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We have carried out wide field imaging observations in the near-infrared (J, H and K′ band) with a large format array camera attached to the prime focus of the 105 cm Schmidt telescope at Kiso Observatory. The image resolution, limiting magnitudes and the effect of thermal radiation are discussed.
We present the results of wide-field imaging of nearby galaxies observed in the near-infrared using a large format array. The total magnitudes and mass-to-luminosity ratios of NGC 253, M 82, NGC 891, and some cluster members are discussed.
We are currently conducting three kinds of IR surveys of star forming regions (SFRs) in order to seek for very low-mass young stellar populations. First is a deep JHKs-bands (simultaneous) survey with the SIRIUS camera on the IRSF 1.4m or the UH 2.2m telescopes. Second is a very deep JHKs survey with the CISCO IR camera on the Subaru 8.2m telescope. Third is a high resolution companion search around nearby YSOs with the CIAO adaptive optics coronagraph IR camera on the Subaru. In this contribution, we describe our SIRIUS camera and present preliminary results of the ongoing surveys with this new instrument.
The region south of the reflection nebula NGC1333 in Perseus is an active star forming region including numerous Herbig-Haro objects and at least 5 protostar candidates with molecular outflows and far-infrared emission. It has been actively studied in various wave bands (e.g. Aspin et al 1994 and references therein). We observed this region with ASCA with the primary objective to detect X-rays from the protostars embedded deep in the molecular cloud.
Near-infrared (NIR) emission in galaxies is mainly radiated by old population low temperature stars, which construct the basic stellar structure and keep the trails of past galaxy evolution. On the other hand, optical observations show recent star formation activity, especially in spiral galaxies. Therefore multi-color observations from optical to near-infrared wavelengths are very important to understand the past and recent star-formation history. Nearby large galaxies are well studied not only in optical but also in mid- and far-infrared by IRAS, CO and HI radio observations. However, the study in the near-infrared is still limited because large format arrays are not common. Here we show a wide-field, near-infrared imaging of nearby elliptical and spiral galaxies and discuss their star-formation history.
Sofue (1996, 1997) presented accurate rotation curves of nearby galaxies, which are almost completely sampled from the inner to outer regions. The conspicuous common feature of the rotation curves is a steep rise at the inner bulge. The rise suggests a compact massive concentration near the nucleus (Sofue 1996). The study of the light distribution at the inner bulge demands accurate surface photometry at near-infrared wavelengths, where dust extinction is much less effective than in the optical. Most of Sofue's samples are nearby large galaxies, so that observations with a wide field view is clue to constructing reliable light distribution models.
Gamma-rays originating from radioactive decays of 56Ni and 56Co and hard X-rays due to Compton degradation of γ-rays have been predicted to emerge when the supernova becomes sufficiently thin. The X-ray detections by Ginga (Dotani et al. 1988) and Kvant (Sunyaev et al. 1988) and more recent report of γ-ray detections by SMM (Matz et al. 1988) were much earlier than the theoretical predictions. (See Itoh et al. 1987 and references therein.)
These observations would give important constraints on the distribution of the heavy elements and 56Co in the ejecta. We adopted the hydrodynamical model 11E1Y6 (Nomoto et al. 1988) and carried out Monte Carlo simulation for photon transfer. A step-like distribution of 56Co was assumed where the mass fraction of 56Co in the layers at Mr ≤ 4.6 M⊙, 4.6 − 6 M⊙, 6 − 8 M⊙, and 8 − 10 M⊙ are XCo = 0.0128, 0.0035, 0.0021, and 0.0011, respectively. Other heavy elements were distributed with mass fractions in proportion to 56Co.
The X-ray spectrum observed by Ginga is characterized by a component below 10keV which decreases with increasing photon energy, and a component above 10keV which is nearly flat. This unusual X-ray spectrum may be understood as follows; X-rays below 10keV is likely to be due to thermal emission coming from the shock-heated ejecta, and X-rays above 10keV to be due to γ-ray degradation inside the ejecta. If thermal emission due to the collision of the ejecta with circumstellar matter (CSM) is responsible for X-rays below 10keV, the epoch of the collision can be estimated to be ∼ 0.2yr after the explosion if ∼ 0.5yr is the time when the X-ray flux at ∼ 10keV reaches its maximum. The X-ray light curve then requires the inner radius of CSM to be ∼ 1×1016cm for an expansion velocity, Vex ≃2×109cm s−1.
We have carried out imaging observations in the near-infrared (J, H and K’ band) with a large format array camera attached to the prime focus of the 105 cm Schmidt telescope at Kiso Observatory. The image resolution, limiting magnitudes and effect of thermal radiation are presented, based on observations of nearby galaxies. Considering the results, we are constructing a new larger near-infrared camera optimized for use with the Kiso Schmidt.
Most of the neutron star cooling calculations with the only exception of Malone's (1974) have assumed an isothermal stellar core. Here we report on a neutron star cooling calculation which makes full use of the stellar evolution code and the recent thermal conductivity calculations by Flowers and Itoh (1976, 1979).
There are serious discrepancies among some of the recent neutron star cooling calculations by various groups. We have been investigating the possible source of these discrepancies. In this paper, we report our findings. We also report the preliminary result of our most recent cooling calculations without assuming an isothermal stellar evolution code. In this work, we used the currently existing best energy transport theories, as well as general relativity, both in thermodynamics and hydrodynamics.
Water-splitting by using electric power produced by solar cells is promising system to produce hydrogen without fossil fuels. Oxygen evolving catalyst is, however, major problem to prevent using this system widely because precious materials are used in the catalyst. Considering from the photosynthesis II of plants, the compound of Ca-Mn-O is one of the candidates for the oxygen evolving catalyst. In this study, the synthesis condition and the oxygen evolving electrocatalytic activity of CaMn2O4•xH2O are investigated. The overpotential at 0.1 mA/cm2 was 0.28 V when using the electrode of carbon paste and CaMn2O4•H2O with the weight ratio of 3:1.
