On the correlation between spin parameter and halo mass

We report on a correlation between virial mass M and spin parameter lambda for dark matter halos forming at redshifts z greater than or similar to 10. We find that the spin parameter decreases with increasing halo mass. Interestingly, our analysis indicates that halos forming at later times do not exhibit such a strong correlation, in agreement with the findings of previous studies. We briefly discuss the implications of this correlation for galaxy formation at high redshifts and the galaxy population we observe today.