Astronomy and Astrophysics – Astrophysics
Scientific paper
2005-09-29
Mon.Not.Roy.Astron.Soc.371:1601-1609,2006
Astronomy and Astrophysics
Astrophysics
10 pages, 8 figures, submitted to MNRAS
Scientific paper
10.1111/j.1365-2966.2006.10736.x
We examine H-band number counts determined using new photometry over 0.30 sq.deg. to H=19, as well as H<14 counts from 2MASS. First, we examine 2MASS counts extracted for the 4000 sq.deg. APM survey area and find a deficiency of 25% at H=13, in line with previous results. In addition the |b|>20 counts display a relatively constant deficit in the counts of 15-20%. We investigate various possible causes for these results: In order to address the issue of the model normalisation, we examine faint number counts for the new faint photometry presented in this work and also for the LCIRS. In each case a zeropoint is chosen to match that of the 2MASS photometry at bright magnitudes. We find a large offset between 2MASS and the LCIRS data of 0.28+/-0.01 magnitudes. Applying a consistent zeropoint, the combined faint data is in good agreement with the homogeneous model prediction used previously. We examine possible effects arising from unexpected galaxy evolution and photometric errors and find no evidence for a significant contribution from either. However, incompleteness in the 2MASS catalogue and in the faint data may have a significant contribution. Addressing the contribution from large-scale structure, we estimate the cosmic variance in the bright counts over the APM survey area and for |b|>20 expected in a LCDM cosmology using 27 LCDM mock 2MASS catalogues. Accounting for the model normalisation uncertainty and taking an upper limit for the incompleteness, the APM survey area bright counts are in line with a rare fluctuation in the local galaxy distribution of 2.5 sigma. However, the |b|>20 counts represent a 4.0 sigma fluctuation, and imply a local hole which extends over the entire local galaxy distribution and is at odds with LCDM.
Frith William J.
Metcalfe Nigel
Shanks Tom
No associations
LandOfFree
New H-band Galaxy Number Counts: A Large Local Hole in the Galaxy Distribution? does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with New H-band Galaxy Number Counts: A Large Local Hole in the Galaxy Distribution?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and New H-band Galaxy Number Counts: A Large Local Hole in the Galaxy Distribution? will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-460396