松原 英雄

Although measuring the gas metallicity in galaxies at various redshifts is crucial to constrain galaxy evolutionary scenarios, only rest-frame optical emission lines have been generally used to measure the metallicity. This has prevented us to accurately measure the metallicity of dust-obscured galaxies, and accordingly to understand the chemical evolution of dusty populations, such as ultraluminous infrared galaxies. Here we propose diagnostics of the gas metallicity based on infrared fine structure emission lines, which are nearly unaffected by dust extinction even the most obscured systems. Specifically, we focus on fine-structure lines arising mostly from HII regions, not in photo-dissociation regions, to minimize the dependence and uncertainties of the metallicity diagnostics from various physical parameters. Based on photoionization models, we show that the emission-line flux ratio of ([OIII]51.80+[OIII]88.33)/[NIII]57.21 is an excellent tracer of the gas metallicity. The individual line ratios [OIII]51.80/[NIII]57.21 or [OIII]88.33/[NIII]57.21 can also be used as diagnostics of the metallicity, but they suffer a stronger dependence on the gas density. The line ratios [OIII]88.33/[OIII]51.80 and [NII]121.7/[NIII]57.21 can be used to measure and, therefore, account for the dependences on the of the gas density and ionization parameter, respectively. We show that these diagnostic fine-structure lines are detectable with Herschel in luminous infrared galaxies out z=0.4. Metallicity measurements with these fine-structure lines will be feasible at relatively high redshift (z=1 or more) with SPICA, the future infrared space observatory.

We present the mid-infrared (MIR) observation of a nearby galaxy cluster, Abell 2255 by the AKARI space telescope. Using the AKARI's continuous wavelength coverage between 3-24 micron and the wide field of view, we investigate the properties of cluster member galaxies to see how the infall of the galaxies, the cluster substructures, and the cluster-cluster merger influence their evolution. We show that the excess of MIR (11 micron) flux is a good indicator to discriminate galaxies at different evolutionary stages, and divide galaxies into three classes accordingly : strong MIR-excess (N3-S11>0.2) galaxies that include both unobscured and obscured star-forming galaxies, weak MIR-excess (-2.0<N3-S11<-1.2) galaxies that are quiescent, old (>5 Gyr) galaxies where the MIR emission arises mainly from the circumstellar dust around AGB stars, and intermediate MIR-excess (-1.2<N3-S11<0.2) galaxies in between the two classes that are less than a few Gyrs old past the prime star formation activity. With the MIR-excess diagnostics, we investigate how local and cluster-scale environments affect the individual galaxies. We derive the total star formation rate of ~130 Msun/yr for A2255 using the strong MIR-excess galaxies, which is consistent with other clusters of galaxies at similar redshifts and with similar masses. We find no strong evidence that supports enhanced star formation neither inside the cluster nor in the substructure region. The intermediate MIR-excess galaxies, representing galaxies in transition from star-forming galaxies to quiescent galaxies, are located preferentially at the medium density region or cluster substructures. Our findings suggest that galaxies are being transformed from star-forming galaxies into red, quiescent galaxies from the infall region through near the core, which can be well-explained by the ram-pressure stripping as previous simulation suggests.

Gravitational lensing is a powerful astrophysical and cosmological probe and is particularly valuable at submillimeter wavelengths for the study of the statistical and individual properties of dusty star-forming galaxies. However, the identification of gravitational lenses is often time-intensive, involving the sifting of large volumes of imaging or spectroscopic data to find few candidates. We used early data from the Herschel Astrophysical Terahertz Large Area Survey to demonstrate that wide-area submillimeter surveys can simply and easily detect strong gravitational lensing events, with close to 100% efficiency.

The Japanese infrared space telescope SPICA mission, following the successful Akari mission, has been studied at the concept design phase in international collaboration with ESA under the framework of the ESA Cosmic Vision 2015-2025. The SPICA spacecraft is to be launched in 2018 and transferred into a halo orbit around the Sun-Earth L2 to obtain a stable thermal environment where the IR space telescope's large mirror of 3 m-class in diameter can be cooled to <5.5 K with mechanical coolers and effective radiative cooling with no use of stored cryogen. The SPICA's large and cold telescope is expected to provide unprecedented scientific observation optimized for mid-IR and far-IR astronomy with ultra-high sensitivity and excellent spatial resolution during a nominal mission life of 3 years (goal 5 years). Thermal and structural analyses show that the obtained design of the SPICA cryogenic system satisfies the mission requirement. Mechanical coolers for the 4.5 K stage and the 1.7 K stage, which have been continuously developed, have a sufficient cooling capacity with low power consumption to lift the heat loads from instruments and parasitic heat loads. As a result, it is concluded that the concept design of the SPICA cryogenic system is confirmed for the initial cooling mode after launch and the nominal operation mode. (c) 2010 Elsevier Ltd. All rights reserved.

A near-infrared (NIR; 2.5 - 4.5 micron) spectroscopic survey of SDSS(Sloan Digital Sky Survey)-selected blue early-type galaxies (BEGs) has been conducted using the AKARI. The NIR spectra of 36 BEGs are secured, which are well balanced in their star-formation(SF)/Seyfert/LINER type composition. For high signal-to-noise ratio, we stack the BEG spectra all and in bins of several properties: color, specific star formation rate and optically-determined spectral type. We estimate the NIR continuum slope and the equivalent width of 3.29 micron PAH emission. In the comparison between the estimated NIR spectral features of the BEGs and those of model galaxies, the BEGs seem to be old-SSP(Simple Stellar Population)-dominated metal-rich galaxies with moderate dust attenuation. The dust attenuation in the BEGs may originate from recent star formation or AGN activity and the BEGs have a clear feature of PAH emission, the evidence of current SF. BEGs show NIR features different from those of ULIRGs, from which we do not find any clear relationship between BEGs and ULIRGs. We find that Seyfert BEGs have more active SF than LINER BEGs, in spite of the fact that Seyferts show stronger AGN activity than LINERs. One possible scenario satisfying both our results and the AGN feedback is that SF, Seyfert and LINER BEGs form an evolutionary sequence: SF - Seyfert - LINER.

