Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.14/27223
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- Title
- HIDEEP - an extragalactic blind survey for very low column-density neutral hydrogen
- Related
- Monthly notices of the Royal Astronomical Society, Vol. 346, Issue 3, p.787-802
- DOI
- 10.1111/j.1365-2966.2003.07134.x
- Publisher
- Blackwell Publishing
- Date
- 2003
- Author/Creator
- Minchin, R. F
- Author/Creator
- Disney, M. J
- Author/Creator
- Haynes, R. F
- Author/Creator
- Boyce, P. J
- Author/Creator
- de Blok, W. J. G
- Author/Creator
- Parker, Q. A
- Author/Creator
- Banks, G. D
- Author/Creator
- Freeman, K. C
- Author/Creator
- Garcia, D. A
- Author/Creator
- Gibson, B. K
- Author/Creator
- Grossi, M
- Description
- We have carried out an extremely long integration time (9000 s beam⁻¹) 21-cm blind survey of 60 deg² in Centaurus using the Parkes multibeam system. We find that the noise continues to fall as √tobs throughout, enabling us to reach an HI column-density limit of 4.2 × 10¹⁸ cm⁻² for galaxies with a velocity width of 200 km s⁻¹ in the central 32 deg² region, making this the deepest survey to date in terms of column density sensitivity. The HI data are complemented by very deep optical observations from digital stacking of multi-exposure UK Schmidt Telescope R-band films, which reach an isophotal level of 26.5 R mag arcsec⁻² (≃27.5 B mag arcsec⁻²). 173 HI sources have been found, 96 of which have been uniquely identified with optical counterparts in the overlap area. There is not a single source without an optical counterpart. Although we have not measured the column densities directly, we have inferred them from the optical sizes of their counterparts. All appear to have a column density of NH I= 10²⁰·⁶⁵±⁰·³⁸ . This is at least an order of magnitude above our sensitivity limit, with a scatter only marginally larger than the errors on NH I. This needs explaining. If confirmed it means that H I surveys will only find low surface brightness (LSB) galaxies with high MH I/LB . Gas-rich LSB galaxies with lower H I mass to light ratios do not exist. The paucity of low column-density galaxies also implies that no significant population will be missed by the all-sky H I surveys being carried out at Parkes and Jodrell Bank.
- Description
- 16 page(s)
- Subject Keyword
- surveys
- Subject Keyword
- galaxies--distances and redshifts
- Subject Keyword
- radio lines--galaxies
- Resource Type
- journal article
- Organisation
- Macquarie University. Dept. of Physics
- Identifier
- http://hdl.handle.net/1959.14/27223
- Identifier
- ISSN:0035-8711
- Identifier
- mq-rm-2003017511
- Language
- eng
- Reviewed
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