Candidate Rotating Toroids around High-Mass (Proto)Stars

Abstract

Using the OVRO, Nobeyama, and IRAM mm-arrays, we searched for ``disk''-outflow systems in three high-mass (proto)star forming regions: G16.59-0.05, G23.01-0.41, and G28.87+0.07. These were selected from a sample of NH3 cores associated with OH and H2O maser emission and with no or very faint continuum emission. Our imaging of molecular line (including rotational transitions of CH3CN and 3mm dust continuum emission revealed that these are compact, massive, and hot molecular cores (HMCs), that is likely sites of high-mass star formation prior to the appearance of UCHII regions. All three sources turn out to be associated with molecular outflows from CO and/or HCO+ J=1--0 line imaging. In addition, velocity gradients of 10 -- 100 km/s per pc in the innermost densest regions of the G23.01 and G28.87 HMCs are identified along directions roughly perpendicular to the axes of the corresponding outflows. All the results suggest that these cores might be rotating about the outflow axis, although the contribution of rotation to gravitational equilibrium of the HMCs appears to be negligible. Our analysis indicates that the 3 HMCs are close to virial equilibrium due to turbulent pressure support. Comparison with other similar objects where rotating toroids have been identified so far shows that in our case rotation appears to be much less prominent; this can be explained by the combined effect of unfavorable projection, large distance, and limited angular resolution with the current interferometers.

Accepted by ApJ main journal, the paper with the original quality figures are available from http://subarutelescope.org/staff/rsf/publication.html

References in corpus (4)

• Infall of gas as the formation mechanism of stars up to 20 times more massive than the Sun
• Molecular Line Emission from Massive Protostellar Disks: Predictions for ALMA and the EVLA
• Dust and gas emission in the prototypical hot core G29.96-0.02 at sub-arcsecond resolution
• The Initial Conditions for Gravitational Collapse of a Core: An Extremely Young Low-Mass Class 0 Protostar GF9-2

Cited by in corpus (4)

• A Class I and Class II Methanol Maser Survey of Extended Green Objects (EGOs) from the GLIMPSE Survey
• Trigonometric Parallaxes of Massive Star Forming Regions: V. G23.01-0.41 and G23.44-0.18
• Spitzer-IRAC GLIMPSE of high mass protostellar objects II - SED modelling of a bonafide sample
• A Search for H2CO 6cm Emission toward Young Stellar Objects III: VLA Observations