Jaemann Kyeong

MULTICOLOR NEAR-INFRARED INTRA-DAY AND SHORT-TERM VARIABILITY OF THE BLAZAR S5 0716+714

In this paper, we report results of our near-infrared (NIR) photometric variability studies of the BL Lacertae (BL Lac) object S5 0716+714. NIR photometric observations were spread over seven nights during our observing run on 2007 April 2-9 at the 1.8 m telescope equipped with the Korea Astronomy and Space Science Institute Near-Infrared Camera System and J, H, and Ks filters at Bohyunsan Optical Astronomy Observatory, South Korea. We searched for intra-day variability (IDV), short-term variability, and color variability in the BL Lac object. We have not detected any genuine IDV in any of the J, H, and Ks passbands in our observing run. Significant short-term variabilities ~32.6%, 20.5% and 18.2% have been detected in the J, H, and Ks passbands, respectively, and ~11.9% in (J – H) color.

UKIRT Widefield Infrared Survey for Fe

The United Kingdom Infrared Telescope (UKIRT)Widefield Infrared Survey for Fe+ (UWIFE) is a 180 deg2 imaging survey of the first Galactic quadrant (7° < l < 62° |b| <1°.5) that uses a narrow-band filter centred on the [Fe II] 1.644-I¼m emission line. The [Fe II] 1.644-I¼m emission is a good tracer of dense, shock-excited gas, and the survey will probe violent environments around stars: star-forming regions, evolved stars, and supernova remnants, among others. The UWIFE survey is designed to complement the existing UKIRTW idefield Infrared Survey for H2 (UWISH2). The survey will also complement existing broad-band surveys. The observed images have a nominal 5I? detection limit of 18.7 mag for point sources, with a median seeing of 0.83 arcsec. For extended sources, we estimate a surface brightness limit of 8.1 A? 10-20 W m-2 arcsec-2. In this paper, we present an overview and some preliminary results of this survey. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

The Taiwan-American Occultation Survey Project Stellar Variability. I. Detection of Low-Amplitude δ Scuti Stars

We analyzed data accumulated during 2005 and 2006 by the Taiwan-American Occultation Survey (TAOS) in order to detect short-period variable stars (periods of <∼ 1 hour) such as δ Scuti. TAOS is designed for the detection of stellar occultation by small-size Kuiper Belt Objects (KBOs) and is operating four 50cm telescopes at an effective cadence of 5Hz. The four telescopes simultaneously monitor the same patch of the sky in order to reduce false positives. To detect short-period variables, we used the Fast Fourier Transform algorithm (FFT) inasmuch as the data points in TAOS light-curves are evenly spaced. Using FFT, we found 41 short-period variables with amplitudes smaller than a few hundredths of a magnitude and periods of about an hour, which suggest that they are low-amplitude δ Scuti stars (LADS). The light-curves of TAOS δ Scuti stars are accessible online at the Time Series Center website (http://timemachine.iic.harvard.edu). Subject headings: (stars: variables:) δ Sct; surveys; methods : data analysisWe analyzed data accumulated during 2005 and 2006 by the Taiwan-American Occultation Survey (TAOS) in order to detect short-period variable stars (periods of ≲ 1 hr) such as δ Scuti. TAOS is designed for the detection of stellar occultation by small-size Kuiper Belt Objects and is operating four 50 cm telescopes at an effective cadence of 5 Hz. The four telescopes simultaneously monitor the same patch of the sky in order to reduce false positives. To detect short-period variables, we used the fast Fourier transform algorithm (FFT) in as much as the data points in TAOS light curves are evenly spaced. Using FFT, we found 41 short-period variables with amplitudes smaller than a few hundredths of a magnitude and periods of about an hour, which suggest that they are low-amplitude δ Scuti stars. The light curves of TAOS δ Scuti stars are accessible online at the Time Series Center Web site (http://timemachine.iic.harvard.edu).

U BV I CCD PHOTOMETRY OF THE OLD OPEN CLUSTER NGC 1193

We present U BV I photometry of the old open cluster NGC 1193. Color-magnitude diagrams (CMDs) of this cluster show a well defined main sequence and a sparse red giant branch. For the inner region of r < 50 ′′ , three blue straggler candidates are newly found in addition to the objects Kaluzny (1988) already found. The color-color diagrams show that the reddening value toward NGC 1193 is E(B − V ) = 0.19 ± 0.04. From the ultraviolet excess measurement, we derived the metallicity to be [Fe/H]= −0.45 ± 0.12. A distance modulus of (m − M )0 = 13.3 ± 0.15 is obtained from zero age main sequence fitting with the empirically calibrated Hyades isochrone of Pinsonneault et al. (2004). CMD comparison with the Padova isochrones by Bertelli et al. (1994) gives an age of log t = 9.7 ± 0.1.

Development status of the prototype of the GMT fast steering mirror

FSM is a secondary mirror of the Giant Magellan Telescope (GMT), which is 3.2 m in diameter. It consists of seven segments, each of which is 1m in diameter. The surrounding six segments are off-axis mirrors. FSM compensates image degradations caused by wind turbulence and structure jitter by using a tip-tilt mechanism. Korea Astronomy and Space Science Institute is developing a prototype of Fast Steering Mirror (FSM) together with four other institutions. The prototype is a full-size FSM segment, and it has two features; an off-axis mirror and a testbed for tip-tilt actuation. The off-axis mirror has the diameter of 1.06 m and fast focal ratio of 0.65. At present, lightweighting is successfully finished, and polishing of the front surface is proceeding. As for the tip-tilt, several test-beds have been assembled and the functions of tip-tilt have been checked. The third testbed is being integrated with a dummy aluminum mirror, three axial supports, a lateral support, and a test-bed frame. It is activated by a vacuum system. The test-bed will examine and verify the tip-tilt parameters. The FSM prototype is expected to be completed by 2012. In this paper, system engineering and progress of the prototype development are to be presented.

