Hyung Mok Lee

Seoul National University, Sŏul, Seoul, South Korea

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Publications (118)414.95 Total impact

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    ABSTRACT: We present infrared galaxy luminosity functions (LFs) in the AKARI North Ecliptic Pole (NEP) deep field using recently-obtained, wider CFHT optical/near-IR images. AKARI has obtained deep images in the mid-infrared (IR), covering 0.6 deg$^2$ of the NEP deep field. However, our previous work was limited to the central area of 0.25 deg$^2$ due to the lack of optical coverage of the full AKARI NEP survey. To rectify the situation, we recently obtained CFHT optical and near-IR images over the entire AKARI NEP deep field. These new CFHT images are used to derive accurate photometric redshifts, allowing us to fully exploit the whole AKARI NEP deep field. AKARI's deep, continuous filter coverage in the mid-IR wavelengths (2.4, 3.2, 4.1, 7, 9, 11, 15, 18, and 24$\mu$m) exists nowhere else, due to filter gaps of other space telescopes. It allows us to estimate restframe 8$\mu$m and 12$\mu$m luminosities without using a large extrapolation based on spectral energy distribution (SED) fitting, which was the largest uncertainty in previous studies. Total infrared luminosity (TIR) is also obtained more reliably due to the superior filter coverage. The resulting restframe 8$\mu$m, 12$\mu$m, and TIR LFs at $0.15<z<2.2$ are consistent with previous works, but with reduced uncertainties, especially at the high luminosity-end, thanks to the wide field coverage. In terms of cosmic infrared luminosity density ($\Omega_{\mathrm{IR}}$), we found that the $\Omega_{\mathrm{IR}}$ evolves as $\propto (1+z)^{4.2\pm 0.4}$.
  • Sang Hoon Oh, Woong-Tae Kim, Hyung Mok Lee
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    ABSTRACT: Using self-consistent three-dimensional (3D) N-body simulations, we investigate the physical properties of non-axisymmetric features in a disk galaxy created by a tidal interaction with its companion. The primary galaxy consists of a stellar disk, a bugle, and a live halo, corresponding to Milky-Way type galaxies, while the companion is represented by a halo alone. We vary the companion mass and the pericenter distance to explore situations with differing tidal strength parameterized by either the relative tidal force P or the relative imparted momentum S. We find that the formation of a tidal tail in the outer parts requires P > 0.05 or S > 0.07. A stronger interaction results in a stronger, less wound tail that forms earlier. Similarly, a stronger tidal forcing produces stronger, more loosely wound spiral arms in the inner parts. The arms are approximately logarithmic in shape, with both amplitude and pitch angle decaying with time. The derived pattern speed decreases with radius and is close to the Omega-kappa/2 curve at late time, with Omega and kappa denoting the angular and epicycle frequencies, respectively. This suggests that the tidally-induced spiral arms are most likely kinematic density waves weakly modified by self-gravity. Compared to the razor-thin counterparts, arms in the 3D models are weaker, have a smaller pitch angle, and wind and decay more rapidly. The 3D density structure of the arms is well described by the concentrated and sinusoidal models when the arms are in the nonlinear and linear regimes, respectively. We demonstrate that dynamical friction between interacting galaxies transfers the orbital angular momentum of one galaxy to the spin angular momentum of the companion halo.
