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Ultralight-axion (ULA) dark matter is one of the possible solutions toresolve small-scale problems, especially the core-cusp problem. This is becauseULA dark matter can create a central soliton core in all dark matter haloesstemmed from the quantum pressure against gravity below the de Brogliewavelength, which becomes manifest on astrophysical scales with axion massrange $\sim10^{-22}$ eV. In this work, we apply our non-spherical dynamicalmodels to the kinematic data of eight classical dwarf spheroidals (dSphs) toobtain more reliable and realistic limits on ULA particle mass. This ismotivated by the reasons that the light distributions of the dSphs are notspherical, nor are the shapes of dark matter haloes predicted by ULA darkmatter simulations. Compared with the previous studies on ULA dark matterassuming spherical mass models, our result is less stringent than thoseconstraints due to the uncertainties on non-sphericity. On the other hand,remarkably, we find that the dSphs would prefer to have a flattened dark matterhalo rather than a spherical one, especially Draco favours a strongly elongateddark matter halo caused naively by the assumption of a soliton-core profile.Moreover, our consequent non-spherical core profiles are much more flattenedthan numerical predictions based on ULA dark matter, even though there arestill uncertainties on the estimation of dark matter halo structure. Toalleviate this discrepancy, further understanding of baryonic and/or ULA darkmatter physics on small mass scales might be needed.

Non-sphericity of ultralight axion dark matter haloes in the Galactic dwarf spheroidal galaxies