和田 武彦

type:Journal Article 第4回観測ロケットシンポジウム, 2022年3月14日-15日, ハイブリッド開催（JAXA相模原キャンパス& オンライン）

Abstract To reveal the causes of infrared absorption in the wavelength region between electronic and lattice absorptions, we measured the temperature dependence of the absorption coefficient of p-type low-resistivity ($$\sim 10^2~ \Omega \mathrm{cm}$$) CdZnTe crystals. We measured the absorption coefficients of CdZnTe crystals in four wavelength bands ($$\lambda =6.45$$, 10.6, 11.6, 15.1$$~\mu $$m) over the temperature range of $$T=8.6$$-300 K with an originally developed system. The CdZnTe absorption coefficient was measured to be $$\alpha =0.3$$-0.5 $$\mathrm{cm}^{-1}$$ at $$T=300$$ K and $$\alpha =0.4$$-0.9 $$\mathrm{cm}^{-1}$$ at $$T=8.6$$ K in the investigated wavelength range. With an absorption model based on transitions of free holes and holes trapped at an acceptor level, we conclude that the absorption due to free holes at $$T=150$$-300 K and that due to trapped-holes at $$T<50$$ K are dominant absorption causes in CdZnTe. We also discuss a method to predict the CdZnTe absorption coefficient at cryogenic temperature based on the room-temperature resistivity.

The total integrated emission from galaxies, known as the Extragalactic Background Light (EBL), is an important observable for understanding the history of star formation over the history of the universe. Spatial fluctuations in the infrared EBL as measured by the Cosmic Infrared Background ExpeRiment (CIBER), Spitzer and AKARI exceed the predicted signal from galaxy clustering alone. The CIBER-2 project seeks to extend CIBER observations of the EBL throughout the near infrared into the optical, through measurements above Earth's atmosphere during a suborbital sounding rocket flight. The experiment has a LN2-cooled 28.5 cm Cassegrain telescope along with three optical paths and dichroic beamsplitters, which are used to obtain three wide-field images in six broad spectral bands between 0.5-2.0 mu m. The three focal planes also contain linear variable filters (LVFs) which simultaneously take spectra with resolution R=20 across the same range. CIBER-2 is scheduled to fly multiple times on a Black Brant IX sounding rocket from White Sands Missile Range in the New Mexico desert. For the first flight, scheduled for early 2021, we have completed a variety of pre-flight optical tests, which we use to make focus adjustments, spectral response measurements, and absolute photometric calibrations. In this paper, we describe the methods behind these tests and present their results for pre-flight performance evaluation. In particular, we present measurements of the PSF for each broad spectral band, along with absolute calibration factors for each band and the LVF. Through monochromator scans, we also measure the spectral responsivity of each LVF as a function of position.

TIR, the thermal infrared imager on Hayabusa2, acquired high-resolution thermal images of the asteroid 162173 Ryugu for one asteroid rotation period on August 1, 2018 to investigate the thermophysical properties of the asteroid. The surface temperatures of Ryugu suggest that the surface has a low thermal inertia, indicating the presence of porous materials. Thermophysical models that neglect or oversimplify surface roughness cannot reproduce the flat diurnal temperature profiles observed during daytime. We performed numerical simulations of a thermophysical model, including the effects of roughness on the diurnal brightness temperature, the predictions of which successfully reproduced the observed diurnal variation of temperature. The global thermal inertia was obtained with a standard deviation of 225 ± 45 J m^-2 s^-0.5 K^-1, which is relatively low but still within the range of the value estimated in our previous study (Okada et al., Nature 579, 518-522, 2020), confirming that the boulders on Ryugu are more porous in nature than typical carbonaceous chondrites. The global surface roughness (the ratio of the variance of the height relative to a local horizontal surface length) was determined as 0.41 ± 0.08, corresponding to a RMS surface slope of 47 ± 5°. We identified a slightly lower roughness distributed along the equatorial ridge, implying a mass movement of boulders from the equatorial ridge to the mid-latitudes....

Kuiper belt objects (KBOs) are thought to be remnants of the early Solar System, and their size distribution provides an opportunity to explore the formation and evolution of the outer Solar System<SUP>1-5</SUP>. In particular, the size distribution of kilometre-sized (radius = 1-10 km) KBOs represents a signature of initial planetesimal sizes when planets form<SUP>5</SUP>. These kilometre-sized KBOs are extremely faint, and it is impossible to detect them directly. Instead, the monitoring of stellar occultation events is one possible way to discover these small KBOs<SUP>6-9</SUP>. However, until now, there has been no observational evidence for occultation events of KBOs with radii of 1-10 km. Here, we report the first detection of a single occultation event candidate by a KBO with a radius of 1.3 km, which was simultaneously provided by two low-cost small telescopes coupled with commercial complementary metal-oxide-semiconductor cameras. From this detection, we conclude that the surface number density of KBOs with radii exceeding 1.2 km is 6 × 10<SUP>5</SUP> deg<SUP>-2</SUP>. This surface number density favours a theoretical size distribution model with an excess signature at a radius of 1-2 km (ref. <SUP>5</SUP>). If this is a true KBO detection, this implies that planetesimals before their runaway growth phase grew into kilometre-sized objects in the primordial outer Solar System and remain as a major population in the present-day Kuiper belt....