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    ABSTRACT: We present the rest-frame optical spectral properties of 155 luminous quasars at 3.3<z<6.4 taken with the AKARI space telescope, including the first detection of H$\alpha$ emission line as far out as z~6. We extend the scaling relation between the rest-frame optical continuum and line luminosity of active galactic nuclei (AGNs) to the high luminosity, high redshift regime that has rarely been probed before. Remarkably, we find that a single log-linear relation can be applied to the 5100${\rm \AA}$ and H$\alpha$ AGN luminosities over a wide range of luminosity (10$^{42}$<$L_{5100}$<10$^{47}$ergs/s) or redshift (0<z<6), suggesting that the physical mechanism governing this relation is unchanged from z=0 to 6, over five decades in luminosity. Similar scaling relations are found between the optical and the UV continuum luminosities or line widths. Applying the scaling relations to the H$\beta$ black hole mass ($M_{\rm BH}$) estimator of local AGNs, we derive the $M_{\rm BH}$ estimators based on H$\alpha$, MgII, and CIV lines, finding that the UV-line based masses are overall consistent with the Balmer-line based, but with a large intrinsic scatter of 0.40dex for the CIV estimates. Our 43 $M_{\rm BH}$ estimates from H$\alpha$ confirm the existence of BHs as massive as ~10$^{10}M_{\odot}$ out to z~5, and provide a secure footing for previous MgII-line based studies that a rapid $M_{\rm BH}$ growth has occurred in the early universe.
    The Astrophysical Journal 03/2015; 806(1). DOI:10.1088/0004-637X/806/1/109 · 6.28 Impact Factor
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    ABSTRACT: We present 2.5-5.0 $\mu$m spectra of 83 nearby ($0.002\,<\,z\,<\,0.48$) and bright ($K<14$mag) type-1 active galactic nuclei (AGNs) taken with the Infrared Camera (IRC) on board $\it{AKARI}$. The 2.5-5.0 $\mu$m spectral region contains emission lines such as Br$\beta$ (2.63 $\mu$m), Br$\alpha$ (4.05 $\mu$m), and polycyclic aromatic hydrocarbons (PAH; 3.3 $\mu$m), which can be used for studying the black hole (BH) masses and star formation activities in the host galaxies of AGNs. The spectral region also suffers less dust extinction than in the ultra violet (UV) or optical wavelengths, which may provide an unobscured view of dusty AGNs. Our sample is selected from bright quasar surveys of Palomar-Green (PG) and SNUQSO, and AGNs with reverberation-mapped BH masses from Peterson et al. (2004). Using 11 AGNs with reliable detection of Brackett lines, we derive the Brackett-line-based BH mass estimators. We also find that the observed Brackett line ratios can be explained with the commonly adopted physical conditions of the broad line region (BLR). Moreover, we fit the hot and warm dust components of the dust torus by adding photometric data of SDSS, 2MASS, $\it{WISE}$, and $\it{ISO}$ to the $\it{AKARI}$ spectra, finding hot and warm dust temperatures of $\sim1100\,\rm{K}$ and $\sim220\,\rm{K}$, respectively, rather than the commonly cited hot dust temperature of 1500 K.
    The Astrophysical Journal Supplement Series 03/2015; 216(1):17. DOI:10.1088/0067-0049/216/1/17 · 14.14 Impact Factor
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    Jongsuk Hong, Hyung Mok Lee
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    ABSTRACT: Stellar black hole (BH) binaries are one of the most promising GW sources for GW detection by the ground-based detectors. Nuclear star clusters (NCs) located at the center of galaxies are known to harbor massive black holes (MBHs) and to be bounded by a gravitational potential by other galactic components such as the galactic bulge. Such an environment of NCs provides a favorable conditions for the BH-BH binary formation by the gravitational radiation (GR) capture due to the high BH number density and velocity dispersion. We carried out detailed numerical study of the formation of BH binaries in the NCs using a series of N-body simulations for equal-mass cases. There is no mass segregation introduced. We have derived scaling relations of the binary formation rate with the velocity dispersion of the stellar system beyond the radius of influence and made estimates of the rate of formation of black hole binaries per unit comoving volume and thus expected detection rate by integrating the binary formation rate over galaxy population within the detection distance of the advanced detectors. We find that the overall formation rates for BH-BH binaries per NC is 10^(-10)/yr for the Milky-Way-like galaxies and weakly dependent on the mass of MBH as M^(3/28). We estimate the detection rate of 0.02-14/yr for advanced LIGO/Virgo considering several factors such as the dynamical evolution of NCs, the variance of the number density of stars and the mass range of MBH giving uncertainties.
