A cold and diffuse giant molecular filament in the region of l = 41°, b = −1°

Abstract

Data of 12CO/13CO/C18O J = 1 → 0 emission toward the Galactic plane region of l = 35° to 45° and b = –5° to +5° are available with the Milky Way Imaging Scroll Painting (MWISP) project. Using the data, we found a giant molecular filament (GMF) around l ≈ 38° ∼ 42°, b ≈ –3.5° ∼ 0°, V LSR ≈ 27 ∼ 40 km s−1, named the GMF MWISP G041–01. At a distance of 1.7 kpc, the GMF is about 160 pc long. 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 the data cube, the GMF is divided into four components among which three show filamentary structure. Masses of the components are 103 ∼ 104 M ⊙, with a total mass for the whole filament being about 7 × 104 M ⊙ from the local thermodynamic equilibrium method. 13CO cores inside each component are searched. Virial parameters are about 2.5 for these cores and have a power-law index of –0.34 against the mass. The mass fraction of dense cores traced by 13CO to the diffuse clouds traced by 12CO is about 7% for all components of the GMF. We found signatures of possible large scale filament-filament collision in the GMF.

OGHReS: Large-scale filaments in the outer Galaxy

“…Additionally, bundles of smaller scale 'fibers' have been found within those filaments (Hacar et al 2013(Hacar et al , 2016Henshaw et al 2016). Extremely long (even longer than 100 pc) and velocity coherent large-scale filaments (LSFs) have been observed in the Milky Way as part of spiral arms or inter-arm regions (Jackson et al 2010;Goodman et al 2014;Ragan et al 2014;Zucker et al 2015;Abreu-Vicente et al 2016;Li et al 2016;Du et al 2017;Zucker et al 2018;Lin et al 2020;Schisano et al 2020). As the physics of filaments appears tightly connected to star formation (e.g.…”

Molecular clouds at the eastern edge of radio nebula W50

“…There is a possibility that the clouds are mere foreground or background sources of W50. As an example, Lin et al (2020) identified a giant molecular filament in the Milky Way Imaging Scroll Painting (MWISP) in front of the SS 433/W50 system in the velocity range from 27 to the molecular clouds that we identified and this giant molecular filament. Lin et al (2020) suggested that GMF MWISP G041-01 comprises four components, three being filamentary structures.…”

“…As an example, Lin et al (2020) identified a giant molecular filament in the Milky Way Imaging Scroll Painting (MWISP) in front of the SS 433/W50 system in the velocity range from 27 to the molecular clouds that we identified and this giant molecular filament. Lin et al (2020) suggested that GMF MWISP G041-01 comprises four components, three being filamentary structures. Two such giant filaments possibly collided in the region around (α J2000 , δ J2000 ) = (19 h 10 m 01.3525 s , +7 d 15 m 03.330 s ) and (19 h 10 m 29.6389 s , +6 d 10 m 32.713 s ), while they might be just overlapping along the line of sight.…”

Molecular Clump Extraction Algorithm Based on Local Density Clustering*

“…As one of the fundamental components of the interstellar medium, molecular clouds mainly consist of molecular gas with a mixture of atoms, ions, dust, and other materials (Heyer & Dame 2015;Heiles et al 2019). The molecular clouds in the galaxy exhibits the structure over a wide range of scales, from 20 pc or more for giant molecular clouds down to 0.05 pc for dense molecular clumps (Williams et al 2012;Kauffmann et al 2013;Lin et al 2020). Modern astronomy proved that the formation of stars is inside the molecular clumps (Krumholz & McKee 2005;Zinnecker & Yorke 2007;Krumholz et al 2009).…”