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PROPERTIES OF DUST OBSCURED GALAXIES IN THE NEP-DEEP FIELD
Nagisa Oi,Hideo Matsuhara,CHRIS PEARSON,Veronique Buat,Denis Burgarella,Matt Malkan,Takamitsu Miyaji 한국천문학회 2017 天文學論叢 Vol.32 No.1
We selected 47 DOGs at z ~ 1.5 using optical $R$ (or $r^{'}$), AKARI 18 $\mu$m, and 24 $\mu$m color in the AKARI North Ecliptic Pole (NEP) Deep survey field. Using the colors among 3, 4, 7, and $9\mu$m, we classified them into 3 groups; bump DOGs (23 sources), power-law DOGs (16 sources), and unknown DOGs (8 sources). We built spectral energy distributions (SEDs) with optical to far-infrared photometric data and investigated their properties using SED fitting method. We found that AGN activity such as a AGN contribution to the infrared luminosity and a Chandra detection rate for bump and power-law DOGs are significantly different, while stellar component properties like a stellar mass and a star-formation rate are similar to each other. A specific star-formation rate range of power-law DOGs is slightly higher than that of bump DOGs with wide overlap. Herschel/PACS detection rates are almost the same between bump and power-law DOGs. On the other hand SPIRE detection rates show large differences between bump and power-law DOGs. These results might be explained by differences in dust temperatures. Both groups of DOGs host hot and/or warm dust (~ 50 Kelvin), and many bump DOGs contain cooler dust ($\hspace{0.3em}\raisebox{0.4ex}{$<$}\hspace{-0.75em}\raisebox{-.7ex}{$\sim$}\hspace{0.3em}$ 30 Kelvin).
Optical – near-infrared catalog for the AKARI north ecliptic pole Deep field
Oi, Nagisa,Matsuhara, Hideo,Murata, Kazumi,Goto, Tomotsugu,Wada, Takehiko,Takagi, Toshinobu,Ohyama, Youichi,Malkan, Matthew,Im, Myungshin,Shim, Hyunjin,Serjeant, Stephen,Pearson, Chris Springer-Verlag 2014 Astronomy and astrophysics Vol.566 No.-
EVOLUTION OF LUMINOUS INFRARED GALAXIES REVEALED BY NEAR-INFRARED MULTI-BAND IMAGING OF THEIR HOSTS
Oi, Nagisa,Imanishi, Masatoshi The Korean Astronomical Society 2012 天文學論叢 Vol.27 No.4
We present the result of our near infrared J- (${\lambda}=1.25{\mu}m$), H- (${\lambda}=1.63{\mu}m$), and $K_s$-band (${\lambda}=2.14{\mu}m$) imaging of ultraluminous ($L_{IR}$ > $10^{12}L_{\odot}$) and luminous ($L_{IR}=10^{11-12}L_{\odot}$) infrared galaxies (ULIRGs and LIRGs), to investigate their relationship through properties of their host galaxies. We find that (1) for single-nucleus ULIRGs and LIRGs, their spheroidal host galaxies have similar properties, but ULIRGs display a substantially higher level of nuclear activity than LIRGs, suggesting that their infrared luminosity difference comes primarily from the different level of current nuclear activity. We infer that LIRGs and ULIRGs have similar progenitor galaxies, follow similar evolutionary processes, and may evolve into optically-selected QSOs. (2) Largely-separated multiple-nuclei ULIRGs have significantly brighter host galaxies than single-nucleus ULIRGs and LIRGs in $K_s$-band, indicating that multiple-nuclei ULIRGs have a bias towards mergers of intrinsically large progenitor galaxies, in order to produce high infrared luminosity ($L_{IR}$ > $10^{12}L_{\odot}$) even at the early merging stage. (3) We derive dust extinction of host galaxies of ULIRGs and LIRGs to be $A_V$ ~ 14 mag in the optical or equivalently $A_K$ ~ 0.8 mag in the near-infrared $K_s$-band, based on the comparison of host galaxy's luminosities in the J-, H-, and $K_s$-bands.
HYPER SUPRIME-CAMERA SURVEY OF THE AKARI NEP WIDE FIELD
Tomotsugu Goto,Yoshiki Toba,Yousuke Utsumi,Nagisa Oi,Toshinobu Takagi,Matt Malkan,Youichi Ohayma,Kazumi Murata,Paul Price,Marios Karouzos,Hideo Matsuhara,TAKAO NAKAGAWA,Takehiko Wada,Steve Serjeant,De 한국천문학회 2017 天文學論叢 Vol.32 No.1
The extragalactic background suggests half the energy generated by stars was reprocessed into the infrared (IR) by dust. At z$\sim$1.3, 90\% of star formation is obscured by dust. To fully understand the cosmic star formation history, it is critical to investigate infrared emission. AKARI has made deep mid-IR observation using its continuous 9-band filters in the NEP field (5.4 deg$^2$), using $\sim$10\% of the entire pointed observations available throughout its lifetime. However, there remain 11,000 AKARI infrared sources undetected with the previous CFHT/Megacam imaging ($r\sim$25.9ABmag). Redshift and IR luminosity of these sources are unknown. These sources may contribute significantly to the cosmic star-formation rate density (CSFRD). For example, if they all lie at 1$<z<$2, the CSFRD will be twice as high at the epoch. We are carrying out deep imaging of the NEP field in 5 broad bands ($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.