2MASS NEAR-IR COLOR-MAGNITUDE DIAGRAM OF THE OLD OPEN CLUSTER KING 11

We study near-infrared properties of the old open cluster King 11, based on the 2MASS photometric data. We determine the location of the red giant clump(RGC) in the (K;J i K) color-magnitude diagram and derive the distance modulus of King 11 to be (m i M)0 = 12.50§0.10 using the mean K magnitude of RGC. From the red giant branch slope i [Fe/H] relation we obtain the metallicity of this cluster, [Fe/H]=i0.17§0.07. The age and interstellar reddening of this cluster are estimated to be log t = 9.48§0.05, E(B i V )=0.90§0.03, by applying Padova isochrone flts to the data.

GROUND-BASED NEAR-INFRARED CENSUS FOR YOUNG STAR CLUSTERS IN THE DWARF STARBURST GALAXY NGC 1569

JHK near-infrared photometry of starclusters in the dwarf irregular/dwarf starburst galaxy NGC 1569 are presented. After adopting several criteria to excludeother sources (foreground stars, backgalaxies, etc.), 154 candidates of star clusters are identified in the near-infraredimages of NGC 1569, which include very young star clusters. Especially, from analysis based on theoretical background, wefound ten very young star clusters near the center of NGC 1569. The total reddening values toward these clusters are estimatedto be A V = 1-9 mag from comparisonwith the theoretical estimates given by the Leitherer et al. (1999)s star cluster model.

NEAR-INFRARED PHOTOMETRIC STUDY OF THE OLD OPEN CLUSTER TRUMPLER 5

We present JHK near-infrared photometric study for the old open cluster (OC) Trumpler 5 (Tr 5), based on the 2MASS data. From the color-magnitude diagrams of Tr 5, we have located the position of the red giant clump (RGC) stars, and used the mean magnitude of the RGC stars in K-band to estimate the distance to Tr 5, d = 3.1±0.1 kpc ((m-M) 0 = 12.46±0.04). From fitting the theoretical isochrones of Padova group, we have estimated the reddening, metallicity, and age : E(B-V ) = 0.64±0.05, [Fe/H] = -0.4 ± 0.1 dex, and t = 2.8 ± 0.2 Gyr (log t = 9.45 ± 0.04), respectively. These parameters generally agree well with those obtained from the previous studies on Tr 5 and confirms that this cluster is an old OC with metallicity being metal-poorer than solar abundance, located in the anti-Galactic center region.

KASINICS: KASI Near-Infrared Camera System

The Korea Astronomy and Space Science Institute (KASI) is building the KASI Near Infrared Camera System (KASINICS) for the 61-cm telescope at the Sobaeksan Optical Astronomy Observatory (SOAO) in Korea. With KASINICS we will mostly do time monitoring observations, e.g., thermal variations of Jovian planet atmospheres, variable stars, and blazars. We use a 512 x 512 InSb array (Aladdin III Quadrant, Raytheon Co.) for L-band observations as well as J, H, and Ks-bands. The field-of-view of the array is 6 x 6 arcmin with 0.7 arcsec/pixel. Since the SOAO 61-cm telescope was originally designed for visible band observations, we adopt an Offner relay optical system with a Lyot stop to eliminate thermal background emission from the telescope structures. In order to minimize weight and volume, and to overcome thermal contraction problems, we optimize the mechanical design of the camera using the finite-element-method (FEM) analysis. Most of the camera parts including the mirrors are manufactured from the same melt of aluminum alloy to ensure homologous contraction from room temperature to 70 K. We also developed a new control electronics system for the InSb array (see the other paper by Cho et al. in this proceedings). KASINICS is now under the performance test and planned to be in operation at the end of 2006.

SPECTROSCOPIC AND PHOTOMETRIC STUDY OF STARBURST GALAXIES: OPTICAL AND NEAR INFRARED PROPERTIES OF A BLUE COMPACT DWARF GALAXY MRK 49 IN THE VIRGO CLUSTER

We present optical and near-infrared imaging and long-slit spectroscopy for the blue compact dwarf galaxy (BCD) Mrk 49 in the Virgo Cluster. The surface brightness distribution analysis shows that Mrk 49 consists of an off-centered blue bright compact core of r = 10′′ and a red faint outer exponential envelope. The Hα image and color difference suggest that these two components have different stellar populations: a high surface brightness population of massive young stars and an underlying low surface brightness population of older stars. The redder near-infrared colors of the inner most region suggest that the near-infrared flux of Mrk 49 originates from evolved massive stars associated with the current star-forming activity. The total apparent magnitude is B T = 14.32 mag and the mean effective surface brightness is μeff (B) = 21.56 mag arcsec -2 . Long-slit spectroscopy shows that Mrk 49 rotates apparently as a solid body within r = 10′′ in a plane at position angle 55 degrees with an amplitude of about 20 km sec -1 . The measured radial velocity of Mrk 49 was derived as 1,535 km sec -1 ; and the total mass of stars and gases is in the range of 3 to 6 × 10 9 M ⊙ . The mass-to-light ratios for the central region of Mrk 49 in I and B band are estimated 1.0 and 0.5, respectively. The upper limit of the dark matter to visible matter ratio seems to be < 5. The oxygen abundance is 12 + log(O/H) = 8.21 ± 0.1 which is about one quarter of the solar value while the relative helium abundance appears to be similar to that of the sun.