SpectroPhotometric Imaging in Astronomy with Kinetic Inductance Detectors

ended

The SPIAKID project will build a camera using Kinetic Inductance Detectors (KIDs) to equip an 8 m class telescope to derive ages and metallicities for stars in Ultra Faint Dwarf galaxies (UFDs) in the Local Group. UFDs are the key to understand early galaxy formation processes, including the properties of the first stars, and the role of environment and internal feedback in shaping the evolution of dwarf galaxies. A full exploitation of UFDs to understand these processes requires knowledge of their precise stellar ages and metallicities. This is difficult, in many cases impossible, to obtain with existing instruments because of the faintness of UFDs. SPIAKID will allow unprecedented efficiency in acquiring wide-band spectrophotometry, making this possible. The KID provides a low resolution spectrum (goal: λ/Δλ~15) over a wide spectral range (goal: 0.45 μm to 1.60 μm), a single exposure instead of many single-band exposures. The instrument throughput is increased as the design is simplified since filtering is unnecessary and the visible and infra-red optical paths are combined. The KIDs are read continuously with zero read-out noise so the integration is driven in real time by monitoring the signal-to-noise ratio. Finally, their response is faster (~ 30 μs) than the coherence time of atmospheric turbulence (a few ms) so diffraction-limited resolution is achieved with existing image reconstruction techniques. The reconstructed images will be sharper and deeper than can be achieved by traditional seeing-limited imagers. The SPIAKID instrument will tackle other science cases, e.g. transiting exoplanets and their atmospheres or the electromagnetic emission from gravitational wave sources, and the instrument will be offered to the community to foster other uses. Our technological developments for the KIDs will place European scientists in a position to design and build innovative instruments, in astronomy but also, for example, in fast imaging for fluorescence microscopy.