観測ロケットを用いて宇宙空間から宇宙背景放射の観測を実施するために、搭載する観測装置を開発する。

赤外線衛星観測データを解析し、宇宙赤外線背景放射の測定およびその起源を探究する。

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

� 2015. The American Astronomical Society. All rights reserved. Using all-sky maps obtained with COBE/DIRBE, we reanalyzed the diffuse sky brightness at 1.25 and which consists of zodiacal light, diffuse Galactic light (DGL), integrated starlight (ISL), and isotropic emission including the extragalactic background light. Our new analysis including an improved estimate of the DGL and the ISL with the 2MASS data showed that deviations of the isotropic emission from isotropy were less than 10% in the entire sky at high Galactic latitude (). We derived the DGL to 100 μm brightness ratios of ∼4.79 and ∼1.49 n W m-2 MJy-1 at 1.25 and 2.2 μm, respectively. The result of our analysis revealed a significantly large isotropic component at 1.25 and with intensities of 60.15 16.14 and respectively. This intensity is larger than the integrated galaxy light, upper limits from γ-ray observation, and potential contribution from exotic sources (i.e., Population III stars, intrahalo light, direct collapse black holes, and dark stars). We therefore conclude that the excess light may originate from the local universe: the Milky Way and/or the solar system.

DOI： 10.1088/0004-637X/811/2/77

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記述言語：英語   掲載種別：研究論文（学術雑誌）

Measuring the absolute brightness of the zodiacal light (ZL), which is the sunlight scattered by interplanetary dust particles, is important not only for understanding the physical properties of the dust but also for constraining the extragalactic background light (EBL) by subtracting the ZL foreground. We describe the results of high-resolution spectroscopic observations of the night sky in the wavelength range of 300-900 nm with the double spectrograph on the Hale telescope to determine the absolute brightness of the ZL continuum spectra from the Fraunhofer absorption line intensities. The observed fields are part of the fields observed by the Spitzer Space Telescope for the EBL study. Assuming that the spectral shape of the zodiacal light is identical to the solar spectrum in a narrow region around the Fraunhofer lines, we decomposed the observed sky brightness into multiple emission components by amplitude parameter fitting with spectral templates of the airglow, ZL, diffuse Galactic light, integrated starlight, and other isotropic components including EBL. As a result, the ZL component with the Ca ii λλ 393.3, 396.8 nm Fraunhofer lines around 400 nm is clearly separated from the others in all fields with uncertainties around 20%, mainly due to the template errors and the time variability of the airglow. The observed ZL brightness in most of the observed fields is consistent with the modeled ZL brightness calculated by combining the most conventional ZL model at 1250 nm based on the Diffuse Infrared Background Experiment and the observational ZL template spectrum based on the Hubble Space Telescope. However, the ecliptic plane observation is considerably fainter than the ZL model, and this discrepancy is discussed in terms of the optical properties of the interplanetary dust accreted in the ecliptic plane.

DOI： 10.1093/pasj/psae016

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記述言語：日本語   掲載種別：研究論文（研究会，シンポジウム資料等）

レポート番号: Ⅴ-3

CiNii Research

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Kyushu Institute of Technology (Kyutech) is developing a 6U CubeSat that is named 'VERTECS' (Visible Extragalactic background RadiaTion Exploration by CubeSat). This is an astronomical CubeSat designed to reveal star formation history by observing visible extragalactic background light [1] and the first satellite for Kyutech to rely on not UHF (around 400 MHz) but only microwave (>1 GHz) to communicate between the satellite and ground station. Microstrip patch antennas are adopted on this CubeSat due to desired characteristics such as low profile, lightweight, and non-deployable structure. However due to the performance of the microstrip patch antenna is limited such as directional radiation pattern and narrow operational bandwidth, the placement of the antenna on CubeSat is more critical compared to that of the conventional antenna for UHF communication, such as dipole and monopole antenna. In this paper, we describe choosing the antenna placement while considering antenna performance, including the coupling of transmission and reception antenna.

