Sulphur within the extreme environment of the central molecular zone of NGC253: A chemical modelling approach
- 1Leiden Observatory, Leiden University
- 2National Radio Astronomy Observatory
- 3Department of Astronomy, University of Virginia
Abstract
Context. Sulphur-bearing species are ubiquitous in Galactic star-forming regions, from dense cold cores to outflows and shocks linked to protostellar activity. A recent observational study investigated the origin of sulphur-bearing species towards the central molecular zone (CMZ) of NGC 253 and showed that sulphur emission is linked to the presence of forming stars. However, more extensive modelling of these observations are required to determine the exact origin of the sulphur emission (e.g. shock or thermal evaporation). Aims. Using chemical modelling, we aim to further explore the origin of the emission of the sulphur-bearing species in the CMZ of NGC 253. We examined how sulphur-bearing species behave in the more extreme environment of the starburst galaxy NGC 253 and, more generally, how they can help us improve our understanding of the emission linked with the dense star-forming gas in external galaxies. Methods. We used the gas-grain time-dependent chemical model UCLCHEM to model static warm clouds and C-type shocks under the physical conditions found in the CMZ of NGC 253. We derived the observed abundances and abundance ratios of CS, H2S, OCS, H2CS, SO, SO2, and CCS using ALMA measurements and compared them to the modelled output abundances. Results. We find that depending on the model type (shock, post-shock, or static cloud), the highest abundance values reached by the sulphur-bearing species vary significantly. Hence, we can use the observed abundances of sulphur-bearing species to distinguish between shocked, post-shocked, or a quiescent (non-shocked) gas. We also confirm observationally based conclusions on their emission origins, including in the case of unresolved emission, such as for the hot dense components of OCS and SO2, likely probing the hot quiescent gas of proto-super star clusters within the giant molecular clouds (GMCs) of NGC 253. Conclusions. Comparing GMC-scale observations with chemical modelling is a powerful method to investigate and constrain the origin of molecular emission towards extragalactic star-forming regions. Sulphur-bearing species are useful to distinguish between different types of interstellar medium components (shocked, post-shocked or quiescent gas).
Related
- Sulphur-bearing molecule survey towards prestellar and starless cores in the Perseus molecular cloud
- Chemical abundance patterns at z=1-7: Carbon, Nitrogen, Neon, Sulphur, and Argon abundances from JWST spectroscopy
- Sulphur-bearing molecule survey towards prestellar and starless cores in the Perseus molecular cloud
- The JWST Ultramassive Galaxy Sample -- II. Supermassive Black Hole Masses for 8 Extreme Early-Type Galaxies via Jeans Anisotropic Modelling of High-Resolution Integral-Field NIRSpec Stellar Kinematics
- J-PAS: Exploring the connection between local environment and the triggering of bursty star formation in Extreme Emission Line Galaxies
BibTeX
@article{bouvier2026sulphur,
title = {{Sulphur within the extreme environment of the central molecular zone of NGC253: A chemical modelling approach}},
author = {Bouvier M. and Dutkowska K. M. and Viti S. and Mangum J. G. and Behrens E. and Eibensteiner C.},
journal = {Astronomy \& Astrophysics},
year = {2026},
month = oct,
doi = {10.1051/0004-6361/202661475},
url = {https://doi.org/10.1051/0004-6361/202661475},
note = {CC BY},
}
RIS
TY - JOUR
TI - Sulphur within the extreme environment of the central molecular zone of NGC253: A chemical modelling approach
AU - Bouvier M.
AU - Dutkowska K. M.
AU - Viti S.
AU - Mangum J. G.
AU - Behrens E.
AU - Eibensteiner C.
PY - 2026
DA - 2026/10/24
JO - Astronomy & Astrophysics
DO - 10.1051/0004-6361/202661475
UR - https://doi.org/10.1051/0004-6361/202661475
AB - Context. Sulphur-bearing species are ubiquitous in Galactic star-forming regions, from dense cold cores to outflows and shocks linked to protostellar activity. A recent observational study investigated the origin of sulphur-bearing species towards the central molecular zone (CMZ) of NGC 253 and showed that sulphur emission is linked to the presence of forming stars. However, more extensive modelling of these observations are required to determine the exact origin of the sulphur emission (e.g. shock or thermal evaporation). Aims. Using chemical modelling, we aim to further explore the origin of the emission of the sulphur-bearing species in the CMZ of NGC 253. We examined how sulphur-bearing species behave in the more extreme environment of the starburst galaxy NGC 253 and, more generally, how they can help us improve our understanding of the emission linked with the dense star-forming gas in external galaxies. Methods. We used the gas-grain time-dependent chemical model UCLCHEM to model static warm clouds and C-type shocks under the physical conditions found in the CMZ of NGC 253. We derived the observed abundances and abundance ratios of CS, H2S, OCS, H2CS, SO, SO2, and CCS using ALMA measurements and compared them to the modelled output abundances. Results. We find that depending on the model type (shock, post-shock, or static cloud), the highest abundance values reached by the sulphur-bearing species vary significantly. Hence, we can use the observed abundances of sulphur-bearing species to distinguish between shocked, post-shocked, or a quiescent (non-shocked) gas. We also confirm observationally based conclusions on their emission origins, including in the case of unresolved emission, such as for the hot dense components of OCS and SO2, likely probing the hot quiescent gas of proto-super star clusters within the giant molecular clouds (GMCs) of NGC 253. Conclusions. Comparing GMC-scale observations with chemical modelling is a powerful method to investigate and constrain the origin of molecular emission towards extragalactic star-forming regions. Sulphur-bearing species are useful to distinguish between different types of interstellar medium components (shocked, post-shocked or quiescent gas).
SN - 0004-6361
SN - 1432-0746
ER -