Fluctuation of cosmic background radiation from interstellar dust emission of forming dwarf galaxies

Abstract

We predict the contribution from interstellar dust emission of very young metalpoor low-mass galaxies（forming dwarf galaxies）at z＞ to the fluctuation of cosmic background radiation（CBR）at observed wavelengths of 200 μm-2.1 mm. For this purpose, we constructed a semi-analytic model of galaxy formation based on the cosmological hierarchical structure formation scenario combined with the model of dust emission of forming dwarf galaxies. Since the small dust grain sizes in forming dwarf galaxies make the appearance of their rest-frame infrared（IR）spectral energy distribution（SED）significantly different from that of nearby more evolved galaxies, we adopt a new model for the evolution of dust content and the IR SED of lowmetallicity, extremely young galaxies. Though the contribution from forming dwarf galaxies to the CBR intensity is small compared with that of giant submillimeter sources at z＝1- , the fluctuation signal at high-. in multipole expansion（. ×10 , or θ 20.）is unique to these forming dwarf populations. Our predictions are useful to construct observational strategies for future facilities, e.g., like ALMA.