We investigate the connection between active galactic nucleus (AGN) and star formation activities of AGN host galaxies by studying the 3.3 mu m polycyclic aromatic hydrocarbon (PAH) emission feature of 79 type 1 AGNs using the AKARI space telescope. Utilizing the slitless spectroscopic capability of the AKARI Infrared Camera, we obtained the spectra in the wavelength range of 2-5 mu m from extended regions of the sample galaxies in order to measure star formation activity from the entire host galaxies. We detected the 3.3 mu m PAH emission feature from 18 sample galaxies and measured the luminosities of the feature (L-PAH3.3). We found that L-PAH3.3 is significantly correlated with AGN luminosities (L-AGN), such as 5100 angstrom monochromatic luminosity, and X-ray luminosity regardless of host galaxy morphology and radio-loudness. The correlation between L-PAH3.3 and L-AGN follows L-PAH3.3 proportional to L-AGN(0.9). Therefore we suggest that host galaxies with stronger AGN activities have stronger star formation activities. We also found that the ratios between L-PAH3.3 and the bolometric infrared luminosity (L-IR) of our sample galaxies are lower than for non-AGN galaxies due to increased L-IR. We suggest that this can be attributed to the contribution of AGN to L-IR.

<italic>Context.</italic> Deep mid-infrared (MIR) surveys have revealed numerous strongly star-forming galaxies at redshift <italic>z</italic> ≲ 2. Their MIR fluxes are produced by a combination of continuum and polycyclic aromatic hydrocarbon (PAH) emission features. The PAH features can dominate the total MIR flux, but are difficult to measure without spectroscopy. <italic>Aims.</italic> We aim to study star-forming galaxies by using a blind spectroscopic survey at MIR wavelengths to understand evolution of their star formation rate (SFR) and specific SFR (SFR per stellar mass) up to <italic>z</italic> ≃ 0.5, by paying particular attention to their PAH properties. <italic>Methods.</italic> We conducted a low-resolution (<italic>R</italic> ≃ 50) slitless spectroscopic survey at 5–13 <italic>μ</italic>m of 9 <italic>μ</italic>m flux-selected sources (&gt;0.3 mJy) around the north ecliptic pole with the infrared camera (IRC) onboard AKARI. After removing 11 AGN candidates by using the IRC photometry, we identify 48 PAH galaxies with PAH 6.2, 7.7, and 8.6 <italic>μ</italic>m features at <italic>z</italic> &lt; 0.5. The rest-frame optical–MIR spectral energy distributions (SEDs) based on CFHT and IRC imaging covering 0.37–18 <italic>μ</italic>m were produced, and analysed in conjunction with the PAH spectroscopy. We defined the PAH enhancement by using the luminosity ratio of the 7.7 <italic>μ</italic>m PAH feature over the 3.5 <italic>μ</italic>m stellar component of the SEDs. <italic>Results.</italic> The rest-frame SEDs of all PAH galaxies have a universal shape with stellar and 7.7 <italic>μ</italic>m bumps, except that the PAH enhancement significantly varies as a function of the PAH luminosities. We identify a PAH-enhanced population at <italic>z</italic> ≳ 0.35, whose SEDs and luminosities are typical of luminous infrared galaxies. They show particularly larger PAH enhancement at high luminosity, implying that they are vigorous star-forming galaxies with elevated specific SFR. Our composite starburst model that combines a very young and optically very thick starburst with a very old population can successfully reproduce most of their SED characteristics, although we cannot confirm this optically think component from our spectral analysis.

We present a photometric catalog for Spitzer Space Telescope warm mission observations of the North Ecliptic Pole (NEP centered at R.A. = 18h00m00s, decl. = 66d33m38.552). The observations are conducted with IRAC in the 3.6 and 4.5 μm bands over an area of 7.04 deg2, reaching 1σ depths of 1.29 μJy and 0.79 μJy in the 3.6 μm and 4.5 μm bands, respectively. The photometric catalog contains 380,858 sources with 3.6 and 4.5 μm band photometry over the full-depth NEP mosaic. Point-source completeness simulations show that the catalog is 80% complete down to 19.7 AB. The accompanying catalog can be used for constraining the physical properties of extragalactic objects, studying the AGN population, measuring the infrared colors of stellar objects, and studying the extragalactic infrared background light.

