Satellite flashes as foreground to sub-second transient searches


  Guy Nir  ,  Eran Ofek  
Weizmann Institute

Searches for sub-second optical flashes from astrophysical phenomena (e.g., GRB or FRB counterparts) are faced with a high foreground of satellite flashes. Sunlight reflecting off surfaces on artificial satellites can often be identified by the streaking of the source. However, we show that rotating satellites (or space debris) can reflect light in very short flashes, and appear as point sources under typical seeing conditions. We used the Weizmann Fast Astronomical Survey Telescope (W-FAST) to collect a sample of such short duration flashes, with magnutides in the range 9-11. We discuss the implications for large area surveys such as ZTF and LSST, and mention some ways to mitigate this effect in searches for astrophysical transients.