DOI： 10.23919/ICEP61562.2024.10535673

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Due to advances in observation and imaging technologies, modern astronomical satellites generate large volumes of data. This necessitates efficient onboard data processing and high-speed data downlink. Reflecting this trend is the Visible Extragalactic background RadiaTion Exploration by CubeSat (VERTECS) 6U Astronomical Nanosatellite. Designed for the observation of Extragalactic Background Light (EBL), this mission is expected to generate a substantial amount of image data, particularly within the confines of CubeSat capabilities. This paper introduces the VERTECS Camera Control Board (CCB), an open-source payload interface board leveraging Commercial Off-The-Shelf (COTS) components, with a Raspberry Pi Compute Module 4 at its core. The VERTECS CCB hardware and software have been designed from the ground up to serve as the sole interface between the VERTECS bus system and astronomical imaging payload, while providing compute capability not usually seen in nanosatellites of this class. Responsible for mission data processing, it will facilitate high-speed data transfer from the imaging payload via gigabit Ethernet, while also providing a high-bitrate serial connection to the payload X-band transmitter for mission data downlink. Additional interfaces for secondary payloads are provided via USB-C and standard 15-pin camera connectors. The Raspberry Pi embedded within the VERTECS CCB operates on a standard Linux distribution, streamlining the software development process. Beyond addressing the current mission’s payload control and data handling requirements, the CCB sets the stage for future missions with heightened data demands. Furthermore, it supports the adoption of machine learning and other compute-intensive applications in orbit. This paper delves into the development of the VERTECS CCB, offering insights into the design and validation of this next-generation payload interface, to ensure that it can survive the rigors of space flight.

DOI： 10.1117/12.3019471

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記述言語：英語   掲載種別：研究論文（学術雑誌）

Zodiacal light (ZL) is sunlight scattered by interplanetary dust particles (IDPs) at optical wavelengths. The spatial distribution of IDPs in the Solar System may hold an important key to understanding the evolution of the Solar System and material transportation within it. The number density of IDPs can be expressed as n(r) ∼ r-α , and the exponent α∼ 1.3 was obtained by previous observations from interplanetary space by Helios 1/2 and Pioneer 10/11 in the 1970s and 1980s. However, no direct measurements of α based on ZL observations from interplanetary space outside Earth’s orbit have been performed since then. Here, we introduce initial results for the radial profile of the ZL at optical wavelengths observed over the range 0.76 - 1.06 au by ONC-T aboard the Hayabusa2# mission in 2021-2022. The ZL brightness we obtained is well reproduced by a model brightness, although there is a small excess of the observed ZL brightness over the model brightness at around 0.9 au. The radial power-law index we obtained is α= 1.30 ± 0.08 , which is consistent with previous results based on ZL observations. The dominant source of uncertainty arises from the uncertainty in estimating the diffuse Galactic light (DGL). Graphical Abstract: [Figure not available: see fulltext.]

DOI： 10.1186/s40623-023-01856-x

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記述言語：英語   掲載種別：研究論文（学術雑誌）

We report near-infrared polarization of the zodiacal light (ZL) measured from space by the Diffuse Infrared Background Experiment (DIRBE) on board the Cosmic Background Explorer in photometric bands centered at 1.25, 2.2, and 3.5 μm. To constrain the physical properties of interplanetary dust, we use DIRBE Weekly Sky Maps to investigate the solar elongation (ϵ), ecliptic latitude (β), and wavelength (λ) dependence of ZL polarization. We find that the polarization of the ZL varies as a function of ϵ and β, consistent with observed polarization at λ = 550 nm. While the polarization dependence on wavelength at (ϵ, β) = (90°, 0°) is modest (increasing from 17.7% ± 0.2% at 1.25% μm to 21.0% ± 0.3% at 3.5 μm), the variation is more pronounced at the north ecliptic pole (23.1% ± 1.6%, 35.1% ± 2.0%, and 39.3% ± 2.1% at 1.25, 2.2, and 3.5 μm, respectively). The variation in ZL polarization with wavelength is not explained by either Rayleigh scattering or absorptive particles larger than 10 μm.

