• Journal of The Korean Astronomical Society
• /
• v.37 no.5
• /
• pp.597-600
• /
• 2004

A substantial number of processes have been suggested as possible contributors to the extragalactic $\gamma$-ray background (EGRB). Yet another contribution to this background will be emission produced in hadronic interactions of cosmic-ray protons with the cluster thermal gas; this class of cosmic rays (CRs) has been shown to be responsible for the EUV emission in the Coma Cluster of galaxies. In this paper we assume the CRs in the Coma Cluster is prototypic of all clusters and derive the contribution to the EGRB from all clusters over time. We examine two different possibilities for the scaling of the CR flux with cluster size: the number density of the CRs scale with the number density of the thermal plasma, and alternatively, the energy density of the CRs scale with the energy density of the plasma. We find that in all scenarios the EGRB produced by this process is sufficiently low that it will not be observable in comparison with other mechanisms that are likely to produce an EGRB.

• Publications of The Korean Astronomical Society
• /
• v.22 no.4
• /
• pp.177-181
• /
• 2007

We present the sensitivity calculation results for observing the Cosmic Infrared Background (CIRB) by the Multi-purpose IR Imaging System (MIRIS), which will be launched in 2010 as a main payload of the Science and Technology Satellite 3 (STSAT-3). MIRIS will observe in I ($0.9{\sim}1.2um$) and H ($1.2{\sim}2.0um$) band with a $4{\times}4$ degree field of view to obtain the large scale structure (${\sim}3$ degree) of the CIRB. With the given specifications of the MIRIS, our sensitivity calculation results show that the MIRIS has a detection limit of ${\sim}9\;nW\;m^{-2}\;sr^{-1}$ (I band) and ${\sim}6\;nW\;m^{-2}\;sr^{-1}$ (H band), which is appropriate to observe the large scale structure of CIRB.

• Journal of Radiation Protection and Research
• /
• v.22 no.3
• /
• pp.219-226
• /
• 1997

Ultralow background gamma-ray measurement system was installed to measure and analyze gamma-rays emitted from environmental and swipe samples. The background reduction techniques applied on this system are the passive shielding to surround the HPGe detector, an active external anticosmic shield to shield cosmic-rays and the nitrogen gas supply to minimize the introduction of ubiquitous radon decay nuclei. The performance test result showed that the system background at energies between 50 keV and 2 MeV is reduced about $10^{-2}$ order and the MDA is so low as to be suitable for the environmental sample analysis. But it is appeared that the neutron produced by cosmic-ray increases the background at low energy region.

• The Bulletin of The Korean Astronomical Society
• /
• v.36 no.2
• /
• pp.72.2-72.2
• /
• 2011

We have performed the first self-consistent, large-scale simulation of cosmic reionization by stellar sources, including the Population III stars that emerged and were hosted by minihalos at very high redshifts (z~40). Based on this result, we calculate the redshifted radiation background from these stars and the relic H II regions which can be observed at near-infrared and infrared regime. Formation of the first stars inside minihalos are quenched by radiative feedback at z~15, while the relic H II regions have much longer lifetime due to the slow recombination rate. Therefore, the radiation output from the relic H II regions, dominated by Lyman alpha photons, will be observed both in the near-infrared and infrared regime. The estimated background from the first stars inside minihalos are still sub-dominant compared to that from stars inside larger halos, however, and thus complementary observations are necessary, such as redshifted 21-cm line observation.

• Fashion & Textile Research Journal
• /
• v.10 no.6
• /
• pp.1014-1022
• /
• 2008

This study focuses on practical appliance of color therapy to skin care. After visiting the notion of color therapy and skin care, this study considers the ideas and background theories for diagnosis of constitution and skin. Cosmic duals force five element theory developed in China was the first introduction; Ayurvedic medicine and seven chakra notion are examined. Cosmic duals force five element theory, an idea describing the composition and movement rule of the cosmic components, adopted five colors(white, yellow, red, blue, and black) for cure purposes. In future, mental effect of the color is examined in the latter part of this study. The practice of the color therapy assigns solarized cream treatment and photo therapy, simultaneously proposes the use of color therapy to the skin care. For the diagnosis of the constitution, cosmic duals force five element theory and ayurvedic medicine are followed in a sequence. Cosmic duals force five element theory introduces five colors. Constitution medicine considers four types, ayurvedic medicine adopts three types, and seven colors are mentioned as chakra colors. Such a variations lead to possible disagreement on constitution analysis and driven colors. This study adopts the above methodologies for selecting potential color therapy for skin care. Adopt of selected cases are purely a part of the proposal. Initially, examined theories serve as a pilot for selecting a representative hypothesis. Followed selection of constitution and matched color for the use of the skin care are the scope of this study. In summary, background methodologies are implemented for the calculation of color therapy.

• The Bulletin of The Korean Astronomical Society
• /
• v.37 no.1
• /
• pp.42-42
• /
• 2012

The First stars (Pop.III stars) in the universe are expected to be formed between the recombination era at z - 1100 and the most distant quasar (z - 8). They have never been directly detected due to its faintness so far, but can be observed as a background radiation at around 1${\mu}m$ which is called the Cosmic Near-Infrared Background (CNB). Main part of the CNB is thought to be redshifted Lyman-alpha from gas clouds surrounding the Pop.III stars. Until now, the COBE (COsmic Background Explorer) and the IRTS (Infrared Telescope in Space) observed excess emission over the background due to galaxies. To confirm the COBE and the IRTS results and pursue more observational evidences, we carried out the sounding rocket experiment named the Cosmic Infrared Background ExpeRiment (CIBER). The CIBER is successfully launched on July 10, 2010 at White Sands Missile Range, New Mexico, USA. It consists of three kinds of instruments. We report the results obtained by LRS (Low Resolution Spectrometer) which is developed to fill the uncovered spectrum around 1${\mu}m$. LRS is a refractive telescope of 5.5 cm aperture with spectral resolution of 20 - 30 and wavelength coverage of 0.7 to 2.0${\mu}m$. After subtracting foreground components (zodiacal light, integrated star light and diffuse galactic light) from the sky brightness of observed five fields, there remained significant residual emission (even for the lower limit case) consistent with the IRTS and the COBE results. In addition, there exists a clear gap at 0.7 - 0.8${\mu}m$ in the CNB spectrum over the background due to galaxies according to recent results (Matsuoka et al. 2011; Mattila et al. 2011). The origin of the excess emission could be ascribed to the Pop.III stars with its active era of z = 7 - 10.

• The Bulletin of The Korean Astronomical Society
• /
• v.33 no.1
• /
• pp.86.1-86.1
• /
• 2008

• The Bulletin of The Korean Astronomical Society
• /
• v.30 no.2
• /
• pp.41.2-41.2
• /
• 2005

• The Bulletin of The Korean Astronomical Society
• /
• v.32 no.1
• /
• pp.57-57
• /
• 2007

• The Bulletin of The Korean Astronomical Society
• /
• v.34 no.2
• /
• pp.49.1-49.1
• /
• 2009