An analysis of data from the Spitzer Space Telescope, Hubble Space Telescope, Chandra X-ray Observatory, and AKARI Infrared Astronomy Satellite is presented for the z = 0.036 merging galaxy system II Zw 096 (CGCG 448-020). Because II Zw 096 has an infrared luminosity of log(L _IR/L _sun) = 11.94, it is classified as a Luminous Infrared Galaxy (LIRG), and was observed as part of the Great Observatories All-sky LIRG Survey (GOALS). The Spitzer data suggest that 80% of the total infrared luminosity comes from an extremely compact, red source not associated with the nuclei of the merging galaxies. The Spitzer mid-infrared spectra indicate no high-ionization lines from a buried active galactic nucleus in this source. The strong detection of the 3.3 μm and 6.2 μm polycyclic aromatic hydrocarbon emission features in the AKARI and Spitzer spectra also implies that the energy source of II Zw 096 is a starburst. Based on Spitzer infrared imaging and AKARI near-infrared spectroscopy, the star formation rate is estimated to be 120 M _sun yr^-1 and &gt;45 M _sun yr^-1, respectively. Finally, the high-resolution B-, I-, and H-band images show many star clusters in the interacting system. The colors of these clusters suggest at least two populations—one with an age of 1-5 Myr and one with an age of 20-500 Myr, reddened by 0-2 mag of visual extinction. The masses of these clusters span a range between 10⁶ and 10⁸ M _sun. This starburst source is reminiscent of the extranuclear starburst seen in NGC 4038/9 (the Antennae Galaxies) and Arp 299 but approximately an order of magnitude more luminous than the Antennae. The source is remarkable in that the off-nuclear infrared luminosity dominates the entire system....

Comet C/2007 N3 (Lulin) was observed with the Japanese infrared satellite AKARI in the near-infrared at a post-perihelion heliocentric distance of 1.7 AU. Observations were performed with the spectroscopic (2.5-5.0 μm) and imaging (2.4, 3.2, and 4.1 μm) modes on 2009 March 30 and 31 UT, respectively. AKARI images of the comet exhibit a sunward crescent-like shape coma and a dust tail extended toward the anti-solar direction. The 4.1 μm image (CO/CO&lt;SUB&gt;2&lt;/SUB&gt; and dust grains) shows a distribution different from the 2.4 and 3.2 μm images (H&lt;SUB&gt;2&lt;/SUB&gt;O and dust grains). The observed spectrum shows distinct bands at 2.66 and 4.26 μm, attributed to H&lt;SUB&gt;2&lt;/SUB&gt;O and CO&lt;SUB&gt;2&lt;/SUB&gt;, respectively. This is the fifth comet in which CO&lt;SUB&gt;2&lt;/SUB&gt; has been directly detected in the near-infrared spectrum. In addition, CO at 4.67 μm and a broad 3.2-3.6 μm emission band from C-H bearing molecules were detected in the AKARI spectrum. The relative abundance ratios CO&lt;SUB&gt;2&lt;/SUB&gt;/H&lt;SUB&gt;2&lt;/SUB&gt;O and CO/H&lt;SUB&gt;2&lt;/SUB&gt;O derived from the molecular production rates are ~4%-5% and &amp;lt;2%, respectively. Comet Lulin belongs to the group that has relatively low abundances of CO and CO&lt;SUB&gt;2&lt;/SUB&gt; among all observed comets....

The Westerbork Radio Synthesis Telescope, WSRT, has been used to make a deep radio survey of an ~ 1.7 sq degree field coinciding with the AKARI North Ecliptic Pole Deep Field. The observations, data reduction and source count analysis are presented, along with a description of the overall scientific objectives. The survey consisted of 10 pointings, mosaiced with enough overlap to maintain a similar sensitivity across the central region that reached as low as 21 microJy per beam at 1.4 GHz. A catalogue containing 462 sources detected with a resolution of 17"x15" is presented. The differential source counts calculated from the WSRT data have been compared with those from the shallow VLA-NEP survey of Kollgaard et al 1994, and show a pronounced excess for sources fainter than ~ 1 mJy, consistent with the presence of a population of star forming galaxies at sub-mJy flux levels. The AKARI North Ecliptic Pole Deep field is the focus of a major observing campaign conducted across the entire spectral region. The combination of these data sets, along with the deep nature of the radio observations will allow unique studies of a large range of topics including the redshift evolution of the luminosity function of radio sources, the clustering environment of radio galaxies, the nature of obscured radio-loud active galactic nuclei, and the radio/far-infrared correlation for distant galaxies. This catalogue provides the basic data set for a future series of paper dealing with source identifications, morphologies, and the associated properties of the identified radio sources.

Context. The AKARI, a Japanese infrared space mission, has performed an All-Sky Survey in six infrared-bands from 9 to 180 μm with higher spatial resolutions and better sensitivities than IRAS. Aims. We investigate the mid-infrared (9 and 18 μm) point source catalog (PSC) obtained with the infrared camera (IRC) onboard AKARI, in order to understand the infrared nature of the known objects and to identify previously unknown objects. Methods. Color-color diagrams and a color-magnitude diagram were plotted with the AKARI-IRC PSC and other available all-sky survey catalogs. We combined the Hipparcos astrometric catalog and the 2MASS all-sky survey catalog with the AKARI-IRC PSC. We furthermore searched literature and SIMBAD astronomical database for object types, spectral types, and luminosity classes. We identified the locations of representative stars and objects on the color-magnitude and color-color diagram schemes. The properties of unclassified sources can be inferred from their locations on these diagrams. Results. We found that the (B-V) vs. (V-S9W) color-color diagram is useful for identifying the stars with infrared excess emerged from circumstellar envelopes or disks. Be stars with infrared excess are separated well from other types of stars in this diagram. Whereas (J-L18W) vs. (S9W-L18W) diagram is a powerful tool for classifying several object types. Carbon-rich asymptotic giant branch (AGB) stars and OH/IR stars form distinct sequences in this color-color diagram. Young stellar objects (YSOs), pre-main sequence (PMS) stars, post-AGB stars, and planetary nebulae (PNe) have the largest mid-infrared color excess and can be identified in the infrared catalog. Finally, we plot the L18W vs. (S9W-L18W) color-magnitude diagram, using the AKARI data together with Hipparcos parallaxes. This diagram can be used to identify low-mass YSOs and AGB stars. We found that this diagram is comparable to the [24] vs. ([8.0]-[24]) diagram of Large Magellanic Cloud sources using the Spitzer Space Telescope data. Our understanding of Galactic objects will be used to interpret color-magnitude diagram of stellar populations in the nearby galaxies that Spitzer Space Telescope observed. Conclusions. Our study of the AKARI color-color and color-magnitude diagrams will be used to explore properties of unknown objects in the future. In addition, our analysis highlights a future key project to understand stellar evolution with a circumstellar envelope, once the forthcoming astronometrical data with GAIA are available. © ESO, 2010.

