Multi-tracer extension of the halo model: probing quenching and
  conformity in eBOSS
  We develop a new Multi-Tracer Halo Occupation Distribution (\texttt{MTHOD})
framework for the galaxy distribution and apply it to the extended Baryon
Oscillation Spectroscopic Survey (eBOSS) final data between $z=0.7-1.1$. We
obtain a best fit \mthod\, for each tracer and describe the host halo
properties of these galaxies. The mean halo masses for LRGs, ELGs and QSOs are
found to be $1.9 \times 10^{13} \msolaroh$, $1.1 \times 10^{12} \msolaroh$ and
$5 \times 10^{12} \msolaroh$ respectively in the eBOSS data. We use the
\texttt{MTHOD} framework to create mock galaxy catalogues and predict auto- and
cross-correlation functions for all the tracers. Comparing these results with
data, we investigate galactic conformity, the phenomenon whereby the properties
of neighbouring galaxies are mutually correlated in a manner that is not
captured by the basic halo model. We detect \textsl{1-halo} conformity at more
than 3$\sigma$ statistical significance, while obtaining upper limit on
\textsl{2-halo} conformity. We also look at the environmental dependence of the
galaxy quenching efficiency and find that halo mass driven quenching
successfully explains the behaviour in high density regions, but it fails to
describe the quenching efficiency in low density regions. In particular, we
show that the quenching efficiency in low density filaments is higher in the
observed data, as compared to the prediction of the \mthod\ with halo mass
driven quenching. The mock galaxy catalogue constructed in this paper is
publicly available on https://www.roe.ac.uk/~salam/MTHOD/ .
