Squeezed between shells? On the origin of the Lupus I molecular cloud. - II. APEX CO and GASS HI observations
arXiv:1710.07446 · doi:10.1051/0004-6361/201628508
Abstract
[Abridged] The Lupus I cloud is found between the Upper-Scorpius and the Upper-Centaurus-Lupus sub-groups, where the expanding USco HI shell appears to interact with a bubble currently driven by the winds of the remaining B-stars of UCL. We investigate if the Lupus I molecular could have formed in a colliding flow, and how the kinematics of the cloud might have been influenced by the larger scale gas dynamics. We performed APEX 13CO and C18O observations of three parts of Lupus. We compare these results to the atomic hydrogen data from the GASS HI survey and our dust emission results presented in the previous paper. Based on the velocity information, we present a geometric model for the interaction zone between the USco shell and the UCL wind bubble. We present evidence that the molecular gas of Lupus I is tightly linked to the atomic material of the USco shell. The CO emission in Lupus I is found mainly at velocities in the same range as the HI velocities. Thus, the molecular cloud is co-moving with the expanding USco atomic Hi shell. The gas in the cloud shows a complex kinematic structure with several line-of-sight components that overlay each other. The non-thermal velocity dispersion is in the transonic regime in all parts of the cloud and could be injected by external compression. Our observations and the derived geometric model agree with a scenario where Lupus I is located in the interaction zone between the USco shell and the UCL wind bubble. The kinematics observations are consistent with a scenario where the Lupus I cloud formed via shell instabilities. The particular location of Lupus I between USco and UCL suggests that counter-pressure from the UCL wind bubble and pre-existing density enhancements, perhaps left over from the gas stream that formed the stellar subgroups, may have played a role in its formation.
arXiv commentAccepted for publication by A&A
References in corpus (27)
- A Hipparcos census of the nearby OB associations
- Rapid Formation of Molecular Clouds and Stars in the Solar Neighborhood
- How to Calculate Molecular Column Density
- Molecular Cloud Formation in Shock-Compressed Layers
- Molecular Cloud Formation Behind Shock Waves
- Dense core formation by fragmentation of velocity-coherent filaments in L1517
- GASS: The Parkes Galactic All-Sky Survey. II. Stray-Radiation Correction and Second Data Release
- Dark matter in the Milky Way, II. the HI gas distribution as a tracer of the gravitational potential
- Molecular Cloud Evolution IV: Magnetic Fields, Ambipolar Diffusion, and the Star Formation Efficiency
- Rapid Molecular Cloud and Star Formation: Mechanisms and Movies
- New 3-D gas density maps of NaI and CaII interstellar absorption within 300pc
- How long does it take to form a molecular cloud?
- Formation of Cold Filamentary Structure from Wind Blown Superbubbles
- Large scale IRAM 30m CO-observations in the giant molecular cloud complex W43
- Star formation in turbulent molecular clouds with colliding flow
- Comparing simulations of ionisation triggered star formation and observations in RCW 120
- Triggered Star Formation
- Supershells as Molecular Cloud Factories: Parsec Resolution Observations of HI and 12CO(J=1-0) in GSH 287+04-17 and GSH 277+00+36
- Lupus I Observations from the 2010 Flight of the Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry
- Filaments in the Lupus molecular clouds
- Spatial distribution of star formation related to ionized regions throughout the inner Galactic plane
- Clump formation through colliding stellar winds in the Galactic Centre
- Multi-line spectral imaging of dense cores in the Lupus molecular cloud
- Squeezed between shells? On the origin of the Lupus I molecular cloud. APEX/LABOCA, Herschel, and Planck observations
- Large-Scale CO Maps of the Lupus Molecular Cloud Complex
- Assessing molecular line diagnostics of triggered star formation using synthetic observations
- Molecular cloud formation as seen in synthetic Hi and molecular gas observations
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- Surround & Squash: The Interstellar Medium around Scorpius Centaurus OB2
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- Galactic 26Al traces metal loss through hot chimneys
- Substructure, supernovae, and a time-resolved star formation history for Upper Scorpius
- Steady-state nucleosynthesis throughout the Galaxy
- The physical properties of Cluster Chains
- Ionized filaments and ongoing physical processes in massive star-forming sites around l = 345.5 degree
- The evolution of velocity dispersion in the Sco-Cen OB association
- Cosmic Radioactivity and Galactic Chemical Evolution