Illuminating Galaxy Evolution at Cosmic Noon with ISCEA: the Infrared Satellite for Cosmic Evolution Astrophysics

Abstract

ISCEA (Infrared Satellite for Cosmic Evolution Astrophysics) is a small astrophysics mission whose Science Goal is to discover how galaxies evolved in the cosmic web of dark matter at cosmic noon. Its Science Objective is to determine the history of star formation and its quenching in galaxies as a function of local density and stellar mass when the Universe was 3-5 Gyrs old (1.2 < z < 2.1). ISCEA is designed to test the Science Hypothesis that during the period of cosmic noon, at 1.7 < z < 2.1, environmental quenching is the dominant quenching mechanism for typical galaxies not only in clusters and groups, but also in the extended cosmic web surrounding these structures. ISCEA meets its Science Objective by making a 10% shot noise measurement of star formation rate down to 6 M_⊙  yr⁻¹ using H-α out to a radius > 10 Mpc in each of 50 protocluster (cluster and cosmic web) fields at 1.2 < z < 2.1. ISCEA measures the star formation quenching factor in those fields, and galaxy kinematics with a precision < 50 km s⁻¹ to deduce the 3D spatial distribution in each field. ISCEA will transform our understanding of galaxy evolution at cosmic noon. ISCEA is a small satellite observatory with a 30 cm equivalent diameter aperture telescope with a FoV of 0.32 deg², and a multi-object spectrograph with a digital micro-mirror device (DMD) as its programmable slit mask. ISCEA will obtain spectra of 1000 galaxies simultaneously at an effective resolving power of R = 1000, with 2.8" x 2.8" slits, over the NIR wavelength range of 1.1 to 2.0 µm, a regime not accessible from the ground without large gaps in coverage. ISCEA will achieve a pointing accuracy of ≤ 2" FWHM over 200s. ISCEA will be launched into a Low Earth Orbit, with a prime mission of 2.5 years. ISCEA's space-qualification of DMDs opens a new window for spectroscopy from space, enabling revolutionary advances in astrophysics.