Multi-Object InfraRed Camera And Spectrograph Research Articles

An AGN with an Ionized Gas Outflow in a Massive Quiescent Galaxy in a Protocluster at z = 3.09

We report the detection of an ionized gas outflow from an X-ray active galactic nucleus hosted in a massive quiescent galaxy in a protocluster at z = 3.09 (J221737.29+001823.4). It is a type-2 QSO with broad (W 80 > 1000 km s−1) and strong (/erg s−1) ≈ 43.4) [O iii]λ λ 4959,5007 emission lines detected by slit spectroscopy in three-position angles using Multi-Object Infra-Red Camera and Spectrograph (MOIRCS) on the Subaru telescope and the Multi-Object Spectrometer For Infra-Red Exploration (MOSFIRE) on the Keck-I telescope. In the all slit directions, [O iii] emission is extended to ∼15 physical kpc and indicates a powerful outflow spreading over the host galaxy. The inferred ionized gas mass outflow rate is 22 ± 3 M ⊙ yr−1. Although it is a radio source, according to the line diagnostics using Hβ, [O ii], and [O iii], photoionization by the central QSO is likely the dominant ionization mechanism rather than shocks caused by radio jets. On the other hand, the spectral energy distribution of the host galaxy is well characterized as a quiescent galaxy that has shut down star formation several hundred Myr ago. Our results suggest a scenario that QSOs are powered after the shutdown of the star formation and help complete the quenching of massive quiescent galaxies at high redshift.

A Planck-selected dusty proto-cluster at z = 2.16 associated with a strong overdensity of massive Hα-emitting galaxies

ABSTRACT We have discovered an overdensity of Hα-emitting galaxies associated with a Planck compact source in the COSMOS field (PHz G237.0+42.5) through narrow-band imaging observations with the Subaru Multi-Object InfraRed Camera and Spectrograph (MOIRCS). This Planck-selected dusty proto-cluster at z = 2.16 has 38 Hα emitters including six spectroscopically confirmed galaxies in the observed MOIRCS 4 × 7 arcmin2 field (corresponding to ∼2.0 × 3.5 Mpc2 in the physical scale). We find that massive Hα emitters with log (M⋆/M⊙) >10.5 are strongly clustered in the core of the proto-cluster (within ∼300 kpc from the density peak of the Hα emitters). Most of the Hα emitters in this proto-cluster lie along the star-forming main sequence using Hα-based estimates of the star formation rate (SFR). Meanwhile, the cluster total SFRs derived by integrating the Hα-based SFRs is an order of magnitude smaller than those estimated from Planck/Herschel far-infrared photometry. Our results suggest that Hα is a good observable for detecting moderately star-forming galaxies and for tracing the large-scale environment in and around high-redshift dusty proto-clusters. However, there is a possibility that a large fraction of star formation could be obscured by dust and undetected in Hα observations.

Novel gratings for astronomical observation

The choice of transmission grating can facilitate downsizing of a spectrograph and make it possible to achieve a perfect Littrow configuration. We are developing transmission gratings for next-generation instruments for the 8.2 m Subaru Telescope, the Thirty Meter Telescope (TMT), and other ground-based and space-borne telescopes. These include, a volume binary grating developed for an echelle grism (direct vision grating) for the Subaru Multi-Object InfraRed Camera and Spectrograph (MOIRCS); a reflector facet transmission (RFT) grating, a surface relief grating with sawtooth-shaped ridges of an acute vertex angle, expected to be deployed for the TMT Wide Field Optical Spectrograph (WFOS), and a hybrid grism for use as a medium-dispersion grism in MOIRCS, developed as a prototype of RFT grating. We describe the simulation results, fabrication methods, and experimental results of these prototype transmission gratings in this article.

An extremely dense group of massive galaxies at the centre of the protocluster atz= 3.09 in the SSA22 field

