Very compact radio emission from high-mass protostars. I. CRL 2136: Continuum and water maser observations

Abstract

We report 5-43 GHz radio observations of the CRL 2136 region at 0.6-6 arcsec resolution. We detect weak (mJy intensity) radio emission from the deeply embedded high-mass protostar IRS 1, which has an optically thick spectrum up to frequencies of 22 GHz, flattening at higher frequencies, which might be explained by emission from a jet. Water maser mapping shows that the strong emission observed redshifted relative to the systemic velocity is spatially coincident with the optically thick continuum emission. The H2O maser emission from this object (and others we know of) seems to have a different origin than most of these masers, which are frequently tracing bipolar high-velocity outflows. Instead, the CRL 2136 H2O emission arises in the close circumstellar environment of the protostar (within 1000 AU). We speculate that most of it is excited in the hot, dense infalling gas after the accretion shock, although this cannot explain all the H2O emission. An accretion shock nature for the continuum emission seems unlikely.

Accepted by A&A; 10 pages, 5 figures. v2: mostly minor corrections. v3: only minor corrections

References in corpus (7)

• High-Mass Proto-Stellar Candidates - II : Density structure from dust continuum and CS emission
• High-Mass Proto-Stellar Candidates - I : The Sample and Initial Results
• CH3OH and H2O masers in high-mass star-forming regions
• Sulphur chemistry in the envelopes of massive young stars
• Outflow 20--2000 AU from a High-Mass Protostar in W51-IRS2
• Expansion of the R4 Water Maser Arc Near Cepheus A HW 2
• A Class of Interstellar OH Masers Associated with Protostellar Outflows

Cited by in corpus (23)

• A Class I and Class II Methanol Maser Survey of Extended Green Objects (EGOs) from the GLIMPSE Survey
• Accretion disks in luminous young stellar objects
• VLA observations of ammonia in high-mass star formation regions
• Magnetic fields in massive star forming regions
• Substructures in the Keplerian disc around the O-type (proto)star G17.64+0.16
• Imaging the Ionized Disk of the High-Mass Protostar Orion-I
• Very compact radio emission from high-mass protostars. II. Dust disks and ionized accretion flows
• Resolved 24.5 micron emission from massive young stellar objects
• Chasing discs around O-type (proto)stars - ALMA evidence for an SiO disc and disc wind from G17.64+0.16
• The VLTI/MIDI survey of massive young stellar objects - Sounding the inner regions around intermediate- and high-mass young stars using mid-infrared interferometry
• Subarcsecond mid-infrared and radio observations of the W3 IRS5 protocluster
• An Extensive, Sensitive Search for SiO Masers in High- and Intermediate-Mass Star-Forming Regions
• A high-frequency radio continuum study of massive young stellar objects
• Accretion disks around massive stars: Hydrodynamic structure, stability and dust sublimation
• Mid-infrared interferometry towards the massive young stellar object CRL 2136: inside the dust rim
• Near-infrared integral field spectroscopy of Massive Young Stellar Objects
• Spectral Energy Distributions of 6.7 GHz methanol masers
• The H${}_2$O Spectrum of the Massive Protostar AFGL 2136 IRS 1 from 2 to 13 $\mu$m at High Resolution: Probing the Circumstellar Disk
• Water Absorption from Gas Very Near the Massive Protostar AFGL 2136 IRS 1
• Fundamental Vibrational Transitions of HCl Detected in CRL 2136
• Synchrotron emission from circumstellar disks around massive stars
• High-resolution observations of water masers in Bok globules
• Non-thermal Radio Emission from Massive Protostars in the SARAO MeerKAT Galactic Plane Survey