UCAC4 761-007365 , the SIMBAD biblio

We characterize an all-sky catalogue of ∼8400 δ Scuti variables in ASAS-SN, which includes ∼3300 new discoveries. Using distances from Gaia DR2, we derive period-luminosity relationships for both the fundamental mode and overtone pulsators in the W_JK, V, Gaia DR2 G, J, H, K_s, and W₁ bands. We find that the overtone pulsators have a dominant overtone mode, with many sources pulsating in the second overtone or higher order modes. The fundamental mode pulsators have metallicity-dependent periods, with log₁₀(P) ∼ -1.1 for [Fe/H]< -0.3 and log₁₀(P) ∼ -0.9 for [Fe/H]> 0, which leads to a period-dependent scale height. Stars with P> 0.100 d are predominantly located close to the Galactic disc ( |Z|< 0.5 kpc). The median period at a scale height of Z∼0 kpc also increases with the Galactocentric radius R, from log₁₀(P) ∼ -0.94 for sources with R> 9 kpc to log₁₀(P) ∼ -0.85 for sources with R< 7 kpc, which is indicative of a radial metallicity gradient. To illustrate potential applications of this all-sky catalogue, we obtained 30 min cadence, image subtraction TESS light curves for a sample of 10 fundamental mode and 10 overtone δ Scuti stars discovered by ASAS-SN. From this sample, we identified two new δ Scuti eclipsing binaries, ASASSN-V J071855.62-434247.3 and ASASSN-V J170344.20-615941.2 with short orbital periods of P_orb = 2.6096 and 2.5347 d, respectively.