We report the discovery of an extremely dense group of massive galaxies at the centre of the protocluster at $z=3.09$ in the SSA22 field from near-infrared spectroscopy conducted with the Multi-Object InfraRed Camera and Spectrograph (MOIRCS) equipped on the Subaru Telecope. The newly discovered group comprises seven galaxies confirmed at $z_{\rm spec}\approx3.09$ within 180 kpc including five massive objects with the stellar masses larger than $10^{10.5}~M_{\odot}$ and is associated with a bright sub-mm source SSA22-AzTEC14. The dynamical mass of the group estimated from the line-of-sight velocity dispersion of the members is $M_{\rm dyn}\sim1.6\pm0.3\times10^{13}~M_{\odot}$. Such a dense group is expected to be very rare at high redshift as we found only a few comparable systems in large-volume cosmological simulations. Such rare groups in the simulations are hosted in collapsed halos with $M_{\rm vir}=10^{13.4}-10^{14.0}~M_{\odot}$ and evolve into the brightest cluster galaxies (BCGs) of the most massive clusters at present. The observed AzTEC14 group at $z=3.09$ is therefore very likely to be a proto-BCG in the multiple merger phase. The observed total stellar mass of the group is $5.8^{+5.1}_{-2.0}\times10^{11}~M_{\odot}$. It suggests that over half the stellar mass of its descendant had been formed by $z=3$. Moreover, we identified over two members for each of the four Ly$\alpha$ blobs (LABs) using our new spectroscopic data. This verifies our previous argument that many of the LABs in the SSA22 protocluster associated with multiple developed stellar components.

An early phase of environmental effects on galaxy properties unveiled by near-infrared spectroscopy of protocluster galaxies at z > 2

This work presents the results from our near-infrared spectroscopy of narrow-band selected H$\alpha$ emitters (HAEs) in two rich over-densities (PKS 1138-262 at $z=2.2$ and USS 1558-003 at $z=2.5$) with the Multi-Object Infrared Camera and Spectrograph (MOIRCS) on the Subaru telescope. These protoclusters are promising candidates for the most massive class of galaxy clusters seen today (Paper I). The confirmed HAEs in the protoclusters at $z>2$ show high excitation levels as characterized by much higher [OIII]/H$\beta$ or [OIII]/H$\alpha$ line ratios than those of general galaxies at low-$z$. Such a high excitation level may not only be driven by high specific star formation rates (sSFRs) and lower gaseous metallicities, but also be contributed by some other effects. We investigate the environmental dependence of gaseous metallicities by comparing the HAEs in the protoclusters with those in the general field at similar redshifts. We find that the gaseous metallicities of protocluster galaxies are more chemically enriched than those of field galaxies at a given stellar mass in the range of M$_\star\lesssim10^{11}$ M$_\odot$. This can be attributed to many processes, such as intrinsic (or nature) effects, external (or nurture) effects, and/or some systematic sampling effects. We also find that the offset of the mass-metallicity relation in dense environment becomes larger at higher redshifts. This can be naturally understood by the fact that the in/out-flow rates in star forming galaxies are much higher at higher redshifts. Therefore the environmental dependence of such "feeding" and "feedback" mechanisms in galaxy formation are probably playing major roles in producing the offset of the mass-metallicity relation for the protocluster galaxies at $z>2$.

Environmental dependence of galaxy formation explored by near-infrared spectroscopy of two protoclusters at z>2

AbstractProtoclusters at high redshifts are the ideal laboratories to study how the environmental dependences of galaxy properties seen in local Universe were initially set up when the progenitors of present-day early-type galaxies were in their early formation phases. We have conducted a deep near-infrared spectroscopy of Hα emitters (HAEs) associated with two protoclusters (PKS 1138–262 at z = 2.16 and USS 1558–003 at z = 2.53) with the Multi-Object Infrared Camera and Spectrograph (MOIRCS) on the Subaru telescope.As a result, the cluster membership of 27 and 36 HAEs are newly confirmed in these two protoclusters, respectively. The inferred dynamical masses of the protocluster cores are consistent with being the typical progenitors of present-day most massive clusters (Shimakawa et al.2014a). Also, those HAEs in the protoclusters show much higher [OIII]/Hβ ratios than local star forming galaxies. It is probably caused by the combination of their much higher specific star formation rates, lower gaseous metallicities and redshift evolution of inter-stellar medium. We also find that the mass-metallicity relation in the protocluster galaxies is offset to higher metallicity compared to those of field galaxies at a given stellar mass at M∗<1011M⊙ (Shimakawa et al.2014b). This trend is compatible with the recent work (Kulas et al.2013). The mass-metallicity relation is regulated not only by star formation history hence metal production history, but also by inflow and outflow processes that are known to be very active at z > 2 (Steide et al.2010). It suggests that the higher gaseous metallicities of protocluster galaxies may be caused by those gas transfer processes that are dependent on surrounding environments.

