Youakim, K.Starkenburg, E.Martin, N. F.Matijevic, G.Aguado, D. S.Allende Prieto, C.Arentsen, A.Bonifacio, P.Carlberg, R. G.Gonzalez Hernandez, J. IHill, VKordopatis, G.Lardo, C.Navarro, J. F.Jablonka, P.Janssen, R. SanchezSestito, F.Thomas, G. F.Venni, K.2020-03-212020-03-212020-03-212020-03-0110.1093/mnras/stz3619https://infoscience.epfl.ch/handle/20.500.14299/167504WOS:000518148000029The Pristine survey uses narrow-band photometry to derive precise metallicities down to the extremely metal-poor regime ([Fe/H] <-3), and currently consists Of over 4 million FGK-type stars over a sky area of similar to 2500 deg(2), We focus our analysis on a subsample of similar to 80 000 main-sequence turn-off stars with heliocentric distances between 6 and 20 kpc, which we take to be a representative sample of the inner halo, The resulting metallicity distribution function (MDF) has a peak at [Fe/H] = -1.6, and a slope of Delta(LogN)/Delta[Fe/H] = 1.0 +/- 0.1 in the metallicity range of -3,4 < [Fe/H] < -2.5. This agrees well with a simple closed-box chemical enrichment model in this range, hut is shallower than previous spectroscopic MDFs presented in the literature, suggesting that there may be a larger proportion of metal-poor stars in the inner halo than previously reported, We identify the Monoceros/TriAnd/ACS/EIRS/A13 structure in metallicity space in a low-latitude field in the anticentre direction, and also discuss the possibility that the inner halo is dominated by a single, large merger event, but cannot strongly support or refute this idea with the current data. Finally, based on the MDF of field stars, we estimate the number of expected metal-poor globular clusters in the Milky Way halo to he 5,4 for [Fe/II] <-2.5 and 1.5 for [Fe/II] <-3, suggesting that the lack of lowmetallicity globular clusters in the Milky Way is not due simply to statistical undersampling.Astronomy & AstrophysicsAstronomy & Astrophysicsstars: abundancesgalaxy: abundancesgalaxy: evolutiongalaxy: formationgalaxy: halogalaxies: dwarfstellar halodwarf galaxysky surveyevolutionstarssagittariusabundancestreamssearchmergertext::journal::journal article::research article