Speaker
Description
Arrakihs is an ESA Fast class mission designed to probe the nature of dark matter and the assembly of Milky Way–type galaxies through ultra-deep imaging of extremely faint stellar halos. By mapping diffuse halos, tidal streams, and satellite populations around nearby galaxies, Arrakihs will provide stringent observational tests of the ΛCDM paradigm in a regime where current surveys are strongly limited by surface-brightness sensitivity. This contribution presents the Arrakihs mission concept with a focus on the Near-Infrared (NIR) channels and its detector system, based on a 1.7 μm cut-off H2RG detector operated at ~150 K, selected to meet the demanding requirements on low noise, stability, and calibration accuracy required for ultra-low surface brightness science. We discuss the key detector performance drivers and system-level challenges, in terms of noise and power constraints, the impact of detector systematics on science return and readout architecture trade-offs to allow the use of the the H2RG science frames for fine guidance.