SiO Outflows as Tracers of Massive Star Formation in Infrared Dark Clouds
Journal article, 2021

To study the early phases of massive star formation, we present ALMA observations of SiO(5-4) emission and VLA observations of 6 cm continuum emission toward 32 Infrared Dark Cloud clumps, spatially resolved down to less than or similar to 0.05 pc. Out of the 32 clumps, we detect SiO emission in 20 clumps, and in 11 of them the SiO emission is relatively strong and likely tracing protostellar outflows. Some SiO outflows are collimated, while others are less ordered. For the six strongest SiO outflows, we estimate basic outflow properties. In our entire sample, where there is SiO emission, we find 1.3 mm continuum and infrared emission nearby, but not vice versa. We build the spectral energy distributions (SEDs) of cores with 1.3 mm continuum emission and fit them with radiative transfer models. The low luminosities and stellar masses returned by SED fitting suggest these are early-stage protostars. We see a slight trend of increasing SiO line luminosity with bolometric luminosity, which suggests more powerful shocks in the vicinity of more massive YSOs. We do not see a clear relation between the SiO luminosity and the evolutionary stage indicated by L/M. We conclude that, as a protostar approaches a bolometric luminosity of similar to 10(2) L (circle dot), the shocks in the outflow are generally strong enough to form SiO emission. The VLA 6 cm observations toward the 15 clumps with the strongest SiO emission detect emission in four clumps, which is likely from shock-ionized jets associated with the more massive ones of these protostellar cores.

Author

Mengyao Liu

University of Virginia

Jonathan Tan

University of Virginia

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

Joshua Marvil

National Radio Astronomy Observatory Socorro

Shuo Kong

University of Arizona

Viviana Rosero

National Radio Astronomy Observatory Socorro

Paola Caselli

Max Planck Institute for Extraterrestrial Physics

Giuliana Cosentino

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

Astrophysical Journal

0004-637X (ISSN) 1538-4357 (eISSN)

Vol. 921 1 96

Massive Star Formation through the Universe (MSTAR)

European Commission (EC) (EC/H2020/788829), 2018-09-01 -- 2023-08-31.

Eld ur is - den massiva stjärnbildningens utvecklingsstadier

Swedish Research Council (VR) (2017-04522), 2018-01-01 -- 2021-12-31.

Subject Categories

Meteorology and Atmospheric Sciences

Astronomy, Astrophysics and Cosmology

Atom and Molecular Physics and Optics

DOI

10.3847/1538-4357/ac0829

More information

Latest update

2/25/2022