A CLUSTER IN THE MAKING: ALMA REVEALS THE INITIAL CONDITIONS FOR HIGH-MASS CLUSTER FORMATION
- CSIRO Astronomy and Space Science, P.O. Box 76, Epping NSW, 1710 (Australia)
- Astrophysics Research Institute, Liverpool John Moores University, 146 Brownlow Hill, Liverpool L3 5RF (United Kingdom)
- Institute for Astrophysical Research, Boston University, Boston, MA 02215 (United States)
- University of Vienna, Türkenschanzstrasse 17, A-1180 Vienna (Austria)
- Center for Astrophysics and Space Astronomy, University of Colorado, UCB 389, Boulder, CO 8030 (United States)
- Department of Astronomy, Yale University, P.O. Box 208101 New Haven, CT 06520-8101 (United States)
- Universidad de Chile, Camino El Observatorio1515, Las Condes, Santiago (Chile)
- Max-Planck Institut fur Astrophysik, Karl-Schwarzschild-Strasse 1, D-85748, Garching (Germany)
- European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching bei Munchen (Germany)
G0.253+0.016 is a molecular clump that appears to be on the verge of forming a high-mass cluster: its extremely low dust temperature, high mass, and high density, combined with its lack of prevalent star formation, make it an excellent candidate for an Arches-like cluster in a very early stage of formation. Here we present new Atacama Large Millimeter/Sub-millimeter Array observations of its small-scale (∼0.07 pc) 3 mm dust continuum and molecular line emission from 17 different species that probe a range of distinct physical and chemical conditions. The data reveal a complex network of emission features with a complicated velocity structure: there is emission on all spatial scales, the morphology of which ranges from small, compact regions to extended, filamentary structures that are seen in both emission and absorption. The dust column density is well traced by molecules with higher excitation energies and critical densities, consistent with a clump that has a denser interior. A statistical analysis supports the idea that turbulence shapes the observed gas structure within G0.253+0.016. We find a clear break in the turbulent power spectrum derived from the optically thin dust continuum emission at a spatial scale of ∼0.1 pc, which may correspond to the spatial scale at which gravity has overcome the thermal pressure. We suggest that G0.253+0.016 is on the verge of forming a cluster from hierarchical, filamentary structures that arise from a highly turbulent medium. Although the stellar distribution within high-mass Arches-like clusters is compact, centrally condensed, and smooth, the observed gas distribution within G0.253+0.016 is extended, with no high-mass central concentration, and has a complex, hierarchical structure. If this clump gives rise to a high-mass cluster and its stars are formed from this initially hierarchical gas structure, then the resulting cluster must evolve into a centrally condensed structure via a dynamical process.
- OSTI ID:
- 22522015
- Journal Information:
- Astrophysical Journal, Vol. 802, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
Similar Records
G0.253 + 0.016: A MOLECULAR CLOUD PROGENITOR OF AN ARCHES-LIKE CLUSTER
The link between turbulence, magnetic fields, filaments, and star formation in the central molecular zone cloud G0.253+0.016