The local hole in the galaxy distribution: new optical evidence
ABSTRACT We present a new CCD survey of bright galaxies predominantly within the Northern and Southern strips of the 2dF Galaxy Redshift Survey (2dFGRS) areas. We use the new CCD data to check the photographic photometry scales of the 2dFGRS 100‐k release, APM Bright Galaxy Catalogue, APM–Stromlo Re...
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| Published in: | Monthly notices of the Royal Astronomical Society Vol. 354; no. 4; pp. 991 - 1004 |
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| Main Authors: | , , , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
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Blackwell Science Ltd
11-11-2004
Blackwell Science |
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| Online Access: | Get full text |
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| Summary: | ABSTRACT
We present a new CCD survey of bright galaxies predominantly within the Northern and Southern strips of the 2dF Galaxy Redshift Survey (2dFGRS) areas. We use the new CCD data to check the photographic photometry scales of the 2dFGRS 100‐k release, APM Bright Galaxy Catalogue, APM–Stromlo Redshift Survey, Durham–UKST (DUKST) Survey, Millennium Galaxy Catalogue (MGC) and Sloan Digital Sky Survey (SDSS). We find evidence for scale and zero‐point errors in the 2dFGRS 100‐k release Northern field, DUKST and APM data of 0.10, 0.24 and 0.31 mag, respectively; we find excellent agreement with the MGC and SDSS photometry. We use our new CCD data to correct the photographic photometry, we then compare the CCD number counts in both the Northern and Southern survey areas. We find conclusive evidence that the Southern counts with B < 17 mag are down by ≈30 per cent relative to both the Northern counts and to the models of Metcalfe et al. in the same magnitude range. We further compare the number redshift distributions from the B < 17 mag Durham–UKST and B < 19.5 2dFGRS redshift surveys using the corrected photometry. While the Northern n(z) from 2dFGRS appears relatively homogeneous over its whole range, the Southern n(z) shows a 30 per cent deficiency out to z= 0.1; at higher redshifts it agrees much better with the Northern n(z) and the homogeneous model n(z). The Durham–UKST n(z) shows that the Southern ‘hole’ extends over a 20 × 75 deg2 area. The troughs with z < 0.1 in the Durham–UKST n(z) appear deeper than for the fainter 2dFGRS data. This effect appears to be real since the troughs also appear to deepen in the 2dFGRS data when magnitude‐limited at B < 17 mag and so this may be evidence that the local galaxy distribution is biased on ≳50 h−1 Mpc scales which is unexpected in a ΛCDM cosmology. Finally, since the Southern local void may persist over the full area of the APM and APM Bright Galaxy Catalogue with a ≈25 per cent deficiency in the counts below B≈ 17, this would mean that its extent is approximately 300 h−1 Mpc × 300 h−1 Mpc on the sky as well as ≈300 h−1 Mpc in the redshift direction. Such a 25 per cent deficiency extending over ≈107h−3 Mpc3 may imply that the power‐law behaviour of the galaxy correlation function extends to ≈150 h−1 Mpc with no break and shows more excess large‐scale power than detected in the 2dFGRS correlation function or expected in the ΛCDM cosmology. |
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| Bibliography: | ArticleID:MNR8217 ark:/67375/WNG-RVFLPNK3-L istex:27662E90E2CFB3FC42A8A2971FEDE6D0DFEC5DD4 ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
| ISSN: | 0035-8711 1365-2966 |
| DOI: | 10.1111/j.1365-2966.2004.08217.x |