The Mid-infrared Imager, Spectrometer, Coronagraph (MISC) is one of the instruments studied both for the Origins Space Telescope (OST) Mission Concept 1 and 2. The highest ever spectro-photometric stability achieved by MISC transit spectrometer module (MISC TRA) enables to detect bio-signatures (e.g., ozone, water, and methane) in habitable worlds in both primary and secondary transits of exoplanets and makes the OST a powerful tool to bring a revolutionary progress in exoplanet sciences. Combined with the spectroscopic capability in the FIR provided by other OST instruments, the MISC widens the wavelength coverage of OST down to 4 mu m, which makes the OST a powerful tool to diagnose the physical and chemical condition of the ISM using dust features, molecules lines and atomic and ionic lines. The MISC also provides the OST with a focal plane guiding function for the other OST science instruments as well as its own use.

The extragalactic background light (EBL) is the integrated emission from all objects outside of the Milky Way galaxy. Imprinted by the history of stellar emission, the EBL in the near infrared traces light back to the birth of the first stars in the Universe and can allow tight constraints on structure formation models. Recent studies using data from the Spitzer Space Telescope and the first Cosmic Infrared Background ExpeRiment (CIBER-1) find that there are excess fluctuations in the EBL on large scales which have been attributed to either high redshift galaxies and quasars, or to stars that were stripped from their host galaxies during merging events. To help disentangle these two models, multi-wavelength data can be used to trace their distinctive spectral features. Following the success of CIBER-1, CIBER-2 is designed to identify the sources of the EBL excess fluctuations using data in six wavebands covering the optical and near infrared. The experiment consists of a cryogenic payload and is scheduled to launch four times on a recoverable sounding rocket. CIBER-2 has a 28.5 cm telescope coupled with an optics system to obtain wide-field images in six broad spectral bands between 0.5 and 2.5 μm simultaneously. The experiment uses 2048 × 2048 Hawaii-2RG detector arrays and a cryogenic star tracker. A prototype of the cryogenic star tracker is under construction for a separate launch to verify its performance and star tracking algorithm. The mechanical, optical, and electrical components of the CIBER-2 experiment will have been integrated into the payload by mid-2018. Here we present the final design of CIBER-2 and our team's instrument characterization efforts. The design and analysis of the optical focus tests will be discussed. We also report on the performance of CIBER-2 support systems, including the cooling mechanisms and deployable components. Finally, we outline the remaining tasks required to prepare the payload for launch.

Cosmic Infrared Background ExpeRiment-2 (CIBER-2) is an international project to make a rocket-borne measurement of the Cosmic Infrared Background (CIB) using three Hawaii-2RG image sensors. Since the rocket telemetry is unable to downlink all the image data in real time, we adopt an onboard data storage board for each sensor electronics. In this presentation, the development of the data storage board and the Ground Station Electronics (GSE) system for CIBER2 are described. We have fabricated, integrated, and tested all systems and confirmed that all work as expected, and are ready for flight.

Measurements in the infrared wavelength domain allow direct assessment of the physical state and energy balance of cool matter in space, enabling the detailed study of the processes that govern the formation and evolution of stars and planetary systems in galaxies over cosmic time. Previous infrared missions revealed a great deal about the obscured Universe, but were hampered by limited sensitivity. SPICA takes the next step in infrared observational capability by combining a large 2.5-meter diameter telescope, cooled to below 8 K, with instruments employing ultra-sensitive detectors. A combination of passive cooling and mechanical coolers will be used to cool both the telescope and the instruments. With mechanical coolers the mission lifetime is not limited by the supply of cryogen. With the combination of low telescope background and instruments with state-of-the-art detectors SPICA provides a huge advance on the capabilities of previous missions. SPICA instruments offer spectral resolving power ranging from R ∼50 through 11 000 in the 17–230 μm domain and R ∼28.000 spectroscopy between 12 and 18 μm. SPICA will provide efficient 30–37 μm broad band mapping, and small field spectroscopic and polarimetric imaging at 100, 200 and 350 μm. SPICA will provide infrared spectroscopy with an unprecedented sensitivity of ∼5 × 10-20 W m-2 (5σ /1 h)—over two orders of magnitude improvement over what earlier missions. This exceptional performance leap, will open entirely new domains in infrared astronomy; galaxy evolution and metal production over cosmic time, dust formation and evolution from very early epochs onwards, the formation history of planetary systems.

Our current knowledge of star formation and accretion luminosity at high redshift (z > 3–4), as well as the possible connections between them, relies mostly on observations in the rest-frame ultraviolet, which are strongly affected by dust obscuration. Due to the lack of sensitivity of past and current infrared instrumentation, so far it has not been possible to get a glimpse into the early phases of the dust-obscured Universe. Among the next generation of infrared observatories, SPICA, observing in the 12–350 µm range, will be the only facility that can enable us to trace the evolution of the obscured star-formation rate and black-hole accretion rate densities over cosmic time, from the peak of their activity back to the reionisation epoch (i.e., 3 < z ≲ 6–7), where its predecessors had severe limitations. Here, we discuss the potential of photometric surveys performed with the SPICA mid-infrared instrument, enabled by the very low level of impact of dust 1 obscuration in a band centred at 34 µm. These unique unbiased photometric surveys that SPICA will perform will fully characterise the evolution of AGNs and star-forming galaxies after reionisation.

