Preliminary clustering properties of the DESI BGS bright targets using
  DR9 Legacy Imaging Surveys
  We characterise the selection cuts and clustering properties of a
magnitude-limited sample of bright galaxies that is part of the Bright Galaxy
Survey (BGS) of the Dark Energy Spectroscopic Instrument (DESI) using the ninth
data release of the Legacy Imaging Surveys (DR9). We describe changes in the
DR9 selection compared to the DR8 one as explored in Ruiz-Macias et al. (2021).
We also compare the DR9 selection in three distinct regions: BASS/MzLS in the
north Galactic Cap (NGC), DECaLS in the NGC, and DECaLS in the south Galactic
Cap (SGC). We investigate the systematics associated with the selection and
assess its completeness by matching the BGS targets with the Galaxy and Mass
Assembly (GAMA) survey. We measure the angular clustering for the overall
bright sample (r $\leq$ 19.5) and as function of apparent magnitude and colour.
This enables to determine the clustering strength and slope by fitting a
power-law model that can be used to generate accurate mock catalogues for this
tracer. We use a counts-in-cells technique to explore higher-order statistics
and cross-correlations with external spectroscopic data sets in order to check
the evolution of the clustering with redshift and the redshift distribution of
the BGS targets using clustering-redshifts. While this work validates the
properties of the BGS bright targets, the final target selection pipeline and
clustering properties of the entire DESI BGS will be fully characterised and
validated with the spectroscopic data of Survey Validation.
