In Search of the Dark Ages -- An Experimental Challenge
| dc.creator | Bland-Hawthorn, J. | |
| dc.creator | Nulsen, P. E. J. | |
| dc.date | 2004-04-13 | |
| dc.date.accessioned | 2026-07-07T02:12:54Z | |
| dc.date.available | 2026-07-07T02:12:54Z | |
| dc.description | Most direct source detections beyond z~7 are likely to arise from wide-field narrowband surveys of Ly-a emission in the J band. For this to be true, the Ly-a emission must somehow escape from compact star-forming regions (CSR) presumably associated with massive haloes. Since the Ly-a escape fraction is <10% from an emitting region of size roughly 1 kpc, these objects will be difficult to find and hard to detect. For CSR sources, existing large-format IR arrays are close to ideal in terms of their noise characteristics for conducting "wide-field" narrowband surveys where pixel sizes are 0.1" or larger. However, we stress that Ly-a can also arise from external large-scale shocks (ELS) due to starburst winds, powered by CSRs, ploughing into gas actively accreting onto the dark halo. The winds effectively carry energy from the dense, dusty environment of a starburst into lower density regions, where the escape probability for Ly-a photons is greater. ELS emission is expected to be considerably more clumpy (<100 pc; ~0.01") than CSR emission. For a "targetted" observation of an ELS source, IR arrays will need two orders of magnitude improvement in dark current if we wish to detect dispersed clumpy emission within the environment of a massive halo. For either targetted or wide-field surveys, the deepest observations will be those where the pixel sampling is well matched to the size of the emitting regions. We show that there are only 3 -- 4 J-band windows [z = 7.72, (8.22), 8.79, 9.37] suitable for observing the Dark Ages in Ly-a; we summarize their cosmological properties in Table 1. | |
| dc.description | 7 pages, 5 figures, all style files | |
| dc.identifier | https://arxiv.org/abs/astro-ph/0404241 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/0404241 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/7622 | |
| dc.subject | Astrophysics | |
| dc.title | In Search of the Dark Ages -- An Experimental Challenge | |
| dc.type | text |