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A massive starburst galaxy with 100 billion solar masses of gas is identified at a redshift of 6.34; a ‘maximum starburst’ converts the gas into stars at a rate more than 2,000 times that of the Milky Way. A massive starburst galaxy unveiled The physical properties of the first massive starburst galaxies in the Universe provide important clues as to patterns of early cosmic structure formation. But as regions of intense star formation tend to be shrouded in dust, the search for such systems at very high redshift has been a major challenge. Now a massive starburst galaxy has been identified at a redshift z = 6.34, just 880 million years after the Big Bang when the Universe was one-sixteenth of its present age. Line-emission data reveal the presence of 100 billion solar masses of gas, equivalent to at least 40% of the galaxy's baryonic (visible matter) mass. The galaxy hosts an intense starburst, converting gas into stars at a rate more than 2,000 times that of the Milky Way. These findings are consistent with the theory that massive galaxies form via extreme starbursts in the early Universe. Massive present-day early-type (elliptical and lenticular) galaxies probably gained the bulk of their stellar mass and heavy elements through intense, dust-enshrouded starbursts—that is, increased rates of star formation—in the most massive dark-matter haloes at early epochs. However, it remains unknown how soon after the Big Bang massive starburst progenitors exist. The measured redshift ( z ) distribution of dusty, massive starbursts has long been suspected to be biased low in z owing to selection effects 1 , as confirmed by recent findings of systems with redshifts as high as ∼5 (refs 2–4 ). Here we report the identification of a massive starburst galaxy at z = 6.34 through a submillimetre colour-selection technique. We unambiguously determined the redshift from a suite of molecular and atomic fine-structure cooling lines. These measurements reveal a hundred billion solar masses of highly excited, chemically evolved interstellar medium in this galaxy, which constitutes at least 40 per cent of the baryonic mass. A ‘maximum starburst’ converts the gas into stars at a rate more than 2,000 times that of the Milky Way, a rate among the highest observed at any epoch. Despite the overall downturn in cosmic star formation towards the highest redshifts 5 , it seems that environments mature enough to form the most massive, intense starbursts existed at least as early as 880 million years after the Big Bang.

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 δ r = 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  μ K arcmin over the frequency range 50–320 GHz.

LiteBIRD is a proposed CMB polarization satellite project to probe the inflationary B-mode signal. The satellite is designed to measure the tensor-to-scalar ratio with a 68 % confidence level uncertainty of σ r < 10 - 3 , including statistical, instrumental systematic, and foreground uncertainties. LiteBIRD will observe the full sky from the second Lagrange point for 3 years. We have a focal plane layout for observing frequency coverage that spans 40–402 GHz to characterize the galactic foregrounds. We have two detector candidates, transition-edge sensor bolometers and microwave kinetic inductance detectors. In both cases, a telecentric focal plane consists of approximately 2 × 10 3 superconducting detectors. We will present the mission overview of LiteBIRD, the project status, and the TES focal plane layout.

We present the first determination of the 18 μm luminosity function (LF) of galaxies at 0.006 < z < 0.7 (the average redshift is ~ 0.04) using the AKARI mid-infrared All-Sky Survey catalogue. We have selected a 18 μm flux-limited sample of 243 galaxies from the catalogue in the SDSS spectroscopic region. We then classified the sample into four types; Seyfert 1 galaxies (including QSOs), Seyfert 2 galaxies, LINERs and Star-Forming galaxies using mainly [OIII]/Hβ vs. [NII]/Hα line ratios obtained from the SDSS. As a result of constructing Seyfert 1 and Seyfert 2 LFs, we found the following results; (i) the number density ratio of Seyfert 2s to Seyfert 1s is 3.98 ± 0.41 obtained from Sy1 and Sy2 LFs; this value is larger than the results obtained from optical LFs. (ii) the fraction of Sy2s in the entire AGNs may be anti-correlated with 18 μm luminosity. These results suggest that the torus structure probably depends on the mid-infrared luminosity of AGNs and most of the AGNs in the local Universe are obscured by dust.