IR spectroscopy in the range 12–230 μm with the SPace IR telescope for Cosmology and Astrophysics (SPICA) will reveal the physical processes governing the formation and evolution of galaxies and black holes through cosmic time, bridging the gap between the James Webb Space Telescope and the upcoming Extremely Large Telescopes at shorter wavelengths and the Atacama Large Millimeter Array at longer wavelengths. The SPICA, with its 2.5-m telescope actively cooled to below 8 K, will obtain the first spectroscopic determination, in the mid-IR rest-frame, of both the star-formation rate and black hole accretion rate histories of galaxies, reaching lookback times of 12 Gyr, for large statistically significant samples. Densities, temperatures, radiation fields, and gas-phase metallicities will be measured in dust-obscured galaxies and active galactic nuclei, sampling a large range in mass and luminosity, from faint local dwarf galaxies to luminous quasars in the distant Universe. Active galactic nuclei and starburst feedback and feeding mechanisms in distant galaxies will be uncovered through detailed measurements of molecular and atomic line profiles. The SPICA’s large-area deep spectrophotometric surveys will provide mid-IR spectra and continuum fluxes for unbiased samples of tens of thousands of galaxies, out to redshifts of z ∼ 6.

The physical processes driving the chemical evolution of galaxies in the last ~ 11Gyr cannot be understood without directly probing the dust-obscured phase of star-forming galaxies and active galactic nuclei. This phase, hidden to optical tracers, represents the bulk of the star formation and black hole accretion activity in galaxies at 1 < z < 3. Spectroscopic observations with a cryogenic infrared observatory like SPICA, will be sensitive enough to peer through the dust-obscured regions of galaxies and access the rest-frame mid- to far-infrared range in galaxies at high-z. This wavelength range contains a unique suite of spectral lines and dust features that serve as proxies for the abundances of heavy elements and the dust composition, providing tracers with a feeble response to both extinction and temperature. In this work, we investigate how SPICA observations could be exploited to understand key aspects in the chemical evolution of galaxies: the assembly of nearby galaxies based on the spatial distribution of heavy element abundances, the global content of metals in galaxies reaching the knee of the luminosity function up to z ~ 3, and the dust composition of galaxies at high-z. Possible synergies with facilities available in the late 2020s are also discussed.

Organized Autotelescopes for Serendipitous Event Survey (OASES) is an optical observation project that aims to detect and investigate stellar occultation events by kilometer-sized trans-Neptunian objects (TNOs). In this project, multiple low-cost observation systems for wide-field and high-speed photometry were developed in order to detect rare and short-timescale stellar occultation events. The observation system consists of commercial off-the-shelf 0.28m aperture f/1.58 optics providing a 2.degrees 3 x 1.degrees 8 field of view. A commercial CMOS camera is coupled to the optics to obtain full-frame imaging with a frame rate greater than 10 Hz. As of 2016 September, this project exploits two observation systems, which are installed on Miyako Island, Okinawa, Japan. Recent improvements in CMOS technology in terms of high-speed imaging and low readout noise mean that the observation systems are capable of monitoring similar to 2000 stars in the Galactic plane simultaneously with magnitudes down to V similar to 13.0, providing similar to 20% photometric precision in light curves with a sampling cadence of 15.4 Hz. This number of monitored stars is larger than for any other existing instruments for coordinated occultation surveys. In addition, a precise time synchronization method needed for simultaneous occultation detection is developed using faint meteors. The two OASES observation systems are executing coordinated monitoring observations of a dense stellar field in order to detect occultations by kilometer-sized TNOs for the first time.

The extragalactic background light (EBL) captures the total integrated emission from stars and galaxies throughout the cosmic history. The amplitude of the near-infrared EBL from space absolute photometry observations has been controversial and depends strongly on the modeling and subtraction of the zodiacal light (ZL) foreground. We report the first measurement of the diffuse background spectrum at 0.8-1.7 mu m from the CIBER experiment. The observations were obtained with an absolute spectrometer over two flights in multiple sky fields to enable the subtraction of ZL, stars, terrestrial emission, and diffuse Galactic light. After subtracting foregrounds and accounting for systematic errors, we find the nominal EBL brightness, assuming the Kelsall ZL model, is 42.7(-10.6) (+11.9) nW m(-2) sr(-1) at 1.4 mu m. We also analyzed the data using the Wright ZL model, which results in a worse statistical fit to the data and an unphysical EBL, falling below the known background light from galaxies at. lambda<. 1.3 mu m. Using a model-independent analysis based on the minimum EBL brightness, we find an EBL brightness of 28.7(-3.3)(+5.1) nWm(-2) s(r-1) at 1.4 mu m. While the derived EBL amplitude strongly depends on the ZL model, we find that we cannot fit the spectral data to ZL, Galactic emission, and EBL from solely integrated galactic light from galaxy counts. The results require a new diffuse component, such as an additional foreground or an excess EBL with a redder spectrum than that of ZL.