Context. AKARI is the first Japanese astronomical satellite dedicated to infrared astronomy. One of the main purposes of AKARI is the all-sky survey performed with six infrared bands between 9 mu m and 200 mu m during the period from 2006 May 6 to 2007 August 28. In this paper, we present the mid-infrared part (9 mu m and 18 mu m bands) of the survey carried out with one of the on-board instruments, the infrared camera (IRC).Aims. We present unprecedented observational results of the 9 mu m and 18 mu m AKARI all-sky survey and detail the operation and data processing leading to the point source detection and measurements.Methods. The raw data are processed to produce small images for every scan, and the point sources candidates are derived above the 5 sigma noise level per single scan. The celestial coordinates and fluxes of the events are determined statistically and the reliability of their detections is secured through multiple detections of the same source within milli-seconds, hours, and months from each other.Results. The sky coverage is more than 90% for both bands. A total of 877 091 sources (851 189 for 9 mu m, 195 893 for 18 mu m) are confirmed and included in the current release of the point source catalog. The detection limit for point sources is 50 mJy and 90 mJy for the 9 mu m and 18 mu m bands, respectively. The position accuracy is estimated to be better than 2 ''. Uncertainties in the in-flight absolute flux calibration are estimated to be 3% for the 9 mu m band and 4% for the 18 mu m band. The coordinates and fluxes of detected sources in this survey are also compared with those of the IRAS survey and are found to be statistically consistent.

Context. The AKARI, a Japanese infrared space mission, has performed an All-Sky Survey in six infrared-bands from 9 to 180 mu m with higher spatial resolutions and better sensitivities than IRAS. Aims. We investigate the mid-infrared (9 and 18 mu m) point source catalog (PSC) obtained with the infrared camera (IRC) onboard AKARI, in order to understand the infrared nature of the known objects and to identify previously unknown objects.Methods. Color-color diagrams and a color-magnitude diagram were plotted with the AKARI-IRC PSC and other available all-sky survey catalogs. We combined the Hipparcos astrometric catalog and the 2MASS all-sky survey catalog with the AKARI-IRC PSC. We furthermore searched literature and SIMBAD astronomical database for object types, spectral types, and luminosity classes. We identified the locations of representative stars and objects on the color-magnitude and color-color diagram schemes. The properties of unclassified sources can be inferred from their locations on these diagrams.Results. We found that the (B - V) vs. (V - S 9W) color-color diagram is useful for identifying the stars with infrared excess emerged from circumstellar envelopes or disks. Be stars with infrared excess are separated well from other types of stars in this diagram. Whereas (J - L18W) vs. (S 9W - L18W) diagram is a powerful tool for classifying several object types. Carbon-rich asymptotic giant branch (AGB) stars and OH/IR stars form distinct sequences in this color-color diagram. Young stellar objects (YSOs), pre-main sequence (PMS) stars, post-AGB stars, and planetary nebulae (PNe) have the largest mid-infrared color excess and can be identified in the infrared catalog. Finally, we plot the L18W vs. (S 9W - L18W) color-magnitude diagram, using the AKARI data together with Hipparcos parallaxes. This diagram can be used to identify low-mass YSOs and AGB stars. We found that this diagram is comparable to the [24] vs. ([8.0] - [24]) diagram of Large Magellanic Cloud sources using the Spitzer Space Telescope data. Our understanding of Galactic objects will be used to interpret color-magnitude diagram of stellar populations in the nearby galaxies that Spitzer Space Telescope observed.Conclusions. Our study of the AKARI color-color and color-magnitude diagrams will be used to explore properties of unknown objects in the future. In addition, our analysis highlights a future key project to understand stellar evolution with a circumstellar envelope, once the forthcoming astronometrical data with GAIA are available.

Aims. Dust-obscured star-formation increases with increasing intensity and increasing redshift. We aim to reveal the cosmic star-formation history obscured by dust using deep infrared observation with AKARI. Methods. We constructed restframe 8 mu m, 12 mu m, and total infrared (TIR) luminosity functions (LFs) at 0.15 &lt; z &lt; 2.2 using 4128 infrared sources in the AKARI NEP-deep field. A continuous filter coverage in the mid-IR wavelength (2.4, 3.2, 4.1, 7, 9, 11, 15, 18, and 24 mu m) by the AKARI satellite allowed us to estimate restframe 8 mu m and 12 mu m luminosities without using a large extrapolation based on an SED fit, which was the largest uncertainty in previous work. Results. We find that all 8 mu m (0.38 &lt; z &lt; 2.2), 12 mu m (0.15 &lt; z &lt; 1.16), and TIR LFs (0.2 &lt; z &lt; 1.6) show continuous and strong evolution toward higher redshift. Our direct estimate of 8 mu m LFs is useful since previous work often had to use a large extrapolation from the Spitzer 24 mu m to 8 mu m, where SED modeling is more difficult because of the PAH emissions. In terms of cosmic infrared luminosity density (Omega(IR)), which was obtained by integrating analytic fits to the LFs, we find good agreement with previous work at z &lt; 1.2. We find the Omega(IR) evolves as proportional to(1 + z)(4.4 +/- 1.0). When we separate contributions to Omega(IR) by LIRGs and ULIRGs, we found more IR luminous sources are increasingly more important at higher redshift. We find that the ULIRG (LIRG) contribution increases by a factor of 10 (1.8) from z = 0.35 to z = 1.4.

Context : AKARI is the first Japanese astronomical satellite dedicated to infrar ed astronomy. One of the main purposes of AKARI is the all-sky survey performed with six infrared bands between 9 and 200um during the period from 2006 May 6 to 2007 August 28. In this paper, we present the mid-infrared part (9um and 18um b ands) of the survey carried out with one of the on-board instruments, the Infrar ed Camera (IRC). Aims : We present unprecedented observational results of the 9 and 18um AKARI al l-sky survey and detail the operation and data processing leading to the point s ource detection and measurements. Methods : The raw data are processed to produce small images for every scan and point sources candidates, above the 5-sigma noise level per single scan, are der ived. The celestial coordinates and fluxes of the events are determined statisti cally and the reliability of their detections is secured through multiple detect ions of the same source within milli-seconds, hours, and months from each other. Results : The sky coverage is more than 90% for both bands. A total of 877,091 s ources (851,189 for 9um, 195,893 for 18um) are confirmed and included in the cur rent release of the point source catalogue. The detection limit for point source s is 50mJy and 90mJy for the 9um and 18um bands, respectively. The position accu racy is estimated to be better than 2". Uncertainties in the in-flight absolute flux calibration are estimated to be 3% for the 9um band and 4% for the 18um ban d. The coordinates and fluxes of detected sources in this survey are also compar ed with those of the IRAS survey and found to be statistically consistent.

We present early results from our multi-wavelength follow-up campaigns of the AKARI Deep Fields at the North and South Ecliptic Poles. We summarize our campaigns in this poster paper, and present three early outcomes. (a) Our AAOmega optical spectroscopy of the Deep Field South at the AAT has observed over 550 different targets, and our preliminary local luminosity function at 90 microns from the first four hours of data is in good agreement with the predictions from Serjeant & Harrison 2005. (b) Our GMRT 610 MHz imaging in the Deep Field North has reached ~30 microJy RMS, making this among the deepest images at this frequency. Our 610 MHz source counts at >200 microJy are the deepest ever derived at this frequency. (c) Comparing our GMRT data with our 1.4 GHz WSRT data, we have found two examples of radio-loud AGN that may have more than one epoch of activity.

