GMRT detections of low mass young stars at 323 and 608 MHz

Abstract

We present the results of a pathfinder project conducted with the Giant Metrewave Radio Telescope (GMRT) to investigate protostellar systems at low radio frequencies. The goal of these investigations is to locate the break in the free-free spectrum where the optical depth equals unity in order to constrain physical parameters of these systems, such as the mass of the ionised gas surrounding these young stars. We detect all three target sources, L1551 IRS 5 (Class I), T Tau and DG Tau (Class II), at frequencies 323 and 608 MHz (wavelengths 90 and 50 cm, respectively). These are the first detections of low mass young stellar objects (YSOs) at such low frequencies. We combine these new GMRT data with archival information to construct the spectral energy distributions for each system and find a continuation of the optically thin free-free spectra extrapolated from higher radio frequencies to 323 MHz for each target. We use these results to place limits on the masses of the ionised gas and average electron densities associated with these young systems on scales of ~1000 au. Future observations with higher angular resolution at lower frequencies are required to constrain these physical parameters further.

arXiv comment11 pages, 10 figures, Accepted for publication in MNRAS

References in corpus (25)

• Circumstellar Dust Disks in Taurus-Auriga: The Submillimeter Perspective
• The SCUBA Legacy Catalogue: Continuum Objects Detected by SCUBA
• An Accurate Flux Density Scale from 1 to 50 GHz
• A Resolved Census of Millimeter Emission from Taurus Multiple Star Systems
• A Magnetized Jet from a Massive Protostar
• Recipes for stellar jets: results of combined optical/infrared diagnostics
• The Mass Distributions of Starless and Protostellar Cores in Gould Belt Clouds
• Discovery of a bipolar X-ray jet from the T Tauri star DG Tau
• A Third Star in the T Tauri System
• VLBA determination of the distance to nearby star-forming regions V. Dynamical mass, distance and radio structure of V773 Tau A
• The Gould's Belt Very Large Array Survey I: The Ophiuchus complex
• The Gould Belt Very Large Array Survey IV: The Taurus-Auriga complex
• Tentative Evidence for Relativistic Electrons Generated by the Jet of the Young Sun-like Star DG Tau
• Deep 610-MHz GMRT observations of the Spitzer extragalactic First Look Survey field - I. Observations, data analysis and source catalogue
• Entrainment Mechanisms for Outflows in the L1551 Star-Forming Region
• Classical T Tauri stars as sources of parsec-scale optical outflows
• Radio continuum emission from knots in the DG Tau jet
• Multiple Bipolar Molecular Outflows in the L1551 IRS5 Protostellar System
• AMI radio continuum observations of young stellar objects with known outflows
• Multi-epoch Sub-arcsecond [Fe II] Spectroimaging of the DG Tau Outflows with NIFS. II. On the Nature of the Bipolar Outflow Asymmetry
• Radio continuum observations of Class I protostellar disks in Taurus: constraining the greybody tail at centimetre wavelengths
• Spatio-Kinematic Structure at the Base of the [Fe II] Jets From L1551 IRS 5
• VLA Observations of DG Tau's Radio Jet: A highly collimated thermal outflow
• Sub-arcsecond high sensitivity measurements of the DG~Tau jet with e-MERLIN
• The long wavelength view of GG Tau A: Rocks in the Ring World

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• A GMRT survey of regions towards the Taurus Molecular Cloud at 323 and 608 MHz
• Radio observations of evaporating objects in the Cygnus OB2 region