Observability of first galaxies with a generic FIR/sub-mm Telescope

DE ROSSI, MARÍA EMILIA; BROMM, VOLKER

Otro; IX La Plata International School (LAPIS) on Astronomy and Geophysics: ?S-PLUS: The Universe in True Colors?; 2020

Luminous sources at high redshifts, such as the first galaxies, constitute promising targets for next-generation surveys as they provide unique tools to test models of early structure formation. We explore the possibility of detecting first galaxies with a generic far-infrared/sub- millimeter (FIR/sub-mm) telescope by applying an analytical model of primordial dust emission. As shown in previous works, galaxies at redshifts z > 7 experience a strong negative K-correction in such a way that systems of similar masses are brighter at higher z. We evaluate the observability of model sources at different z > 7 as a function of the observed survey area (∆Ω) and sensitivity (S) of a generic instrument. Assuming ∆Ω ∼ 10 deg^2 and a plausible S ∼ 1 µJy for a near futuresurvey, we could assure the detection of at least one typical source with dust-to-metal ratio (D/M ) ∼ 5 × 10^(−3) at z > 7. For S > 1 µJy and ∆Ω < 10 deg^2 , higher than typical D/M are required to detect at least one individual source at z > 7. Considering the strong dependence of the predictedFIR/sub-mm radiation on the nature of primordial dust, future FIR/sub-mm campaigns could playa crucial role in exploring the nature of the interstellar medium and star formation in the earlyuniverse.