A Collimated Protostellar Outflow Likely Driven by Jet and Reshaped by Environment in the Sagittarius C Cloud of the Central Molecular Zone
Abstract
The Central Molecular Zone (CMZ) at the center of the Galaxy provides a nearby laboratory for studying star formation under extreme physical and chemical conditions. Recent ALMA (Atacama Large Millimeter/Submillimeter Array) observations have identified 43 candidate protostellar outflows in three CMZ clouds. One of these, the Sgr C-F#2 outflow in Sagittarius C (Sgr C), has a highly collimated lobe extending approximately 0.8 pc in projection. Here we present a joint analysis of ALMA observations of SiO J=8-7, 5-4, and 2-1. We use local thermodynamic equilibrium (LTE) and non-LTE methods to constrain the SiO column densities, H2 number density, and gas temperature. The low SiO rotational temperatures and higher kinetic temperatures inferred from non-LTE methods suggest subthermal excitation. The elongated SiO morphology, shock-excited gas, position-velocity structure, and the alignment of the red shifted molecular lobe with JWST infrared knots altogether favor jet-dominated entrainment, whereas a broader disk-wind component close to the source cannot be excluded. The outflow shows asymmetries in its morphology and physical properties, which can be attributed to dense gas on the path of its lobe impeding its propagation and feedback from a nearby HII region imposing different pressure on its two sides.
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BibTeX
@misc{bo2026collimated,
title = {{A Collimated Protostellar Outflow Likely Driven by Jet and Reshaped by Environment in the Sagittarius C Cloud of the Central Molecular Zone}},
author = {Sen-Di Bo and Xing Lu and Tian-Yu Tu and Weiyuan Zhang and Samuel Crowe and Junhao Liu and Shanghuo Li and John Bally},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.36573},
eprint = {2610.36573},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.36573},
}
RIS
TY - UNPB
TI - A Collimated Protostellar Outflow Likely Driven by Jet and Reshaped by Environment in the Sagittarius C Cloud of the Central Molecular Zone
AU - Sen-Di Bo
AU - Xing Lu
AU - Tian-Yu Tu
AU - Weiyuan Zhang
AU - Samuel Crowe
AU - Junhao Liu
AU - Shanghuo Li
AU - John Bally
PY - 2026
DA - 2026/10/27
PB - arXiv
DO - 10.48550/arxiv.2610.36573
UR - https://arxiv.org/abs/2610.36573
AB - The Central Molecular Zone (CMZ) at the center of the Galaxy provides a nearby laboratory for studying star formation under extreme physical and chemical conditions. Recent ALMA (Atacama Large Millimeter/Submillimeter Array) observations have identified 43 candidate protostellar outflows in three CMZ clouds. One of these, the Sgr C-F#2 outflow in Sagittarius C (Sgr C), has a highly collimated lobe extending approximately 0.8 pc in projection. Here we present a joint analysis of ALMA observations of SiO J=8-7, 5-4, and 2-1. We use local thermodynamic equilibrium (LTE) and non-LTE methods to constrain the SiO column densities, H2 number density, and gas temperature. The low SiO rotational temperatures and higher kinetic temperatures inferred from non-LTE methods suggest subthermal excitation. The elongated SiO morphology, shock-excited gas, position-velocity structure, and the alignment of the red shifted molecular lobe with JWST infrared knots altogether favor jet-dominated entrainment, whereas a broader disk-wind component close to the source cannot be excluded. The outflow shows asymmetries in its morphology and physical properties, which can be attributed to dense gas on the path of its lobe impeding its propagation and feedback from a nearby HII region imposing different pressure on its two sides.
ER -