Identification of the progenitors of rich clusters and member galaxies in rapid formation at z > 2

Abstract We present the results of near-infrared spectroscopy of Hα emitters (HAEs) associated with two protoclusters around radio galaxies (PKS 1138−262 at z = 2.2 and USS 1558−003 at z = 2.5) with the Multi-Object Infrared Camera and Spectrograph (MOIRCS) on the Subaru telescope. Among the HAE candidates constructed from our narrow-band imaging, we have confirmed membership of 27 and 36 HAEs for the respective protoclusters, with a success rate of 70 per cent of our observed targets. The large number of spectroscopically confirmed members per cluster has enabled us for the first time to reveal the detailed kinematical structures of the protoclusters at z > 2. The clusters show prominent substructures such as clumps, filaments and velocity gradients, suggesting that they are still in the midst of rapid construction to grow to rich clusters at later times. We also estimate the dynamical masses of the clusters and substructures, assuming their local virialization. The inferred masses (∼1014 M⊙) of the protocluster cores are consistent with their being typical progenitors of the present-day most massive class of galaxy clusters (∼1015 M⊙) if we take into account the typical mass growth history of clusters. We then calculate the integrated star formation rates of the protocluster cores normalized by the dynamical masses and compare these with lower redshift descendants. We see a marked increase of star-forming activities in the cluster cores, by almost three orders of magnitude, as we go back in time to 11 billion years ago; this scales as (1 + z)6.

MOIRCS Deep Survey. IX. Deep Near-Infrared Imaging Data and Source Catalog

Abstract We present deep $J$-, $H$-, and $K_{\rm s}$-band imaging data of the MOIRCS Deep Survey (MODS), which was carried out with the Multi-Object Infrared Camera and Spectrograph (MOIRCS) mounted on the Subaru Telescope in the GOODS-North region. The data reach 5$\ \sigma$ total limiting magnitudes for point sources of $J$$=$ 23.9, $H$$=$ 22.8, and $K_{\rm s}$$=$ 22.8 (Vega magnitude) over 103 arcmin$^{2}$ (wide field). In 28 arcmin$^{2}$ of the survey area, which is an ultra-deep field of the MODS (deep field), the data reach 5$\ \sigma$ depths of $J$$=$ 24.8, $H$$=$ 23.4, and $K_{\rm s}$$=$ 23.8. The spatial resolutions of the combined images are FWHM $\sim\ $0$''\!\!\!.$6 and $\sim\ $0$''\!\!\!.$5 for the wide and deep fields in all bands, respectively. Combining the MODS data with the multi-wavelength public data taken with the HST, Spitzer, and other ground-based telescopes in the GOODS field, we constructed a multi-wavelength photometric catalog of $K_{\rm s}$-selected sources. Using the catalog, we present $K_{\rm s}$-band number counts and near-infrared color distribution of the detected objects; we also demonstrate some selection techniques with the NIR colors for high redshift galaxies. These data and catalog are publicly available via Internet.

MOIRCS DEEP SURVEY. VIII. EVOLUTION OF STAR FORMATION ACTIVITY AS A FUNCTION OF STELLAR MASS IN GALAXIES SINCEz∼ 3

We study the evolution of star formation activity of galaxies at 0.5<z<3.5 as a function of stellar mass, using very deep NIR data taken with Multi-Object Infrared Camera and Spectrograph (MOIRCS) on the Subaru telescope in the GOODS-North region. The NIR imaging data reach K ~ 23-24 Vega magnitude and they allow us to construct a nearly stellar mass-limited sample down to ~ 10^{9.5-10} Msun even at z~3. We estimated star formation rates (SFRs) of the sample with two indicators, namely, the Spitzer/MIPS 24um flux and the rest-frame 2800A luminosity. The SFR distribution at a fixed Mstar shifts to higher values with increasing redshift at 0.5<z<3.5. More massive galaxies show stronger evolution of SFR at z>~1. We found galaxies at 2.5<z<3.5 show a bimodality in their SSFR distribution, which can be divided into two populations by a constant SSFR of ~2 Gyr^{-1}. Galaxies in the low-SSFR group have SSFRs of ~ 0.5-1.0 Gyr^{-1}, while the high-SSFR population shows ~10 Gyr^{-1}. The cosmic SFRD is dominated by galaxies with Mstar = 10^{10-11} Msun at 0.5<z<3.5, while the contribution of massive galaxies with Mstar = 10^{11-11.5} Msun shows a strong evolution at z>1 and becomes significant at z~3, especially in the case with the SFR based on MIPS 24um. In galaxies with Mstar = 10^{10-11.5} Msun, those with a relatively narrow range of SSFR (<~1 dex) dominates the cosmic SFRD at 0.5<z<3.5. The SSFR of galaxies which dominate the SFRD systematically increases with redshift. At 2.5<z<3.5, the high-SSFR population, which is relatively small in number, dominates the SFRD. Major star formation in the universe at higher redshift seems to be associated with a more rapid growth of stellar mass of galaxies.