We investigated the relationships between conception rates (CRs) at first service in Japanese Holstein heifers (i.e. animals that had not yet had their first calf) and cows and their test-day (TD) milk yields. Data included records of artificial insemination (AI) for heifers and cows that had calved for the first time between 2000 and 2008 and their TD milk yields at 6 through 305 days in milk (DIM) from first through third lactations. CR was defined as a binary trait for which first AI was a failure or success. A threshold-linear animal model was applied to estimate genetic correlations between CRs of heifers or cows and TD milk yield at various lactation stages. Two-trait genetic analyses were performed for every combination of CR and TD milk yield by using the Bayesian method with Gibbs sampling. The posterior means of the heritabilities of CR were 0.031 for heifers, 0.034 for first-lactation cows and 0.028 for second-lactation cows. Heritabilities for TD milk yield increased from 0.324 to 0.433 with increasing DIM but decreased slightly after 210 DIM during first lactation. These heritabilities from the second and third lactations were higher during late stages of lactation than during early stages. Posterior means of the genetic correlations between heifer CR and all TD yields were positive (range, 0.082 to 0.287), but those between CR of cows and milk yields during first or second lactation were negative (range, −0.121 to −0.250). Therefore, during every stage of lactation, selection in the direction of increasing milk yield may reduce CR in cows. The genetic relationships between CR and lactation curve shape were quite weak, because the genetic correlations between CR and TD milk yield were constant during the lactation period.
Positron annihilation and electron spin resonance (ESR) have been used to study defects introduced by lMeV electron irradiation in n-type cubic silicon carbide (3C-SiC) epitaxially grown on Si by chemical vapor deposition. Positron annihilation measurements by using variable-energy positron beams indicated the narrowing of the Doppler-broadened energy spectrum of annihilation gamma-rays and the decrease in the effective diffusion length of positrons with increasing the electron fluence. These results show the formation of vacancy-type defects in 3C-SiC. An ESR spectrum labeled T1, which has an isotropie g-value of 2.0029±0.0001, was observed in electron irradiated 3C-SiC. The T1 spectrum is interpreted by hyperfine interactions of paramagnetic electrons with 13C at four carbon sites and 29Si at twelve silicon sites, leads that the Tl center results from a point defect at a silicon sublattice site. The production rate of the Tl center was in good agreement with the carrier removal rate, indicating that the Tl center captures an electron from the conduction band. All these results are accounted for by the introduction of negatively charged vacancies at silicon sublattice sites in 3C-SiC by the irradiation.
We have fabricated Bi2212 and Bi2223 bulk samples by shock compaction technique. Seed crystals were added to the starting materials in order to promote crystallization. The grain size of the prepared sample was increased by the addition of seed crystals to the starting material.
Optical and near-infrared observations of novae give us useful information for understanding the diversity of nova eruptions. Classical nova V1723 Aql was discovered by F. Kabashima and K. Nishiyama on 2010 September 11. We have conducted photometric and spectroscopic observations of V1723 Aql in both optical and near-infrared (NIR) wavelength regions since its discovery. The V-band decline time by 2 mag after the maximum, t2, was ~12 d. The apparent Fe II emission lines were also seen in the optical spectra. The Rc- and Ic-band light curves exhibited rapid declines (0.16 mag d−1 in Rc) 20 days after the visual maximum, while the NIR (J, H, and Ks) showed slow decline rates (~0.07 mag d−1). This rapid reddening suggests that dust particles formed during the very early phase of the expansion in V1723 Aql.
Results of our experimental investigation on the ozone zero phenomenon
suggested us the importance of the electrode surface condition. This means
that the main cause of the phenomenon, that is, temporal decrease of ozone
concentration at the outlet of DBD type ozone generator and the recovery
characteristics from the phenomenon are considered as the surface reaction
process, which are influenced strongly by the surface condition. The surface
condition is never constant during the ozone generation and varies gradually
or remarkably with time depending on the experimental conditions. Therefore
we have been continued to make clear the cause of the phenomenon, for
example, the reproducibility of the phenomenon, using new electrodes and
together with the surface analysis technique etc. In this paper, we describe
on the above results and discussion.
The preparation of non c-axis oriented HTS films with longer coherence length is one of key technologies toward realisation of viable Josephson devices. We reports on the successful growth of (119)Bi-2223 films by MOCVD using a two-step growth temperature procedure and on AFM observation of the film surface. This temperature procedure was found to be effective for orientation control and phase control in comparison with a fixed growth temperature procedure. As a result, superconducting properties were much improved. The surface morphology observed by AFM showed a mountain-range-shaped one, which strongly reflects the epitaxial relationship between the (119)Bi-2223 film and (110) SrTiO3 substrate.
We report on the successful preparation of intrinsic Josephson junctions on high-quality BSCCO-2212/2223 superlattice thin films grown by MOCVD. The surface of as-grown films was very smooth with the roughness of the order of a half unit cell. Mesas were effectively structured on the film by the liquid-nitrogen-cooled dry etching method. A typical I-V characteristic in the c-axis direction of a BSCCO film shows the hysteresis and multiple resistive branches. The number of branches is consistent with that of junctions calculated from the height of a mesa structure. This indicates that BSCCO-2212/2223 superlattice films consist of a series array of S(CuO2 bilayer) / I(SrO, BiO layers) / S(CuO2 trilayer) junction. The formation of stacked Josephson junctions was also confirmed by the temperature dependence and the magnetic field dependence of Ic.