Radial gradient of stellar populations

Our analysis combines data obtained in this work with previously published HST data from an earlier article of this series and {encompasses} a broad portion of the cluster's radial extension. Our findings reveal a significant radial variation in the fraction of stars within the two largest stellar populations, showing that one of the main second-population groups (referred to as the blue main sequence (bMS) group) is more centrally concentrated than the first-population group (referred to as the red main sequence (rMS) group).

Additionally, we explore the spatial variations of the other, smaller stellar populations (referred to as MSa and MSd) and find a qualitatively similar, but weaker, radial decrease in the fraction of stars in these populations at larger distances from the cluster centre. Only one of the populations identified (MSe) does not show any significant radial variation.