Large area surveys in the infrared wavelengths have revealed a significant evolution of the star formation activity of the universe in the past. Extragalactic surveys we have conduced with AKARI towards the north ecliptic pole (NEP) are unique, in terms of a comprehensive wavelength coverage from 2 to 24 μm using all 9 photometric bands of the IRC. This includes new wavelength windows for extragalactic surveys, such as 18 μm. We demonstrate that this IRC all-band photometry is capable of tracing a steep rise in the flux at the blue side of the polycyclic aromatic hydrocarbon (PAH) 6.2 μm emission feature of infrared luminous galaxies at z&lt 1. Starburst-dominated ULIRGs are identified using IRC all-band photometry. The PAH-to-total IR luminosity ratio of these starburst ULIRGs is systematically higher than that of local ULIRGs. The nature of ULIRGs could be different from local ones even at z∼1. © 2010 American Institute of Physics.

The conceptual design of the Space Infrared Telescope for Cosmology and Astrophysics (SPICA) has been studied as a pre-project of the Japan Aerospace Exploration Agency (JAXA) in collaboration with ESA to be launched in 2018. The SPICA is transferred into a halo orbit around the second Lagrangian point in the Sun-Earth system, where radiant cooling is available effectively. The SPICA has a large IR telescope 3 m in diameter, which is cooled without cryogen to below 6 K by the radiant and mechanical cooling system. Therefore, the SPICA mission will cover mid- and far-IR astronomy with high sensitivity and spatial resolution during a long period of over 5 years for goal. Most heat radiation from the sun and spacecraft is blocked by the Sun Shield and thermal radiation shields covered with Multi-Layer Insulator (MLI) to limit heat radiation to the Scientific Instrument Assembly (SIA). The SIA, which is composed of the primary mirrors and optical benches equipped with Focal Plane Instruments (FPIs), is refrigerated to below 6 K by two sets of 4K-class Joule-Thomson (JT) cooler with a cooling power of 40 mW at 4.5 K. The Far-IR detector is refrigerated to 1.7 K by two sets of 1K-class JT coolers with a cooling power of 10 mW at 1.7 K. Improvements for the higher reliability and sufficient cooling performance are required in the development of SPICA mechanical cryocoolers. Thermal analysis indicates that the SPICA cryogenic system works effectively to limit the total heat load on the SIA to 41.2 mW. This paper describes the conceptual design of the SPICA cryogenic system, which was established with thermal feasibility for nominal operation mode. © 2010 SPIE.

The SPICA mission aims to achieve high spatial resolution and unprecedented sensitivity in the mid to far-infrared wavelength astronomy. We derived a set of pointing requirements from SPICA's mission requirements. Disturbance management over the SPICA system and an implementation of isolators are necessary, because cryogenic coolers' disturbances could generate vibration. Alignment and random pointing errors for focal-plane instruments are reduced with a focal-plane guidance camera. Furthermore, an additional focal-plane camera and a tip-tilt mirror actuator are installed for coronagraph mode. This paper presents an overview of the SPICA pointing requirements and a feasibility study to achieve the requirements.

SPICA is a next generation infrared astronomy mission to reveal the origin of planets and galaxies. The mission is led by Japan Aerospace Exploration Agency (JAXA) in collaboration with the European Space Agency (ESA) and international consortiums in Japan, Europe, USA, and the Republic of Korea. SPICA is an "observatory" based on the heritage of AKARI's "all sky survey". ESA provides a 3-m class telescope using technology heritage of Herschel. The SPICA will achieve superior sensitivity in the mid-to far-infrared astronomy to be launched into space. SPICA has a completely new cooling system, which utilizes efficient mechanical coolers. This system enables a large, cryogenically cooled telescope in space. SPICA system concept and requirements are clear, but it is not easy to design. SPICA spacecraft consists of the Payload Module (PLM) and the Bus Module (BM). The PLM includes mechanical coolers and passive thermal shields, which enable to cool down the telescope and scientific instruments below 6K. The PLM is connected to the BM with low thermal conductivity truss structure to keep the PLM cool and the BM warm. This paper describes how to meet the system requirements to establish the feasible design of SPICA spacecraft.

AKARI, the Japanese satellite mission dedicated for infrared astronomy launched in 2006 February, exhausted its 180 litter liquid helium (LHe) in 2007 August. After the LHe exhaustion, the telescope and focal plane of AKARI have still been kept less than 50K by the onboard cryocooler and near-infrared (NIR) observations with the Infrared Camera (IRC) are continuing. The data reduction software optimized for the warm mission enables us to carry out efficient and sensitive observations in the NIR despite the increase of hot pixels. In particular, the NIR spectroscopic capability of the IRC provides a unique opportunity to obtain spectra in 2.5-5 mu m with a high sensitivity, which will not be able to be carried out with any other facilities until JWST. An overview of the AKARI warm mission is given together with the performance and some observational results taken during the warm mission.

The SPace Infrared telescope for Cosmology and Astrophysics (SPICA) is a proposed mid-to-far infrared (4-200 um) astronomy mission, scheduled for launch in 2017. A single, 3.5m aperture telescope would provide superior image quality at 5-200 um, and its very cold (~5 K) instrumentation would provide superior sensitivity in the 25-200 um wavelength regimes. This would provide a breakthrough opportunity for studies of exoplanets, protoplanetary and debris disk, and small solar system bodies. This paper summarizes the potential scientific impacts for the proposed instrumentation.

We present the first broadband λ = 1 mm spectrum toward the z = 2.56 Cloverleaf quasar, obtained with Z-Spec, a grating spectrograph on the 10.4 m Caltech Submillimeter Observatory. The 190-305 GHz observation band corresponds to the rest frame 272-444 μm, and we measure the dust continuum as well as all four transitions of carbon monoxide (CO) lying in this range. The power-law dust emission, F _ν = 14 mJy(ν/240 GHz)^3.9 is consistent with the published continuum measurements. The CO J = 6 → 5, J = 8 → 7, and J = 9 → 8 measurements are the first, and now provide the highest-J CO information in this source. Our measured CO intensities are very close to the previously published interferometric measurements of J = 7 → 6, and we use all available transitions and our ¹³CO upper limits to constrain the physical conditions in the Cloverleaf molecular gas disk. We find a large mass (2-50 × 10⁹ M _sun) of highly excited gas with thermal pressure nT &gt; 10⁶ K cm^-3. The ratio of the total CO cooling to the far-IR dust emission exceeds that in the local dusty galaxies, and we investigate the potential heating sources for this bulk of warm molecular gas. We conclude that both UV photons and X-rays likely contribute, and discuss implications for a top-heavy stellar initial mass function arising in the X-ray-irradiated starburst. Finally, we present tentative identifications of other species in the spectrum, including a possible detection of the H₂O 2_0,2 → 1_1,1 transition at λ_rest = 303 μm....

