A comparison of the R_h=ct and LCDM cosmologies based on the observed halo mass function

Understand

The growth of structure probes the re-ionization history and quasar abundance in the Universe, constituting an important probe of the cosmological predictions.

• Halos are not directly observable, however, so their mass and evolution must be inferred indirectly.
• Studies based on the assumption of a constant halo to stellar mass ratio M_h/M_* (extrapolated from z<4) reveal significant tension with LCDM---a failure known as &#34;The Impossibly Early Galaxy Problem&#34;.
• But whether this ratio evolves or remains constant through redshift 4<z<10 is still being debated.