PHANGS–JWST First Results: Massive Young Star Clusters and New Insights from JWST Observations of NGC 1365

A primary new capability of JWST is the ability to penetrate dust in star forming galaxies identify and study properties young clusters that remain embedded gas. In this paper we combine infrared images taken with our optical HST star-bursting barred (Seyfert2) spiral galaxy NGC 1365. We find has richest population massive any known within 30 Mpc, $\sim$ are more than 10$^6$ Msolar younger 10 Myr. Sixteen these newly discovered from observations. An examination reveals 4 ($\sim$13$\%$) so deeply they cannot be seen I band (AV $\gt$ mag), 11 ($\sim$37$\%$) missing B band, age mass estimates measurements alone challenging. These numbers suggest 1365 obscured visible for 1.3 $\pm$ 0.7 Myr, either completely or partially 3.7 1.1 also use observations gain insights into triggering cluster formation by collision gas streamers bar. The reveal previously unknown structures (e.g., bridges overshoot regions stars form bar) help us better understand orbital dynamics associated star-forming rings. Finally, note excellent spatial resolution NIRCAM F200W filter provides a way separate barely resolved compact individual based on their sizes.