HIDEEP - An extragalactic blind survey for very low column-density neutral hydrogen

R. F. Minchin; M. J. Disney; P. J. Boyce; W. J.G. De Blok; Q. A. Parker; G. D. Banks; K. C. Freeman; D. A. Garcia; B. K. Gibson; M. Grossi; R. F. Haynes; P. M. Knezek; R. H. Lang; D. F. Malin; R. M. Price; I. M. Stewart; A. E. Wright

doi:10.1111/j.1365-2966.2003.07134.x

HIDEEP - An extragalactic blind survey for very low column-density neutral hydrogen

R. F. Minchin^*, M. J. Disney, P. J. Boyce, W. J.G. De Blok, Q. A. Parker, G. D. Banks, K. C. Freeman, D. A. Garcia, B. K. Gibson, M. Grossi, R. F. Haynes, P. M. Knezek, R. H. Lang, D. F. Malin, R. M. Price, I. M. Stewart, A. E. Wright

^*Corresponding author for this work

Research output: Contribution to journal › Review article › peer-review

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Abstract

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 √t_obs throughout, enabling us to reach an HI column-density limit of 4.2 × 10^-18 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 N_HI = 10^20.65±0.38 This is at least an order of magnitude above our sensitivity limit, with a scatter only marginally larger than the errors on N_HThis needs explaining. If confirmed it means that HI surveys will only find low surface brightness (LSB) galaxies with high M_HI/L _B. Gas-rich LSB galaxies with lower Hi 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 HI surveys being carried out at Parkes and Jodrell Bank.

Original language	English
Pages (from-to)	787-802
Number of pages	16
Journal	Monthly Notices of the Royal Astronomical Society
Volume	346
Issue number	3
DOIs	https://doi.org/10.1111/j.1365-2966.2003.07134.x
Publication status	Published - 11 Dec 2003

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Minchin, R. F., Disney, M. J., Boyce, P. J., De Blok, W. J. G., Parker, Q. A., Banks, G. D., Freeman, K. C., Garcia, D. A., Gibson, B. K., Grossi, M., Haynes, R. F., Knezek, P. M., Lang, R. H., Malin, D. F., Price, R. M., Stewart, I. M., & Wright, A. E. (2003). HIDEEP - An extragalactic blind survey for very low column-density neutral hydrogen. Monthly Notices of the Royal Astronomical Society, 346(3), 787-802. https://doi.org/10.1111/j.1365-2966.2003.07134.x

@article{022ab33c2f7145c9b51a5069b24b3913,

title = "HIDEEP - An extragalactic blind survey for very low column-density neutral hydrogen",

abstract = "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 × 10-18 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 NHI = 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 NHThis needs explaining. If confirmed it means that HI surveys will only find low surface brightness (LSB) galaxies with high MHI/L B. Gas-rich LSB galaxies with lower Hi 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 HI surveys being carried out at Parkes and Jodrell Bank.",

keywords = "Galaxies: distances and redshifts, Radio lines: galaxies, Surveys",

author = "Minchin, {R. F.} and Disney, {M. J.} and Boyce, {P. J.} and {De Blok}, {W. J.G.} and Parker, {Q. A.} and Banks, {G. D.} and Freeman, {K. C.} and Garcia, {D. A.} and Gibson, {B. K.} and M. Grossi and Haynes, {R. F.} and Knezek, {P. M.} and Lang, {R. H.} and Malin, {D. F.} and Price, {R. M.} and Stewart, {I. M.} and Wright, {A. E.}",

year = "2003",

month = dec,

day = "11",

doi = "10.1111/j.1365-2966.2003.07134.x",

language = "English",

volume = "346",

pages = "787--802",

journal = "Monthly Notices of the Royal Astronomical Society",

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Minchin, RF, Disney, MJ, Boyce, PJ, De Blok, WJG, Parker, QA, Banks, GD, Freeman, KC, Garcia, DA, Gibson, BK, Grossi, M, Haynes, RF, Knezek, PM, Lang, RH, Malin, DF, Price, RM, Stewart, IM & Wright, AE 2003, 'HIDEEP - An extragalactic blind survey for very low column-density neutral hydrogen', Monthly Notices of the Royal Astronomical Society, vol. 346, no. 3, pp. 787-802. https://doi.org/10.1111/j.1365-2966.2003.07134.x

TY - JOUR

T1 - HIDEEP - An extragalactic blind survey for very low column-density neutral hydrogen

AU - Minchin, R. F.

AU - Disney, M. J.

AU - Boyce, P. J.

AU - De Blok, W. J.G.

AU - Parker, Q. A.

AU - Banks, G. D.

AU - Freeman, K. C.

AU - Garcia, D. A.

AU - Gibson, B. K.

AU - Grossi, M.

AU - Haynes, R. F.

AU - Knezek, P. M.

AU - Lang, R. H.

AU - Malin, D. F.

AU - Price, R. M.

AU - Stewart, I. M.

AU - Wright, A. E.

PY - 2003/12/11

Y1 - 2003/12/11

N2 - 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 × 10-18 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 NHI = 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 NHThis needs explaining. If confirmed it means that HI surveys will only find low surface brightness (LSB) galaxies with high MHI/L B. Gas-rich LSB galaxies with lower Hi 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 HI surveys being carried out at Parkes and Jodrell Bank.

AB - 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 × 10-18 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 NHI = 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 NHThis needs explaining. If confirmed it means that HI surveys will only find low surface brightness (LSB) galaxies with high MHI/L B. Gas-rich LSB galaxies with lower Hi 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 HI surveys being carried out at Parkes and Jodrell Bank.

KW - Galaxies: distances and redshifts

KW - Radio lines: galaxies

KW - Surveys

UR - http://www.scopus.com/inward/record.url?scp=17544390057&partnerID=8YFLogxK

U2 - 10.1111/j.1365-2966.2003.07134.x

DO - 10.1111/j.1365-2966.2003.07134.x

M3 - Review article

SN - 0035-8711

VL - 346

SP - 787

EP - 802

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

IS - 3

ER -

HIDEEP - An extragalactic blind survey for very low column-density neutral hydrogen

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