Observers examine a close-by galaxy cluster merger

Using the Very Large Array (VLA), a world crew of astronomers have noticed a close-by galaxy merger referred to as CIZA J0107.7+5408. Results of the observational marketing campaign, offered December 20 on the preprint server arXiv, might assist us higher perceive the merging processes that happen between galaxy clusters.

Galaxy clusters comprise as much as hundreds of galaxies sure collectively by gravity. They usually kind because of mergers and develop by accreting sub-clusters. These processes present a superb alternative to check matter in circumstances that can’t be explored in laboratories on Earth. In explicit, merging galaxy clusters might assist us higher perceive the physics of shock and chilly fronts seen within the diffuse intra-cluster medium, the cosmic ray acceleration in clusters, and the self-interaction properties of darkish matter.

At a redshift of roughly 0.1, CIZA J0107.7+5408, or CIZA0107 for brief, is a close-by, post-core passage, dissociative binary cluster merger. It is a big, roughly equal mass disturbed system consisting of two subclusters, internet hosting two optical density peaks, with related however offset X-ray emission peaks.

A gaggle of astronomers led by Emma Schwartzmann of the U.S. Naval Research Laboratory in Washington, D.C., explored CIZA0107 with VLA, to be able to shed extra gentle on its properties.

“We current new 240–470 MHz and a couple of.0–4.0 GHz Very Large Array observations of CIZA0107. We picture the diffuse emission at excessive decision, constrain its built-in spectrum, and map the spectral index distribution,” the researchers wrote within the paper.

The new VLA observations confirmed the complicated dynamical state of CIZA0107. The photographs present a dramatically disturbed merger system with a merger axis alongside the northeast–southwest course.

The observations at 340 MHz and three.0 GHz showcase diffuse radio emission on a scale of about 1.6 million gentle years in every of the 2 subclusters of CIZA0107. At 340 MHz, the astronomers additionally detected emission from two ultra-steep spectrum areas situated to the northwest and southeast of the diffuse radio emission peak within the southwestern subcluster.

Furthermore, the research discovered that the 2 subclusters have an analogous spectral index of roughly -1.3. For the ultra-steep spectrum areas, the researchers measured steeper spectral slopes between 74 MHz and 340 MHz of about −2.2 and −2.9 for the northwestern and southeastern areas, respectively.

The observations additionally discovered that the diffuse emission related to the southwestern subcluster reveals a pointy radio edge at 340 MHz. However, at 3.0 GHz the diffuse emission doesn’t present any function on the location of the 340 MHz radio edge and X-ray shock entrance, and actually it extends past the shock.

Summing up the outcomes, the authors of the paper underlined that the properties of the emission in CIZA0107 counsel that the system could host a double halo construction, or the emission could have its origin in two relics projected on the central cluster areas.

© 2024 Science X Network