Solving the conundrum of intervening strong Mg II absorbers towards gamma-ray bursts and quasars

YDUN [DFF 4090-00079]; French National Research Agency (ANR) [ANR-16-CE31-0003 BEaPro]; FONDECYT [1140838]; PFB-06 CATA; Ramon y Cajal fellowships; RSR a BBVA Foundation Grant for Researchers and Cultural Creators; Spanish Ministry of Economy and Competitiveness [AYA2014-58381-P]; National Science Foundation [AST-1615814]; Juan de la Cierva Incorporacion fellowship [IJCI-2014-21669]; Spanish research project [AYA2014-58381-P]; Project Grant from Icelandic Research Fund [162948-051]; NOVA; NWO-FAPESP grant for advanced instrumentation in astronomy; ASI (Italian Space Agency) [2015-046-R.0]; European Union Horizon Programme under the AHEAD project [654215]; Danish Council for Independent Research [DFF 4002-00275]