After the Dark Ages: the Evolution of Luminous Sources at z<5
| dc.creator | Madau, Piero | |
| dc.date | 1998-12-04 | |
| dc.date | 1998-12-04 | |
| dc.date.accessioned | 2026-07-07T02:29:29Z | |
| dc.date.available | 2026-07-07T02:29:29Z | |
| dc.description | I review recent observational and theoretical progress in our understanding of the cosmic evolution of luminous sources. Through a combination of deep imaging, Keck spectroscopy, and COBE background measurements, important constraints have emerged on the emission history of the galaxy population as a whole. A simple stellar evolution model, defined by a star-formation density that rises from z=0 to z=1.5, a universal Salpeter IMF, and a moderate amount of dust with A_V=0.23 mag (A_1500=1.2 mag), is able to account for most of the optical-FIR extragalactic background light, and reproduces the global ultraviolet, optical, and near-IR photometric properties of the universe. By contrast, a star-formation density that stayed roughly constant at all epochs appears to overproduce the local K-band luminosity density. While the bulk of the stars present today formed relatively recently, the existence of a decline in the star-formation density above z=2 remains uncertain. If stellar sources are responsible for photoionizing the intergalactic medium at z=5, the rate of star formation at this epoch must be comparable or greater than the one inferred from optical observations of galaxies at z=3. A population of dusty AGNs at z>2 could make a significant contribution to the FIR background if the accretion efficiency is close to 10%. | |
| dc.description | LaTeX, 10 pages, invited review at the Xth Rencontres de Blois meeting ``The Birth of Galaxies'', eds. B. Guiderdoni, F. R. Bouchet, Trinh X. Thuan, & Tran Thanh Van (Gif-sur-Yvette: Edition Frontieres) | |
| dc.identifier | https://arxiv.org/abs/astro-ph/9812087 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/9812087 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/13490 | |
| dc.subject | Astrophysics | |
| dc.title | After the Dark Ages: the Evolution of Luminous Sources at z<5 | |
| dc.type | text |