THE RESOLVED NEAR-INFRARED EXTRAGALACTIC BACKGROUND

We present a current best estimate of the integrated near-infrared (NIR) extragalactic background light (EBL) attributable to resolved galaxies in J, H, and Ks. Our results in units of nW m-2 sr-1 are 11.7+5.6 -2.6 in J, 11.5+4.5 -1.5 in H and 10.0+2.8 -0.8 in Ks. We derive these new limits by combining our deep wide-field NIR photometry from five widely separated fields with other studies from the literature to create a galaxy counts sample that is highly complete and has good counting statistics out to JHKs ~ 27-28. As part of this effort we present new ultradeep Ks-band galaxy counts from 22 hours of observations with the Multi Object Infrared Camera and Spectrograph (MOIRCS) instrument on the Subaru Telescope. We use this MOIRCS Ks-band mosaic to estimate the total missing flux from sources beyond our detection limits. Our new limits to the NIR EBL are in basic agreement with, but 10 - 20% higher than previous estimates, bringing them into better agreement with estimates of the total NIR EBL (resolved + unresolved sources) obtained from TeV gamma-ray opacity measurements and recent direct measurements of the total NIR EBL. We examine field to field variations in our photometry to show that the integrated light from galaxies is isotropic to within uncertainties, consistent with the expected large-scale isotropy of the EBL. Our data also allow for a robust estimate of the NIR light from Galactic stars, which we find to be 14.7 +/- 2.4 in J, 10.1 +/- 1.9 in H and 7.6 +/- 1.8 in Ks in units of nW m-2 sr-1.

A z = 1.82 ANALOG OF LOCAL ULTRA-MASSIVE ELLIPTICAL GALAXIES

We present observations of a very massive galaxy at z=1.82 which show that its morphology, size, velocity dispersion and stellar population properties that are fully consistent with those expected for passively evolving progenitors of today's giant ellipticals. These findings are based on a deep optical rest-frame spectrum obtained with the Multi-Object InfraRed Camera and Spectrograph (MOIRCS) on the Subaru telescope of a high-z passive galaxy candidate (pBzK) from the COSMOS field, for which we accurately measure its redshift of z=1.8230 and obtain an upper limit on its velocity dispersion sigma_star<326 km/s. By detailed stellar population modeling of both the galaxy broad-band SED and the rest-frame optical spectrum we derive a star-formation-weighted age and formation redshift of t_sf~1-2 Gyr and z_form~2.5-4, and a stellar mass of M_star~(3-4)x10^{11} M_sun. This is in agreement with a virial mass limit of M_vir<7x10^{11}M_sun, derived from the measured sigma_star value and stellar half-light radius, as well as with the dynamical mass limit based on the Jeans equations. In contrast with previously reported super-dense passive galaxies at z~2, the present galaxy at z=1.82 appears to have both size and velocity dispersion similar to early-type galaxies in the local Universe with similar stellar mass. This suggests that z~2 massive and passive galaxies may exhibit a wide range of properties, then possibly following quite different evolutionary histories from z~2 to z=0.

REDDENING AND DISTANCE OF THE LOCAL GROUP STARBURST GALAXY IC 10

We estimate the reddening and distance of the nearest starburst galaxy IC 10 using deep near infrared $JHK_{S}$ photometry obtained with the Multi-Object InfraRed Camera and Spectrograph (MOIRCS) on the Subaru telescope. We estimate the foreground reddening toward IC 10 using $UBV$ photometry of IC 10 from the Local Group Survey, obtaining $E(B-V)=0.52\pm 0.04$ mag. We derive the total reddening including the internal reddening, $E(B-V)=0.98\pm 0.06$ mag, using $UBV$ photometry of early-type stars in IC 10 and comparing $JHK_{S}$ photometry of red giant branch stars in IC 10 and the SMC. Using the 2MASS point source catalog of 20 Galactic globular clusters, we derive a relation between the metallicity [Fe/H]$_{CG97}$ and the slope of the red giant branch in the $K_{S}- (J-K_{S})$ color-magnitude diagram. The mean metallicity of the red giant branch stars in IC 10 is estimated to be [Fe/H]$_{CG97}=-1.08\pm0.28$. The magnitude of the tip of the red giant branch (TRGB) of IC 10 in the $K_{S}$ band is measured to be $K_{S,TRGB}=18.28\pm0.01$. Based on the TRGB method, we estimate the distance modulus of IC 10 to be $(m-M)_{0}=24.27\pm0.03{\rm (random)}\pm0.18{\rm (systematic)}$, corresponding to the distance of $d=715\pm10\pm60$ kpc. This confirms that IC 10 is a member of the Local Group.

