Small-scale Peculiar Velocities
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For galaxies with distance less then 5Mpc/h (=500km/s) |
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rms 1D peculiar velocity is 60km/s |
Governato et al 1997: Sigma_v =150-300km/s
"We find than neither the Omega=1 nor Omega=0.3 cold dark matter models can produce a SINGLE candidate Local Group that is embedded in a region with such small peculiar velocities"
Another issue: dwarfs in voids:
Peebles (2000, 0011252): "These dwarfs [in Local Group] are visible; why should similar primeval halos in the voids be so cunningly hidden?"