The star-forming complex LMC-N79 as a future rival to 30 Doradus

Abstract

Within the early Universe, `extreme' star formation may have been the norm rather than the exception. Super Star Clusters (SSCs; $M_\star$ $\gtrsim$ 10$^5$ M$_\odot$) are thought to be the modern-day analogs of globular clusters, relics of a cosmic time ($z$ $\gtrsim$ 2) when the Universe was filled with vigorously star-forming systems. The giant HII region 30 Doradus in the Large Magellanic Cloud (LMC) is often regarded as a benchmark for studies of extreme star formation. Here, we report the discovery of a massive embedded star forming complex spanning $\sim$ 500 pc in the unexplored southwest region of the LMC, which manifests itself as a younger, embedded twin of 30 Doradus. Previously known as N79, this region has a star formation efficiency exceeding that of 30 Doradus by a factor of $\sim$ 2 as measured over the past $\lesssim$ 0.5 Myr. Moreover, at the heart of N79 lies the most luminous infrared (IR) compact source discovered with large-scale IR surveys of the LMC and Milky Way, possibly a precursor to the central SSC of 30 Doradus, R136. The discovery of a nearby candidate SSC may provide invaluable information to understand how extreme star formation proceeds in the current and high-redshift Universe.