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We present our search for flares from M dwarf stars in the SkyMapper SouthernSurvey DR1, which covers nearly the full Southern hemisphere with six-filtersequences that are repeatedly observed in the passbands $uvgriz$. This allowsus to identify bona-fide flares in single-epoch observations on timescales ofless than four minutes. Using a correlation-based outlier search algorithm wefind 254 flare events in the amplitude range of $\Delta u \sim 0.1$ to 5~mag.In agreement with previous work, we observe the flaring fraction of M dwarfs toincrease from $\sim 30$ to $\sim $1,000 per million stars for spectral types M0to M5. We also confirm the decrease in flare fraction with larger verticaldistance from the Galactic plane that is expected from declining stellaractivity with age. Based on precise distances from Gaia DR2, we find a steepdecline in the flare fraction from the plane to 150~pc vertical distance and asignificant flattening towards larger distances. We then reassess the strongtype dependence in the flaring fraction with a volume-limited sample within adistance of 50~pc from the Sun: in this sample the trend disappears and we findinstead a constant fraction of $\sim$1,650 per million stars for spectral typesM1 to M5. Finally, large-amplitude flares with $\Delta i > 1$ mag are very rarewith a fraction of $\sim 0.5$ per million M dwarfs. Hence, we expect thatM-dwarf flares will not confuse SkyMapper's search for kilonovae fromgravitational-wave events.

Photometric Flaring Fraction of M dwarf Stars from the SkyMapper Southern Survey