Tentative Evidence for Relativistic Electrons Generated by the Jet of the Young Sun-like Star DG Tau

TL;DR

This study presents low-frequency radio observations of the young Sun-like star DG Tau, providing tentative evidence of relativistic electrons generated by its jet, similar to phenomena observed in massive protostars and active galactic nuclei.

Contribution

First low-frequency investigation of a low-mass young stellar object, revealing synchrotron emission indicative of relativistic particle acceleration in its jet.

Findings

Detection of synchrotron emission near DG Tau jet

Evidence of particle acceleration to relativistic energies

Magnetic field strength estimated at 0.11 mG

Abstract

Synchrotron emission has recently been detected in the jet of a massive protostar, providing further evidence that certain jet formation characteristics for young stars are similar to those found for highly relativistic jets from AGN. We present data at 325 and 610 MHz taken with the GMRT of the young, low-mass star DG Tau, an analog of the Sun soon after its birth. This is the first investigation of a low-mass YSO at at such low frequencies. We detect emission with a synchrotron spectral index in the proximity of the DG Tau jet and interpret this emission as a prominent bow shock associated with this outflow. This result provides tentative evidence for the acceleration of particles to relativistic energies due to the shock impact of this otherwise very low-power jet against the ambient medium. We calculate the equipartition magnetic field strength (0.11 mG) and particle energy (4x10^40 erg), which are the minimum requirements to account for the synchrotron emission of the DG Tau bow shock. These results suggest the possibility of low energy cosmic rays being generated by young Sun-like stars.