Astronomers discover collisional signature of filamentous structures in galactic molecular cloud G34

Using CO (J=1-0) molecular line data obtained from the 13.7-meter millimeter-wave telescope at the Delingha Observatory of the Purple Mountain Observatory, Sun Mingke, a Ph.D. A student from the Xinjiang Astronomical Observatory of the Chinese Academy of Sciences and his collaborators conducted a systematic study of the galactic molecular cloud G34. They revealed the collisional signatures and dynamic mechanisms of filamentary structures in this region. The results are published in Astronomy and astrophysics.

Star formation is one of the key processes that determine the evolution of galaxies and the interstellar medium. Recent observations and theoretical studies suggest that interactions and collisions between large-scale filamentous structures could play an important role in triggering the formation of high-mass stars.

In this study, the researchers identified two giant filaments, designated F1 and F2, in the G34 region. By analyzing their spatial distribution and velocity field, the researchers found clear evidence of ongoing collisions between the filaments.

High column density gas fractions (N(H₂)>1.0×10²²cm^-2) within F1 and F2 are relatively low, only 4.16% and 8.33% respectively. Throughout the region, a single dense cluster is spatially associated with a 22 μm WISE infrared dust core. These findings suggest that F1 and F2 are early in their evolution and currently forming low-mass stars.

In addition, the speed and linear mass of the filaments gradually increase from their ends towards the center, in anti-correlation with the gravitational potential. This indicates that gravitational potential energy is converted into kinetic energy, highlighting the importance of gravity in the evolution of filaments.

Furthermore, no H II regions were associated with F1 and F2, implying that these large-scale structures are not yet influenced by stellar feedback from ionized regions. Instead, their dynamics are primarily governed by autogravity, supporting the scenario that filament collision is a key mechanism of system evolution.

This study not only provides new observational evidence on the formation and evolution of filamentary structures, but also highlights the important role of gravitational processes in shaping their dynamics. The results contribute to a deeper understanding of the early evolutionary mechanisms of giant filamentous structures in the Milky Way.