We present the {\it AKARI} InfraRed Camera (IRC) imaging observation of early-type galaxies in A2218 at z $\simeq$ 0.175. Mid-infrared (MIR) emission from early-type galaxies traces circumstellar dust emission from AGB stars or/and residual star formation. Including the unique imaging capability at 11 and 15 $\mu$m, our {\it AKARI} data provide an effective way to investigate MIR properties of early-type galaxies in the cluster environment. Among our flux-limited sample of 22 red sequence early-type galaxies with precise dynamical and line strength measurements ($<$ 18 mag at 3 $\mu m$), we find that at least 41% have MIR-excess emission. The $N3-S11$ versus $N3$ (3 and 11 $\mu$m) color-magnitude relation shows the expected blue sequence, but the MIR-excess galaxies add a red wing to the relation especially at the fainter end. A SED analysis reveals that the dust emission from AGB stars is the most likely cause for the MIR-excess, with low level of star formation being the next possible explanation. The MIR-excess galaxies show a wide spread of $N3-S11$ colors, implying a significant spread (2--11 Gyr) in the estimated mean ages of stellar populations. We study the environmental dependence of MIR-excess early-type galaxies over an area out to a half virial radius ($\sim$1 Mpc). We find that the MIR-excess early-type galaxies are preferentially located in the outer region. From these evidences, we suggest that the fainter, MIR-excess early-type galaxies have just joined the red sequence, possibly due to the infall and subsequent morphological/spectral transformation induced by the cluster environment.

We present our latest results on near- to mid-infrared (MIR) observation of supernova (SN) 2006jc at 200 days after the discovery using the Infrared Camera (IRC) on board AKARI. The near-infrared (2-5 μm) spectrum of SN 2006jc is obtained for the first time and is found to be well interpreted in terms of the thermal emission from amorphous carbon of 800 ± 10 K with the mass of 6.9 ± 0.5 × 10 M that was formed in the SN ejecta. This dust mass newly formed in the ejecta of SN 2006jc is in a range similar to those obtained for other several dust-forming core-collapse supernovae based on recent observations (i.e., 10 -10 M ). MIR photometric data with AKARI/IRC MIR-S/S7, S9W, and S11 bands have shown excess emission over the thermal emission by hot amorphous carbon of 800 K. This MIR excess emission is likely to be accounted for by the emission from warm amorphous carbon dust of 320 ± 10 K with the mass of 2.7 -0.5 × 10 M rather than by the band emission of astronomical silicate and/or silica grains. This warm amorphous carbon dust is expected to have been formed in the mass-loss wind associated with the Wolf-Rayet stellar activity before the SN explosion. Our result suggests that a significant amount of dust is condensed in the mass-loss wind prior to the SN explosion. © 2009. The American Astronomical Society. All rights reserved. -5 -3 -5 +0.7 -3 ⊙ ⊙ ⊙ ⊙

We present the survey strategy and the data characteristics of the North Ecliptic Pole (NEP) Wide Survey of AKARI. The survey was carried out for about one year starting from May 2006 with 9 passbands from 2.5 to 24 micron and the areal coverage of about 5.8 sq. degrees centered on NEP. The survey depth reaches to 21.8 AB magnitude near infrared (NIR) bands, and ~ 18.6 AB maggnitude at the mid infrared (MIR) bands such as 15 and 18 micron. The total number of sources detected in this survey is about 104,000, with more sources in NIR than in the MIR. We have cross matched infrared sources with optically identified sources in CFHT imaging survey which covered about 2 sq. degrees within NEP-Wide survey region in order to characterize the nature of infrared sources. The majority of the mid infrared sources at 15 and 18 micron band are found to be star forming disk galaxies, with smaller fraction of early type galaxies and AGNs. We found that a large fraction (60~80 %) of bright sources in 9 and 11 micron stars while stellar fraction decreases toward fainter sources. We present the histograms of the sources at mid infrared bands at 9, 11, 15 and 18 micron. The number of sources per magnitude thus varies as m^0.6 for longer wavelength sources while shorter wavelength sources show steeper variation with m, where m is the AB magnitude.

I outline some results from the Z-Spec instrument at the CSO and present a concept for CCAT survey spectrometer.

AKARI All-sky Survey observations were carried out in the mid- to far-infrared spectral region with six photometric bands during the cryogenic mission phase of AKARI from May 8, 2006 to August 26, 2007. This paper reports the mid-infrared part of the AKARI all-sky survey. It was carried out with two mid-infrared broad bands centered at 9 and 18 gm. More than 90 percent of entire sky was observed by both bands during this period. The 5 sigma sensitivities for point sources are about 50 and 120 mJy, respectively. The spatial resolution is better than 10 '' at both bands. The AKARI mid-infrared survey achieved a deeper sensitivity and a finer spatial resolution than the previous IRAS survey. the AKARI mid-infrared survey has the sensitivity to detect a debris disk of beta Pic at a distance of 100 pc and several new debris disk candidates have already been discovered at 18 mu m in a preliminary study, separately discussed by Fujiwara et al. (in this volume). More debris disk candidates are expected to be found in further investigations, which will make a significant impact on the statistical study of debris disks.

SPICA will provide the best sensitivity and image quality than ever at 5-210 mu m. This will revolutionize our understanding of exoplanets, protoplanetary disks, debris disks, and Solar system small bodies. This paper summarizes such key sciences with SPICA discussed so far among the Japanese SPICA Science Working Group, stressing on the planetary formation, and exoplanet detection and characterization.

We have been investigating the formation and evolution of clusters of galaxies from low redshift to high redshift using the NIR/MIR images taken with the AKARI/IRC,C, as part of the AKARI mission program: CLEVL. We present an infrared view of these clusters. It is found that the cluster galaxies detected in MIR are divided into two groups: MIR-blue galaxies with (N3 - S11) &lt; 0 and MIR-red galaxies with (N3 - S11) &gt; 0. MIR-red galaxies are star forming galaxies with varying star formation rates, corresponding to late type galaxies. MIR-blue galaxies are red sequence galaxies with varying stellar ages or with low-level star formation activity. The fraction of the MIR-red galaxies varies significantly from cluster to cluster.

The PAH emission in the mid-infrared wavelengths is thought to be a good star formation rate indicator, which is less sensitive to the effect of dust extinction compared to the tracers in the UV/optical wavelengths. The robustness of the PAH/SFR relationship, however, is still not be established well because of lack of unbiased, large number of spectral samples of PAH emission from galaxies. We will present the initial results from the unbiased slit-less spectroscopic survey of galaxies (SPICY) in the near- and mid-infrared wavelengths by AKARI The survey is conducted by the Infrared Camera (IRC) onboard AKARI in the slit-less spectroscopy mode (R similar or equal to 50). We have covered over 1000 sq. arcmin. within the AKARI deep field toward the North Ecliptic Pole (NEP) with a sensitivity down to 1 mJy (5 sigma) for continuum at 9 mu m, and obtained more than 100 samples of mid-infrared spectra of galaxies with good S/N ratio. We will discuss property of the PAH features of these galaxies.