    Monthly Notices of the Royal Astronomical Society 01/2015; 448(1). DOI:10.1093/mnras/stv035 · 5.23 Impact Factor
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    ABSTRACT: We present the J- and H-band source catalog covering the AKARI North Ecliptic Pole field. Filling the gap between the optical data from other follow-up observations and mid-infrared (MIR) data from AKARI, our near-infrared (NIR) data provides contiguous wavelength coverage from optical to MIR. For the J- and H-band imaging, we used the FLoridA Multi-object Imaging Near-ir Grism Observational Spectrometer on the Kitt Peak National Observatory 2.1 m telescope covering a 5.1 deg2 area down to a 5σ depth of ~21.6 mag and ~21.3 mag (AB) for the J and H bands with an astrometric accuracy of 0.''14 and 0.''17 for 1σ in R.A. and decl. directions, respectively. We detected 208,020 sources for the J band and 203,832 sources for the H band. This NIR data is being used for studies including the analysis of the physical properties of infrared sources such as stellar mass and photometric redshifts, and will be a valuable data set for various future missions.
    The Astrophysical Journal Supplement Series 09/2014; 214(2):20. DOI:10.1088/0067-0049/214/2/20 · 14.14 Impact Factor
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    ABSTRACT: A compact infrared space telescope called MIRIS (Multi-purpose Infra-Red Imaging System) was developed by the Korea Astronomy and Space Science Institute (KASI), and launched onboard the Science and Technology Satellite-3 of Korea (STSAT-3) in 2013 November. The main mission of MIRIS is the Paschen-α emis-sion line survey along the Galactic plane and the cosmic infrared background (CIB) observation, particularly around the north ecliptic pole region. For these missions, a wide field of view (3:67 × 3:67°) with an angular resolution of 51.6″ and wavelength coverage from 0:9 ∼ 2:0 μm have been adopted for MIRIS, having optical components con-sisting of a 80 mm main lens and four other lenses with F/2 focal ratio optics. The opto-mechanical system was carefully designed to minimize any effects from shock during the launch process and thermal variation. Also, the telescope was designed to use a passive cooling technique to maintain the temperature around 200 K in order to reduce thermal noise. A micro Stirling cooler was used to cool down the Teledyne PICNIC infrared array to 90 K, which was equipped in a dewar with four filters for infrared passbands of I, H, and Paschen-α and a dual-band continuum line filter. MIRIS system was integrated into the STSAT-3 as its primary payload and successfully passed required tests in the laboratory, such as thermal-vacuum, vibration, and shock tests. MIRIS is now operating in sun synchronous orbits for initial tests and has observed its first images successfully.
    Publications of the Astronomical Society of the Pacific 09/2014; 126(943):853-862. DOI:10.1086/678130 · 3.23 Impact Factor
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    ABSTRACT: The United Kingdom Infrared Telescope (UKIRT) Widefield Infrared Survey for Fe$^+$ (UWIFE) is a 180 deg$^2$ imaging survey of the first Galactic quadrant (7$^{\circ}$ < l < 62$^{\circ}$; |b| < 1.5$^{\circ}$) using a narrow-band filter centered on the [Fe II] 1.644 {\mu}m emission line. The [Fe II] 1.644 {\mu}m 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 UKIRT Widefield Infrared Survey for H2 (UWISH2; Froebrich et al. 2011). The survey will also complement existing broad-band surveys. The observed images have a nominal 5{\sigma} detection limit of 18.7 mag for point sources, with the median seeing of 0.83". For extended sources, we estimate surface brightness limit of 8.1 x 10$^{-20}$ W m$^{-2}$ arcsec$^{-2}$ . In this paper, we present the overview and preliminary results of this survey.
