Conceptual design of a wide-field near UV transient survey in a 6U CubeSat

Abstract

A conceptual design of a wide-field near UV transient survey in a 6U CubeSat is presented. Ultraviolet is one of the frontier in the transient astronomy. To open up the discovery space, we are developing a 6U CubeSat for transient exploration. The possible targets will be supernova shock-breakouts, tidal disruption events, and the blue emission from NS-NS mergers in very early phase. If we only focused on nearby/bright sources, the required detection limit is around 20 mag (AB). To avoid the background and optical light, we chose a waveband of 230−280 nm. As an imaging detector, we employ a delta-doped back-illuminated CMOS. In addition to delta doping, the multi-layer coating directly deposited on the detector enables both a high in-band UV QE and the ultra-low optical rejection ratio. Taking into account these specifications, even an 8 cm telescope can achieve the detection limit of 20 mag AB for a FoV larger than 60 deg 2. We also designed the satellite bus system for this mission by utilizing commercially available cubesat components satisfying the mission requirements.

High-speed readout system of X-ray CMOS image sensor for time domain astronomy

“…The developed readout system comprises an FPGA board and a CMOS sensor board with stack structure and a compact size of 90 mm × 110 mm × 39 mm combined with the CMOS sensor (figure 1). This system can be installed on middle-class satellites (e.g., HiZ-GUNDAM) and nanosatellites, such as the 6U CubeSat developed by the Tokyo Institute of Technology [14]. The FPGA board was equipped with a Xilinx Kintex-7 (XC7K325T-1FFG676I) with 400 I/Os [15] and an internal block RAM of ∼2 MB [16], providing sufficient capabilities for controlling the CMOS sensor, reading out image data from the CMOS sensor, and extracting X-ray events from the raw image data, as mentioned in section 3.…”