TITLE:
Galaxy-galaxy weak lensing in SDSS: intrinsic alignments and shear calibration errors
AUTHOR(S):
Christopher M. Hirata1,
Rachel Mandelbaum1,
Uros Seljak1,
Jacek Guzik2,
Nikhil Padmanabhan1,
Cullen Blake1,
Jonathan Brinkmann3,
Tamas Budavari4,
Andrew Connolly5,
Istvan Csabai6,
Ryan Scranton5,
and Alexander S. Szalay4
(1Princeton Univ.;
2Jagiellonian Univ.;
3Apache Point Obs.;
4Johns Hopkins Univ.;
5Univ. of Pittsburgh;
6Eotvos Univ.)
DATE:
2004 Mar 10 (arXiv, v1, posted);
2004 Mar 10 (MNRAS, submitted);
2004 May 23 (revised);
2004 Jun 02 (MNRAS, accepted);
2004 Jun 02 (arXiv, v2, posted);
2004 Jul 09 (published).
AVAILABILITY:
arXiv astro-ph/0403255 (free).
PUBLICATION INFORMATION: Monthly Notices of the Royal Astronomical Society, 353, 529--549
(2004), 21 pages.
ABSTRACT:
Galaxy-galaxy lensing has emerged as a powerful probe of the dark matter haloes of galaxies, but is subject to contamination if
intrinsically aligned satellites of the lens galaxy are used as part of the source sample. We present a measurement of this intrinsic
shear using 200,747 lens galaxies from the Sloan Digital Sky Survey (SDSS) spectroscopic sample and a sample of satellites selected
using photometric redshifts. The mean intrinsic shear at transverse separations of 30--446h-1 kpc is constrained to be
-0.0062<Dg<+0.0066 (99.9 per cent confidence, including identified systematics), which limits
contamination of the galaxy-galaxy lensing signal to at most ~15 per cent on these scales. We present these limits as a function of
transverse separation and lens luminosity. We furthermore investigate shear calibration biases in the SDSS, which can also affect
galaxy-galaxy lensing, and conclude that the shear amplitude is calibrated to better than 18 per cent. This includes noise-induced
calibration biases in the ellipticity, which are small for the sample considered here, but which can be more important if low
signal-to-noise or poorly resolved source galaxies are used.
ADS BIBLIOGRAPHIC CODE: 2004MNRAS.353..529H
COMMENTS:
SDSS Publication #352.