    Monthly Notices of the Royal Astronomical Society 06/2014; 443(3). DOI:10.1093/mnras/stu1146 · 5.23 Impact Factor
  • Yeong-Bok Bae, Chunglee Kim, Hyung Mok Lee
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    ABSTRACT: Performing N-body simulations, we examine the dynamics of black hole-black hole (BH-BH) (10 M☉ each) and neutron star-neutron star (NS-NS) (1.4 M☉ each) binaries formed in a cluster and its implications for gravitational wave detection. A significant fraction of compact binaries are ejected from a globular cluster after core collapse. Among the total number of ejected compact objects, 30 per cent of them are in binaries. Merging time-scales of ejected binaries, which depend on the cluster's velocity dispersion, are in some cases shorter than the age of the Universe. During the merging event, these dynamically formed compact mergers are expected to produce gravitational waves that can be detectable by the advanced ground-based interferometers. Based on our reference assumptions, merger rates of ejected BH-BH and NS-NS binaries per globular cluster are estimated to be 2.5 and 0.27 per Gyr, respectively. Assuming the spatial density of globular clusters to be 8.4 h3 clusters Mpc-3 and extrapolating the merger rate estimates to the horizon distance of the advanced Laser Interferometer Gravitational Wave Observatory-Virgo network, we expect the detection rates for BH-BH and NS-NS binaries with cluster origin to be 15 and 0.024 yr-1, respectively. We find out that some of the dynamically formed binaries are ejected with a large escape velocity. They can be responsible for short gamma-ray bursts whose locations are far from host galaxies.
    Monthly Notices of the Royal Astronomical Society 04/2014; 440(3). DOI:10.1093/mnras/stu381 · 5.23 Impact Factor
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    ABSTRACT: Several lines of argument support the existence of a link between activity at the nuclei of galaxies, in the form of an accreting supermassive black hole, and star-formation activity in these galaxies. The exact nature of this link is still under debate. Radio jets have long been argued to be an ideal mechanism that allows AGN to interact with their host galaxy and regulate star-formation. In this context, we are using a sample of radio sources in the North Ecliptic Pole (NEP) field to study the nature of the putative link between AGN activity and star-formation. This is done by means of spectral energy distribution (SED) fitting. We use the excellent spectral coverage of the AKARI infrared space telescope together with the rich ancillary data available in the NEP to build SEDs extending from UV to far-IR wavelengths. Through SED fitting we constrain both the AGN and host galaxy components. We find a significant AGN component in our sample of relatively faint radio-sources ($<$mJy), that increases in power with increasing radio-luminosity. At the highest radio-luminosities, the presence of powerful jets dominates the radio emission of these sources. A positive correlation is found between the luminosity of the AGN component and that of star-formation in the host galaxy, independent of the radio luminosity. By contrast, for a given redshift and AGN luminosity, we find that increasing radio-luminosity leads to a decrease in the specific star-formation rate. The most radio-loud AGN are found to lie on the main sequence of star-formation for their respective redshifts. For the first time, such a two-sided feedback process is seen in the same sample. We conclude that radio jets do suppress star-formation in their host galaxies but appear not to totally quench it. Our results therefore support the maintenance nature of "radio-mode" feedback from radio-AGN jets.
    The Astrophysical Journal 09/2013; 784(2). DOI:10.1088/0004-637X/784/2/137 · 6.28 Impact Factor
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    ABSTRACT: We present tentative H-alpha emission line detections of four submillimetre-detected galaxies at z>3.5: the radio galaxies 8C1909+722 and 4C60.07 at signal-to-noise ratios (SNRs) of 3.1 and 2.5, and two submillimetre-selected galaxies (SMGs) near the first of these at SNRs of 10.0 and 2.4, made with the AKARI Space Telescope as part of the FUHYU mission program. These are the highest-redshift H-alpha detections in such galaxies, made possible by AKARI's unique near-infrared spectroscopic capability. The two radio galaxies had known redshifts and surrounding structure, and we have detected broad H-alpha components indicating the presence of dust-shrouded quasars. We conclude that powerful AGNs at z>3.5 occur in peaks of the star-formation density fields, supporting a close connection between stellar mass build-up and black hole mass assembly at this redshift. We also show that 4C60.07 is a binary AGN. The H-alpha detections of the two SMGs are the first redshift determinations for these sources, confirming their physical association around their companion radio galaxy. The H-alpha-derived star formation rates (SFRs) for the SMGs are lower than their far-infrared derived SFRs by a factor of ~10, suggesting a level of dust obscuration similar to that found in studies at ~1<z<2.7.
