Searching for coronal radio emission from protostars using Very-Long-Baseline Interferometry

Abstract

In order to directly study the role of magnetic fields in the immediate vicinity of protostars, we use Very-Long-Baseline Interferometry (VLBI), aiming at the detection of non-thermal centimetric radio emission. This is technically the only possibility to study coronal emission at sub-AU resolution. We performed VLBI observations of the four nearby protostars HL Tau, LDN 1551 IRS5, EC 95, and YLW 15 in order to look for compact non-thermal centimetric radio emission. For maximum sensitivity, we used the High Sensitivity Array (HSA) where possible, involving the Very Long Baseline Array (VLBA), the phased Very Large Array (VLA), as well as the Arecibo, Green Bank, and Effelsberg radio telescopes. While all four protostars were detected in VLA-only data, only one source (YLW 15 VLA 2) was detected in the VLBI data. The possibility of non-detections due to free-free absorption, possibly depending on source geometry, is considered. For YLW 15 VLA 2, the prospects for an accurate orbit determination appear to be good.

8 pages, 4 figures, accepted for publication in A&A

References in corpus (14)

• Unveiling the Circumstellar Envelope and Disk: A Sub-Arcsecond Survey of Circumstellar Structures
• Rotation and X-ray emission from protostars
• X-ray Study of the Intermediate-Mass Young Stars Herbig Ae/Be Stars
• Quasi-periodic X-ray Flares from the Protostar YLW15
• Multi-epoch VLBA observations of T Tauri South
• The discovery of X-ray emission from the protostellar jet L1551 IRS5 (HH 154)
• HST/NICMOS Imaging Survey of the Ophiuchus (Lynds 1688) Cluster
• Synchrotron emission from the T Tauri binary system V773 Tau A
• The discovery of an expanding X-ray source in the HH 154 protostellar jet
• An XMM-Newton-based X-ray survey of pre-main sequence stellar emission in the L1551 star-forming complex
• VLA 3.5 cm continuum sources in the Serpens cloud core
• A High-Resolution Very Large Array Observation of a Protostar in OMC-3: Shock-induced X-ray Emission by a Protostellar Jet
• On the Evolutionary State of the Components of the YLW 15 Binary System
• Bispectrum speckle interferometry of the massive protostellar outflow source IRAS 23151+5912

Cited by in corpus (14)

• The Gould's Belt Distances Survey (GOBELINS) I. Trigonometric parallax distances and depth of the Ophiuchus complex
• VLBA determination of the distance to nearby star-forming regions IV. A preliminary distance to the proto-Herbig AeBe star EC95 in the Serpens Core
• Radio Jets from Young Stellar Objects
• The Gould's Belt Very Large Array Survey I: The Ophiuchus complex
• Large grains in disks around young stars: ATCA observations of WW Cha, RU Lup, and CS Cha
• The Gould Belt Very Large Array Survey IV: The Taurus-Auriga complex
• VLBA determination of the distance to nearby star-forming regions VI. The distance to the young stellar object HW 9 in Cepheus A
• Grain growth across protoplanetary discs: 10-micron silicate feature versus millimetre slope
• A search for pre-substellar cores and proto-brown dwarf candidates in Taurus: multiwavelength analysis in the B213-L1495 clouds
• The Gould's Belt Very Large Array Survey II: The Serpens region
• The Gould's Belt Very Large Array Survey V: The Perseus Region
• VLA cm-wave survey of young stellar objects in the Oph A cluster: constraining extreme UV- and X-ray-driven disk photo-evaporation -- A pathfinder for Square Kilometre Array studies
• A Very Long Baseline Interferometry Detection of the Class I Protostar IRS 5 in Corona Australis
• A Dual-Band Centimetre Continuum Monitoring Survey of Young Stellar Objects in the Coronet Cluster