Galaxy-Galaxy Weak Lensing Measurements from SDSS: I. Image Processing
  and Lensing signals
  As the first paper in a series on the study of the galaxy-galaxy lensing from
Sloan Digital Sky Survey Data Release 7 (SDSS DR7), we present our image
processing pipeline that corrects the systematics primarily introduced by the
Point Spread Function (PSF). Using this pipeline, we processed SDSS DR7 imaging
data in $r$ band and generated a background galaxy catalog containing the shape
information of each galaxy. Based on our own shape measurements of the galaxy
images from SDSS DR7, we extract the galaxy-galaxy (GG) lensing signals around
foreground spectroscopic galaxies binned in different luminosity and stellar
mass. The overall signals are in good agreement with those obtained by
\citet{Mandelbaum2005, Mandelbaum2006} from the SDSS DR4. The results in this
paper with higher signal to noise ratio is due to the larger survey area than
SDSS DR4, confirm that more luminous/massive galaxies bear stronger GG lensing
signal. We also divide the foreground galaxies into red/blue and star
forming/quenched subsamples and measured their GG lensing signals,
respectively. We find that, at a specific stellar mass/luminosity, the
red/quenched galaxies have relatively stronger GG lensing signals than their
counterparts especially at large radii. These GG lensing signals can be used to
probe the galaxy-halo mass relations and their environmental dependences in the
halo occupation or conditional luminosity function framework.
