A high-frequency radio continuum study of massive young stellar objects
arXiv:0705.4664 · doi:10.1111/j.1365-2966.2007.12046.x
Abstract
We present high-resolution observations made with the Very Large Array (VLA) in its A configuration at frequencies between 5 and 43 GHz of a sample of five massive young stellar objects (YSOs): LkHa101, NGC2024-IRS2, S106-IR, W75N and S140-IRS1. The resolution varied from 0.04 arcsec (at 43 GHz) to 0.5 arcsec (at 5 GHz), corresponding to a linear resolution as high as 17 AU for our nearest source. A MERLIN observation of S106-IR at 23 GHz with 0.03-arcsec resolution is also presented. S106-IR and S140-IRS1 are elongated at 43 GHz perpendicular to their large scale bipolar outflows. This confirms the equatorial wind picture for these sources seen previously in MERLIN 5 GHz observations. The other sources are marginally resolved at 43 GHz. The spectral indices we derive for the sources in our sample range from +0.2 to +0.8, generally consistent with ionized stellar winds. We have modelled our sources as uniform, isothermal spherical winds, with LkHa101 and NGC2024-IRS2 yielding the best fits. However, in all cases our fits give wind temperatures of only 2000 to 5000 K, much less than the effective temperatures of main-sequence stars of the same luminosity, a result which is likely due to the clumpy nature of the winds.
18 pages, 10 figures. Accepted for publication in MNRAS
References in corpus (22)
- Structure and Evolution of the Envelopes of Deeply Embedded Massive Young Stars
- The Formation of Massive Stars by Accretion Through Trapped Hypercompact HII Regions
- A disk of dust and molecular gas around a high-mass protostar
- Three-Dimensional Simulations of Jets from Keplerian Disks: Self--Regulatory Stability
- Proper Motions of the BN Object and the I Radio Source in Orion: Where and When Did BN Become a Runaway Star?
- Star Formation at High Angular Resolution
- Tropospheric Phase Calibration in Millimeter Interferometry
- Very compact radio emission from high-mass protostars. II. Dust disks and ionized accretion flows
- A detailed study of G35.2-0.7N: collimated outflows in a cluster of high-mass young stellar objects
- Identification of the ionizing source of NGC 2024
- Clustered Star Formation in W75 N
- Imaging the disk around the luminous young star LkHalpha 101 with infrared interferometry
- Subarcsecond mid-infrared and radio observations of the W3 IRS5 protocluster
- 2-D Monte Carlo simulations of H I line formation in massive YSO disk winds
- An equatorial wind from the massive young stellar object S140 IRS 1
- The Nature of the Massive Young Stars in W75 N
- Very compact radio emission from high-mass protostars. I. CRL 2136: Continuum and water maser observations
- Massive Star Formation
- Near-IR speckle imaging of massive young stellar objects
- A Cluster of Compact Radio Sources in NGC 2024 (Orion B)
- The peculiar circumstellar environment of NGC2024-IRS2
- Chandra observations of the massive star-forming region S106: X-ray emission from the embedded massive protostellar object IRS 4
Cited by in corpus (29)
- A Class I and Class II Methanol Maser Survey of Extended Green Objects (EGOs) from the GLIMPSE Survey
- The Co-ordinated Radio and Infrared Survey for High Mass Star Formation (The CORNISH Survey) - I. Survey Design
- From the Convergence of Filaments to Disk-Outflow Accretion: Massive-Star Formation in W33A
- A search for ionized jets towards massive young stellar objects
- A sub-millimeter Mapping Survey of Herbig AeBe Stars
- Weak and Compact Radio Emission in Early High-Mass Star Forming Regions: I. VLA Observations
- Resolved 24.5 micron emission from massive young stellar objects
- Rotation of the Warm Molecular Gas Surrounding Ultracompact HII Regions
- Survey of intermediate/high-mass star-forming regions at centimeter and millimeter wavelengths
- NGC7538 IRS1 - an ionized jet powered by accretion
- A population of hypercompact HII regions identified from young HII regions
- A SiO J = 5 - 4 Survey Toward Massive Star Formation Regions
- A pilot survey of the binarity of Massive Young Stellar Objects with band adaptive optics
- Multiwavelength Signatures of Magnetic Activity from Young Stellar Objects in the LkH\alpha101 Cluster
- Medium resolution near-infrared spectroscopy of Massive Young Stellar Objects
- The interactions of winds from massive young stellar objects: X-ray emission, dynamics, and cavity evolution
- Ultra- and Hyper-compact HII regions at 20 GHz
- SOFIA observations of S106: Dynamics of the warm gas
- Accelerating a water maser face-on jet from a high mass young stellar object
- Herschel PACS and SPIRE spectroscopy of the Photodissociation Regions associated with S 106 and IRAS 23133+6050
- Supersonic Expansion of the Bipolar Hii Region Sh2-106: A 3,500 Year-Old Explosion?
- Anatomy of the massive star-forming region S106: The OI 63 micron line observed with GREAT/SOFIA as a versatile diagnostic tool for the evolution of massive stars
- Multiple Sources toward the High-mass Young Star S140 IRS1
- Surveys of Clumps, Cores, and Condensations in the Cygnus X: II. Radio Properties of the Massive Dense Cores
- Aligned grains and inferred toroidal magnetic fields in the envelopes of massive young stellar objects
- The ionizing source of the bipolar HII region S106: a close massive binary
- Non-thermal Radio Emission from Massive Protostars in the SARAO MeerKAT Galactic Plane Survey
- Properties of dense molecular gas along the major axis of M 82
- Study of the molecular and ionized gas in a possible precursor of an ultra-compact HII region