2025AJ....170..144D

We present near-infrared JHK_s and narrowband H₂(1-0) photometric observations of the W51A region, obtained with GTC EMIR, aiming to characterize its young stellar population, and provide mass estimates for individual cluster members and the protoclusters. Our observations reveal over 3000 new sources, out of which 88 are located in the protoclusters, W51 IRS2 and W51 Main. The average extinction (A_V), measured from the J - H color, of sources is 19A_V in W51 IRS2 and 14A_V in W51 Main. We document 17 new instances of H₂ emission in the region by utilizing observations from the H₂(1-0) narrowband filter. Despite limited completeness, we estimated masses for each cluster member and estimated the total cluster mass to be in the range of 900-4700M_⊙for W51 IRS2 and 500-2700M_⊙ for W51 Main, using an assumed age range of 1-3 Myr. We measured the initial mass function (IMF) in the proto-clusters assuming a range of ages from 1-3 Myr and found that the IMF slopes for both protoclusters are consistent with the Salpeter IMF in the mass range M ≳ 8M_⊙within 1σ-2σ.