2025/07/30 by Adam Ginsburg, Dawson, Aden, C. Román-Zúñiga +2
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #Solar and Stellar Astrophysics (astro-ph.SR) #Stellar, planetary, and galactic studies
paper · pdf · doi:10.48550/arxiv.2507.23112
openalex publication_date 2025/07/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We present near-infrared JHKs and narrow-band 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 proto-clusters. Our observations reveal over 3000 new sources, out of which 88 are located in the proto-clusters, W51 IRS2 and W51 Main. The average extinction (AV), measured from the J-H color, of sources is 19 AV in W51 IRS2 and 14 AV in W51 Main. We document 17 new instances of H2 emission in the region by utilizing observations from the H2(1-0) narrow-band filter. Despite limited completeness, we estimated masses for each cluster member and estimated the total cluster mass to be in the range of 900-4700 solar masses for W51 IRS2 and 500-2700 solar masses 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 proto-clusters are consistent with the Salpeter IMF in the mass range greater than or equal to 8 solar masses within 1 to 2 sigma.