De-contamination of cosmological 21-cm maps
| dc.creator | Gleser, Liron | |
| dc.creator | Nusser, Adi | |
| dc.creator | Benson, Andrew J. | |
| dc.date | 2007-12-04 | |
| dc.date | 2008-10-27 | |
| dc.date.accessioned | 2026-07-07T12:20:38Z | |
| dc.date.available | 2026-07-07T12:20:38Z | |
| dc.description | We present a method for extracting the expected cosmological 21-cm signal from the epoch of reionization, taking into account contaminating radiations and random instrumental noise. The method is based on the maximum a-posteriori probability (MAP) formalism and employs the coherence of the contaminating radiation along the line-of-sight and the three-dimensional correlations of the cosmological signal. We test the method using a detailed and comprehensive modeling of the cosmological 21-cm signal and the contaminating radiation. The signal is obtained using a high resolution N-body simulation where the gas is assumed to trace the dark matter and is reionized by stellar radiation computed from semi-analytic galaxy formation recipes. We model contaminations to the cosmological signal from synchrotron and free-free galactic foregrounds and extragalactic sources including active galactic nuclei, radio haloes and relics, synchrotron and free-free emission from star forming galaxies, and free-free emission from dark matter haloes and the intergalactic medium. We provide tests of the reconstruction method for several rms values of instrumental noise from $σ_{N}=1$ to 250 mK. For low instrumental noise, the recovered signal, along individual lines-of-sight, fits the true cosmological signal with a mean rms difference of $d_{rms}\approx 1.7\pm 0.6$ for $σ_{N}=1$ mK, and $d_{rms}\approx 4.2\pm 0.4$ for $σ_{N}=5$ mK. The one-dimensional power spectrum is nicely reconstructed for all values of $σ_{N}$ considered here, while the reconstruction of the two-dimensional power spectrum and the Minkowski functionals is good only for noise levels of the order of few mK. | |
| dc.description | 19 pages, 17 figures, accepted for publication in MNRAS | |
| dc.identifier | https://arxiv.org/abs/0712.0497 | |
| dc.identifier | http://arxiv.org/abs/0712.0497 | |
| dc.identifier | 2008MNRAS.391..383G | |
| dc.identifier | doi:10.1111/j.1365-2966.2008.13897.x | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/213122 | |
| dc.subject | Astrophysics | |
| dc.title | De-contamination of cosmological 21-cm maps | |
| dc.type | text |