We describe the AKARI Infra Red Camera (IRC) imaging observation of early-type galaxies (ETGs) in A2218 at z similar or equal to 0.175. With the imaging capability at 11 and 15 pm, we investigate mid-infrared (MIR) properties of ETGs in the cluster environment. Among our flux-limited sample of 22 optical red sequence ETGs, we find that more than 50% have MIR-excess emission, and the most likely cause of the MIR excess is the circumstellar dust emission from asymptotic giant branch (AGB) stars. The MIR-excess galaxies reveal a wide spread in N3-S11 (3 and 11 mu m) colors, indicative of a significant spread (2-11 Cyr) in the mean ages of stellar populations. They are also preferentially located in the outer region, suggesting the environment dependence of MIR-excess ETGs over an area out to a half virial radius.

The AKARI FU-HYU mission program has carried out mid-infrared imaging of several well studied Spitzer fields. This imaging fills in the wavelength coverage lacking from the Spitzer surveys and gives an extremely high scientific return for minimal input for AKARI. We select fields already rich in multi-wavelength data from radio to X-ray wavelengths and present the results from our initial analysis in the GOODS-N field. We utilize the comprehansive multiwavelength coverage in the GOODS-N field to produce a multiwavelength catalogue from infrared to ultraviolet wavelengths including photometric red-shifts. Using the FU-HYU catalogue we present colour-colour diagrams that map the passage of PAT-I features through our observation bands. These colour-colours diagrams are used as tools to extract anomalous colour populations, in particular a population of Silicate Break galaxies from the GOODS-N field.

The North Ecliptic Pole (NEP) Wide Survey was carried out for about one year starting from May 2006 with 9 passbands from 2.5 to 24 mu m and the areal coverage of about 5.8 sq. degrees centered on NEP. We present the initial results of the data analysis of all passbands except for the 24 mu m. The survey depth reaches to around 22 magnitude (AB) at the near infrared (NIR) bands, and similar to 18.5 magnitude at the mid infrared (MIR) bands such as 15 and 18 mu m. We matched our infrared sources with the optical sources detected in CFHT imaging survey of about 2 sq. degree area that lies inside the NEP-Wide survey region in order to characterize the nature of infrared sources. The stars are identified by the stellarity parameter of CFHT's r'-band image data given by SExtractor. The fraction of the stars among the infrared sources are found to dependent sensitively on the brightness as well as the wavelength. For example, the majority of bright sources in 9 and 11 mu m are stars while stellar fraction decreases toward fainter sources. The stellar fraction at longer 15 and 18 mu m bands remains to be less than 10 % regardless of the brightness. Most of the non-stellar objects detected in mid-infrared are found to be star forming disk galaxies, with smaller fraction of early type galaxies and AGNs.

We have made a deep and wide imaging survey with all nine AKARI/IRC bands from 2 to 24 mu m within a half degree of the North Ecliptic Pole. The survey covered a circular area of 0.38 deg(2) centered at RA = 17(h)56(m), Dec = 66 degrees 37' where a deep optical multi-band survey has been conducted by Subaru/Suprime-Cam. The 5 sigma sensitivity of the survey for point sources is 11.0, 48, 117, and 275 mu Jy at wavelengths 3, 7, 15, and 24 Am, respectively. The survey is limited by sky noise at wavelengths from 7 to 24 mu m, and limited by source confusion from 2 to 4 mu m. We have also made a point source catalog at each band, consisting of more than 5000 sources with a 50% completeness limit of 93 mu Jy at 15 Am. Our results are consistent with the pilot survey at faint fluxes and has better statistical significance at the bright fluxes. This is the first near- and mid-infrared sub-mJy extragalactic survey with contiguous wavelength coverage from 2 to 24 mu m and a large band-merged catalogue. It will provide powerful and unique diagnostics of obscured star-formation and AGN activities in the galaxies up to z = 2.

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(4um) imaging with the AKARI. The z'-N4 color is a powerful separator of cluster galaxies at z>1, taking advantage of the 4000A break and the 1.6um 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 S15um/S9um flux ratio is an extinction-free indicator of galaxy star formation activity due to the redshifted PAH emission lines (6.2,7.7 and 8.6um). We show statistically that the cluster galaxies have a lower S15um/S9um 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 to a higher redshift.

We present environmental dependence of dusty star forming activity in and around the cluster RXJ1716.4+6708 at z=0.81 based on wide-field and multi-wavelength observations with Suprime-Cam on the Subaru telescope and IRC onboard the AKARI satellite. Our optical data shows that the optical colour distribution of galaxies starts to dramatically change from blue to red at the medium-density environment such as cluster outskirts, groups and filaments. By combining with infrared data, we find that 15 micron galaxies tend to have optical colours between the red sequence and the blue cloud with a tail into the red sequence. The spatial distribution of the 15 micron galaxies over ~200 arcmin^2 around the cluster reveals that few 15 micron galaxies are detected in the cluster central region. This is probably due to the low star forming activity in the cluster core. However, interestingly, the fraction of 15 micron galaxies in the medium-density environments is as high as in the low-density field, despite the fact that the optical colours start to change in the medium-density environments. Furthermore, we find that 15 micron galaxies which have optically red colours (candidates for dusty red galaxies) and galaxies with high specific star formation rates are also concentrated in the medium-density environment. These results imply that the star forming activity in galaxies in groups and filaments is enhanced due to some environmental effects specific to the medium-density environment, and such a phenomenon is probably directly connected to the truncation of star forming activity in galaxies seen as the dramatic change in optical colours in such environments.

We present the number counts of Ks-band selected high redshift galaxy populations such as extremely red objects (EROs), B, z & K -band selected galaxies (BzKs) and distant red galaxies (DRGs) in the AKARI NEP field. The final catalogue contains 308 EROs (Ks<19.0 ; 54 percent are dusty star-forming EROs and the rest are passive old EROs), 137 star-forming BzKs and 38 passive old BzKs (Ks<19.0) and 64 DRGs (Ks<18.6). We also produce individual component source counts for both the dusty star-forming and passive populations. We compare the observed number counts of the high redshift passively evolving galaxy population with a backward pure luminosity evolution (PLE) model allowing different degrees of number density evolution. We find that the PLE model without density evolution fails to explain the observed counts at faint magnitudes, while the model incorporating negative density evolution is consistent with the observed counts of the passively evolving population. We also compare our observed counts of dusty star-forming EROs with a phenomenological evolutionary model postulating that the near-infrared EROs can be explained by the source densities of the far-infrared - submillimetre populations. Our model predicts that the dusty ERO source counts can be explained assuming a 25 percent contribution of submillimetre star-forming galaxies with the majority of brighter Ks -band detected dusty EROs having luminous (rather than HR10 type ultra-luminous) submillimetre counterparts. We propose that the fainter Ks>19.5 population is dominated by the sub-millijansky submillimetre population. We also predict a turnover in in dusty ERO counts around 19<Ks<20.

