The linear velocity field of 2MASS Redshift Survey, Ks= 11.75 galaxies: constraints on β and bulk flow from the luminosity function

Using the nearly full-sky K s = 11.75 2MASS Redshift Survey (2MRS; Huchra et al.) of 45 000 galaxies, we reconstruct the underlying peculiar velocity field and constrain the cosmological bulk flow within 100 h -1 Mpc. These results are obtained by maximizing the probability to estimate the absolute magnitude of a galaxy given its observed apparent magnitude and redshift. At a depth of 60 h -1 Mpc, we find a bulk flow v B = (90 65, -230 65, 50 65) km s -1 in agreement with the theoretical predictions of the cold dark matter model. The reconstructed peculiar velocity field v that maximizes the likelihood is characterized by the parameter = 0.32 0.08. Both results are in agreement with those obtained previously using the 23 000 galaxies of the shallower K s = 11.25 2MRS survey.