DOI： 10.3847/1538-4357/acb937

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担当区分：筆頭著者,　責任著者   記述言語：日本語   掲載種別：研究論文（研究会，シンポジウム資料等）

レポート番号: S2-004

CiNii Research

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Nanosatellites are proliferating as low-cost dedicated sensing systems with lean development cycles. Kyushu Institute of Technology (Kyutech) and collaborators have launched a joint venture for a nanosatellite mission, Visible Extragalactic background RadiaTion Exploration by CubeSat (VERTECS). The primary mission is to elucidate the formation history of stars by observing the optical-wavelength cosmic background radiation. The VERTECS satellite will be equipped with a small-Aperture telescope and a high-precision attitude control system to capture the astronomical data for analysis on the ground. However, nanosatellites are limited by their onboard memory resources and downlink speed capabilities. Additionally, due to a limited number of ground stations, the satellite mission will face issues meeting the required data budget for mission success. To alleviate this issue, we propose an on-orbit system pipeline to autonomously classify and then compress desirable image data for downlink prioritization and optimization. The system comprises a prototype Camera Controller Board (CCB) which carries a Raspberry Pi Compute Module 4 which is used for classification and compression. The system uses a lightweight Convolutional Neural Network (CNN) model to classify and determine the desirability of captured image data. The model is designed to be lean and robust to reduce the computational and memory load on the satellite. The model is trained and tested on a novel star field dataset consisting of data captured by the Sloan Digital Sky Survey (SDSS). The dataset is meant to simulate the expected data produced by the 6U satellite. The compression step implements GZip, RICE or HCOMPRESS compression, which are standards for astronomical data. Preliminary testing on the proposed CNN model results in a validation classification accuracy of 100% on the star field dataset, with compression ratios of 3.99, 5.16 and 5.43 for GZip, RICE and HCOMPRESS that were achieved on tested FITS image data.

DOI： 10.1117/12.2684047

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記述言語：英語   掲載種別：研究論文（学術雑誌）

Scattered sunlight from the interplanetary dust (IPD) cloud in our solar system presents a serious foreground challenge for spectrophotometric measurements of the extragalactic background light (EBL). In this work, we report on inferred measurements of the absolute intensity of the zodiacal light (ZL) using the novel technique of Fraunhofer line spectroscopy on the deepest 8542 Å line of the near-infrared Ca ii absorption triplet. The measurements are performed with the narrow band spectrometer (NBS) on board the Cosmic Infrared Background Experiment sounding rocket instrument. We use the NBS data to test the accuracy of two ZL models widely cited in the literature, the Kelsall and Wright models, which have been used in foreground removal analyses that produce high and low EBL results respectively. We find a mean reduced χ 2 = 3.5 for the Kelsall model and χ 2 = 2.0 for the Wright model. The best description of our data is provided by a simple modification to the Kelsall model, which includes a free ZL offset parameter. This adjusted model describes the data with a reduced χ 2 = 1.5 and yields an inferred offset amplitude of 46 ± 19 nW m-2 sr-1 extrapolated to 12500 Å. These measurements elude to the potential existence of a dust cloud component in the inner solar system whose intensity does not strongly modulate with the Earth's motion around the Sun.

