic resonance cholangiopancreatography (MRCP) is a non-invasive imaging tool for detecting pancreatic and biliary trees. MRCP is the first-choice modality for diagnosing choledochal cysts and APBJ in pediatric patients. Cystoenterostomy is been performed because of high complication and mortality rates. Complete excision of the cysts with Roux-en-Y hepatojejunostomy is a standard procedure for choledochal cysts to prevent postoperative complications, including development of cancer. In this study, we review classification, pathogenesis, diagnosis, and treatment of types I and IV-A choledochal cysts.
Elevated Root-Zone Temperature Modulates Growth and Quality of Hydroponically Grown Carrots  [PDF]
Masaru Sakamoto, Takahiro Suzuki
Agricultural Sciences (AS) , 2015, DOI: 10.4236/as.2015.68072
Abstract: Air and soil temperatures strongly influence the growth and quality of crops. However, in root vegetables, such as carrot, few experiments aimed at regulating growth and quality by manipulating root-zone temperature have been reported. We investigated the effect of root-zone temperatures (20°C, 25°C, 29°C, and 33°C) on carrot growth and components using a hydroponic system. High root-zone temperatures for 14 days reduced shoot and rootgrowth and water content. In contrast, total phenolic compounds and soluble-solid content increased in tap roots under high-temperature treatment. Root oxygen consumption was upregulated after 7 days under high-temperature treatment. These results suggest that high root-zone temperatures induce drought-like stress responses that modulate carrot biomass and components. High root-zone temperature treatments administered to hydroponically grown crops may be a valuable tool for improving and increasing the quality and value of crops.
Effect of Root-Zone Temperature on Growth and Quality of Hydroponically Grown Red Leaf Lettuce (Lactuca sativa L. cv. Red Wave)  [PDF]
Masaru Sakamoto, Takahiro Suzuki
American Journal of Plant Sciences (AJPS) , 2015, DOI: 10.4236/ajps.2015.614238
Abstract: Soil temperature influences crop growth and quality under field and greenhouse conditions; however, precise investigation using controlled cultivation systems is largely lacking. We investigated effects of root-zone temperatures on growth and components of hydroponically grown red leaf lettuce (Lactuca sativa L. cv. Red Wave) under a controlled cultivation system at 20°C. Compared with ambient root-zone temperature exposure, a 7-day low temperature exposure reduced leaf area, stem size, fresh weight, and water content of lettuce. However, root-zone heating treatments produced no significant changes in growth parameters compared with ambient conditions. Leaves under low root-zone temperature contained higher anthocyanin, phenols, sugar, and nitrate concentrations than leaves under other temperatures. Root oxygen consumption declined with low temperature root exposure, but not with root heating. Leaves of plants under low rootzone temperature showed hydrogen peroxide production, accompanied by lipid peroxidation. Therefore, low temperature root treatment is suggested to induce oxidative stress responses in leaves, activating antioxidative secondary metabolic pathways.
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