2026-10-14T01:13:35Z https://www.scidb.cn/oai

10.57760/sciencedb.40019 2026-08-05T17:23:50Z

2026-08-05 Molecular clouds at the edge of the Galaxy. II. Physical properties and scaling relations doi:10.57760/sciencedb.40019 en The outer Galaxy presents an optimal setting for investigating molecular clouds and star formation in environments with low-metallicity. A total of 72 Galactic edge clouds were surveyed using the CO,(2--1) line with the IRAM,30,m telescope, leading to the identification of 112 CO clumps within molecular clouds with linear resolutions of 0.5--0.9,pc. The parameters such as size, mass, surface density, and velocity dispersion of these CO clumps, derived from CO,(2--1) observations, exhibit ranges of 0.6--3.4,pc, 34--8250,M_⊙, 12--1025,M_⊙,pc-2, and -1 , respectively. Over the galactocentric distance range of 14--23,kpc, no systematic variations are found in these parameters. The velocity dispersion--size relationship of the Galactic edge clumps is modeled as σ_̊m v,=,0.69(±0.03)R_ ̊m eff ^ 0.36( , indicating that turbulence is present within the Galactic edge clumps, similarly to observations in the inner Galactic disk clouds. Furthermore, the luminous mass--size relation of the Galactic edge clumps is described by M_̊m lum,=,196(±17)R_ ̊m eff ^ ,2.18,( , suggesting the average column density remains almost constant for clouds of different sizes. The virial parameters range from 0.6 to 15.3, with a median value of 2.8,±,0.6, suggesting that most clumps are gravitationally unbound. Furthermore, the virial parameters of our Galactic edge clumps show a decreasing trend with increasing galactocentric distances, described by an exponential relation α_̊m vir,=,33.0(±,10.4),e -R_ ̊m g /6.7( , consistent with previous results. stars: formation; ISM: clouds; ISM: molecules 罗春盛 汤新弟 PUBLIC https://creativecommons.org/licenses/by-nc-nd/4.0/ dataset http://www.doi.org/10.1051/0004-6361/202453007 Science Data Bank