DOI： 10.3847/1538-4357/ac44ff

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記述言語：英語   掲載種別：研究論文（学術雑誌）

We report the first measurement of the zodiacal light (ZL) polarization spectrum in the near-infrared between 0.8 and 1.8 μm. Using the low-resolution spectrometer on board the Cosmic Infrared Background Experiment, calibrated for absolute spectrophotometry and spectropolarimetry, we acquire long-slit polarization spectral images of the total diffuse sky brightness toward five fields. To extract the ZL spectrum, we subtract the contribution of other diffuse radiation, such as the diffuse galactic light, the integrated starlight, and the extragalactic background light. The measured ZL polarization spectrum shows little wavelength dependence in the near-infrared, and the degree of polarization clearly varies as a function of the ecliptic coordinates and solar elongation. Among the observed fields, the North Ecliptic Pole shows the maximum degree of polarization of ∼20%, which is consistent with an earlier observation from the Diffuse Infrared Background Experiment on board on the Cosmic Background Explorer. The measured degree of polarization and its solar elongation dependence are reproduced by an empirical scattering model in the visible band and also by a Mie scattering model for large absorptive particles, while a Rayleigh scattering model is ruled out. All of our results suggest that the interplanetary dust is dominated by large particles.

DOI： 10.3847/1538-4357/ac416f

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記述言語：英語   掲載種別：研究論文（学術雑誌）

We study the stellar halos of 0.2 ≲ z ≲ 0.5 galaxies with stellar masses spanning M ∗ ∼ 1010.5 to 1012 M o˙ (approximately L ∗ galaxies at this redshift) using imaging data from the Cosmic Infrared Background Experiment (CIBER). A previous CIBER fluctuation analysis suggested that intra-halo light (IHL) contributes a significant portion of the near-infrared extragalactic background light (EBL), the integrated emission from all sources throughout cosmic history. In this work, we carry out a stacking analysis with a sample of ∼30,000 Sloan Digital Sky Survey (SDSS) photometric galaxies from CIBER images in two near-infrared bands (1.1 and 1.8 μm) to directly probe the IHL associated with these galaxies. We stack galaxies in five sub-samples split by brightness and detect an extended galaxy profile beyond the instrument point-spread function (PSF) derived by stacking stars. We jointly fit a model for the inherent galaxy light profile plus large-scale one- and two-halo clustering to measure the extended galaxy IHL. We detect nonlinear one-halo clustering in the 1.8 μm band at a level consistent with numerical simulations. By extrapolating the fraction of extended galaxy light we measure to all galaxy mass scales, we find ∼30%/15% of the total galaxy light budget from galaxies is at radius r > 10/20 kpc, respectively. These results are new at near-infrared wavelengths at the L ∗ mass scale and suggest that the IHL emission and one-halo clustering could have appreciable contributions to the amplitude of large-scale EBL background fluctuations.

DOI： 10.3847/1538-4357/ac0f5b

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

HiZ-GUNDAM is a future satellite mission which will lead the time-domain astronomy and the multi-messenger astronomy through observations of high-energy transient phenomena. A mission concept of HiZ-GUNDAM was approved by ISAS/JAXA, and it is one of the future satellite candidates of JAXA's medium-class mission. We are in pre-phase A (before pre-project) and elaborating the mission concept, mission/system requirements for the launch in the late 2020s. The main themes of HiZ-GUNDAM mission are (1) exploration of the early universe with high-redshift gamma-ray bursts, and (2) contribution to the multi-messenger astronomy. HiZ-GUNDAM has two kinds of mission payload. The wide field X-ray monitors consist of Lobster Eye optics array and focal imaging sensor, and monitor ~1 steradian field of view in 0.5 - 4 keV energy range. The near infrared telescope has an aperture size 30 cm in diameter, and simultaneously observes four wavelength bands between 0.5 - 2.5 µm. In this paper, we introduce the mission overview of HiZ-GUNDAM.

