5,258 research outputs found
Precision Measurement of the Position-space Wave Functions of Gravitationally Bound Ultracold Neutrons
Gravity is the most familiar force at our natural length scale. However, it
is still exotic from the view point of particle physics. The first experimental
study of quantum effects under gravity was performed using a cold neutron beam
in 1975. Following this, an investigation of gravitationally bound quantum
states using ultracold neutrons was started in 2002. This quantum bound system
is now well understood, and one can use it as a tunable tool to probe gravity.
In this paper, we review a recent measurement of position-space wave functions
of such gravitationally bound states, and discuss issues related to this
analysis, such as neutron loss models in a thin neutron guide, the formulation
of phase space quantum mechanics, and UCN position sensitive detectors. The
quantum modulation of neutron bound states measured in this experiment shows
good agreement with the prediction from quantum mechanics.Comment: 13 pages, 5 figure
CO Observations of Luminous IR Galaxies at Intermediate Redshift
We present new measurement of CO() emission from 16 luminous
infrared galaxies (LIGs) at intermediate redshift (). These new data were selected by isolated and normal
morphology. The CO observations were performed using the NRO 45-m telescope.
Comparison of the CO and dust properties of the new result with those from
other CO measurements revealed characteristics of this sample: (1) It is the
deepest CO observations of IRAS galaxies at intermediate redshift without
strong interaction features. (2) It has typical properties of normal IRAS
galaxies in terms of star-formation efficiency, color-color diagrams and
galactic nuclear activity. (3) It has smaller gas-to-dust ratio than normal
IRAS galaxies. This can be explained by two-component dust model, and our
sample consists of most of warm dust.Comment: To appear in PASJ, text 9 pages, 5 tables, and 12 figure
Distance Measurement of Galaxies to Redshift of 0.1 using the CO-Line Tully-Fisher Relation
We report on the first results of a long-term project to derive distances of
galaxies at cosmological distances by applying the CO-line width-luminosity
relation. We have obtained deep CO-line observations of galaxies at redshifts
up to 29,000 km/s using the Nobeyama 45-m mm-wave Telescope, and some
supplementary data were obtained by using the IRAM 30-m telescope. We have
detected the CO line emission for several galaxies, and used their CO line
widths to estimate the absolute luminosities using the line-width-luminosity
relation. In order to obtain photometric data and inclination correction, we
also performed optical imaging observations of the CO-detected galaxies using
the CFHT 3.6-m telescope at high resolution. The radio and optical data have
been combined to derive the distance moduli and distances of the galaxies, and
Hubble ratios were estimated for these galaxies. We propose that the CO line
width-luminosity relation can be a powerful method to derive distances of
galaxies to redfhift of z = 0.1 and to derive the Hubble ratio in a significant
volume of the universe.
Key words: Cosmology - Galaxies: general - Distance scale - CO lineComment: To appear in PASJ, Plain Tex, 3 figures (in 10 ps files
Preparation and characteristics of superconducting cuprate thin films: Nd(2-x)Ce(x)CuO4 and substrated Bi-system
Characteristics of the electron-doped-type Nd(sub 2-x)Ce(sub x)CuO4 system and substituted Bi-system were studied using the high quality thin film samples grown by rf magnetron sputtering and/or subsequent heat treatment. The Nd(sub 2-x)Ce(sub x)CuO4 samples with excellent superconducting properties were obtained in thin films and their optical and X-ray photoelectron spectroscopy (XPS) studies were performed with regard to the Ce content and reducing treatment. Substituted BiSr-Ln-Cu-O thin films were prepared and growth conditions for Bi-system with 2-2-1-2 and 2-2-2-2 phases were found. Moreover, a new 2-2-1-2 phase in the simple Bi-Sr-Cu-O system was fabricated by thin film processing and 80 K superconductivity was obtained
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