On the Nitrogen variation in ?2 Gyr old massive star clusters in the large Magellanic Cloud

We present ESO/VLT FORS2 low resolution spectroscopy of red giant branch stars in three massive, intermediate age ($\sim 1.7-2.3$ Gyr) star clusters the Large Magellanic Cloud. measure CH and CN index bands at 4300A, 3883A, as well [C/Fe] [N/Fe] abundance ratios for 24, 21 12 member NGC 1978, 1651, 1783, respectively. find a significant intrinsic spread 1978 signal multiple stellar populations (MPs) within clusters. On contrary, we report null 1783 our measurement precision. For separated two distribution translated into an internal N variation $\Delta$[N/Fe]$=0.63\pm0.49$ dex. 1651 put upper limits on variations $\Delta$[N/Fe]$\leq 0.2, 0.4$ dex, The spectroscopic analysis confirms previous results from HST photometry, where was found to host MPs form spreads, while slightly younger (e.g. $<$ 2 Gyr old) were not, uncertainties. It also that massive show lower with respect ancient globular clusters, although this is part due effect first dredge up these masses, recently reported literature. stress importance future studies estimate initial variations, free evolutionary mixing processes, by observing unevolved young