71 research outputs found
The Sunyaev-Zel'dovich Effect by Cocoons of Radio Galaxies
We estimate the deformation of the cosmic microwave background radiation by
the hot region (``cocoon'') around a radio galaxy. A simple model is adopted
for cocoon evolution while the jet is on, and a model of evolution is
constructed after the jet is off. It is found that at low redshift the phase
after the jet is off is longer than the lifetime of the jets. The Compton
y-parameter generated by cocoons is calculated with a Press-Schechter number
density evolution. The resultant value of y is of the same order as the COBE
constraint. The Sunyaev-Zeldovich effect due to cocoons could therefore be a
significant foreground source of small angular scale anisotropies in the cosmic
microwave background radiation.Comment: Published version, 23 pages with 5 figure
Cosmology from cosmic shear power spectra with Subaru Hyper Suprime-Cam first-year data
We measure cosmic weak lensing shear power spectra with the Subaru Hyper
Suprime-Cam (HSC) survey first-year shear catalog covering 137deg of the
sky. Thanks to the high effective galaxy number density of 17
arcmin even after conservative cuts such as magnitude cut of
and photometric redshift cut of , we obtain a high
significance measurement of the cosmic shear power spectra in 4 tomographic
redshift bins, achieving a total signal-to-noise ratio of 16 in the multipole
range . We carefully account for various uncertainties
in our analysis including the intrinsic alignment of galaxies, scatters and
biases in photometric redshifts, residual uncertainties in the shear
measurement, and modeling of the matter power spectrum. The accuracy of our
power spectrum measurement method as well as our analytic model of the
covariance matrix are tested against realistic mock shear catalogs. For a flat
cold dark matter (CDM) model, we find for
( for ) from our HSC tomographic
cosmic shear analysis alone. In comparison with Planck cosmic microwave
background constraints, our results prefer slightly lower values of ,
although metrics such as the Bayesian evidence ratio test do not show
significant evidence for discordance between these results. We study the effect
of possible additional systematic errors that are unaccounted in our fiducial
cosmic shear analysis, and find that they can shift the best-fit values of
by up to in both directions. The full HSC survey data
will contain several times more area, and will lead to significantly improved
cosmological constraints.Comment: 43 pages, 21 figures, accepted for publication in PAS
First Data Release of the Hyper Suprime-Cam Subaru Strategic Program
The Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) is a three-layered
imaging survey aimed at addressing some of the most outstanding questions in
astronomy today, including the nature of dark matter and dark energy. The
survey has been awarded 300 nights of observing time at the Subaru Telescope
and it started in March 2014. This paper presents the first public data release
of HSC-SSP. This release includes data taken in the first 1.7 years of
observations (61.5 nights) and each of the Wide, Deep, and UltraDeep layers
covers about 108, 26, and 4 square degrees down to depths of i~26.4, ~26.5, and
~27.0 mag, respectively (5sigma for point sources). All the layers are observed
in five broad bands (grizy), and the Deep and UltraDeep layers are observed in
narrow bands as well. We achieve an impressive image quality of 0.6 arcsec in
the i-band in the Wide layer. We show that we achieve 1-2 per cent PSF
photometry (rms) both internally and externally (against Pan-STARRS1), and ~10
mas and 40 mas internal and external astrometric accuracy, respectively. Both
the calibrated images and catalogs are made available to the community through
dedicated user interfaces and database servers. In addition to the pipeline
products, we also provide value-added products such as photometric redshifts
and a collection of public spectroscopic redshifts. Detailed descriptions of
all the data can be found online. The data release website is
https://hsc-release.mtk.nao.ac.jp/.Comment: 34 pages, 20 figures, 7 tables, moderate revision, accepted for
publication in PAS
Akt1 in Osteoblasts and Osteoclasts Controls Bone Remodeling
Bone mass and turnover are maintained by the coordinated balance between bone formation by osteoblasts and bone resorption by osteoclasts, under regulation of many systemic and local factors. Phosphoinositide-dependent serine-threonine protein kinase Akt is one of the key players in the signaling of potent bone anabolic factors. This study initially showed that the disruption of Akt1, a major Akt in osteoblasts and osteoclasts, in mice led to low-turnover osteopenia through dysfunctions of both cells. Ex vivo cell culture analyses revealed that the osteoblast dysfunction was traced to the increased susceptibility to the mitochondria-dependent apoptosis and the decreased transcriptional activity of runt-related transcription factor 2 (Runx2), a master regulator of osteoblast differentiation. Notably, our findings revealed a novel role of Akt1/forkhead box class O (FoxO) 3a/Bim axis in the apoptosis of osteoblasts: Akt1 phosphorylates the transcription factor FoxO3a to prevent its nuclear localization, leading to impaired transactivation of its target gene Bim which was also shown to be a potent proapoptotic molecule in osteoblasts. The osteoclast dysfunction was attributed to the cell autonomous defects of differentiation and survival in osteoclasts and the decreased expression of receptor activator of nuclear factor-κB ligand (RANKL), a major determinant of osteoclastogenesis, in osteoblasts. Akt1 was established as a crucial regulator of osteoblasts and osteoclasts by promoting their differentiation and survival to maintain bone mass and turnover. The molecular network found in this study will provide a basis for rational therapeutic targets for bone disorders
The Hyper Suprime-Cam SSP survey: Overview and survey design
Hyper Suprime-Cam (HSC) is a wide-field imaging camera on the prime focus of the 8.2-m Subaru telescope on the summit of Mauna Kea in Hawaii. A team of scientists from Japan, Taiwan, and Princeton University is using HSC to carry out a 300-night multi-band imaging survey of the high-latitude sky. The survey includes three layers: the Wide layer will cover 1400 deg2 in five broad bands (grizy), with a 5 σ point-source depth of r ≈ 26. The Deep layer covers a total of 26 deg2 in four fields, going roughly a magnitude fainter, while the UltraDeep layer goes almost a magnitude fainter still in two pointings of HSC (a total of 3.5 deg2). Here we describe the instrument, the science goals of the survey, and the survey strategy and data processing. This paper serves as an introduction to a special issue of the Publications of the Astronomical Society of Japan, which includes a large number of technical and scientific papers describing results from the early phases of this survey
DETERMINATION OF REACTION RATE AND DIFFUSION CONSTANTS OF THE RADICAL IN SILANE PLASMAS
Author Institution: Institute for Molecular Science; Nagoya UniversityTime resolved infrared spectra of were observed in pulsed discharge silane plasmas using diode laser kinetic spectroscopy. The rate of recombination plus disproportionation reactions was determined for the first time, together with the diffusion constants of in hydrogen and argon. These fundamental quantities will be useful in discussing CVD mechanisms leading to amorphous silicon
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