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| Paper: |
Radio galaxies and the star formation history of the universe |
| Volume: |
290, Active Galactic Nuclei: from Central Engine to Host Galaxy |
| Page: |
319 |
| Authors: |
Gopal-Krishna; Wiita, P. J.; Osterman, M. A. |
| Abstract: |
Multi-wavelength observations made in the last decade strongly suggest that the universe underwent an intense phase of star-formation in the past (z > 1). This intensive activity is commonly attributed to a higher galaxy merger rate when the universe was a fraction of its present age. After briefly reviewing these evidences, we examine the role of the powerful radio sources whose comoving density is known to be a few orders of magnitude higher at z ∼2 (the so called `quasar era'). Taking into account the most recent theoretical models for the temporal evolution of the size and luminosity of a powerful double radio source, as well as advanced Lambda-CDM simulations of the cosmic web of baryonic material at different redshifts, it is argued that during the quasar era a high fraction of the volume of the web was occupied by the lobes of double radio sources. Wide-spread compression of proto-stellar clouds, triggered by the high pressure of the synchrotron plasma of the radio lobes, can thus be expected to have played a significant role in the star formation history of the universe, and also in causing a rather high level of magnitization of the galactic and intergalactic material at early epochs. |
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