2023ApJ...944L..55L

We present the results of a James Webb Space Telescope NIRCam investigation into the young massive star cluster (YMC) population in the luminous infrared galaxy VV 114. We identify 374 compact YMC candidates with signal-to-noise ratios ≥ 3, 5, and 5 at F150W, F200W, and F356W, respectively. A direct comparison with our HST cluster catalog reveals that ∼20% of these sources are undetected at optical wavelengths. Based on yggdrasil stellar population models, we identify 17 YMC candidates in our JWST imaging alone with F150W - F200W and F200W - F356W colors suggesting they are all very young, dusty (A_V = 5-15), and massive (10^5.8 < M_⊙ < 10^6.1). The discovery of these “hidden” sources, many of which are found in the “overlap” region between the two nuclei, quadruples the number of t < 3 Myr clusters and nearly doubles the number of t < 6 Myr clusters detected in VV 114. Now extending the cluster age distribution (${dN}/d\tau \propto {\tau }^{\gamma }$) to the youngest ages, we find a slope of γ = -1.30 ± 0.39 for 10⁶ < τ(yr) < 10⁷, which is consistent with the previously determined value from 10⁷ < τ(yr) < 10^8.5, and confirms that VV 114 has a steep age distribution slope for all massive star clusters across the entire range of cluster ages observed. Finally, the consistency between our JWST- and HST-derived age distribution slopes indicates that the balance between cluster formation and destruction has not been significantly altered in VV 114 over the last 0.5 Gyr.