IMPROVEMENT OF AKARI NEP-DEEP 2-24 MICRON IMAGES/CATALOGUES WITH NEW CALIBRATIONS
Murata, Kazumi,Matsuhara, Hideo,Takagi, Toshinobu,Wada, Takehiko,Oyabu, Shinki,Oi, Nagisa The Korean Astronomical Society 2012 天文學論叢 Vol.27 No.4
We have created new catalogues of AKARI/IRC $2-24{\mu}m$ North Ecliptic Pole Deep survey through new methods of image analysis. In the new catalogues the number of false detection decreased by a factor of 10 and the number of objects detected in multiple bands increased by more than 1,500 compared to the previous work. In this proceedings the new methods of image analysis and the performance of the new catalogues are described.
THE SYNERGY OF LARGE AREA SURVEYS WITH AKARI AND HERSCHEL
Pearson, Chris,Serjeant, Stephen,Sedgwick, Chris,White, Glenn J.,Matsuhara, Hideo,Takagi, Toshinobu,Nagisa, Oi,Murata, Kazumi,Nakagawa, Takao,Yamamura, Issei The Korean Astronomical Society 2012 天文學論叢 Vol.27 No.4
The Herschel Space Observatory is the European Space Agency's state of the art infrared space telescope launched into space on 14 May 2009, covering the wavelength range from 70-700 microns with 3 instruments SPIRE, PACS and HIFI. Large area surveys are being carried out by Herschel in the AKARI legacy fields at the North and South Ecliptic Poles and the AKARI All-Sky Survey provides additional synergy with the largest survey with Herschel, H-ATLAS, covering more than 500 square degrees. This paper reports on some of the early results of these synergies between Herschel and AKARI including the first comparison of the AKARI All-Sky Survey number counts with the deeper Herschel surveys.
THE AGN POPULATION IN THE AKARI NEP DEEP FIELD
Laia Barrufet de Soto,Glenn J. White,Chris Pearson,STEPHEN SERJEANT,Tanya Lim,Hideo Matsuhara,Nagisa Oi,Marios Karouzos 한국천문학회 2017 天文學論叢 Vol.32 No.1
The AKARI North Ecliptic Pole Deep Field is a natural location to accomplish deep extragalactic surveys. It is supported by comprehensive ancillary data extending from radio to X-ray wavelengths, which have been used to classify radio sources as radio-loud and radio-quiet objectsand to create a catalogue of Active Galactic Nuclei (AGN). This has been achieved by using a radio-optical classificationand colour-colour diagrams rather than the more usual way based on spectroscopyFurthermore, we explore whetherthis technique can be extended by using a far-Infrared (FIR) colour-colour diagram which has been used to identify 268 high redshift candidates.
THE RADIO-FAR INFRARED CORRELATION IN THE NEP DEEP FIELD
Laia Barrufet,Glenn J. White,Chris Pearson,STEPHEN SERJEANT,Tanya Lim,Hideo Matsuhara,Nagisa Oi,Marios Karouzos 한국천문학회 2017 天文學論叢 Vol.32 No.1
We report the results of a multi-wavelength study in the North Ecliptic Pole (NEP) deep field and examine the far infrared-radio correlation (FIRC) for high and low redshift objects. We have found a correlation between the GMRT data at 610 MHz and the Herschel data at $\mathrm{250 \mu m}$ that has been usedto define a spectral index. This spectral index shows no evolution against redshift. As a result of the study, we show a radio colour-infrared diagram that can be used as a redshift indicator.
GALAXIES ON DIET: FEEDBACK SIGNATURES IN RADIO-AGN HOST GALAXIES
Marios Karouzos,임명신,Markos Trichas,Tomogotsu Goto,Matthew Malkan,Angel Ruiz,전이슬,김지훈,이형목,김성진,Nagisa Oi,Hideo Matsuhara,Toshinobu Takagi,Kazumi Murata,Takehiko Wada,Kensuke Wada,심현진,Hitoshi Hanami,STEPH 한국천문학회 2017 天文學論叢 Vol.32 No.1
There exists strong evidence supporting the co-evolution of central supermassive black holesand their host galaxies; however it is still under debate how such a relation comes about and whether itis relevant for all or only a subset of galaxies. An important mechanism connecting AGN to their hostgalaxies is AGN feedback, potentially heating up or even expelling gas from galaxies. AGN feedbackmay hence be responsible for the eventual quenching of star formation and halting of galaxy growth. Arich multi-wavelength dataset ranging from the X-ray regime (\textit{Chandra}), to far-IR (\textit{Herschel}), and radio(\textit{WSRT}) is available for the North Ecliptic Pole field, most notably surveyed by the \textit{AKARI} infraredspace telescope, covering a total area on the sky of 5.4 sq. degrees. We investigate the star formationproperties and possible signatures of radio feedback mechanisms in the host galaxies of 237 radiosources below redshift z = 2 and at a radio 1.4 GHz flux density limit of 0.1 mJy. Using broadbandSED modelling, the nuclear and host galaxy components of these sources are studied simultaneously as a function of their radio luminosity. Here we present results concerning the AGN content of the radio sources in this field, while also offering evidence showcasing a link between AGN activity and host galaxy star formation. In particular, we show results supporting a maintenance type of feedback from powerful radio-jets.