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Featured researches published by Shunsuke Baba.


Publications of the Astronomical Society of Japan | 2016

Revised wavelength and spectral response calibrations for AKARI near-infrared grism spectroscopy: Cryogenic phase

Shunsuke Baba; Takao Nakagawa; Mai Shirahata; Naoki Isobe; Fumihiko Usui; Youichi Ohyama; Takashi Onaka; Kenichi Yano; Chihiro Kochi

We perform revised spectral calibrations for the AKARI near-infrared grism to quantitatively correct for the effect of the wavelength-dependent refractive index. The near-infrared grism covering the wavelength range of 2.5--5.0 micron with a spectral resolving power of 120 at 3.6 micron, is found to be contaminated by second-order light at wavelengths longer than 4.9 micron which is especially serious for red objects. First, we present the wavelength calibration considering the refractive index of the grism as a function of the wavelength for the first time. We find that the previous solution is positively shifted by up to 0.01 micron compared with the revised wavelengths at 2.5--5.0 micron. In addition, we demonstrate that second-order contamination occurs even with a perfect order-sorting filter owing to the wavelength dependence of the refractive index. Second, the spectral responses of the system from the first- and second-order light are simultaneously obtained from two types of standard objects with different colors. The response from the second-order light suggests leakage of the order-sorting filter below 2.5 micron. The relations between the output of the detector and the intensities of the first- and second-order light are formalized by a matrix equation that combines the two orders. The removal of the contaminating second-order light can be achieved by solving the matrix equation. The new calibration extends the available spectral coverage of the grism mode from 4.9 micron up to 5.0 micron. The revision can be used to study spectral features falling in these extended wavelengths, e.g., the carbon monoxide fundamental ro-vibrational absorption within nearby active galactic nuclei.


Publications of the Astronomical Society of Japan | 2016

X-ray and infrared diagnostics of nearby active galactic nuclei with MAXI and AKARI

Naoki Isobe; Taiki Kawamuro; Shinki Oyabu; Takao Nakagawa; Shunsuke Baba; Kenichi Yano; Yoshihiro Ueda; Yoshiki Toba

Nearby active galactic nuclei were diagnosed in the X-ray and mid-to-far infrared wavelengths, with Monitor of All-sky X-ray Image (MAXI) and the Japanese infrared observatory AKARI, respectively. Among the X-ray sources listed in the second release of the MAXI all-sky X-ray source catalog, 100 ones are currently identified as a non-blazar-type active galactic nucleus. These include 95 Seyfert galaxies and 5 quasars, and they are composed of 73 type-1 and 27 type-2 objects. The AKARI all-sky survey point source catalog was searched for their mid- and far-infrared counterparts at 9, 18, and 90


The Astrophysical Journal | 2018

The Near-infrared CO Absorption Band as a Probe to the Innermost Part of an AGN-obscuring Material

Shunsuke Baba; Takao Nakagawa; Naoki Isobe; Mai Shirahata

\mu


Publications of The Korean Astronomical Society | 2017

STUDY OF SPECTRAL ENERGY DISTRIBUTION OF GALAXIES WITH PRINCIPAL COMPONENT ANALYSIS

Chihiro Kochi; Takao Nakagawa; Naoki Isobe; Mai Shirahata; Kenichi Yano; Shunsuke Baba

m. As a result, 69 Seyfert galaxies in the MAXI catalog (48 type-1 and 21 type-2 ones) were found to be detected with AKARI. The X-ray (3-4 keV and 4-10 keV) and infrared luminosities of these objects were investigated, together with their color information. Adopting the canonical photon index,


International conference on Technology and Instrumentation in Particle Physics | 2017

Development of Superconducting Tunnel Junction Detector Using Hafnium for COBAND Experiment

Kenichi Takemasa; Shin-Hong Kim; Y. Takeuchi; K. Nagata; Kota Kasahara; Shunsuke Yagi; Rena Wakasa; Chisa Asano; Youiti Ootuka; S. Mima; K. Kiuchi; Yasuo Arai; Ikuo Kurachi; Masashi Hazumi; H. Ishino; A. Kibayashi; Takuo Yoshida; Makoto Sakai; Takahiro Nakamura; Yukihiro Kato; Shuji Matsuura; Shoji Kawahito; Hirokazu Ikeda; Takehiko Wada; Koichi Nagase; Shunsuke Baba; Shigetomo Shiki; Go Fujii; Masataka Ohkubo; E. Ramberg