Passive spiral galaxies, despite their spiral morphological appearance, do not have any emission lines indicative of ongoing star formation in their optical spectra. Previous studies have suggested that passive spiral galaxies preferentially exist in infall regions of galaxy clusters, suggesting that the cluster environment is likely to be responsible for creating these galaxies. By carrying out spatially resolved long-slit spectroscopy on four nearby passive spiral galaxies with the Apache Point Observatory 3.5-m telescope, we investigated the stellar populations of passive spiral galaxies separately for their inner and outer regions. In the two unambiguously passive spiral galaxies among the four observed galaxies, H$\delta$ absorption lines are more prominent in the outer regions of the galaxies, whereas the 4000-{\AA} breaks (D$_{4000}$) are strongest in the inner regions of the galaxies. A comparison with a simple stellar population model for the two passive spiral galaxies indicates that the outer regions of the galaxies tend to harbour younger populations of stars. The strong H$\delta$ absorption observed in the outer regions of the sample galaxies is consistent with that of galaxies whose star formation ceased a few Gyrs ago. Because of the large uncertainty in the absorption indices in our samples, further observations are needed in order to place constraints on the mechanisms that quench star formation in passive spiral galaxies.

Z-Spec([1,2,3,4,5,6]) is a cryogenic, broadband, millimeter-wave grating spectrometer. it is capable of obtaining many spectral lines simultaneously because of its unprecedented broad bandwidth (185-305GHz). The bandpass covers the 1 mm atmospheric transmission window with a resolving power of 250-400. Z-Spec uses 160 silicon nitride micromesh bolometers cooled down to less than 100mK for background-limited performance. The unique capability of Z-Spec to detect multiple lines Simultaneously allows us to obtain information efficiently on the physical and chemical conditions of nearby Ultra-luminous Infrared Galaxies (ULIRGs) powered by starbursts or Active Galactic Nuclei. Here we report on new millimeter-wave broadband data for ULIRGs acquired with Z-Spec and the noise performance and achieved sensitivity in observations with the CSO. We found that during the observations the noise scales with the atmospheric opacity and can be explained well by our sensitivity model, considering the photon noise originating from the sky and the telescope, as well as the detector and electronics noise. The photon noise is found to dominate the total noise.

The SPICA, Japanese next generation infrared space telescope with a cooled 3.5 m primary mirror, will be a quite unique observatory in the mid and far-infrared with unprecedented sensitivity and the spatial resolving power. Here we briefly describe the key scientific objectives which can be performed only with SPICA, based on its unique design concepts. We then describe the scientific requirements for the focal plane instruments, and summarize the constraints on the various resources available for the focal plane instruments, derived from the spacecraft system design. We also outline the concept of the planned focal plane instruments, and the future development plan.Within the focal-plane instrument space (2.5m diameter, 0.5m height), two major instruments are so far planned to be equipped: one is a mid-infrared instrument, consisting of a mid-infrared camera, mid-infrared spectrometers, and a mid-infrared coronagraph, while the another is a far-infrared camera and spectrometer. The mid-infrared camera will consist of four channels covering 5-38 mu m with approximately 25-40 square arcminutes, while the mid-infrared spectrometer will have high-dispersion (R=30000) channels at 4-18 mu m and moderate-dispersion (R=3000) channels at 16-38 mu m. The mid-infrared coronagraph will have both imaging and spectroscopic capability at 5-27 mu m, with the contrast higher than 10(-6). As for the far-infrared camera and spectrometer, a Fourier-type imaging spectrometer covering 30-210 mu m is proposed and extensively studied by the European consortium (SAFARI consortium). A far-infrared and sub-millimeter grating spectrometer instrument is also under consideration by the US SPICA team.

We present a concept for BLISS, a sensitive far-IR-submillimeter spectrograph for SPICA. SPICA is a JAXA-led mission featuring a 3.5-meter telescope actively cooled to below 5K, envisioned for launch in 2017. The low-background platform is especially compelling for moderate-resolution survey spectroscopy, for which BLISS is designed. The BLISS / SPICA combination will offer line sensitivities below 10 Wm in modest integrations, enabling rapid survey spectroscopy of galaxies out to redshift 5. The far-IR fine-structure and molecular transitions which BLISS / SPICA will measure are immune to dust extinction, and will unambiguously reveal these galaxies' redshifts, stellar and AGN contents, gas properties, and heavy-element abundances. Taken together, such spectra will reveal the history of galaxies from 1 GY after the Big Bang to the present day. BLISS is comprised of five sub-bands, each with two R ∼ 700 grating spectrometer modules. The modules are configured with polarizing and dichroic splitters to provide complete instantaneous spectral coverage in two sky positions. To approach background-limited performance, BLISS detectors must have sensitivities at or below 5 × 10 WHz , and the format is 10 arrays of several hundred pixels each. It is anticipated that these requirements can be met on SPICA's timescale with leg-isolated superconducting (TES) bolometers cooled with a 50 mK magnetic refrigerator. -20 -2 -20 -1/2

We present a preliminary optical design and layout for the mid-infrared (4-18 mu m) high-resolution spectrograph for I SPICA, Japanese next-generation space IR observatory with 3.5 m telescope. MIR high-resolution spectroscopy is a powerful probe to study gas-phase molecules/atoms in a, variety of astronomical objects. Space observation provides a great opportunity to study many molecular lines especially in between the atmospheric windows. SPICA gives us a, chance to realize MIR high-resolution spectroscopy from space with the large telescope aperture. The major technical challenge is the size of the spectrograph, which tends to be too large for space. We hope to overcome this problem with a novel MIR immersion grating, which can make the instrument smaller by a factor of the refractive index of the grating material. We plan to fabricate a large pitch ZnSe (n = 2.4) immersion grating with the fly-cutting technique at LLNL (see Poster paper 7018-183 by Ikeda et al.(1) and 7018-181 by Kuzmenko et al.(2) in the proceedings of this conference). We show our preliminary spectrograph designs with a spectral resolution of similar to 30,000 in 4-8 mu m (short mode) and 12-18 mu m (long mode). The instrument size can be as small as 200 x 400 mm thanks to the MIR immersion gratings. With unprecedented spectral resolution in space, which is 10-times higher than ISO-SWS. the high-resolution spectrograph for SPICA (SPICA-HIRES) could be a unique instrument that can provide most sensitive and clear spectra of this kind.

