Testing extreme-axion wave-like dark matter using the BOSS Lyman-alpha forest data

Using cosmological particle hydrodynamical simulations and uniform ultraviolet backgrounds, we compare Lyman-alpha forest flux spectra predicted by the conventional cold dark matter (CDM) model, the free-particle wave dark matter (FP psi DM) model, and extreme-axion wave dark matter (EA psi DM) models of different initial axion field angles but with a fixed boson mass m(b) similar to 10(-22) eV against the BOSS Lyman-alpha forest absorption spectrum. We recover results reported previously that the CDM model agrees better with the BOSS data than the FROM model by a large margin, and we find that the difference of total chi(2) 's is 120 for 420 data bins. These previous results demand a larger boson mass by a factor >10 to be consistent with the date and are in tension with the favoured value determined from local satellite galaxies. We however find that such tension is alleviated as some EA psi DM models predict Lyman-alpha flux spectra agreeing better with the BOSS data than the CDM model, and the difference of total chi(2)' s can be as large as 24 for the same bin number. We stress that our results are obtained based on optimization of a limited set of parameters with others fixed to a well-known heating model as priors; hence, the results are not fully optimized and should be taken as a strong indicator.