Primordial non-Gaussianity induces a scale-dependent bias in large scale structure ( LSS ) data , proportional to f _ { NL } / k ^ { 2 } for the exact local ansatz .
Recent work has shown that models of inflation that predict a large squeezed limit bispectrum , such as multi-field models and single field inflation with a modified initial state , typically give rise to a generalized local ansatz , with the scale-dependent bias now proportional to { \cal A } _ { NL } / k ^ { \alpha } .
We use photometric measurements of the angular power spectrum of luminous red galaxies and quasars in the Sloan Digital Sky Survey Data Release Eight ( SDSS DR8 ) with the above parameterization to constrain the amplitude { \cal A } _ { NL } and scale-dependence \alpha .
We find that the marginalized upper limit on \alpha is 2.0 at the 95 \% confidence level , consistent with the local ansatz .
We also present Fisher forecasts for a survey of the same size as DR8 to assess the role of systematics in current photometric LSS data .
Moreover , we present analytic results on the expected mass dependence of { \cal A } _ { NL } for different inflationary models , which can be an important observable for future surveys , if primordial non-Gaussianity is non-zero .