Redshifted 21-cm bispectrum: impact of the source models on the signal and the IGM physics from the Cosmic Dawn

Abstract The emissions from the first luminous sources drive fluctuations in 21-cm signal at Cosmic Dawn (CD) via two main astrophysical processes, namely Ly ? coupling and X-ray heating, yielding a highly non-Gaussian signal. impact of these processes on its non-Gaussianity depends properties light. In this work, we consider different CD scenarios by varying major source parameters i.e. minimum halo mass M h, min photon production efficiency f X using 1D radiative transfer code grizzly . We study variation large scale ( K 1 = 0.16 Mpc -1 ) bispectrum for all possible unique triangles Fourier domain. Our detailed comparative analysis power spectrum shows that shape, sign magnitude jointly provide better measure than alone. also conclude it is important to sequence changes along with variations shape throughout history arrive robust conclusion about dominant intergalactic medium cosmic times. further observe among k -triangles, large-scale best probed small -triangles squeezed limit triangle shapes vicinity. This opens up possibility constraining during bispectrum.