Interstellar magnetic cannon targeting the Galactic halo : A young bubble at the origin of the Ophiuchus and Lupus molecular complexes

TL;DR

This paper reports the discovery of a young Galactic bubble likely formed by a supernova remnant, influencing the local molecular complexes and exhibiting hot gas outflows, magnetic interactions, and potential challenges to existing Galactic models.

Contribution

It presents the detection and analysis of a new Galactic bubble, linking it to supernova activity, magnetic fields, and large-scale Galactic outflows, which advances understanding of Galactic halo-disc interactions.

Findings

Detection of a young (<3 Myr) Galactic bubble at the halo-disc interface.

Identification of hot X-ray gas and HI cavities associated with the bubble.

Evidence of magnetic field interactions and outflows breaching the cavity.

Abstract

We report the detection of a new Galactic bubble at the interface between the halo and the Galactic disc. We suggest that the nearby Lupus complex and parts of the Ophiuchus complex constitute the denser parts of the structure. This young bubble, < 3 Myr old, could be the remnant of a supernova and expands inside a larger HI loop that has been created by the outflows of the Upper Scorpius OB association. An HI cavity filled with hot X-ray gas is associated with the structure, which is consistent with the Galactic chimney scenario. The X-ray emission extends beyond the west and north-west edges of the bubble, suggesting that hot gas outflows are breaching the cavity, possibly through the fragmented Lupus complex. Analyses of the polarised radio synchrotron and of the polarised dust emission of the region suggest the connection of the Galactic centre spur with the young Galactic bubble. A distribution of HI clumps that spatially corresponds well to the cavity boundaries was found at V_LSR ~ -100 km/s. Some of these HI clumps are forming jets, which may arise from the fragmented part of the bubble. We suggest that these clumps might be `dripping' cold clouds from the shell walls inside the cavity that is filled with hot ionised gas. It is possible that some of these clumps are magnetised and were then accelerated by the compressed magnetic field at the edge of the cavity. Such a mechanism would challenge the Galactic accretion and fountain model, where high-velocity clouds are considered to be formed at high Galactic latitude from hot gas flows from the Galactic plane.