Toward the fabric of the Milky Way I. The density of disk streams from a local 250<sup>3</sup> pc<sup>3</sup> volume

Author(s): Sebastian Ratzenböck, João Alves, Emily L. Hunt, Núria Miret-Roig, Stefan Meingast, Torsten Möller
Abstract: We studied 12 disk streams found in a 250³ pc³ volume in the solar neighborhood, which we define as coeval and comoving stellar structures with aspect ratios greater than 3:1. Using Gaia Data Release 3 data and the advanced clustering algorithms SigMA and Uncover, we identified and characterized these streams beyond the search volume, doubling, on average, their known populations. We estimate the number density of disk streams to be ≈820 objects / kpc³ (for |Z| < 100 pc), or surface densities of ≈160 objects / kpc². These estimates surpass N-body estimates by one to two orders of magnitude and challenge the prevailing understanding of their destruction mechanisms. Our analysis reveals that these 12 disk streams are dynamically cold with 3D velocity dispersions between 2 and 5 km s⁻¹, exhibit narrow sequences in the Hertzsprung-Russell diagram, and are highly elongated with average aspect ratios of 7:1, extending up to several hundred parsecs. We find evidence suggesting that one of the disk streams, currently embedded in the Scorpius-Centaurus association, is experiencing disruption, likely due to the primordial gas mass of the association.
Organisation(s): Department of Astrophysics, Faculty of Computer Science, Research Network Data Science, Research Group Visualization and Data Analysis
External organisation(s): Landessternwarte Königstuhl (LSW)
Journal: Astronomy and Astrophysics
Volume: 694
ISSN: 0004-6361
DOI: https://doi.org/10.1051/0004-6361/202451866
Publication date: 02-2025
Peer reviewed: Yes
Austrian Fields of Science 2012: 103003 Astronomy, 103004 Astrophysics
Keywords
ASJC Scopus subject areas: Astronomy and Astrophysics, Space and Planetary Science
Portal url: https://ucrisportal.univie.ac.at/en/publications/8db8d0e7-cbc6-4192-b958-7193f5eb882c