Low frequency radio spectrum and spectral turnover of LS 5039

TL;DR

This study reports the detection of a spectral turnover around 964 MHz in LS 5039, a candidate black hole binary, highlighting the importance of simultaneous multi-frequency radio observations for understanding its jet emission.

Contribution

It provides the first indication of a spectral turnover in LS 5039's radio spectrum through combined observational data and spectral fitting.

Findings

Spectral turnover around 964 MHz identified

Inverted spectrum at low frequencies observed

Need for simultaneous multi-frequency observations emphasized

Abstract

LS 5039, a possible black hole x-ray binary, was recently observed with Giant Meterwave Radio Telescope. The observed spectrum presented here shows that the spectrum is inverted at the low frequency. When combined with the archival data with orbital phase similar to the present observations, it shows a clear indication of a spectral turnover. The combined data are fitted with a broken power-law and the break frequency signifies a possible spectral turnover of the spectrum around 964 MHz. Truly simultaneous observations in radio wavelength covering a wide range of frequencies are required to fix the spectrum and the spectral turn over which will play a crucial role in developing a deeper understanding of the radio emitting jet in LS 5039.