Cosmological evolution of extragalactic sources in the infrared and contributions to the background radiation

De Zotti, G. and Franceschini, A. and Mazzei, P. and Granato, G. L. and Danese, L. (1997) Cosmological evolution of extragalactic sources in the infrared and contributions to the background radiation. Il nuovo cimento C, 20 C (5). pp. 657-666. ISSN 1826-9885

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Infrared surveys provide essential insights on galaxy evolution. If near-IR studies suggest a mild evolution of stellar populations with cosmic time, indications of a substantial evolution have been seen in the far IR, although the available information is largely insufficient to delineate precise evolutionary properties. A consistent picture encompassing all the currently available data may be obtained assuming that dust extinction hides the early evolutionary phases of spheroidal galaxies in the optical band, while the corresponding dust re-radiation in the far IR may have been, during the early evolutionary phases, orders of magnitude larger than today. Hyperluminous IRAS galaxies might be extreme examples of this situation. Additional indications that at least some spheroidal galaxiesmay have been very dusty during their early evolution are provided by recent data on high redshift radio galaxies and quasars. Galaxies are the likely dominant contributors to the IR background. However, in the framework of unified models for Active Galactic Nuclei, a large number of nuclei hidden by a dusty torus may be expected. Implications for the IR background are discussed.

Item Type: Article
Additional Information: Paper presented at the VII Cosmic Physics National Conference, Rimini, October 26-28, 1994.
Uncontrolled Keywords: Cosmic rays; normal galaxies; extragalactic objects and systems (by type); conference proceedings
Subjects: 500 Scienze naturali e Matematica > 530 Fisica
500 Scienze naturali e Matematica > 550 Scienze della Terra > 551 Geologia, Idrologia, Meteorologia > 551.5 Meteorologia (Classificare qui l'atmosfera) (Classificare la previsione e le previsioni di specifici fenomeni meteorologici in 551.64; classificare la Micrometeorologia in 551.66) > 551.52 Termodinamica, interazioni atmosferiche con la superficie terrestre, temperature, radiazioni > 551.527 Radiazioni (per fenomeni ottici, vedi 551.565) > 551.5276 Radiazioni cosmiche (Include il rumore cosmico) (Classificare qui i raggi cosmici)
Depositing User: Marina Spanti
Date Deposited: 08 Feb 2018 09:35
Last Modified: 08 Feb 2018 09:35

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