The AKARI (formerly known as ASTRO-F) mission is the first Japanese satellite dedicated for large area surveys in the infrared (Murakami et al. 2004). AKARI was launched successfully on February 22nd 2006 (JST) from JAXA's Uchinoura Space Centre, Japan. AKARI is now orbiting around the Earth in a Sun-synchronous polar orbit at the altitude of 700 km. The 68.5 cm aperture telescope and scientific instruments are cooled to 6K by liquid Helium and mechanical coolers. The expected liquid Helium holding time is now found to be at least one year after the successful aperture lid-opening on 2006 April 13th (JST). AKARI will perform the most advanced all-sky survey in 6 mid- to far-infrared wavebands since the preceding IRAS mission over 2 decades ago. Deep imaging and spectroscopic surveys near the ecliptic poles with pointed observations are also on-going in 13 wavelength bands at 2-160 μm (see Table 1, details are given in Matsuhara et al. 2006). AKARI is a perfect complement to Spitzer in respect of its wide sky area and wavelength coverage. Two unique aspects of the pointing deep surveys with AKARI are: many imaging bands including the wavelength gap of Spitzer (8-24 μm), and the slitless spectroscopic capability (Ohyama et al. in this proceeding). Not only the All-Sky Survey but also the deep pointing surveys near the ecliptic poles over ~15 deg2 in total will be particularly well suited to construct the luminosity functions of the infrared galaxies, to evaluate their clustering nature, and also to discover rare, exotic objects at various redshifts out to z ~ 3. AKARI is also capable of detecting and measuring the spectrum and the fluctuations of the cosmic infrared background. The in-orbit sensitivity and spatial resolution of the surveys are found to be sufficient to achive the scientific goals listed above.

We introduce a Japanese plan for infrared (z-band: 0.9 $\\mu$m) space astrometry (the JASMINE-project). It will measure parallaxes, positions with the accuracy of 10 $\\mu$as and proper motions with the accuracy of 10 $\\mu$as/yr for stars brighter than z$\\sim$14. JASMINE can observe about $10^8$ stars belonging to the disk and bulge components of our Galaxy which are hidden by interstellar dust extinction in optical bands. The number of stars with $\\sigma_{\\pi}/\\pi<0.1$ in the direction of the Galactic central bulge is about $10^3$ times larger than those observed in optical bands, where $\\pi$ is a parallax and $\\sigma_{\\pi}$ is an error of the parallax. The main objective of JASMINE is to provide very useful and important astrometric parameters for studying fundamental structures and evolution of the disk and bulge components of the Milky Way Galaxy. Furthermore, the astrometric parameters given by JASMINE will give us exact absolute luminosities and motions of many stars in the bulge and the disk far away from us, so it will promote the study of stellar physics. The information of infrared astrometry that JASMINE will provide is very useful also for investigating stars in star formation regions, gravitational lens effects due to disk stars, extra-solar planets, etc. JASMINE will be launched around 2014 and a candidate for the orbit is a Lissajous orbit around the Sun-Earth L2 point with about a 5-yr mission life. We adopt a 3-mirror optical system (modified Korsch system) with a primary mirror of $\\sim$1.5-m diameter in an instrument design of JASMINE. A beam combiner should be used for performance of the global astrometry as used in the Hipparcos satellite. On the astro-focal plane, we put about 100 new-type CCDs for the z-band in which TDI mode (drift scan mode) can be operated. The effective field of view is 0.23 square degrees. The consideration of overall system (bus) design is now going on in cooperation with the Japan Aerospace Exploration Agency (JAXA). Furthermore, we introduce the Nano-JASMINE project which uses a nano-satellite with a size of about 20 cm3 and a weight of a few kg. The objective of Nano-JASMINE is verification of the observing strategy adopted in JASMINE and examination of some important technical issues for the JASMINE project. It will be launched around 2006.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

In a search for extragalactic background radiation, we measured the absolute sky brightness at high galactic latitude at near-infrared wavelengths (1.4-4 µm) using a liquid-helium-cooled spectrometer flown on board the Japanese rocket S-520-15. For the purpose of estimating statistical and systematic uncertainties for future experiments, the instrumentation, the calibration, and the performance are described in detail. The observations clearly show time-dependent components of terrestrial and environmental origin. The observed residual brightness was slightly brighter than that of previous rocket-borne experiments and the recent result of COBE/DIRBE. We set upper limits on the extragalactic continuum intensity of λ·Iλ <2.0×10⁻¹¹ W cm⁻² sr-1 at 2.5 µm and <2.5X10⁻¹¹ W cm⁻² sr⁻¹ at 4.0 µm and on the extragalactic line intensity of I<5X10⁻¹³ W cm⁻² sr⁻¹ at 1.7-2.5 µm.

We have constructed a mid-infrared Fabry-Perot imager (MIRFI) at Nagoya University. At present, MIRFI is tuned to the 12.813 µm fine-structure line of [Ne II], and it provides line images with a spectral resolving power of R~2500 over a 5x5 pixel Si:P photoconductive detector array. This array has a plate scale of 1\".3 pixel⁻¹ and a field of 8\"x8\" when mounted on the 3-m NASA Infrared Telescope (IRTF). The Fabry-Perot driving mechanism utilizes solenoid magnets and is cooled by liquid He. MIRFI achieves background-limited performance, and its noise equivalent line flux sensitivity is currently 1.6×10⁻²⁰ W cm⁻² pixel⁻¹ per spectral resolution element for a 17-s on-source integration on the IRTF. Future upgrade plans for MIRFI are also described.