Exploring the region encompassing gamma Cygni SNR and MAGIC J2019+408 with the GMRT at 325 and 610 MHz

TL;DR

This study used GMRT radio observations at 325 and 610 MHz to identify and analyze radio sources in the gamma Cygni supernova remnant region, aiming to understand their relation to TeV gamma-ray emission detected by MAGIC.

Contribution

First detailed radio survey of the gamma Cygni region at these frequencies, identifying potential sources related to gamma-ray emission and highlighting candidates for further study.

Findings

Detected multiple radio sources overlapping the gamma Cygni and MAGIC J2019+408 region.

Identified diffuse emission areas possibly interacting with the supernova remnant and high-density regions.

Found some sources with peculiar characteristics, suggesting the need for multi-wavelength follow-up.

Abstract

Gamma Cygni is a young supernova remnant located in the Cygnus region. MAGIC (Major Atmospheric Gamma Imaging Cherenkov) telescopes detected TeV emission (MAGIC J2019+408) to the north-west of this remnant, about 5 arcmin from its border. We want to identify the radio sources within the region encompassing gamma Cygni and MAGIC J2019+408 to shed light on their nature and investigate if these radio sources could be potential contributors to gamma-ray emission. We carried out a detailed study of the data we obtained with a survey of the Cygnus region at 325 and 610 MHz with the Giant Metrewave Radio Telescope (GMRT). We detected several radio sources in the region where the radio and the TeV emission overlap, as well as several areas of enhanced radio emission. In particular, two of these areas of diffuse enhanced emission may correspond to the supernova remnant interacting with a high density region, which seems to be the best candidate for the MAGIC source. Another two radio sources, which may or may not contribute to the gamma rays, are also spatially coincident with the emission peak of the MAGIC TeV source. One of them displays a rather peculiar extended morphology whose nature is completely unknown. We have identified the radio sources overlapping gamma Cygni and MAGIC J2019+408 and have shown that their potential gamma-ray contribution is likely not dominant. In addition, some of the studied sources show peculiar physical characteristics that deserve deeper multi-wavelength observations.