The Japanese led Space Infrared telescope for Cosmology and Astrophysics (SPICA) will observe the universe over the 5 to 210 micron band with unprecedented sensitivity owing to its cold (similar to 5 K) 3.5m telescope. The scientific case for a European involvement in the SPICA mission has been accepted by the ESA advisory structure and a European contribution to SPICA is undergoing an assessment study as a Mission of Opportunity within the ESA Cosmic Vision 1015-2015 science mission programme. In this paper we describe the elements that are being studied for provision by Europe for the SPICA mission. These entail ESA directly providing the cryogenic telescope and ground segment support and a consortium of European insitutes providing a Far Infrared focal plane instrument. In this paper we describe the status of the ESA study and the design status of the FIR focal plane instrument.

The Infrared Camera (IRC) is one of two focal-plane instruments on the AKARI satellite. It is designed for wide-field deep imaging and low-resolution spectroscopy in the near- to mid-infrared (1.8-26.5 micron) in the pointed observation mode of AKARI. The IRC is also operated in the survey mode to make an All-Sky Survey at 9 and 18 microns. The IRC is composed of three channels. The NIR channel (1.8-5.5 micron) employs a, 512x412 InSb photodiode array, whereas both the MIR-S (4.6-13.4 micron) and MIR-L (12.6-26.5 micron) channels use 256x256 Si:As impurity band conduction (IBC) arrays. Each of the three channels has a field-of-view of approximately 10x10 arcmin., and they are operated simultaneously. The NIR and MIR-S channels share the same field-of-view by virtue of a beam splitter. The MIR-L observes the sky about 25 arcmin. away from the NIR/MIR-S field-of-view. The in-flight performance of the IRC has been confirmed to be in agreement with the pre-flight expectation. More than 4000 pointed observations dedicated for the IRC are successfully completed, and more than 90% of the sky are covered by the all-sky survey before the exhaustion of the Akari's cryogen. The focal-plane instruments are currently cooled by the mechanical cooler and only the NIR channel is still working properly. Brief introduction, in-flight performance and scientific highlights from the IRC cool mission, together with the result of performance test in the,,arm mission, are presented.

Infrared Camera (IRC) onboard AKARI satellite has carried out more than 4000 pointed observations during the phases 1 and 2, a significant amount of which were performed in the spectroscopic mode. In this paper, we investigate the properties of the spectroscopic data taken with MIR-S channel and propose a new data reduction procedure for slit-less spectroscopy of sources embedded in complicated diffuse background structures. The relative strengths of the 0(th) to 1(st) order light as well as the efficiency profiles of the 2(nd) order light are examined for various objects taken with MIR-S dispersers. The boundary shapes of the aperture mask are determined by using the spectroscopic data of uniform zodiacal emission. Based on these results, if the appropriate template spectra of zodiacal light emission and the diffuse background emission are prepared and the geometries of the diffuse structures are obtained by the imaging data, we can reproduce the slit-less spectroscopic patterns made by a uniform zodiacal emission and the diffuse background emission by a convolution of those template profiles. This technique enables us to obtain the spectra of infrared sources in highly complicated diffuse background and/or foreground structures, such as in the Galactic plane and in nearby galaxies.

AKARI is the first Japanese astronomical infrared satellite mission orbiting around the Earth in a sun-synchronous polar orbit at the altitude of 700 kin. One of the major observation programs of the AKARI is an all-sky survey in the mid- to far-infrared spectral regions with 6 photometric bands. The mid-infrared part of the AKARI All-Sky Survey was carried out with the Infrared Camera (IRC) at the 9 and 18 mu m bands with the sensitivity of about 50 and 120 mJy (5(5 per scan), respectively. The spatial resolution is about 9.4 '' at both bands. AKARI mid-infrared (MIR) all-sky survey substantially improves the MIR dataset of the IRAS survey of two decades ago and provides a significant database for studies of various fields of astronomy ranging from star-formation and debris disk systems to cosmology. This paper describes the current status of the data reduction and the characteristics of the AKARI MIR all-sky survey data.

The Infrared Camera (IRC) is one of two focal-plane instruments on the AKARI satellite. It is designed for wide-field deep imaging and low-resolution spectroscopy in the near- to mid-infrared (1.8-26.5 mu m) in the pointed observation mode of AKARI. The IRC is also operated in the survey mode to make an All-Sky Survey at 9 and 18 Am. It comprises three channels. The NIR channel (1.8-5.5 mu m) employs a 512 x 412 InSb array, whereas both the MIR-S (4.6-13.4 mu m) and MIR-L (12.6-26.5 mu m) channels use 256 x 256 Si:As impurity band conduction arrays. Each of the three channels has a field-of-view of about 10' x 10' and they are operated simultaneously. The NIR and MIR-S share the same field-of-view by virtue of a beam splitter. The MIR-L observes the sky about 25' away from the NIR/MIR-S field-of-view. The IRC gives us deep insights into the formation and evolution of galaxies, the evolution of planetary disks, the process of star-formation, the properties of interstellar matter under various physical conditions, and the nature and evolution of solar system objects. The in-flight performance of the IRC has been confirmed to be in agreement with the pre-flight expectation. This paper summarizes the design and the in-flight operation and imaging performance of the IRC.

The Infrared Camera (IRC) is one of the two instruments on board the AKARI satellite. In addition to deep imaging from 1.8-26.5um for the pointed observation mode of the AKARI, it has a spectroscopic capability in its spectral range. By replacing the imaging filters by transmission-type dispersers on the filter wheels, it provides low-resolution (lambda/d_lambda ~ 20-120) spectroscopy with slits or in a wide imaging field-of-view (approximately 10'X10'). The IRC spectroscopic mode is unique in space infrared missions in that it has the capability to perform sensitive wide-field spectroscopic surveys in the near- and mid-infrared wavelength ranges. This paper describes specifications of the IRC spectrograph and its in-orbit performance.

We report the first results of a near- and mid- infrared deep survey with the Infrared Camera (IRC) onboard AKARI in the performance verification phase. Simultaneous observations by the NIR, MIR-S and MIR-L channels of the IRC with effective integration times of 4529, 4908, and 4417 seconds at 3, 7, and 15 micron, covering 86.0, 70.3, and 77.3 arcmin^2 area, detected 955, 298 and 277 sources, respectively. The 5 sigma detection limits of the survey are 6.0, 31.5 and 71.2 micro Jy and the 50% completeness limit are 24.0, 47.5, and 88.1 micro Jy at 3, 7, and 15 micron, respectively. The observation is limited by source confusion at 3 micron. We have confirmed the turnover in the 15 micron differential source counts around 400 micro Jy, previously detected by surveys with the Infrared Space Observatory. The faint end of 15 micron raw source counts agree with the results from the deep surveys in the GOODS fields carried out with the Spitzer IRS peak up imager and the predictions of current galaxy evolution models. These results indicate that deep surveys with comprehensive wavelength coverage at mid-infrared wavelength are very important to investigate the evolution of infrared galaxies at high redshifts.