The AKARI (formerly Astro-F) mission is a Japanese second generation all-sky infrared
survey mission. SkyView currently includes surveys from the four bands of the FIS instrument:
N60, WIDE-S, WIDE-L and N160.
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These surveys cover
99% of the sky in four photometric bands centred at 65μm, 90μm, 140μm, and 160μm,
with spatial resolutions ranging from 1-1.5'.
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These data provide crucial information on the investigation and characterisation of the proper-
ties of dusty material in the interstellar medium (ISM), since a significant portion of its
energy is emitted between
∼50 and 200 μm. The large-scale distribution of interstellar
clouds, their thermal dust temperatures, and their column densities can be investigated
with the improved spatial resolution compared to earlier all-sky survey observations.
In addition to the point source distribution, the large-scale distribution of ISM cirrus emis-
sion, and its filamentary structure, are well traced.
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Data are obtained using using the <a href="https://jvo.nao.ac.jp/index-e.html">JVO</a> AKARI Simple Image Access Service. Provenance: AKARI FIS map making team [Univ of Tokyo, ISAS/JAXA, Tohoku Univ, Tsukuba Univ,
The Rutherford Appleton Laboratory, The Open Univ]. This is a service of NASA HEASARC.
Knowledge of water in the solar system is important for the understanding of a wide range of evolutionary processes and the thermal history of the solar system. To explore the existence of water in the solar system, it is indispensable to investigate hydrated minerals and/or water ice on asteroids. These water-related materials show absorption features in the 3um band (wavelengths from 2.7 to 3.1um). We conducted a spectroscopic survey of asteroids in the 3um band using the Infrared Camera (IRC) on board the Japanese infrared satellite AKARI. In the warm mission period of AKARI, 147 pointed observations were performed for 66 asteroids in the grism mode for wavelengths from 2.5 to 5um. According to these observations, most C-complex asteroids have clear absorption features (>10% with respect to the continuum) related to hydrated minerals at a peak wavelength of approximately 2.75um, while S-complex asteroids have no significant features in this wavelength range. The present data are released to the public as the Asteroid Catalog using AKARI Spectroscopic Observations (AcuA-spec).
We present a new catalogue of mid-IR sources using the AKARI NEP-Deep survey. The InfraRed Camera (IRC) onboard AKARI has a comprehensive mid-IR wavelength coverage with 9 photometric bands at 2-24 micron. We designed the catalogue to include most of sources detected in 7, 9, 11, 15, and 18 micron bands, and found 7284 sources in a 0.67 square degree area.
This is the revised catalogue of the AKARI North Ecliptic Pole Deep survey. The survey was carried out with the InfraRed Camera (IRC) onboard AKARI which has a comprehensive mid-IR wavelength coverage in nine photometric bands at 2-24 micron. For mid-IR source extraction we used a detection image while for near-IR source detection we used optical to near-IR ground-based catalogue which is based on CFHT/MegaCam z', CFHT/WIRCam Ks and Subaru/Scam z' band detection. Here we present an AKARI source with the identification from the ground-based catalogue. For objects with multiple counterparts, all of these were listed in the catalogue with an upper limit for the AKARI flux. The magnitudes are given in the AB system.
We present the J- and H-band source catalog covering the AKARI North Ecliptic Pole field. Filling the gap between the optical data from other follow-up observations and mid-infrared (MIR) data from AKARI, our near-infrared (NIR) data provides contiguous wavelength coverage from optical to MIR. For the J- and H-band imaging, we used the FLoridA Multi-object Imaging Near-ir Grism Observational Spectrometer on the Kitt Peak National Observatory 2.1m telescope covering a 5.1deg^2^ area down to a 5{sigma} depth of ~21.6mag and ~21.3mag (AB) for the J and H bands with an astrometric accuracy of 0.14" and 0.17" for 1{sigma} in R.A. and decl. directions, respectively. We detected 208020 sources for the J band and 203832 sources for the H band. This NIR data is being used for studies including the analysis of the physical properties of infrared sources such as stellar mass and photometric redshifts, and will be a valuable data set for various future missions.
We present the first galaxy counts at 18{mu}m using the Japanese AKARI satellite's survey at the North Ecliptic Pole (NEP), produced from the images from the NEP-Deep and NEP-Wide surveys covering 0.6 and 5.8deg^2^, respectively. We describe a procedure using a point source filtering algorithm to remove background structure and a minimum variance method for our source extraction and photometry that delivers the optimum signal to noise for our extracted sources, confirming this by comparison with standard photometry methods. The final source counts are complete and reliable over three orders of magnitude in flux density, resulting in sensitivities (80 per cent completeness) of 0.15 and 0.3mJy for the NEP-Deep and NEP-Wide surveys, respectively, a factor of 1.3 deeper than previous catalogues constructed from this field. The differential source counts exhibit a characteristic upturn from Euclidean expectations at around a milliJansky and a corresponding evolutionary bump between 0.2-0.4mJy consistent with previous mid-infrared surveys with ISO and Spitzer at 15 and 24{mu}m. We compare our results with galaxy evolution models confirming the striking divergence from the non-evolving scenario. The models and observations are in broad agreement implying that the source counts are consistent with a strongly evolving population of luminous infrared galaxies at redshifts higher than unity. Integrating our source counts down to the limit of the NEP survey at the 150{mu}Jy level we calculate that AKARI has resolved approximately 55 per cent of the 18{mu}m cosmic infrared background relative to the predictions of contemporary source count models.