DOI： 10.1117/12.2560603

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

© COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only. Extragalactic background light (EBL) consists of entire radiation emitted throughout the cosmic history and is one crucial observable quantity to study astrophysics in the early universe, such as first stellar objects or primordial black holes. In the visible and near-infrared, zodiacal light (ZL), sunlight scattered by interplanetary dust, is the brightest foreground for observer in the near-earth orbit and its uncertainty limits accuracy of the EBL measurement. To overcome this problem, observations from heliocentric distance beyond 5 au, where the ZL is negligible, is promising. To achieve the EBL observation in deep space, we have been developing EXo- Zodiacal Infrared Telescope (EXZIT) onboard a solar sail spacecraft to Jovian Trojans planned in Japan around 2030. According to our mission study, a three-mirror reflective telescope optics design with a 90mm × 50mm effective aperture and 16 deg × 8 deg field of view (FoV) followed by a focal plane array HAWAII-2RG with a linear variable filter makes available to detect the EBL at high significance in 0.4-1.6 μm with specific wavelength resolution of ∼20. In the present study, we develop test optics to demonstrate optical performance in room temperature for the future observation. By adopting only mirrors of aspherical surface, we design the optics whose aberration is minimized to show point spread function (PSF) of approximately 3 pix × 3 pix on the focal plane. The mirrors are fabricated by machining aluminum alloy A6061 with a honeycomb processing on the back surface to reduce the mirror mass. After integrating and aligning the mirrors with support jigs, we measure the PSF on the focal plane by a visible camera by inserting collimated beam of different angle of incidence, covering the whole FoV. We evaluate the PSF size by analyzing encircled energy in comparison with that expected from the ray-trace simulation of the optics. Throughout the FoV of the optics, the measured PSF size is comparable to the simulation. The present study demonstrates the precision machining of the aspherical mirrors and the optical performance of the designed optics. As a next step, we plan to develop thermal structure of EXZIT to demonstrate the optical performance in low temperature.

DOI： 10.1117/12.2559169

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

© COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only. 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 observa- tions 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 μm. 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 y 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.

DOI： 10.1117/12.2561917

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

© COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only. The HiZ-GUNDAM (high-z Gamma-ray bursts for UNraveling the Dark Ages Mission) is a time-domain and multi-messenger astronomy mission by monitoring high-energy astronomical transient events such as gamma-ray bursts (GRBs). The HiZ-GUNDAM is designed to provide alerts of high-redshift GRBs with an ultra-wide field X-ray monitor and a co-onboard 30-cm telescope for immediate photometric follow-up observations in the visible and near-infrared. The HiZ-GUNDAM satellite automatically changes its attitude toward the discovered transient object, starts the follow-up observations with the telescope, and sends alert information including the detailed position, the apparent magnitude and photometric redshift of the transient object within one hour. This mission was selected as one of the mission concept candidates of the competitively-chosen medium-class mission of ISAS/JAXA in the mid-2020s. The basic design of the breadboard model of the telescope is undergoing, and the verification plan of it is studied. The optics are cooled down to 200 K by radiation cooling, and infrared detectors are additionally cooled down to 120 K by a mechanical cooler. All mirrors in the telescope are made of the same aluminum-alloy to reduce the alignment errors during cooling. The four-band simultaneous observation is realized by three beam splitters. The HgCdTe and HyViSi detectors are installed in this telescope. Basic technologies for these specifications are demonstrated by our other missions. In addition, the onboard detection algorithm of high-redshift GRBs by distinguishing them from nearby dusty galaxies in the orbit is also studied. In this paper, we introduce the current status of the development of the telescope onboard HiZ-GUNDAM.

DOI： 10.1117/12.2560654

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

© The Author(s) 2018. Published by Oxford University Press on behalf of the Astronomical Society of Japan. All rights reserved. We report near-infrared (IR) observations of high Galactic latitude clouds to investigate diffuse Galactic light (DGL), which is starlight scattered by interstellar dust grains. The observations were performed at 1.1 and 1.6 μm with a wide-field camera instrument, the Multi-purpose Infra-Red Imaging System (MIRIS) onboard the Korean satellite STSAT-3. The DGL brightness is measured by correlating the near-IR images with a far-IR 100 μm map of interstellar dust thermal emission. The wide-field observation of DGL provides the most accurate DGL measurement achieved to-date. We also find a linear correlation between optical and near-IR DGL in the MBM32 field. To study interstellar dust properties in MBM32, we adopt recent dust models with and without μm-sized very large grains and predict the DGL spectra, taking into account the reddening effect of the interstellar radiation field. The result shows that the observed color of the near-IR DGL is closer to the model spectra without very large grains. This may imply that dust growth in the observed MBM32 field is not active owing to the low density of its interstellar medium.