SUBSTELLAR OBJECTS IN NEARBY YOUNG CLUSTERS (SONYC): THE BOTTOM OF THE INITIAL MASS FUNCTION IN NGC 1333

SONYC-Substellar Objects in Nearby Young Clusters-is a survey program to investigate the frequency and properties of substellar objects with masses down to a few times that of Jupiter in nearby star-forming regions. Here, we present the first results from SONYC observations of NGC 1333, a {approx}1 Myr old cluster in the Perseus star-forming complex. We have carried out extremely deep optical and near-infrared imaging in four bands (i', z', J, K) using Subaru Prime Focus Camera and Multi-Object InfraRed Camera and Spectrograph (MOIRCS) instruments at the Subaru telescope. The survey covers 0.25 deg{sup 2} and reaches completeness limits of 24.7 mag in the i' band and 20.8 mag in the J band. We select 196 candidates with colors as expected for young, very low mass objects. Follow-up multi-object spectroscopy with MOIRCS is presented for 53 objects. We confirm 19 objects as likely brown dwarfs (BDs) in NGC 1333, seven of them previously known. Nine additional objects are classified as possible stellar cluster members, likely with early to mid M spectral types. The confirmed objects are strongly clustered around the peak in the gas distribution and the core of the cluster of known stellar members. For 11 of them, we confirmmore » the presence of disks based on Spitzer/Infrared Array Camera photometry. The effective temperatures for the BD sample range from 2500 K to 3000 K, which translates to masses of {approx}0.015-0.1 M{sub sun}, based on model evolutionary tracks. For comparison, the completeness limit of our survey translates to mass limits of 0.004 M{sub sun} for A{sub V} {approx}< 5 mag or 0.008 M{sub sun} for A{sub V} {approx}< 10 mag. Compared with other star-forming regions, NGC 1333 shows an overabundance of BDs relative to low-mass stars, by a factor of 2-5. On the other hand, NGC 1333 has a deficit of planetary-mass objects: based on the surveys in {sigma} Orionis, the Orion Nebula Cluster and Chamaeleon I, the expected number of planetary-mass objects in NGC 1333 is 8-10, but we find none. It is plausible that our survey has detected the minimum mass limit for star formation in this particular cluster, at around 0.012-0.02 M{sub sun}. If confirmed, our findings point to significant regional/environmental differences in the number of BDs and the minimum mass of the initial mass function.« less

Multi-Object Infrared Camera and Spectrograph (MOIRCS) for the Subaru Telescope* I. Imaging

Abstract MOIRCS is a fully cryogenic near-infrared instrument for the 8.2 m Subaru Telescope. MOIRCS has two observation modes: a wide-field imaging mode and a multiobject spectroscopy mode. This paper describes the imaging mode, its specifications, and actual performances that we confirmed through laboratory tests and commissioning observations. The imaging mode provides a 4' $\times$ 7' field of view with a pixel scale of 0”.117pixel$^{-1}$ in the wavelength range of 0.85 to 2.5$\mu$ using cooled optics and two 2048 $\times$ 2048 HgCdTe HAWAII-2 focal plane arrays. Good-quality images are obtained over the entire field of view with practically no chromatic aberration. The limiting magnitudes for a point source estimated from observed background brightness and throughput are 23.7 in the $J$ band, 23.0 in the $H$ band, and 22.6 in the $K_{\rm s}$ band (Vega) with $S/N$$=$ 5, 0”.5 seeing, 1”.0 aperture, and 1hr exposure.

