A survey of SiO $J=$ 1 -- 0 emission toward massive star-forming regions

Abstract

The application of silicon monoxide (SiO) as a shock tracer arises from its propensity to occur in the gas phase as a result of shock-induced phenomena, including outflow activity and interactions between molecular clouds and expanding HII regions or supernova remnants. We searched for indications of shocks toward 366 massive star-forming regions by observing the ground rotational transition of SiO ($v=0$, $J=1-0$) at 43 GHz with the Korean VLBI Network (KVN) 21 m telescopes to extend our understanding on the origins of SiO in star-forming regions. We detected SiO emission toward 104 regions that consist of 57 IRDCs, 21 HMPOs, and 26 UCHIIs. The determined median SiO column density, $N$(SiO), and abundance, $X$(SiO), relative to $N$(H${}_2$) are $8.12\times 10^{12}$ cm${}^{-2}$ and $1.28\times 10^{-10}$, respectively. These values are similar to those obtained toward other star-forming regions and also consistent with predicted values from shock models with low-velocity shocks ($\lesssim$10 - 15 km s${}^{-1}$). While the $X$(SiO) does not exhibit any strong correlation with the evolutionary stages of their host clumps, $L_{\mathrm{SiO}}$ is highly correlated with dust clump mass, and $L_{\mathrm{SiO}}/L_{\mathrm{bol}}$ also has a strong negative correlation with $T_{\mathrm{dust}}$. This shows that colder and younger clumps have high $L_{\mathrm{SiO}}/L_{\mathrm{bol}}$ suggestive of an evolutionary trend. This trend is not due to excess emission at higher velocities, such as SiO wing features, as the colder sources with high $L_{\mathrm{SiO}}/L_{\mathrm{bol}}$ ratios lack wing features. Comparing SiO emission with H${}_2$O and Class I CH${}_3$OH masers, we find a significant correlation between $L_{\mathrm{SiO}}$/$L_{\mathrm{bol}}$ and $L_{\mathrm{C}{\mathrm{H}}_3\mathrm{OH}}/L_{\mathrm{bol}}$ ratios, whereas no similar correlation is seen for the H${}_2$O maser emission. This suggests a similar origin for the SiO and Class I CH${}_3$OH emission in these sources.

23 pages, 16 figures, accepted for A&A for publication

References in corpus (22)

• A Catalog of Extended Green Objects (EGOs) in the GLIMPSE Survey: A new sample of massive young stellar object outflow candidates
• ATLASGAL --- properties of a complete sample of Galactic clumps
• The earliest phases of high-mass star formation: a 3 square degree millimeter continuum mapping of Cygnus X
• Parametrization of C-shocks. Evolution of the Sputtering of Grains
• Multi-temperature mapping of dust structures throughout the Galactic Plane using the PPMAP tool with Herschel Hi-GAL data
• The Hi-GAL compact source catalogue -- II. The 360° catalogue of clump physical properties
• ATLASGAL-selected massive clumps in the inner Galaxy III. Dust Continuum Characterization of an Evolutionary Sample
• The integrated properties of the molecular clouds from the JCMT CO(3-2) High Resolution Survey
• Cosmic ray induced ionisation of a molecular cloud shocked by the W28 supernova remnant
• SiO emission from low- and high-velocity shocks in Cygnus-X massive dense clumps
• Massive 70 micron quiet clumps II: non-thermal motions driven by gravity in massive star formation?
• Tracing extended low-velocity shocks through SiO emission - Case study of the W43-MM1 ridge
• Molecular shock tracers in NGC 1068: SiO and HNCO
• Negative and Positive Feedback from a Supernova Remnant with SHREC: A detailed Study of the Shocked Gas in IC443
• Structure and kinematics of shocked gas in Sgr B2: further evidence of a cloud-cloud collision from SiO emission maps
• SiO emission as a probe of Cloud-Cloud Collisions in Infrared Dark Clouds
• Localized SiO emission triggered by the passage of the W51C SNR shock
• Searching for shocks in high-mass starless clump candidates
• ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions -- VII. A catalogue of SiO clumps from ACA observations
• Infall and Outflow Towards High-mass Starless Clump Candidates
• Shaken or stirred: the diffuse interstellar medium with exceptionally high SiO abundance
• Origins of the shocks in high-mass starless clump candidates

Cited by in corpus (5)

• Star Formation in Extreme Environments: A 200 pc High Velocity Gas Stream in the Galactic Centre
• ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions -- XIX. The origin of SiO emission
• Low-velocity large-scale shocks in the infrared dark cloud G035.39-00.33: bubble-driven cloud-cloud collisions
• The Cygnus Allscale Survey of Chemistry and Dynamical Environments: CASCADE III. The large scale distribution of DCO+, DNC and DCN in the DR21 filament
• Parsec-scale SiO emission in the Galactic Center