The integrated radio spectrum of G2.4$+$1.4

Abstract

The Galactic source G2.4$+$1.4 is an optical and radio nebula containing an extreme Wolf--Rayet star. At one time this source was regarded as a supernova remnant, because of its apparent non-thermal radio spectrum, although this was based on limited observations. Subsequent observations instead supported a flat, optically thin thermal radio spectrum for G2.4$+$1.4, and it was identified as a photoionized, mass-loss bubble, not a supernova remnant. Recently, however, it has been claimed that this source has a non-thermal integrated radio spectrum. I discuss the integrated radio flux densities available for G2.4$+$1.4 from a variety of surveys, and show that it has a flat spectrum at gigahertz frequencies (with a spectral index $\alpha$ of $0.02\pm 0.08$, where flux density $S$ scales with frequency $\nu$ as $S\propto {\nu }^{-\alpha }$).

5 pages

References in corpus (4)

• A southern-sky total intensity source catalogue at 2.3 GHz from S-band Polarisation All-Sky Survey data
• Investigating Particle Acceleration in the Wolf-Rayet Bubble G2.4+1.4
• High-sensitivity radio study of the non-thermal stellar bow shock EB27
• And then they were two: detection of non-thermal radio emission from the bow shocks of two runaway stars

Cited by in corpus (2)

• Probing the non-thermal physics of stellar bow shocks using radio observations
• Radio study of the colliding wind binary HD93129A near periastron and its surroundings