Astronomers study the galaxy cluster Abell 119

Astronomers have used NASA’s Chandra spacecraft to carry out detailed X-ray observations of the complex galaxy cluster known as Abell 119. This cluster contains about 70 member galaxies and has two narrow-angle tail radio sources ( NATs). The researchers sought to gain a better understanding of the properties and nature of Abell 119.

The observations revealed that the cluster’s X-ray emission is asymmetric, with an elongation to the northeast, giving it a “teardrop” shape. The X-ray image also showed the presence of irregular substructures within the cluster’s inner medium (ICM). The researchers identified two cold fronts (CF1 and CF2) that could be connected to form an upheaval spiral structure, possibly the result of off-center melting. This structure corresponds to the elongated teardrop-shaped X-ray emission observed in the northeast direction.

In addition, a shock front was detected approximately 250 arcseconds from the cluster’s core, just outside the potential churning cold front. This shock front has a Mach number of 1.21 and an estimated velocity of 1,530 km/s, indicating a merger shock.

The study also found evidence of filamentary structures formed by galaxies in Abell 119, which extend nearly 26 million light-years in a north-northeast direction. These structures appear to connect Abell 119 with another galaxy cluster, Abell 116.

In conclusion, the researchers stated that Abell 119 is a complex system with a possible upheaval spiral, a merger shock, and a possible connection to a neighboring cluster through large-scale filamentary structures. They believe that their observations provide evidence of recent or ongoing melting and support the idea that melting activity occurs in the northeast-southwest direction.

Overall, the observations of Abell 119 have contributed to our understanding of galaxy clusters and their evolution.

More information: Courtney B. Watson et al, Chandra X-Ray Observations of Abell 119: Cold Fronts And A Shock In An Evolved Off-Axis Merger, arXiv (2023). DOI: 10.48550/arxiv.2308.04367