    Monthly Notices of the Royal Astronomical Society 08/2013; 436(1). DOI:10.1093/mnras/stt1572 · 5.23 Impact Factor
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    Yeong-Bok Bae, Chunglee Kim, Hyung Mok Lee
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    ABSTRACT: Performing N-body simulations, we examine the dynamics of BH-BH (10 Msun each) and NS-NS (1.4 Msun each) binaries formed in a cluster and its implications for gravitational wave detection. A significant fraction of compact binaries are ejected from a globular cluster after core collapse. Among the total number of ejected compact objects, 30 per cent of them are in binaries. Merging time-scales of ejected binaries, which depend on the cluster's velocity dispersion, are in some cases shorter than the age of the universe. During the merging event, these dynamically formed compact mergers are expected to produce gravitational waves that can be detectable by the advanced ground-based interferometers. Based on our reference assumptions, merger rates of ejected BH-BH and NS-NS binaries per globular cluster are estimated to be 2.5 and 0.27 per Gyr, respectively. Assuming the spatial density of globular clusters to be 8.4 h^3 clusters Mpc^-3 and extrapolating the merger rate estimates to the horizon distance of the advanced LIGO-Virgo network, we expect the detection rates for BH-BH and NS-NS binaries with cluster origin are to be 15 and 0.024 yr^-1, respectively. We find out that some of the dynamically formed binaries are ejected with a large escape velocity. They can be responsible for short gamma-ray bursts whose locations are far from host galaxies.
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    ABSTRACT: We present spectra of 1796 sources selected in the AKARI North Ecliptic Pole Wide Survey field, obtained with MMT/Hectospec and WIYN/Hydra, for which we measure 1645 redshifts. We complemented the generic flux-limited spectroscopic surveys at 11 μm and 15 μm, with additional sources selected based on the MIR and optical colors. In MMT/Hectospec observations, the redshift identification rates are ~80% for objects with R < 21.5 mag. On the other hand, in WIYN/Hydra observations, the redshift identification rates are ~80% at R magnitudes brighter than 19 mag. The observed spectra were classified through the visual inspection or from the line diagnostics. We identified 1128 star-forming or absorption-line-dominated galaxies, 198 Type-1 active galactic nuclei (AGNs), 8 Type-2 AGNs, 121 Galactic stars, and 190 spectra in unknown category due to low signal-to-noise ratio. The spectra were flux-calibrated but to an accuracy of 0.1-0.18 dex for most of the targets and worse for the remainder. We derive star formation rates (SFRs) from the mid-infrared fluxes or from the optical emission lines, showing that our sample spans an SFR range of 0.1 to a few hundred M ☉ yr–1. We find that the extinction inferred from the difference between the IR and optical SFR increases as the IR luminosity increases but with a large scatter.
    The Astrophysical Journal Supplement Series 08/2013; 207(2):37. DOI:10.1088/0067-0049/207/2/37 · 14.14 Impact Factor
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    ABSTRACT: We present a fully general relativistic open-source code that can be used for simulating a system of spherically symmetric perfect fluid matter. It is based on the Arnowitt-Deser-Misner 3+1 formalism with maximal slicing and isotropic spatial coordinates. For hydrodynamic matter High Resolution Shock Capturing (HRSC) schemes with a monotonized central-difference limiter and approximated Riemann solvers are used in the Eulerian viewpoint. The accuracy and the convergence of our numerical code are verified by performing several test problems. These include a relativistic blast wave, relativistic spherical accretion of matter into a black hole, Tolman-Oppenheimer-Volkoff (TOV) stars and Oppenheimer-Snyder (OS) dust collapses. In particular, a dynamical code test is done for the OS collapse by explicitly performing numerical coordinate transformations between our coordinate 8system and the one used for the analytic solution. Finally, some TOV star solutions are presented for the Eddington-inspired Born-Infeld gravity theory.
