Takao Nakagawa

We produce a catalogue of polycyclic aromatic hydrocarbon (PAH) 3.3 $\mu$m, Br$\alpha$ and infrared luminosity ($L$(IR)) of 412 local galaxies, and investigate a relation between these physical parameters. We measure the PAH 3.3 $\mu$m and Br$\alpha$ flux using AKARI 2-5 $\mu$m spectra and the $L$(IR) using the AKARI-all-sky-survey data. The $L$(IR) and redshift ranges of our sample are $L$(IR)=$10^{9.7-12.8}$L$_\odot$ and $z_{\rm spec}=0.002-0.3$, respectively. We found that the ratio of $L$(PAH 3.3 $\mu$m) to $L$(IR) is constant at $L$(IR) $<$ $10^{11} \rm L_\odot$ whereas it decreases with the $L$(IR) at higher $L$(IR). Also, the ratio of $L$(Br$\alpha$) to $L$(IR) decreases with the $L$(IR). The both $L$(PAH)/$L$(IR) and $L$(Br$\alpha$)/$L$(IR) ratios are not strongly dependent on galaxy type and dust temperature. The relative weakness of the two ratios could be attributed to destruction of PAH, a lack of UV photons exciting PAH molecules or ionising hydrogen gas, extremely high dust attenuation, or active galactic nucleus contribution to the $L$(IR). Although we cannot determine the cause of the decreases of the luminosity ratios, a clear correlation between them implies that they are related with each other. The catalogue presented in our work will be available at the AKARI archive web page.

16th Space Science Symposium (January 6-7, 2016. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS)Sagamihara Campus), Sagamihara, Kanagawa Japan

大気球シンポジウム 平成27年度（2015年11月5-6日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)）, 相模原市, 神奈川県資料番号: SA6000044016レポート番号: isas15-sbs-016

The Space Infrared Telescope for Cosmology and Astrophysics (SPICA) is a pre-project of JAXA in collaboration with ESA to be launched around 2025. The 3m-class infrared telescope must be below 6K, based on scientific requirements, and features effective radiant cooling into deep space at L2 point combined with a mechanical cooler system in order to cool scientific instruments as well as the telescope. The thermal design of the SPICA payload module must involve researching and measuring the thermophysical properties of materials in order to achieve a highly reliable cooling chain. Accordingly, all critical materials, particularly FRPs were determined and their thermal properties (thermal conductivity, specific heat, and thermal expansion) measured. Subsequently, the measured values were compared with those in literature and included in a thermal model analysis. This paper introduces details of these thermal properties measurements, comparisons with values in literature, and a thermal model analysis of the SPICA payload module. 形態: カラー図版あり Physical characteristics: Original contains color illustrations 資料番号: PA1610072000