The Kramers-Heisenberg Formula and the Gunn-Peterson Trough from the First Objects in the Universe
| dc.creator | Bach, Kiehunn | |
| dc.creator | Lee, Hee-Won | |
| dc.date | 2001-10-09 | |
| dc.date.accessioned | 2026-07-07T02:00:46Z | |
| dc.date.available | 2026-07-07T02:00:46Z | |
| dc.description | Recent cosmological observations indicate that the reionized universe may have started at around z=6, where a significant suppression around Ly alpha has been observed from the neutral intergalactic medium. The associated neutral hydrogen column density is expected to exceed 10^{21}cm^{-2}},where it is very important to use the accurate scattering cross section known as the Kramers-Heisenberg formula that is obtained from the fully quantum mechanical time-dependent second order perturbation theory. We present the Kramers-Heisenberg formula and compare it with the formula introduced in a heuristic way by Peebles (1993) treating the hydrogen atom as a two-level atom, from which we find a devitaion by a factor of two in the red wing region far from the line center. Adopting simple cosmological models, we compute the Gunn-Peterson optical depths and the trough profiles. Our results are compared with the works performed by Madau & Rees (2000), who adopted the cross section introduced by Peebles. We find deviations up to 5 per cent in the Gunn-Peterson transmission coefficient for an accelerated expanding universe in the red off-resonance wing part with the rest wavelength Delta_lambda~10{AA}. | |
| dc.description | 3 pages, 2 figures | |
| dc.identifier | https://arxiv.org/abs/astro-ph/0110234 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/0110234 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/3515 | |
| dc.subject | Astrophysics | |
| dc.title | The Kramers-Heisenberg Formula and the Gunn-Peterson Trough from the First Objects in the Universe | |
| dc.type | text |