Testing Bump in the Cosmological Power Spectrum Using Dwarf Galaxies

Abstract We analyze the possibility of using observational data on nearby dwarf galaxies—their luminosity functions and spatial distributions—to constrain deviations of the cosmological power spectrum from the standard one. Specifically, we consider a cosmological model with a “bump” in the power spectrum at a wavelength of 1.3 Mpc and a dimensionless amplitude $$\mathcal{A} = 2.0$$ . Such a spectrum is motivated by observations of an excess number of galaxies at high redshifts. The bump leads to a noticeable increase in the luminosity function in the range $$ - 13 > {{M}_{{\text{B}}}} > - 17$$ at $$z = 0$$ . Comparison with observations constrains the bump amplitude to $$\mathcal{A} < 0.25$$ at a $$3\sigma $$ significance level for a wavelength of 1.3 Mpc. For wavelengths smaller than 0.8 Mpc, the bump manifests only in the luminosity function of dwarfs with $${{M}_{{\text{B}}}} > - 14$$ .