On the thermal structure of the proto-Super Star Cluster 13 in NGC 253

Abstract

Using high angular resolution ALMA observations ($0.02^{\prime \prime }\approx 0.34$ pc), we study the thermal structure and kinematics of the proto super star cluster $13$ in the central region of NGC253 through their continuum and vibrationally excited HC${}_3$N emission from $J=24-23$ and $J=26-25$ lines arising from vibrational states up to $v_4=1$. We have carried 2D-LTE and non-local radiative transfer modelling of the radial profile of the HC${}_3$N and continuum emission in concentric rings of $0.1$ pc width. From the 2D-LTE analysis, we found a Super Hot Core (SHC) of $1.5$ pc with very high vibrational temperatures ($>500$ K), and a jump in the radial velocity ($21$ km s${}^{-1}$) in the SE-NW direction. From the non-local models, we derive the HC${}_3$N column density, H${}_2$ density and dust temperature ($T_{\text{dust}}$) profiles. Our results show that the thermal structure of the SHC is dominated by the greenhouse effect due to the high dust opacity in the IR, leading to an overestimation of the LTE $T_{\text{dust}}$ and its derived luminosity. The kinematics and $T_{\text{dust}}$ profile of the SHC suggest that star formation was likely triggered by a cloud-cloud collision. We compare proto-SSC $13$ to other deeply embedded star-forming regions, and discuss the origin of the $L_{\text{IR}}/M_{{\text{H}}_2}$ excess above $\sim 100$ L${}_{\odot }$ M${}_{\odot }^{-1}$ observed in (U)LIRGs.

References in corpus (15)

• Distances to PHANGS Galaxies: New Tip of the Red Giant Branch Measurements and Adopted Distances
• Do cloud-cloud collisions trigger high-mass star formation? I. Small cloud collisions
• Molecular clouds towards RCW 49 and Westerlund 2; Evidence for cluster formation triggered by cloud-cloud collision
• AUTO-MULTITHRESH: A General Purpose Automasking Algorithm
• The Physical Conditions in a Pre Super Star Cluster Molecular Cloud in the Antennae Galaxies
• CON-quest: Searching for the most obscured galaxy nuclei
• Young star clusters in interacting galaxies - NGC 1487 and NGC 4038/4039
• Do star clusters form in a completely mass-segregated way?
• Outflows from Super Star Clusters in the Central Starburst of NGC253
• New Insights into the Physical Conditions and Internal Structure of a Candidate Proto-Globular Cluster
• The formation of the young massive cluster B1 in the Antennae galaxies (NGC 4038/NGC 4039) triggered by cloud-cloud collision
• The effect of primordial mass segregation on the size scale of globular clusters
• Vibrationally excited HC3N emission in NGC1068: Tracing the recent star formation in the starburst ring
• Distance and mass of the NGC 253 galaxy group
• The Youngest Globular Clusters

Cited by in corpus (3)

• Molecular isotopologue measurements toward super star clusters and the relation to their ages in NGC253 with ALCHEMI
• Positive feedback, quenching and sequential super star cluster (SSC) formation in NGC 4945
• A multi-scale investigation into the diagnostic potential of the HCN/HCO${}^{+}$ ratio for AGN and starburst activity in nearby galaxies