Probing the large scale velocity field with clusters of galaxies
Apr, 1994
14 pages
Published in:
- Astrophys.J.Lett. 430 (1994) L13-L16
e-Print:
- astro-ph/9405075 [astro-ph]
DOI:
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Abstract: (arXiv)
What is the role of clusters of galaxies in probing the large-scale velocity field of the universe? We investigate the distribution of peculiar velocities of clusters of galaxies in the popular low-density () flat Cold-Dark-Matter (CDM) cosmological model, which best fits many large-scale structure observations. An CDM model is also studied for comparison. We find that clusters of galaxies are efficient tracers of the large-scale velocity field. The clusters exhibit a Maxwellian distribution of peculiar velocities, as expected from Gaussian initial density fluctuations. The cluster 3-D velocity distribution for the model peaks at km s, and extends to high velocities of km s. The rms peculiar velocity of the clusters is km s. Approximately 10\% of all model clusters move with high peculiar velocities of km s. The observed velocity distribution of clusters of galaxies is compared with the predictions from cosmological models. The observed data exhibit a larger velocity tail than seen in the model simulations; however, due to the large observational uncertainties, the data are consistent at a level with the model predictions, and with a Gaussian initial density field. The large peculiar velocities reported for some clusters of galaxies ( km s) are likely to be overestimated, if the current model is viable.References(27)
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