Unveiling the early-stage anatomy of a protocluster hub with ALMA
Date Issued
2017
Author(s)
Henshaw, J. D.
•
Jiménez-Serra, I.
•
Longmore, S. N.
•
Caselli, P.
•
Pineda, J. E.
•
Avison, A.
•
Barnes, A. T.
•
Tan, J. C.
•
Abstract
High-mass stars shape the interstellar medium in galaxies, and yet, largely because the initial conditions are poorly constrained, we do not know how they form. One possibility is that high-mass stars and star clusters form at the junction of filamentary networks, referred to as `hubs'. In this Letter we present the complex anatomy of a protocluster hub within an Infrared Dark Cloud (IRDC), G035.39-00.33, believed to be in an early phase of its evolution. We use high-angular resolution ({θmaj, θmin} = {1.4 arcsec, 0.8 arcsec} ∼ {0.02 pc, 0.01 pc}) and high-sensitivity (0.2 mJy beam-1; ∼0.2 M☉) 1.07 mm dust continuum observations from the Atacama Large Millimeter Array (ALMA) to identify a network of narrow, 0.028 ± 0.005 pc wide, filamentary structures. These are a factor of ≳3 narrower than the proposed `quasi-universal' ∼0.1 pc width of interstellar filaments. Additionally, 28 compact objects are reported, spanning a mass range 0.3 M☉ < Mc < 10.4 M☉. This indicates that at least some low-mass objects are forming coevally with more massive counterparts. Comparing to the popular `bead-on-a-string' analogy, the protocluster hub is poorly represented by a monolithic clump embedded within a single filament. Instead, it comprises multiple intra-hub filaments, each of which retains its integrity as an independent structure and possesses its own embedded core population.
Volume
464
Issue
1
Start page
L31
Issn Identifier
0035-8711
Ads BibCode
2017MNRAS.464L..31H
Rights
open.access
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