\Gamma = 1.9


Journal of Low Temperature Physics | 2016

Development for Germanium Blocked Impurity Band Far-Infrared Image Sensors with Fully-Depleted Silicon-On-Insulator CMOS Readout Integrated Circuit

Takehiko Wada; Y. Arai; Shunsuke Baba; Misaki Hanaoka; Yusuke Hattori; Hirokazu Ikeda; Hidehiro Kaneda; Chihiro Kochi; A. Miyachi; Koichi Nagase; H. Nakaya; Morifumi Ohno; Shinki Oyabu; T. Suzuki; Sota Ukai; Kentaroh Watanabe; Keita Yamamoto

, of the intrinsic X-ray spectrum of the Seyfert galaxies, the X-ray hardness ratio between the 3-4 and 4-10 keV ranges derived with MAXI was roughly converted into the absorption column density. After the X-ray luminosity was corrected for absorption from the estimated column density, the well-known X-ray-to-infrared luminosity correlation was confirmed at least in the Compton-thin regime. In contrast, NGC 1365, only one Compton-thick object in the MAXI catalog, was found to deviate from the correlation toward a significantly lower X-ray luminosity by nearly an order of magnitude. It was verified that the relation between the X-ray hardness below 10 keV and X-ray-to-infrared color acts as an effective tool to pick up Compton-thick objects. The difference in the infrared colors between the type-1 and type-2 Seyfert galaxies and its physical implication on the classification and unification of active galactic nuclei were briefly discussed.


Journal of Low Temperature Physics | 2016

A Demonstration of TIA Using FD-SOI CMOS OPAMP for Far-Infrared Astronomy

Koichi Nagase; Takehiko Wada; Hirokazu Ikeda; Y. Arai; Morifumi Ohno; Misaki Hanaoka; Hidehiro Kanada; Shinki Oyabu; Yasuki Hattori; Sota Ukai; T. Suzuki; Kentaroh Watanabe; Shunsuke Baba; Chihiro Kochi; Keita Yamamoto

We performed a systematic analysis of the 4.67


Publications of The Korean Astronomical Society | 2017

EVALUATION OF FAR-INFRARED BIB-TYPE GE DETECTORS FABRICATED WITH THE SURFACE-ACTIVATED WAFER BONDING TECHNOLOGY

Misaki Hanaoka; Hidehiro Kaneda; Shinki Oyabu; Yasuki Hattori; Kotomi Tanaka; Sota Ukai; Kazuyuki Shichi; Takehiko Wada; T. Suzuki; Kentaroh Watanabe; Koichi Nagase; Shunsuke Baba; Chihiro Kochi

\mu


Publications of The Korean Astronomical Society | 2017

AN EXTENSION OF A RELIABLE WAVELENGTH COVERAGE OF THE AKARI NG GRISM MODE

Shunsuke Baba; Takao Nakagawa; Naoki Isobe; Mai Shirahata; Youichi Ohyama; Kenichi Yano; Chihiro Kochi

m CO ro-vibrational absorption band toward nearby active galactic nuclei (AGNs) and analyzed the absorption profiles of ten nearby galaxies collected from the AKARI and Spitzer spectroscopic observations that show the CO absorption feature by fitting a plane-parallel local thermal equilibrium gas model. We found that CO gas is warm (200--500 K) and has a large column density (


Publications of The Korean Astronomical Society | 2017

INFRARED - X-RAY CONNECTION IN NEARBY ACTIVE GALACTIC NUCLEI; AKARI AND MAXI RESULTS

Naoki Isobe; Takao Nakagawa; Kenichi Yano; Shunsuke Baba; Shinki Oyabu; Yoshiki Toba; Yoshihiro Ueda; Taiki Kawamuro

N_\mathrm{H}\gtrsim10^{23}~\mathrm{cm^{-2}}

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Chihiro Kochi

Japan Aerospace Exploration Agency

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Takao Nakagawa

Japan Aerospace Exploration Agency

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Kenichi Yano

Japan Aerospace Exploration Agency

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Koichi Nagase

Japan Aerospace Exploration Agency

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Mai Shirahata

Japan Aerospace Exploration Agency

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Takehiko Wada

Japan Aerospace Exploration Agency

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Hirokazu Ikeda

Japan Aerospace Exploration Agency

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