Search for primordial non-Gaussianity in the quasars of SDSS-III BOSS
  DR9
  We analyse the clustering of 22,361 quasars between redshift 2.2 < z < 2.9
observed with the Sloan Digital Sky Survey (SDSS)-III Baryon Oscillation
Spectroscopic Survey (BOSS), which are included in the ninth data release
(DR9). We fit the clustering results with a {\Lambda}CDM model to calculate the
linear bias of the quasar sample, b=3.74\pm 0.12. The measured value of bias is
consistent with the findings of White et al. (2012), where they analyse almost
the same quasar sample, although only in the range, s<40 Mpc/h. At large scales
we observe an excess or plateau in the clustering correlation function. By
fitting a model that incorporates a scale dependent additional term in the bias
introduced by primordial non-Gaussianity of the local type, we calculate the
amplitude of the deviation from the Gaussian initial conditions as 70<f_NL< 190
at the 95% confidence level. We correct the sample from systematics according
to the methods of Ross et al. (2011); Ho et al. (2012) and Ross et al.
(2011,2012b), with the f_NL measurements after the application of the two
methods being consistent with each other. Finally we use cross-correlations
across redshift slices to test the corrected sample for any remaining unknown
sources of systematics, but the results give no indication of any such further
errors. We consider as our final results on non-Gaussianity of the local type,
46<f_NL< 158 at 95% confidence, after correcting the sample with the weights
method of Ross et al. (2011, 2012b). These results are consistent with previous
tight constraints on non-Gaussianity from other LSS surveys, but are in tension
with the latest results from the CMB.