The extragalactic background suggests half the energy generated by stars was reprocessed into the infrared (IR) by dust. At z ∼1.3, 90% of star formation is obscured by dust. To fully understand the cosmic star formation history, it is critical to investigate infrared emission. AKARI has made deep mid-IR observation using its continuous 9-band filters in the NEP field (5.4 deg^2), using ∼10% of the entire pointed observations available throughout its lifetime. However, there remain 11,000 AKARI infrared sources undetected with the previous CFHT/Megacam imaging (r ∼25.9ABmag). Redshift and IR luminosity of these sources are unknown. These sources may contribute significantly to the cosmic star-formation rate density (CSFRD). For example, if they all lie at 1 &lt; z &lt; 2, the CSFRD will be twice as high at the epoch. We are carrying out deep imaging of the NEP field in 5 broad bands (g,r,i,z, and y) using Hyper Suprime-Camera (HSC), which has 1.5 deg field of view in diameter on Subaru 8m telescope. This will provide photometric redshift information, and thereby IR luminosity for the previously-undetected 11,000 faint AKARI IR sources. Combined with AKARI's mid-IR AGN/SF diagnosis, and accurate mid-IR luminosity measurement, this will allow a complete census of cosmic star-formation/AGN accretion history obscured by dust....

We propose an all-silicon multi-layer interference filter composed solely of silicon with sub-wavelength structure (SWS) in order to realize high performance optical filters operating in the THz frequency region with robustness against cryogenic thermal cycling and mechanical damage. We demonstrate fabrication of a three-layer prototype using well-established common micro-electro-mechanical systems (MEMS) technologies as a first step toward developing practical filters. The measured transmittance of the three-layer filter agrees well with the theoretical transmittances calculated by a simple thin-film calculation with effective refractive indices as well as a rigorous coupled-wave analysis simulation. We experimentally show that SWS layers can work as homogeneous thin-film interference layers with effective refractive indices even if there are multiple SWS layers in a filter.

SPICA (Space Infrared Telescope for Cosmology and Astrophysics) is an astronomical mission optimized for mid- and far-infrared astronomy with a cryogenically cooled 3-m class telescope, envisioned for launch in early 2020s. Mid-infrared Camera and Spectrometer (MCS) is a focal plane instrument for SPICA with imaging and spectroscopic observing capabilities in the mid-infrared wavelength range of 5 - 38µm. MCS consists of two relay optical modules and following four scientific optical modules of WFC (Wide Field Camera 5 × 5 field of view, f/11.7 and f/4.2 cameras), LRS (Low Resolution Spectrometer 2.5 long slits, prism dispersers, f/5.0 and f/1.7 cameras, spectral resolving power R ~ 50 - 100), MRS (Mid Resolution Spectrometer echelles, integral field units by image slicer, f/3.3 and f/1.9 cameras, R ~ 1100-3000) and HRS (High Resolution Spectrometer immersed echelles, f/6.0 and f/3.6 cameras, R ~ 20000-30000). Here, we present optical design and expected optical performance of MCS. Most parts of MCS optics adopt off-axis reflective system for covering the wide wavelength range of 5-38µm without chromatic aberration and minimizing problems due to changes in shapes and refractive indices of materials from room temperature to cryogenic temperature. In order to achieve the high specification requirements of wide field of view, small F-number and large spectral resolving power with compact size, we employed the paraxial and aberration analysis of off-axial optical systems (Araki 2005 [1]) which is a design method using free-form surfaces for compact reflective optics such as head mount displays. As a result, we have successfully designed compact reflective optics for MCS with as-built performance of diffraction-limited image resolution.

The mid-infrared range contains many spectral features associated with large molecules and dust grains such as polycyclic aromatic hydrocarbons and silicates. These are usually very strong compared to fine-structure gas lines, and thus valuable in studying the spectral properties of faint distant galaxies. In this paper, we evaluate the capability of low-resolution mid-infrared spectroscopic surveys of galaxies that could be performed by SPICA. The surveys are designed to address the question how star formation and black hole accretion activities evolved over cosmic time through spectral diagnostics of the physical conditions of the interstellar/circumnuclear media in galaxies. On the basis of results obtained with Herschel far-infrared photometric surveys of distant galaxies and Spitzer and AKARI near- to mid-infrared spectroscopic observations of nearby galaxies, we estimate the numbers of the galaxies at redshift z > 0.5, which are expected to be detected in the polycyclic aromatic hydrocarbon features or dust continuum by a wide (10 deg2) or deep (1 deg2) blind survey, both for a given observation time of 600 h. As by-products of the wide blind survey, we also expect to detect debris disks, through the mid-infrared excess above the photospheric emission of nearby main-sequence stars, and we estimate their number. We demonstrate that the SPICA mid-infrared surveys will efficiently provide us with unprecedentedly large spectral samples, which can be studied further in the far-infrared with SPICA.

