1609.08167
Galaxy bias from galaxy-galaxy lensing in the DES science verification data
Prat et al
Present a measurement of GGL around a magnitude-limited (i_AB<22.5) sample of galaxies selected from the DES-SV data. Split these lenses into 3 photometric-redshift bins from 0.2 to 0.8, and determine the product of the galaxy bias b and cross-correlation coefficient between the galaxy and DM overdensity fields r in each bin, using scales above 4 Mpc/h comoving, where the linear bias model is found to be valid given the current uncertainties. Compare the galaxy bias results from GGL with those obtained from galaxy clustering (Crocce+2016) and CMB lensing (Giannantonio+ 2016) for the same sample of galaxies, and found the measurements to be in good agreement with those in Crocce+2016, while, in the lowest z bin (z~0.3), they show some tension with the findings in Giannantonio+2016. The results are found to be rather insensitive to a large range of systematic effects. Measure (b x r) to be 0.87±0.11, 1.12±0.16 and 1.24±0.23, respectively for the 3 redshift bins of width Delta z = 0.2 in the range 0.2<z<0.8, defined with the photo-z algorithm BPZ. Using a different code to split the lens sample, TPZ, leads to changes in the measured biases at the 10-20% level, but it does not alter the main conclusion of this work: when comparing with Crocce+2016, do not find strong evidence for a cross-correlation parameter significantly below one in this galaxy sample, except possibly at the lowest redshift bin (z~0.3), where it is found r=0.71±0.11 when using TPZ, and 0.83±0.12 with BPZ, assuming the difference between the results from the 2 probes can be solely attributed to the cross-correlation parameter.
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