We present the development of a spectral dispersion device for wideband spectroscopy for which the primary scientic objective is the characterization of transiting exoplanets. The principle of the disperser is simple: a grating is fabricated on the surface of a prism. The direction of the spectral dispersion power of the prism is crossed with the grating. Thus, the prism separates the spectrum into individual orders while the grating produces a spectrum for each order. In this work, ZnS was selected as the material for the cross disperser, which was designed to cover the wavelength region, ⋋ = 0.6-13 μm, with a spectral resolving power, R ≥ 50. A disperser was fabricated, and an evaluation of its surface was conducted. Two spectrometer designs, one adopting ZnS (⋋ = 0.6-13 μm, R ≥ 300) and the other adopting CdZnTe (⋋ = 1-23 μm, R ≥ 250), are presented. The spectrometers, each of which has no moving mechanical parts, consist simply of a disperser, a focusing mirror, and a detector.

We propose a cosmological survey to probe star formation and nuclear activity in galaxies at redshifts of z=2-4 by polycyclic aromatic hydrocarbon (PAH) features using the SPICA mid-infrared instrument (SMI) with a spectral resolution of R=20. We will cover a wavelength range of 20-36 μm that corresponds to z=2-4 for the PAH features (11.3, 7.7, and 6.2 μm). The sensitivity will be 1 X 10-19 W/m2 (5 σ) in case of a reference survey that covers 4 arcmin2 field in a one-hour observation. It corresponds to LIR=2 X 1011 L⊙ at z=3 and will give us more than 10000 galaxies in a 450 hour survey.

We present physical properties of 24 μm galaxies detected by AKARI and Spitzer and their evolution between redshifts 0:4 < z < 2. Using multi-wavelength data from X-ray to radio observations in NEP Deep Field (for AKARI) and Subaru/XMM-Newton Deep Field (for Spitzer), we derive photometric redshift, stellar mass, star-formation rate (SFR), dust extinction magnitude and rest-frame luminosities/colors of the 24 μm galaxies from photometric SED fitting. We infer the SFRs from rest-frame ultraviolet luminosity and total infrared luminosity calibrated against Herschel photometric data. For both survey elds, we obtain complete samples with stellar mass of > 1010M⊙ and SFR of > 30M⊙=yr up to z = 2. We nd that specific SFRs evolves with redshift at all stellar masses in NON-power-law galaxies (non-PLGs) as star-formation dominant luminous infrared galaxies (LIRGs). The correlations between specific SFR and stellar mass in the Spitzer and AKARI galaxy samples are well consistent with trends of the main sequence galaxies. We also discuss nature of PLGs and their evolution.