Vibrationally excited HC3N emission in NGC 1068: tracing the recent star formation in the starburst ring

Using ALMA data, we have studied the HC$_3$N and continuum emission in starburst ring (SB ring) circumnuclear disc (CND) of SB/AGN composite galaxy NGC 1068. We detected from vibrationally excited (HC$_3$N*) only towards one star-forming region SB ring. Remarkably, HC$_3$N* was not CND despite its large $v=0$ column density. From LTE non-LTE modelling HC$_3$N*, obtained a dust temperature $ T_\text{dust} \sim 250$ K density $n_{\text{H}_2}=6\times10^5$ cm$^{-3}$ for this region. The estimated IR luminosity $5.8\times10^8$ L$_\odot$ is typical proto-Super Star Clusters (proto-SSC) observed 253. use emissions at $147$ GHz $350$ GHz, along with CO Pa $\alpha$, to estimate ages other $14$ SSCs find youngest be associated connecting nuclear bar ring, supporting scenario sequential star formation. For CND, our analysis yields $T_\text{dust} \leqslant 100$ $n_{\text{H}_2}\sim(3-6)\times10^5$cm$^{-3}$. very different temperatures found proto-SSC indicates that, while being efficiently heated inside by radiation massive proto-stars, externally AGN, which optically thin case can heat $56$ K. discuss implications non-detection near luminous AGN 1068 on interpretation galaxies 4418 Arp 220.