We are developing a fully depleted silicon-on-insulator (FD-SOI) CMOS readout integrated circuit (ROIC) operated at temperatures below 4 K. Its application is planned for the readout circuit of high-impedance far-infrared detectors for astronomical observations. We designed a trans-impedance amplifier (TIA) using a CMOS operational amplifier (OPAMP) with FD-SOI technique. The TIA is optimized to readout signals from a germanium blocked impurity band (Ge BIB) detector which is highly sensitive to wavelengths of up to 200 m. For the first time, we demonstrated the FD-SOI CMOS OPAMP combined with the Ge BIB detector at 4.5 K. The result promises to solve issues faced by conventional cryogenic ROICs.

We present the latest results of the sensitivity estimate for spectrometers of the SPICA Mid-Infrared Instrument (SMI). SMI has three spectroscopic channels; low resolution spectrometer (LRS), medium resolution spectrometer (MRS) and high resolution spectrometer (HRS). Taking account of the results of optical design of each spectrometer and the latest information of the expected performance of detector arrays, the continuum sensitivity for a point source, the continuum sensitivity for an extended source, the line sensitivity for a point source, the line sensitivity for an extended source, and the saturation limit are calculated for LRS, MRS and HRS and are provided in this paper.

We present the current status of the Cosmic Infrared Background ExpeRiment-2 (CIBER-2) project, whose goal is to make a rocket-borne measurement of the near-infrared Extragalactic Background Light (EBL), under a collaboration with U.S.A., Japan, South Korea, and Taiwan. The EBL is the integrated light of all extragalactic sources of emission back to the early Universe. At near-infrared wavelengths, measurement of the EBL is a promising way to detect the diffuse light from the first collapsed structures at redshift z similar to 10, which are impossible to detect as individual sources. However, recently, the intra-halo light (IHL) model is advocated as the main contribution to the EBL, and our new result of the EBL fluctuation from CIBER-1 experiment is also supporting this model. In this model, EBL is contributed by accumulated light from stars in the dark halo regions of low-redshift (z<2) galaxies, those were tidally stripped by the interaction of satellite dwarf galaxies. Thus, in order to understand the origin of the EBL, both the spatial fluctuation observations with multiple wavelength bands and the absolute spectroscopic observations for the EBL are highly required. After the successful initial CIBER-1 experiment, we are now developing a new instrument CIBER-2, which is comprised of a 28.5-cm aluminum telescope and three broad-band, wide-field imaging cameras. The three wide-field (2.3x2.3 degrees) imaging cameras use the 2Kx2K HgCdTe HAWAII-2RG arrays, and cover the optical and near-infrared wavelength range of 0.5-0.9 mu m, 1.0-1.4 mu m and 1.5-2.0 mu m, respectively. Combining a large area telescope with the high sensitivity detectors, CIBER-2 will be able to measure the spatial fluctuations in the EBL at much fainter levels than those detected in previous CIBER-1 experiment. Additionally, we will use a linear variable filter installed just above the detectors so that a measurement of the absolute spectrum of the EBL is also possible. In this paper, the scientific motivation and the expected performance for CIBER-2 will be presented. The detailed designs of the telescope and imaging cameras will also be discussed, including the designs of the mechanical, cryogenic, and electrical systems.

SMI (SPICA Mid-infrared Instrument) is one of the two focal-plane scientific instruments planned for new SPICA, and the Japanese instrument proposed and managed by a university consortium in Japan. SMI covers the wavelength range of 12 to 36 μm, using the following three spectroscopic channels with unprecedentedly high sensitivities: low-resolution spectroscopy (LRS; R = 50 - 120, 17 - 36 μm), mid-resolution spectroscopy (MRS; R = 1300 - 2300, 18 - 36 μm), and high-resolution spectroscopy (HRS; R = 28000, 12 - 18 μm). The key functions of these channels are high-speed dustband mapping with LRS, high-sensitivity multi-purpose spectral mapping with MRS, and high-resolution molecular-gas spectroscopy with HRS. This paper describes the technical concept and scientific capabilities of SMI.

We present infrared (IR) galaxy luminosity functions (LFs) in the AKARI North Ecliptic Pole (NEP) deep field using recently-obtained, wider Canada-France-Hawaii Telescope (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 rest-frame 8 and 12 mu m luminosities without using a large extrapolation based on spectral energy distribution fitting, which was the largest uncertainty in previous studies. Total infrared (TIR) luminosity is also obtained more reliably due to the superior filter coverage. The resulting rest-frame 8 and 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(IR)), we found that the Omega(IR) evolves as proportional to(1 + z)(4.2+0.4).

