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| Main Authors: | , , , , , |
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| Format: | Preprint |
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2026
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| Online adgang: | https://arxiv.org/abs/2601.05310 |
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| _version_ | 1866914242420015104 |
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| author | Tafalla, M. Johnstone, D. Santiago-Garcia, J. Zhang, Q. Shang, H. Lee, C. -F. |
| author_facet | Tafalla, M. Johnstone, D. Santiago-Garcia, J. Zhang, Q. Shang, H. Lee, C. -F. |
| contents | $Context.$ The outflow from the Class 0 protostar IRAS 04166+2706 (hereafter IRAS 04166) contains a remarkably symmetric jet-like component of extremely high-velocity (EHV) gas.
$Aims.$ We studied the IRAS 04166 outflow and investigated the relation between its EHV component and the slower outflow gas.
$Methods.$ We mosaicked the CO(2--1) emission from the IRAS 04166 outflow using the 12m and the Compact Arrays of ALMA. We also developed a ballistic toy model of the gas ejected laterally from a jet to interpret the data.
$Results.$ In agreement with previous observations, the ALMA data show that the slow outflow component is distributed in two opposed conical lobes and has a shear-flow pattern with velocity increasing toward the axis. The EHV gas consists of a series of arc-like condensations that span the full width of the conical lobes and merge with their walls, suggesting that the fast and slow outflow components are physically connected. In addition, position--velocity diagrams along the outflow axis show finger-like extensions that connect the EHV emission with the origin of the diagram, as if part of the EHV gas had been decelerated by its interaction with the low-velocity outflow. A ballistic model can reproduce these finger-like extensions assuming that the EHV gas consists of jet material that has been ejected laterally over a short period of time and has transferred part of its momentum to the surrounding shear flow.
$Conclusions.$ The EHV gas in the IRAS 04166 outflow seems to play a role in the acceleration of the slower gas component. The presence of similar finger-like extensions in the position-velocity diagrams of other outflows suggests that this process may be occurring in other systems, even if the EHV component is not seen because it has an atomic composition. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2601_05310 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Interaction of the central jet with the surrounding gas in the protostellar outflow from IRAS 04166+2706 Tafalla, M. Johnstone, D. Santiago-Garcia, J. Zhang, Q. Shang, H. Lee, C. -F. Astrophysics of Galaxies $Context.$ The outflow from the Class 0 protostar IRAS 04166+2706 (hereafter IRAS 04166) contains a remarkably symmetric jet-like component of extremely high-velocity (EHV) gas. $Aims.$ We studied the IRAS 04166 outflow and investigated the relation between its EHV component and the slower outflow gas. $Methods.$ We mosaicked the CO(2--1) emission from the IRAS 04166 outflow using the 12m and the Compact Arrays of ALMA. We also developed a ballistic toy model of the gas ejected laterally from a jet to interpret the data. $Results.$ In agreement with previous observations, the ALMA data show that the slow outflow component is distributed in two opposed conical lobes and has a shear-flow pattern with velocity increasing toward the axis. The EHV gas consists of a series of arc-like condensations that span the full width of the conical lobes and merge with their walls, suggesting that the fast and slow outflow components are physically connected. In addition, position--velocity diagrams along the outflow axis show finger-like extensions that connect the EHV emission with the origin of the diagram, as if part of the EHV gas had been decelerated by its interaction with the low-velocity outflow. A ballistic model can reproduce these finger-like extensions assuming that the EHV gas consists of jet material that has been ejected laterally over a short period of time and has transferred part of its momentum to the surrounding shear flow. $Conclusions.$ The EHV gas in the IRAS 04166 outflow seems to play a role in the acceleration of the slower gas component. The presence of similar finger-like extensions in the position-velocity diagrams of other outflows suggests that this process may be occurring in other systems, even if the EHV component is not seen because it has an atomic composition. |
| title | Interaction of the central jet with the surrounding gas in the protostellar outflow from IRAS 04166+2706 |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2601.05310 |