Star-forming content of the giant molecular filaments in the Milky Way
Journal article, 2019

Through observations numerous giant molecular filaments (GMFs) have been discovered in the MilkyWay. Their role in the Galactic star formation and Galaxy-scale evolution of dense gas is unknown. Aims. We investigate systematically the star-forming content of all currently known GMFs. This allows us to estimate the star formation rates (SFRs) of the GMFs and to establish relationships between the SFRs and the GMF properties. Methods. We identified and classified the young stellar object (YSO) population of each GMF using multiwavelength photometry from near-to far-infrared. We estimated the total SFRs assuming a universal and fully sampled initial mass function and luminosity function. Results. We uniformly estimate the physical properties of 57 GMFs. The GMFs show correlations between the (CO)-C-13 line width, mass, and size, similar to Larson's relations. We identify 36 394 infrared excess sources in 57 GMFs and obtain SFRs for 46 GMFs. The median SFR surface density (Sigma(SFR)) and star formation efficiency (SFE) of GMFs are 0.62 M-circle dot Myr(-1) pc(-2) and 1%, similar to the nearby star-forming clouds. The star formation rate per free-fall time of GMFs is between 0.002-0.05 with the median value of 0.02. We also find a strong correlation between SFR and dense gas mass that is defined as gas mass above a visual extinction of 7 mag, which suggests that the SFRs of the GMFs scale similarly with dense gas as those of nearby molecular clouds. We also find a strong correlation between the mean SFR per unit length and dense gas mass per unit length. The origin of this scaling remains unknown, calling for further studies that can link the structure of GMFs to their SF activity and explore the differences between GMFs and other molecular clouds.

infrared: stars

stars: pre-main sequence

stars: formation

ISM: clouds

ISM: structure


M. Zhang

Chinese Academy of Sciences

Max Planck Society

Jouni Kainulainen

Chalmers, Space, Earth and Environment

M. Mattern


M. Fang

University of Arizona

Th. Henning

Max Planck Society

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 622 A52

Subject Categories

Astronomy, Astrophysics and Cosmology

Other Chemistry Topics

Probability Theory and Statistics



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