A CO And Its Isotopologues Observational Study Towards Giant Molecular Filament MWISP G041-01

Molecular clouds are tightly associated with the star formation processes,and the filament structures inside clouds are the main places where massive stars form.How-ever,such filamentary structures were also found in the scale of giant molecular cloud,meaning that clouds can be parts of giant molecular filaments(GMFs).Analyses of kinematics and dynamics inside GMFs will lead to knowledges about the large scale evolution of molecular clouds.The Milky Way Imaging Scroll Painting(MWISP)project has completed a CO J=(1-0)survey towards the Galactic plane region covering l=35° to 45° and b=-5° to+5°.Using these data,the author found a GMF around l≈ 38～42°,b≈-3.5～0°,VLSR ≈ 26～40 km s-1.At a distance about 1.7 kpc,the GMF is about 160 pc long,and the largest distance to the Galactic plane is about 80 pc.With a median excitation temperature about 7.5 K and a median column density about 1021 cm-2,this GMF is very cold and very diffuse compared to known GMFs.Using the morphology in data cube,the GMF is divided into four parts in which three parts show filamentary structure.Masses of each part are about 103～104M⊙ with a total mass about 7×104M⊙ for the entire GMF from the LTE method.13CO cores inside each part are searched.Virial parameters are about 3 for these cores and have a power-law index of-0.43 against its mass.The mass fraction of dense cores traced by 13CO to the diffuse clouds traced by 12CO are about 7%for all components of the GMF.A filament-filament collision scenario between two filamentary parts is proposed for the first time.Such a scenario for large scale(>10pc)collisions between GMFs has the potential to link the formation of clouds with the spiral arms of galaxies.