Using a large collection of near-infrared spectra (2.5-5.4 {mu}m) of Galactic HII regions and HII region-like objects, we perform a systematic investigation of astronomical polycyclic aromatic hydrocarbon (PAH) features. Thirty-six objects were observed using the infrared camera on board the AKARI satellite as a part of a director's time program. In addition to the well known 3.3-3.6 {mu}m features, most spectra show a relatively weak emission feature at 5.22 {mu}m with sufficient signal-to-noise ratios, which we identify as the PAH 5.25 {mu}m band (previously reported).
In this work we matched the AKARI archival data to the Optical Gravitational Lensing Experiment III (OGLE-III) catalogue to derive the mid-infrared period-luminosity (PL) relations for Small Magellanic Cloud (SMC) Cepheids. Mismatched AKARI sources were eliminated using random-phase colours obtained from the full I-band light curves from OGLE-III. It was possible to derive PL relations in the N3 and N4 bands only, although the S7-, S11-, L15- and L24-band data were also tested. Random-phase correction was included when deriving the PL relation in the N3 and N4 bands using the available time of observations from AKARI data. The final adopted PL relations were N3=-3.370logP+16.527 and N4=-3.402logP+16.556. However, these PL relations may be biased due to the small number of Cepheids in the sample.
We investigate the photometric redshift accuracy achievable with the AKARI infrared data in deep multiband surveys, such as in the North Ecliptic Pole field. We demonstrate that the passage of redshifted polycyclic aromatic hydrocarbons (PAH) and silicate features into the mid-infrared wavelength window covered by AKARI is a valuable means to recover the redshifts of starburst galaxies. To this end, we have collected a sample of ~60 galaxies drawn from the Great Observatories Origins Deep Survey-North Field with spectroscopic redshift 0.5<~zspec<~1.5 and photometry from 3.6 to 24um, provided by the Spitzer, Infrared Space Observatory and AKARI satellites. The infrared spectra are fitted using synthetic galaxy spectral energy distributions which account for starburst and active nuclei emission. For ~90 per cent of the sources in our sample, the redshift is recovered with an accuracy |zphot-zspec|/(1+zspec)~<10%. A similar analysis performed on a set of simulated spectra shows that the AKARI infrared data alone can provide photometric redshifts accurate to |zphot-zspec|/(1+zspec)~10% (1sigma) at z~<2 . At higher redshifts, the PAH features are shifted outside the wavelength range covered by AKARI and the photo-z estimates rely on the less prominent 1.6um stellar bump; the accuracy achievable in this case on (1+z) is ~10-15%, provided that the active galactic nuclei contribution to the infrared emission is subdominant. Our technique is no more prone to redshift aliasing than optical-ultraviolet photo-z, and it may be possible to reduce this aliasing further with the addition of submillimetre and/or radio data.
Local infrared (IR) luminosity functions (LFs) are necessary benchmarks for high-redshift IR galaxy evolution studies. Any accurate IR LF evolution studies require accordingly accurate local IR LFs. We present IR galaxy LFs at redshifts of z<=0.3 from AKARI space telescope, which performed an all-sky survey in six IR bands (9, 18, 65, 90, 140, and 160um) with 10 times better sensitivity than its precursor Infrared Astronomical Satellite. Availability of 160um filter is critically important in accurately measuring total IR luminosity of galaxies, covering across the peak of the dust emission. By combining data from Wide-field Infrared Survey Explorer (WISE), Sloan Digital Sky Survey (SDSS) Data Release 13 (DR 13), six-degree Field Galaxy Survey and the 2MASS Redshift Survey, we created a sample of 15638 local IR galaxies with spectroscopic redshifts, factor of 7 larger compared to previously studied AKARI-SDSS sample. After carefully correcting for volume effects in both IR and optical, the obtained IR LFs agree well with previous studies, but comes with much smaller errors. Measured local IR luminosity density is {OMEGA}_IR_=1.19+/-0.05x10^8^L_{sun}_/Mpc^3^. The contributions from luminous IR galaxies and ultraluminous IR galaxies to {OMEGA}_IR_ are very small, 9.3 per cent and 0.9 per cent, respectively. There exists no future all-sky survey in far-IR wavelengths in the foreseeable future. The IR LFs obtained in this work will therefore remain an important benchmark for high-redshift studies for decades.
