Dissecting the super-critical filaments embedded in the 0.5 pc subsonic region of Barnard 5


Anika Schmiedeke, Jaime E. Pineda, Paola Caselli, Héctor G. Arce, Gary A Fuller, Alyssa A. Goodman, María José Maureira, Stella S. R. Offner, Dominique Segura-Cox, and Daniel Seifried. 2021. “Dissecting the super-critical filaments embedded in the 0.5 pc subsonic region of Barnard 5.” arXiv, 2101, 00248. Publisher's Version


We characterize in detail the two ~0.3 pc long filamentary structures found within the subsonic region of Barnard 5. We use combined GBT and VLA observations of the molecular lines NH3(1,1) and (2,2) at a resolution of 1800 au, as well as JCMT continuum observations at 850 and 450 μm at a resolution of 4400 au and 3000 au, respectively. We find that both filaments are highly super-critical with a mean mass per unit length, M/L, of ~80 M⊙ pc−1, after background subtraction, with local increases reaching values of ~150 M⊙ pc−1. This would require a magnetic field strength of ~500 μG to be stable against radial collapse.
We extract equidistant cuts perpendicular to the spine of the filament and fit a modified Plummer profile as well as a Gaussian to each of the cuts. The filament widths (deconvolved FWHM) range between 6500-7000 au (~0.03 pc) along the filaments. This equals ~2.0 times the radius of the flat inner region. We find an anti-correlation between the central density and this flattening radius, suggestive of contraction. Further, we also find a strong correlation between the power-law exponent at large radii and the flattening radius. We note that the measurements of these three parameters fall in a plane and derive their empirical relation. Our high-resolution observations provide direct constraints of the distribution of the dense gas within super-critical filaments showing pre- and protostellar activity.
See also: Astrophysics, 2021
Last updated on 02/16/2021