Fiber networks in Orion: star formation and width variations

Abstract: The Herschel observations unveiled the complex organisation of the interstellar medium in networks of parsec-scale filaments over the past decade. Despite their variety of scales throughout the interstellar medium, the analysis of these same observations revealed filaments in nearby low-mass clouds to have a characteristic width of ~0.1 pc. The origin of this characteristic width and its impact on star formation, however, has been a matter of intense discussions in the past years. Even more with the identification of small-scale filamentary structures harboured inside the Herschel filaments. These networks of fibers have been recognised describing the gas structures in star-forming regions at sub-parsec scales, thus critically challenging the existence of a typical width for filaments.
I am going to present our study of the dense gas organisation prior to the formation of stars in a sample of 7 star-forming regions within Orion. This EMERGE Early ALMA Survey includes OMC-1/-2/-3/-4 South, LDN 1641N, NGC 2023, and the Flame Nebula, all surveyed at high spatial resolution (4.5'' or ~2000 au) in N2H+ (1−0) using ALMA+IRAM-30m observations. I will present the star-forming gas spatial distribution, its column density variations, its thermal structure, and its internal motions across the152 fibers identified in our survey.
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