The Space Infrared Telescope for Cosmology and Astrophysics (SPICA) is an astronomical mission optimized for mid-and far-infrared astronomy, envisioned for launch in the 2020s. The Mid-infrared Camera and Spectrometer (MCS) is a model instrument that covers the 5-38 mu m wavelength range and enables imaging and spectroscopic observations via four modules named WFC-S, WFC-L, HRS, and MRS. Both of the wide field camera (WFC) modules have a 5-arcmin square field of view (FOV) but cover di r erent wavelength ranges; WFC for the short wavelength region (WFC-S) covers 5 to 24 mu m, whereas WFC for the long wavelength region (WFC-L) covers 18 to 38 mu m. The High Resolution Spectrometer (HRS) covers the 12-18 mu m range with a resolving power of 22,000-30,000, and the Mid Resolution Spectrometer (MRS) performs integral filed units spectroscopy with a 12'' by 8'' FOV. MRS simultaneously covers the 12-38 mu m range with a moderate resolving power of 720-2000. Here, we report sensitivity estimates from a detailed modeling process involving the instrument itself, the telescope, environmental conditions, and the system error budgets. We show that the WFC-S and HRS modules require an adaptive system to correct for telescope pointing error. In particular, band pass fi lters (BPFs) longer than 26 mu m should be developed.

We present the development of Superconducting Tunnel Junction (STJ) detectors as a far-infrared single photon spectrometer, which is motivated for an application to a search for the radiative decay of the cosmic neutrino background (C nu B). The photon energy spectrum from the radiative decays of C nu B is expected to have a sharp edge at high energy end in a far-infrared region ranging from 14 meV to 25 meV (from 50 mu m to 90 mu m in wavelength) in the cosmic infrared background and the overwhelming infrared foreground from the zodiacal emission. Thus, the detector is required photon-by-photon detection with sufficiently high energy resolution, in order to gain the best signal-to-noise ratio as well as to identify the edge structure. The following two types of photon detectors are under consideration: an array of niobium/aluminum STJ (Nb/Al-STJ) pixels with a diffraction grating, and STJ using hafnium (Hf-STJ). Each Nb/Al-STJ pixel is required to be capable of detecting single photons in the far-infrared region, and the pixel array measures the photon wavelength spectrum which the diffraction grating creates. Hf-STJ is expected to achieve 2% energy resolution for single photon of 25 meV due to very small gap energy of hafnium.

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 on board AKARI. The 2.5-5.0 mu m spectral region contains emission lines such as Br alpha (2.63 mu m), Bra (4.05 mu m), and polycyclic aromatic hydrocarbons (3.3 mu m), which can be used for studying the black hole (BH) masses and star formation activity 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 and SNUQSO, and AGNs with reverberation-mapped BH masses from Peterson et al. 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. Moreover, we fit the hot and warm dust components of the dust torus by adding photometric data of SDSS, 2MASS, WISE, and ISO to the AKARI spectra, finding hot and warm dust temperatures of similar to 1100K and similar to 220 K, respectively, rather than the commonly cited hot dust temperature of 1500 K.

Extragalactic background light (EBL) anisotropy traces variations in the total production of photons over cosmic history and may contain faint, extended components missed in galaxy point-source surveys. Infrared EBL fluctuations have been attributed to primordial galaxies and black holes at the epoch of reionization (EOR) or, alternately, intrahalo light (IHL) from stars tidally stripped from their parent galaxies at low redshift. We report new EBL anisotropy measurements from a specialized sounding rocket experiment at 1.1 and 1.6 micrometers. The observed fluctuations exceed the amplitude from known galaxy populations, are inconsistent with EOR galaxies and black holes, and are largely explained by IHL emission. The measured fluctuations are associated with an EBL intensity that is comparable to the background from known galaxies measured through number counts and therefore a substantial contribution to the energy contained in photons in the cosmos.

LiteBIRD is a next-generation satellite mission to measure the polarization of the cosmic microwave background (CMB) radiation. On large angular scales the B-mode polarization of the CMB carries the imprint of primordial gravitational waves, and its precise measurement would provide a powerful probe of the epoch of inflation. The goal of LiteBIRD is to achieve a measurement of the characterizing tensor to scalar ratio r to an uncertainty of δr = 0.001. In order to achieve this goal we will employ a kilo-pixel superconducting detector array on a cryogenically cooled sub-Kelvin focal plane with an optical system at a temperature of 4 K. We are currently considering two detector array options; transition edge sensor (TES) bolometers and microwave kinetic inductance detectors. In this paper we give an overview of LiteBIRD and describe a TES-based polarimeter designed to achieve the target sensitivity of 2 μK arcmin over the frequency range 50-320 GHz. © 2014 Springer Science+Business Media New York.

