The velocity field of the Scorpius-Centaurus OB association

Fuente: arXiv
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Main Authors: Hutschenreuter, S., Alves, J., Posch, L., Großschedl, J., Piecka, M., Miret-Roig, N., Ratzenböck, S., Swiggum, C.
Format: Preprint
Published: 2025
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author Hutschenreuter, S.
Alves, J.
Posch, L.
Großschedl, J.
Piecka, M.
Miret-Roig, N.
Ratzenböck, S.
Swiggum, C.
author_facet Hutschenreuter, S.
Alves, J.
Posch, L.
Großschedl, J.
Piecka, M.
Miret-Roig, N.
Ratzenböck, S.
Swiggum, C.
contents We present a non-parametric reconstruction of the three-dimensional velocity field of the Scorpius-Centaurus OB association (Sco- Cen). Using Gaia DR3 astrometry and radial velocities, we infer the velocity field using information field theory on a 70 x 70 x 50 grid at 3 pc resolution. Our model suggests the existence of a primary stellar velocity field with a secondary field that accounts for an additional young kinematic component in Upper Scorpius and Lupus. We find clear tracers of a feedback-driven expansion of the association, while Galactic rotation appears to play a subordinate role. The results confirm the existence of cluster chains and reveal coherent large-scale expansion with characteristic speeds of 1-2 km s$^{-1}$ and local maxima of about 10 km s$^{-1}$. Power spectra indicate an excess of small-scale structure and slopes shallower than Kolmogorov, consistent with energy injection from stellar feedback. Maps of the divergence reveal net positive values, implying an approximate dispersal timescale of 10-15 Myr. A comparison with molecular gas in Lupus and Ophiuchus shows broadly consistent patterns but systematic velocity offsets of several km s$^{-1}$, suggesting partial decoupling for optically visible young stars and gas. The framework presented provides a physically motivated description of the Sco-Cen velocity field and a basis for quantifying the dynamical state and feedback history of OB associations in the local Galaxy.
format Preprint
id arxiv_https___arxiv_org_abs_2509_13607
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The velocity field of the Scorpius-Centaurus OB association
Hutschenreuter, S.
Alves, J.
Posch, L.
Großschedl, J.
Piecka, M.
Miret-Roig, N.
Ratzenböck, S.
Swiggum, C.
Astrophysics of Galaxies
We present a non-parametric reconstruction of the three-dimensional velocity field of the Scorpius-Centaurus OB association (Sco- Cen). Using Gaia DR3 astrometry and radial velocities, we infer the velocity field using information field theory on a 70 x 70 x 50 grid at 3 pc resolution. Our model suggests the existence of a primary stellar velocity field with a secondary field that accounts for an additional young kinematic component in Upper Scorpius and Lupus. We find clear tracers of a feedback-driven expansion of the association, while Galactic rotation appears to play a subordinate role. The results confirm the existence of cluster chains and reveal coherent large-scale expansion with characteristic speeds of 1-2 km s$^{-1}$ and local maxima of about 10 km s$^{-1}$. Power spectra indicate an excess of small-scale structure and slopes shallower than Kolmogorov, consistent with energy injection from stellar feedback. Maps of the divergence reveal net positive values, implying an approximate dispersal timescale of 10-15 Myr. A comparison with molecular gas in Lupus and Ophiuchus shows broadly consistent patterns but systematic velocity offsets of several km s$^{-1}$, suggesting partial decoupling for optically visible young stars and gas. The framework presented provides a physically motivated description of the Sco-Cen velocity field and a basis for quantifying the dynamical state and feedback history of OB associations in the local Galaxy.
title The velocity field of the Scorpius-Centaurus OB association
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2509.13607