Issue |
A&A
Volume 592, August 2016
|
|
---|---|---|
Article Number | A75 | |
Number of page(s) | 21 | |
Section | Cosmology (including clusters of galaxies) | |
DOI | https://doi.org/10.1051/0004-6361/201527971 | |
Published online | 28 July 2016 |
The PCA Lens-Finder: application to CFHTLS
1 Laboratoire d’Astrophysique, École
Polytechnique Fédérale de Lausanne (EPFL), Observatoire de
Sauverny, 1290 Versoix, Switzerland
e-mail: danuta.paraficz@epfl.ch
2 Department of Astronomy, University
of Geneva, Ch. d’Écogia
16, 1290
Versoix,
Switzerland
3 Dipartimento di Fisica e Astronomia,
Universita di Bologna, via Berti
Pichat 6/2, 40127
Bologna,
Italy
Received:
15
December
2015
Accepted:
21
April
2016
We present the results of a new search for galaxy-scale strong lensing systems in CFHTLS Wide. Our lens-finding technique involves a preselection of potential lens galaxies, applying simple cuts in size and magnitude. We then perform a Principal Component Analysis of the galaxy images, ensuring a clean removal of the light profile. Lensed features are searched for in the residual images using the clustering topometric algorithm DBSCAN. We find 1098 lens candidates that we inspect visually, leading to a cleaned sample of 109 new lens candidates. Using realistic image simulations we estimate the completeness of our sample and show that it is independent of source surface brightness, Einstein ring size (image separation) or lens redshift. We compare the properties of our sample to previous lens searches in CFHTLS. Including the present search, the total number of lenses found in CFHTLS amounts to 678, which corresponds to ∼4 lenses per square degree down to i(AB) = 24.8. This is equivalent to ∼60.000 lenses in total in a survey as wide as Euclid, but at the CFHTLS resolution and depth.
Key words: gravitational lensing: strong / galaxies: general / surveys
© ESO, 2016
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