Year: 2025
Type: article
Abstract: We present new radio observations of the galaxy cluster merger CIZA J0107.7+5408 (CIZA0107), a large, roughly equal mass, postcore passage, dissociative binary system at z = 0.1066. CIZA0107 is an elongated, disturbed system, hosting two subclusters with optical galaxy number density peaks offset from their associated X-ray density peaks and double-peaked diffuse radio structure. We present new 240–470 MHz and 2.0–4.0 GHz Very Large Array observations of CIZA0107. We image the diffuse emission at high resolution, constrain its integrated spectrum, and map the spectral index distribution. We confirm the presence of steep-spectrum (α ∼ −1.3) emission on a scale of ∼0.5 Mpc in both subclusters. We identify two smaller ultrasteep spectrum (α < −2) regions, superimposed on larger-scale radio emission associated with the southwestern subcluster. At 340 MHz, we detect a radio edge bounding the emission to the south and show that it is coincident with a weak (M ∼ 1.2) shock identified in the Chandra image. At 3 GHz, the emission does not show any corresponding edgelike feature, and in fact it extends beyond the shock. We investigate the nature of the emission in CIZA0107 and find that, while the system may host a double halo structure, we cannot rule out a scenario in which the emission arises from two relics projected on the central cluster regions.
Source: The Astrophysical Journal
Institutions: United States Naval Research Laboratory, George Mason University, Center for Astrophysics Harvard & Smithsonian, Leiden University, Leiden Observatory, Vassar College, University of Minnesota, Boston University, California Institute of Technology, Infrared Processing and Analysis Center, European Southern Observatory, The University of Western Australia, International Centre for Radio Astronomy Research
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,499
OpenAlex ID: W4408167613