The first appearance of the red sequence of galaxies in proto-clusters at 2 lsimzlsim 3

We explore the evolved galaxy population in the proto-clusters around four high-z radio galaxies at 2 ≤ z ≤ 3 based on wide-field near-infrared (NIR) imaging. Three of the four fields are known proto-clusters as demonstrated by overdensities of line-emitting galaxies at the same redshifts as the radio galaxies found by narrow-band surveys and spectroscopic follow-up observations. We imaged the fields of three targets (PKS 1138-262, USS 0943-242 and MRC 0316-257) to a depth of K s ∼ 22 (Vega magnitude, 5σ) over a 4 x 7 arcmin 2 area centred on the radio galaxies with a new wide-field NIR camera, Multi-Object Infra-Red Camera and Spectrograph (MOIRCS), on the Subaru Telescope. Another target (USS 1558-003) was observed with Son of ISAAC on the New technology Telescope (NTT) to a depth of K s = 20.5 (5σ) over a 5 x 5 arcmin 2 area. We apply colour cuts in J-K s and/or JHK s in order to exclusively search for galaxies located at high redshifts: z > 2. To the 5σ limiting magnitudes, we see a significant excess of NIR-selected galaxies by a factor of 2 to 3 compared to those found in the field of GOODS-South. The spatial distribution of these NIR-selected galaxies is not uniform and traces structures similar to those of emission-line galaxies, although the samples of NIR-selected galaxies and emitters show little overlap, from which we conclude that the former tend to be an evolved population with much higher stellar mass than the latter, young and active emitters. We focus on the NIR colour-magnitude sequence of the evolved population and find that the bright-end (M stars > 10 11 M ⊙ ) of the red sequence is well populated by z ∼ 2 but much less so in the z ∼ 3 proto-clusters. This may imply that the bright-end of the colour-magnitude sequence first appeared between z = 3 and 2, an era coinciding with the appearance of sub-mm galaxies and the peak of the cosmic star formation rate. Our observations show that during the same epoch, massive galaxies are forming in high-density environments by vigorous star formation and assembly.

MOIRCS Deep Survey. I: DRG Number Counts

Abstract We used very deep near-infrared imaging data taken with the Multi-Object InfraRed Camera and Spectrograph (MOIRCS) on the Subaru Telescope to investigate the number counts of Distant Red Galaxies (DRGs). We observed a $4' \times 7'$ field in the Great Observatories Origins Deep Survey-North (GOODS-N), and our data reached $J=24.6$ and $K=23.2$ ($5\,\sigma$, Vega magnitude). The surface density of DRGs selected by $J-K \gt 2.3 J-K \gt 2.3$ is $2.35 \pm 0.31 \,\mathrm{arcmin}^{-2}$ at $K &amp;lt; 22$ and $3.54 \pm 0.38 \,\mathrm{arcmin}^{-2}$ at $K &amp;lt; 23$, respectively. These values are consistent with those in the GOODS-South and FIRES. Our deep and wide data suggest that the number counts of DRGs turn over at $K \sim 22$, and the surface density of the faint DRGs with $K \gt 22$ is smaller than that expected from the number counts at the brighter magnitude. The result indicates that while there are many bright galaxies at $2 &amp;lt; z &amp;lt; 4$ with the relatively old stellar population and/or heavy dust extinction, the number of faint galaxies with a similar red color is relatively small. Different behavior patterns of the number counts of the DRGs and bluer galaxies with $2 &amp;lt; z_{\mathrm{phot}} &amp;lt; 4$ at $K \gt 22$ suggest that the mass-dependent color distribution, where most of the low-mass galaxies are blue, while more massive galaxies tend to have redder colors, had already been established at that epoch.

THE LATEST RESULTS FROM SUBARU TELESCOPE

The latest scientific highlights obtained with the Subaru telescope are given together with its current status and on-going instrumentation. We have been successfully operating the telescope and 8 observatory instruments (including an adaptive optics system) since January 1999, when the first light was accomplished. Open-use of Subaru began in December 2000. Subaru has a unique capability of its prime focus among other 8-10 meter class telescopes and has an excellent imaging performance as a result of its sophisticated active optics combined with the high stability of the sky at Mauna Kea. Scientific highlights are given on the discoveries of the most distant galaxies, spiral structure on a protoplanetary disk around AB Aur, and planetesimal belts in the debris disk around <TEX>$\beta$</TEX> Pic. Brief summaries are given for three new instruments: the Multi-Object Infrared Camera and Spectrograph (MOIRCS), 188 element adaptive optics system, and Fiber Multi-Object Spectrograph (FMOS)