• Journal of The Korean Astronomical Society
• /
• v.39 no.4
• /
• pp.89-94
• /
• 2006

We present JHK-band near-infrared photometry of the star clusters in the dwarf irregular galaxy IC 5152. After excluding possible foreground stars, a number of candidate star clusters are identified in the near-infrared images of IC 5152, which include young populations. Especially, five young star clusters are identified in the(J-H, H-K) two color diagram and the total extinction values toward these clusters are estimated to be $A_v=2-6$ from the comparison with the theoretical values given by the Leitherer et al.(1999)'s theoretical star cluster model.

• Journal of Astronomy and Space Sciences
• /
• v.25 no.3
• /
• pp.245-248
• /
• 2008

We determined values of distance modulus to nearby dwarf galaxy NGC 185 from the Tip of Red-Giant Branch (TRGB) method. Apparent magnitudes of the TRGB are estimated from the near-infrared JHK luminosity functions (LFs) of the resolved giant branch stars. Theoretical absolute magnitudes of the TRGB in near-infrared bands have been extracted from the Yonsei-Yale isochrones. The observed apparent and theoretical absolute magnitudes of the TRGB provide values of distance modulus to NGC 185 as (m - M) = $23.39{\pm}0.14$, $23.23{\pm}0.22$, and $23.27{\pm}0.26$ for J,H, and K bands, respectively. Distance modulus in bolometric magnitude is also derived as (m - M) = $23.62{\pm}0.12$.

• The Bulletin of The Korean Astronomical Society
• /
• v.38 no.2
• /
• pp.82.2-82.2
• /
• 2013

The NISS (Near-infrared Imaging Spectrometer for Star formation history) onboard NEXTSat-1 is being developed by KASI. The NISS will perform the imaging low-resolution spectroscopic observation in the near-infrared range for nearby galaxies, low background regions, starforming regions and so on. The off-axis reflecting telescope with a wide field of view (2 deg. ${\times}$ 2 deg.) will be operated in the wavelength range from 0.95 to $3.8{\mu}m$. In order to reduce thermal noise, a telescope and a HgCdTe infrared sensor will be cooled down to 200K and 80K, respectively. To evade a stray light outside a field of view and use limited space efficiently, the NISS adopted the off-axis reflective optical system. The primary and secondary mirrors, optomechanical part and mechanical structure were designed to use the same material. It will lessen the degradation of optical performance due to a thermal variation. The purpose of NISS is the observation of cosmic near-infrared background in the wide wavelength range as well as the detection of near-infrared spectral lines in nearby galaxies, cluster of galaxies and star forming regions. It will give us less biased information on the star formation history. In addition, we will demonstrate the space technologies related to the development of the Korea's leading near-infrared instrument for the future large infrared telescope, SPICA.

• Journal of The Korean Astronomical Society
• /
• v.43 no.1
• /
• pp.1-8
• /
• 2010

JHK near-infrared photometry of star clusters in the dwarf irregular/dwarf starburst galaxy NGC 1569 are presented. After adopting several criteria to exclude other sources (foreground stars, background galaxies, etc.), 154 candidates of star clusters are identified in the near-infrared images of NGC 1569, which include very young star clusters. Especially, from analysis based on theoretical background, we found ten very young star clusters near the center of NGC 1569. The total reddening values toward these clusters are estimated to be $A_V$=1-9 mag from comparison with the theoretical estimates given by the Leitherer et al. (1999)'s star cluster model.

• Proceedings of the KSME Conference
• /
• 2001.11b
• /
• pp.493-498
• /
• 2001

In the low velocity displacement air-conditioning system, the conditioned air is supplied from the diffuser placed on the wall near the floor and vented near the ceiling. This system has some advantages upon the traditional mixing system; the air quality near the people is improved by the displacing action of the system and the energy may be saved by neglecting the cooling or heating load for the upper space of the space above the people. This study is to examine the temperature and velocity distributions in the room and near the diffuser. It is found that the temperature is stratified uniformly all over the room space to show the displacing function of the system.

• Journal of The Korean Astronomical Society
• /
• v.46 no.6
• /
• pp.253-259
• /
• 2013

We present near-infrared light curves of HBC 722 after its the September 2010 outburst. We have been monitoring its near-infrared light curves since November 2010 with Korean Astronomy and Space Science Institute Infrared Camera System (KASINICS). HBC 722 exhibits large changes in optical and near-infrared brightness since its outburst. The J, H, and $K_s$ light curves over about 2.5 years show that in all observed bands HBC 722 progressively became fainter until around April 2011, down to J ~10.7, H ~9.9, $K_s$ ~9.3, but it is getting brighter again. Large scatter in the obtained light curve prevents us from finding whether there is any short timescale variation as reported in other optical observations. The near-infrared color of HBC 722 is becoming bluer since its outburst. The pre-outburst Spectral Energy Distribution (SED) of HBC 722 is consistent with that of a slightly reddened Class II YSO with the exception of the extraordinary IR-excess in the far-infrared region.

• Bulletin of the Korean Space Science Society
• /
• 2004.10b
• /
• pp.243-246
• /
• 2004

We calculate theoretical isochrones in a consistent way for five filters near the K-band, K, K', $K_s$, F205W, and F222M. Even when displayed in the same Vega magnitude system, the near-infrared colors of the same isochrone can differ by up to 0.18 mag at its bright end, depending on the filter. We analyze isochrones for several different extinction values, and find that a care is needed when comparing extinction values that are estimated by different filter sets, in particular when comparing those between atmospheric and space filter sets. To alleviate this problem, we present an 'effective extinction law' for each filter set and isochrone model, which describes extinction behaviour of isochrones in the observed color-magnitude diagram.

• The Bulletin of The Korean Astronomical Society
• /
• v.44 no.1
• /
• pp.68.1-68.1
• /
• 2019

Using IPHAS $H{\alpha}$ data, we found bright $H{\alpha}$ regions inside the elongated $^{13}CO$ cavity around a Herbig star, MWC 1080. To investigate the ionized hydrogen regions and the molecular cavity, we perform near-IR high-resolution spectroscopic of hydrogen Brackett lines and molecular hydrogen lines by Immersion GRating INfrared Spectrograph (IGRINS) observations. We detected broad Brackett line series and sharp molecular lines with various velocity components. We present three ionized hydrogen regions (near MWC 1080A, MWC 1080E, and CO boundary) with different line widths, central radial velocities, and line ratios. We also show two spatially-separate $Br{\gamma}$ ${\lambda}2.1662{\mu}m$ peaks near MWC 1080A. To reveal a 3D structure of the cavity around MWC 1080, we try to use the detected sharp molecular lines.

• Bulletin of the Korean Space Science Society
• /
• 2004.10b
• /
• pp.62-62
• /
• 2004

• Communications of the Korean Mathematical Society
• /
• v.28 no.4
• /
• pp.669-677
• /
• 2013

In this paper we introduce the notion of NI near-rings similar to the notion introduced in rings. We give topological properties of collection of strongly prime ideals in NI near-rings. We have shown that if N is a NI and weakly pm near-ring, then $Max(N)$ is a compact Hausdorff space. We have also shown that if N is a NI near-ring, then for every $a{\in}N$, $cl(D(a))=V(N^*(N)_a)=Supp(a)=SSpec(N){\setminus}int\;V(a)$.