DOI： 10.1093/pasj/psy070

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

© COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only. 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.

DOI： 10.1117/12.2311595

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

© COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only. 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.

DOI： 10.1117/12.2313184

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

© The Author 2017. Published by Oxford University Press on behalf of the Astronomical Society of Japan. All rights reserved. We present an analysis of the blank-sky spectra observed with the Faint Object Spectrograph on board the Hubble Space Telescope. We study the diffuse sky emission from ultraviolet to optical wavelengths, which is composed of zodiacal light (ZL), diffuse Galactic light (DGL), and residual emission. The observations were performed towards 54 fields distributed widely over the sky, with spectral coverage from 0.2 to 0.7 μm. In order to avoid contaminating light from earthshine, we use the data collected only in orbital nighttime. The observed intensity is decomposed into the ZL, DGL, and residual emission, in eight photometric bands spanning our spectral coverage. We found that the derived ZL reflectance spectrum is flat in the optical, which indicates major contribution of C-type asteroids to the interplanetary dust (IPD). In addition, the ZL reflectance spectrum has an absorption feature at ∼0.3 μm. The shape of the DGL spectrum is consistent with those found in earlier measurements and model predictions. While the residual emission contains a contribution from the extragalactic background light, we found that the spectral shape of the residual looks similar to the ZL spectrum. Moreover, its optical intensity is much higher than that measured from beyond the IPD cloud by Pioneer 10/11, and also than that of the integrated galaxy light. These findings may indicate the presence of an isotropic ZL component, which is missed in the conventional ZL models.

DOI： 10.1093/pasj/psx003

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

© 2016 SPIE. 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 zâ1/410, 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 (2.3×2.3 degrees) imaging cameras use the 2K×2K HgCdTe HAWAII-2RG arrays, and cover the optical and near-infrared wavelength range of 0.5-0.9 μm, 1.0-1.4 μm and 1.5-2.0 μm, 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.

DOI： 10.1117/12.2229567

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記述言語：英語   掲載種別：研究論文（学術雑誌）

© 2015. The American Astronomical Society. All rights reserved. We report measurements of the diffuse galactic light (DGL) spectrum in the near-infrared, spanning the wavelength range 0.95-1.65 μm by the Cosmic Infrared Background ExpeRiment. Using the low-resolution spectrometer calibrated for absolute spectro-photometry, we acquired long-slit spectral images of the total diffuse sky brightness toward six high-latitude fields spread over four sounding rocket flights. To separate the DGL spectrum from the total sky brightness, we correlated the spectral images with a 100 μm intensity map, which traces the dust column density in optically thin regions. The measured DGL spectrum shows no resolved features and is consistent with other DGL measurements in the optical and at near-infrared wavelengths longer than 1.8 μm. Our result implies that the continuum is consistently reproduced by models of scattered starlight in the Rayleigh scattering regime with a few large grains.

DOI： 10.1088/0004-637X/806/1/69

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開催期間： 2021年09月13日 - 2021年09月15日   記述言語：日本語  

開催期間： 2021年03月   記述言語：日本語  

開催期間： 2021年03月   記述言語：日本語  

開催期間： 2021年02月02日 - 2021年02月05日   記述言語：英語  

開催期間： 2020年12月   記述言語：英語  

開催期間： 2019年08月   記述言語：日本語  

開催期間： 2018年11月   記述言語：英語  

開催期間： 2018年08月   記述言語：英語  

開催期間： 2018年08月   記述言語：英語  

開催期間： 2017年08月   記述言語：英語  

開催期間： 2016年10月   記述言語：英語  

開催期間： 2016年08月   記述言語：英語