Astronomy and Astrophysics – Astrophysics
Scientific paper
2003-10-07
Mon.Not.Roy.Astron.Soc. 347 (2004) 895
Astronomy and Astrophysics
Astrophysics
Accepted for publication in MNRAS, 15 pages, 18 figures
Scientific paper
10.1111/j.1365-2966.2004.07264.x
We estimate and remove the contamination of weak gravitational lensing measurements by the intrinsic alignment of close pairs of galaxies. We do this by investigating both the aperture mass B mode statistic, and the shear correlations of close and distant pairs of galaxies. We re-analyse the COMBO-17 survey, and study published results from the RCS and the VIRMOS-DESCART survey, concluding that the intrinsic alignment effect is at the lower end of the range of theoretical predictions. We also revisit this theoretical issue, and show that misalignment of baryon and halo angular momenta may be an important effect which can reduce the intrinsic ellipticity correlations estimated from numerical simulations to the level that we and the SuperCOSMOS survey observe. We re-examine the cosmological parameter estimation from the COMBO-17 survey, now marginalising over the Hubble constant. Assuming no evolution in galaxy clustering, and marginalising over the intrinsic alignment signal, we find the mass clustering amplitude is reduced by 0.03 to sigma_8(Omega_m / 0.27)^0.6 = 0.71 +/- 0.11. We consider the forthcoming SNAP wide weak lensing survey, and the CFHTLS wide synoptic survey, and expect them to be contaminated on scales >1 arcmin by intrinsic alignments at the level of ~1% and ~2% respectively. Division of the SNAP survey for lensing tomography significantly increases the contamination in the lowest redshift bin to ~7% and possibly higher. Removal of the intrinsic alignment effect by the downweighting of nearby galaxy pairs will therefore be vital for SNAP, (abridged).
Brown Michael
Heavens Alan
Heymans Catherine
Meisenheimer Klaus
Taylor Andy
No associations
LandOfFree
Weak lensing with COMBO-17: estimation and removal of intrinsic alignments 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 Weak lensing with COMBO-17: estimation and removal of intrinsic alignments, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Weak lensing with COMBO-17: estimation and removal of intrinsic alignments will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-320078