Different molecular filament widths as tracers of accretion on to filaments. Issue 1 (5th April 2022)

• Record Type: Journal Article
• Authors: Gómez, Gilberto C; Walsh, Catherine; Palau, Aina
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 513:Issue 1(2022)
• Page Start: 1244
• Page End: 1253
• Publication Date: 2022-04-05
• Subjects: astrochemistry -- ISM: clouds -- ISM: kinematics and dynamics -- ISM: molecules; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stac912
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: We explore how dense filament widths, when measured using different molecular species, may change as a consequence of gas accretion towards the filament. As a gas parcel falls into the filament, it will experience different density, temperature, and extinction values. The rate at which this environment changes will affect differently the abundance of different molecules. So, a molecule that forms quickly will better reflect the local physical conditions a gas parcel experiences than a slower forming molecule. Since these differences depend on how the respective time-scales compare, the different molecular distributions should reflect how rapidly the environment changes, i.e. the accretion rate towards the filament. We find that the filament widths measured from time-dependent abundances for C2 H, CO, CN, CS, and C3 H2 are the most sensitive to this effect. This is because these molecules are the ones presenting also the wider filament widths. On the contrary, molecules such as N2 H +, NH3, H2 CO, HNC, and CH3 OH are not so sensitive to accretion and present the narrowest filament widths. We propose that ratios of filament widths for different tracers could be a useful tool to estimate the accretion rate on to the filament.