    Journal- Korean Physical Society 02/2013; 62(3). DOI:10.3938/jkps.62.393 · 0.43 Impact Factor
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    ABSTRACT: Polycyclic aromatic hydrocarbon (PAH) emission features dominate the mid-infrared spectra of star-forming galaxies and can be useful to calibrate star formation rates (SFRs) and diagnose ionized states of grains. However, the PAH 3.3 {mu}m feature has not been studied as much as other PAH features since it is weaker than others and resides outside of Spitzer capability. In order to detect and calibrate the 3.3 {mu}m PAH emission and investigate its potential as an SFR indicator, we carried out an AKARI mission program, AKARI mJy Unbiased Survey of Extragalactic Sources (AMUSES), and compared its sample with various literature samples. We obtained 2-5 {mu}m low-resolution spectra of 20 flux-limited galaxies with mixed spectral energy distribution classes, which yielded the detection of the 3.3 {mu}m PAH emission from 3 out of 20 galaxies. For the combined sample of AMUSES and literature samples, the 3.3 {mu}m PAH luminosities correlate with the infrared luminosities of star-forming galaxies, albeit with a large scatter (1.5 dex). The correlation appears to break down at the domain of ultraluminous infrared galaxies (ULIRGs), and the power of the 3.3 {mu}m PAH luminosity as a proxy for the infrared luminosity is hampered at log[L {sub PAH3.3} erg{sup -1} s{sup -1}] > {approx}42.0. Possible origins for this deviation in the correlation are discussed, including contributions from active galactic nuclei and strongly obscured young stellar objects, and the destruction of PAH molecules in ULIRGs.
    The Astrophysical Journal 12/2012; 760(2). DOI:10.1088/0004-637X/760/2/120 · 6.28 Impact Factor
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    ABSTRACT: To understand the effects of the initial rotation on the evolution of the tidally limited clusters with mass spectrum, we have performed N-body simulations of the clusters with different initial rotations and compared the results with those of the Fokker-Planck (FP) simulations. We confirmed that the cluster evolution is accelerated by not only the initial rotation but also the mass spectrum. For the slowly rotating models, the time evolutions of mass, energy and angular momentum show good agreements between N-body and FP simulations. On the other hand, for the rapidly rotating models, there are significant differences between these two approaches at the early stage of the evolutions because of the development of bar instability in N-body simulations. The shape of the cluster for N-body simulations becomes tri-axial or even prolate, which cannot be produced by the 2-dimensional FP simulations. The total angular momentum and the total mass of the cluster decrease rapidly while bar-like structure persists. After the rotational energy becomes smaller than the critical value for the bar instability, the shape of the cluster becomes nearly axisymmetric again, and follows the evolutionary track predicted by the FP equation. We have confirmed again that the energy equipartiton is not completely achieved when M2/M1(m2>/m1)^(3/2) > 0.16. By examining the angular momentum at each mass component, we found that the exchange of angular momentum between different mass components occurs, similar to the energy exchange leading to the equipartition.