We study the behaviour of polycyclic aromatic hydrocarbon (PAH) emission in galaxies at z = 0.3-1.4 using 1868 samples from the revised catalogue of AKARI North Ecliptic Pole Deep survey. The continuous filter coverage at 2-24 μm makes it possible to measure 8 μm luminosity, which is dominated by PAH emission, for galaxies at up to z = 2. We compare the IR8 (≡L_IR/L(8)) and 8 μm to 4.5 μm luminosity ratio (νL(8) /νL(4.5)) with the starburstiness, R_SB, defined as excess of specific star-formation rate over that of main-sequence galaxy. All AGN candidates were excluded from our sample using a spectral energy distribution fitting. We find νL(8) /νL(4.5) increases with starburstiness at log R_SB&lt; 0.5 and stays constant at higher starburstiness. On the other hand, IR8 is constant at log R_SB&lt; 0, while it increases with starburstiness at log R_SB&gt; 0. This behaviour is seen in all redshift range of our study. These results indicate that starburst galaxies have deficient PAH emission compared with main-sequence galaxies. We also find that galaxies with extremely high νL(8) /νL(4.5) ratio have only moderate starburstiness. These results suggest that starburst galaxies have compact star-forming regions with intense radiation, which destroys PAHs, and/or have dusty HII regions resulting in a lack of ionising photons....

Aims. We present an 8-band (u*, g', r', i', z', Y, J, Ks) optical to NIR deep photometric catalog based on the observations made with MegaCam and WIRCam at CFHT, and compute photometric redshifts, zp in the North Ecliptic Pole (NEP) region. Our catalog provides us to identify the counterparts, and zp for AKARI NIR/MIR sources. Results. The estimated 4sigma detection limits within an 1" aperture radius are 26.7, 25.9, 25.1, and 24.1 mag [AB] for g', r', i', and z'-bands and 23.4, 23.0, and 22.7 mag for Y, J, and Ks-bands, respectively. There are a total of 85797 sources in the band-merged catalog. An astrometric accuracy of this catalog determined by examining coordinate offsets with regard to 2MASS is 0.013" with a root mean square offset of 0.32". We distinguish 5441 secure stars from extended sources using u*-J vs. g'-Ks colors, combined with the SExtractor stellarity index of the images. Comparing with galaxy spectroscopic redshifts, we find a photometric redshift dispersion, sigma_(dz/(1+z)), of 0.032 and catastrophic failure rate, dz/(1+z)>0.15, of 5.8% at z<1, while a dispersion of 0.117 and a catastrophic failures rate of 16.6% at z>1. We extend estimate of the zp uncertainty over the full magnitude/redshift space with a redshift probability distribution function and find that our redshift are highly accurate with z'<22 at zp<2.5 and for fainter sources with z'<24 at z<1. From the investigation of photometric properties of AKARI infrared sources (23354 sources) using the g'z'Ks diagram, <5% of AKARI sources with optical counterparts are classified as high-z (1.4<z<2.5) star-forming galaxies. Among the high-z star-forming galaxies, AKARI MIR detected sources seem to be affected by stronger dust extinction compared with sources with non-detections in the AKARI MIR bands. The full, electronic version of our catalog with zp will be available at the CDS.

Fluctuations in the extragalactic background light trace emission from the history of galaxy formation, including the emission from the earliest sources from the epoch of reionization. A number of recent near-infrared measurements show excess spatial power at large angular scales inconsistent with models of z < 5 emission from galaxies. These measurements have been interpreted as arising from either redshifted stellar and quasar emission from the epoch of reionization, or the combined intra-halo light from stars thrown out of galaxies during merging activity at lower redshifts. Though astrophysically distinct, both interpretations arise from faint, low surface brightness source populations that are difficult to detect except by statistical approaches using careful observations with suitable instruments. The key to determining the source of these background anisotropies will be wide-field imaging measurements spanning multiple bands from the optical to the near-infrared.The Cosmic Infrared Background ExpeRiment 2 (CIBER-2) will measure spatial anisotropies in the extragalactic infrared background caused by cosmological structure using six broad spectral bands. The experiment uses three 2048 x 2048 Hawaii-2RG near-infrared arrays in three cameras coupled to a single 28.5 cm telescope housed in a reusable sounding rocket-borne payload. A small portion of each array will also be combined with a linear-variable filter to make absolute measurements of the spectrum of the extragalactic background with high spatial resolution for deep subtraction of Galactic starlight. The large field of view and multiple spectral bands make CIBER-2 unique in its sensitivity to fluctuations predicted by models of lower limits on the luminosity of the first stars and galaxies and in its ability to distinguish between primordial and foreground anisotropies. In this paper the scientific motivation for CIBER-2 and details of its first flight instrumentation will be discussed, including detailed designs of the mechanical, cryogenic, and electrical systems. Plans for the future will also be presented.