Where has all the neutral hydrogen gone?

M. J. Disney; R. F. Minchin

doi:10.1007/978-94-010-0115-1_56

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arXiv · astro-ph/0211288

Where has all the neutral hydrogen gone?

M. J. Disney·R. F. Minchin

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Abstract

Our extremely deep survey for extragalactic HI (HIDEEP) finds no intergalactic gas clouds, and no galaxies with HI at inferred global column-densities below 10^20 cm^-2 when we could have detected such objects down to a completeness limit of 4 x 10^18 cm^-2. We speculate that low surface-density hydrogen is either ionised or locked up in ``frozen discs'', i.e. structures where the local Ly-alpha is insufficient to excite the 21-cm transition to a spin-temperature above the cosmic background. Such ``frozen discs'' might be responsible for many QSOALSs.

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M. J. Disney, R. F. Minchin. 2002-11-13. Where has all the neutral hydrogen gone?. https://doi.org/10.1007/978-94-010-0115-1_56

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