    Monthly Notices of the Royal Astronomical Society 11/2012; 430(4). DOI:10.1093/mnras/stt099 · 5.23 Impact Factor
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    ABSTRACT: Fokker-Planck simulations for rotating star clusters: I. Equal-mass system
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    ABSTRACT: (Received –; accepted –) We present the properties of 11 µm selected sources detected in the early data of the North Ecliptic Pole Deep (NEP-Deep) Survey of AKARI. The data set covers 6 wavelength bands from 2.5 to 11 µm, with the exposure time of 10 ∼ 20 minutes. This field lies within the CFHT survey with four filter bands (g ′,r ′,i ′,z ′), enabling us to establish nearly continuous spectral energy distributions (SEDs) for wavelengths ranging from 0.4 to 11 µm. The main sample studied here consists of 72 sources whose 11 µm AB magnitudes are equal to or brighter than 18.5 (251 µJy), which is complete to more than 90%. The 11 µm band has an advantage of sampling star forming galaxies with low to medium redshifts since the prominent PAH feature shifts into this band. As expected, we find that the majority ( 69%) of 11 µm bright sources are star forming galaxies at 0.2 < ∼ z < ∼ 0.7 with LIR ∼ 10 10 – 10 12 L ⊙ based on the detailed modelling of SEDs. We also find four AGNs lying at various redshifts in the main sample. In addition, we discuss a few sources which have non-typical SEDs of the main sample, including a brown dwarf candidate, a steep power-law source, flat spectrum object, and an early-type galaxy at moderate redshift.
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    ABSTRACT: There is a huge gap between properties of red-sequence selected massive galaxy clusters at z < 1 and Lyman-break selected proto-clusters at z> 3. It is important to understand when and how the z> 3 proto-clusters evolve into passive clusters at z < 1. We aim to fill this cluster desert by using the space-based N4(4µm) imaging with the AKARI. The z ′ −N4 color is a powerful separator of cluster galaxies at z> 1, taking advantage of the 4000˚A break and the 1.6µm bump. We carefully selected 16 promising cluster candidates at 0.9 < z < 1.7, which all show obvious over-density of galaxies and a prominent red-sequence. At this redshift range, the mid-infrared S15µm/S9µm flux ratio is an extinction-free indicator of galaxy star formation activity due to the redshifted PAH emission lines (6.2,7.7 and 8.6µm). We show statistically that the cluster galaxies have a lower S15µm/S9µm flux ratio than field galaxies, i.e., cluster galaxies already have lower star-formation activity at 0.9 < z < 1.7, pushing the formation epoch of these galaxy clusters
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    ABSTRACT: This paper presents emission line detections for four galaxies at z > 3.5 made with AKARI as part of the FUHYU mission program. These are the highest-redshift detections to date in star-forming galaxies. AKARI's unique near-infrared spectroscopic capability has made these detections possible. For two of these galaxies, this represents the first evidence of their redshifts and confirms their physical association with a companion radio galaxy. The star formation rates (SFRs) estimated from the lines under-predict the SFRs estimated from their far-infrared luminosities by a factor of ~ 2 - 3. We have also detected broad components in the two radio galaxies which indicate the presence of quasars.
    11/2012; 27(4):357-360. DOI:10.5303/PKAS.2012.27.4.357

Publication Stats

1k Citations
414.95 Total Impact Points

Institutions

  • 1999–2015
    • Seoul National University
      • • Department of Physics and Astronomy
      • • Department of Earth and Environmental Sciences
      Sŏul, Seoul, South Korea
    • Kyungpook National University
      • Department of Astronomy and Atmospheric Sciences
      Daikyū, Daegu, South Korea
  • 2012
    • Korea Aerospace Research Institute
      Sŏul, Seoul, South Korea
  • 2010
    • Korea Astronomy and Space Science Institute
      • Division of Space Science
      Daiden, Daejeon, South Korea
  • 2007
    • University of Massachusetts Amherst
      Amherst Center, Massachusetts, United States
  • 2004
    • University of Kent
      • Center for Astrophysics and Planetary Science
      Cantorbery, England, United Kingdom
  • 1997–1998
    • Pusan National University
      Tsau-liang-hai, Busan, South Korea
    • Korea Advanced Institute of Science and Technology
      • Department of Physics
      Sŏul, Seoul, South Korea
  • 1990
    • McMaster University
      Hamilton, Ontario, Canada
  • 1988–1990
    • University of Toronto
      Toronto, Ontario, Canada