2025/12/16 by Wittman, David, Stancioli, Rodrigo, Bouhrik, Faik +2
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #High Energy Astrophysical Phenomena (astro-ph.HE)
paper · doi:10.48550/arxiv.2512.14945
openalex publication_date 2025/12/16 · openalex created_date 2025/12/19 · openalex updated_date 2026/07/28
The galaxy cluster RXC J0032.1+1808 has been well-studied with optical imaging and gravitational lensing mass maps, both of which reveal an elongated morphology in the north-south direction. We find that its X-ray morphology is bimodal, suggesting that it is in the process of merging; combined with a previously reported detection of a radio relic, we suggest that the system is seen after first pericenter. We extract the global X-ray temperature and unabsorbed luminosity from archival XMM-Newton data, finding TX=8.5+1.1-0.9 keV and LX=1.04 ± 0.03 × 1045 erg s-1 at 90% confidence in the 0.5--10.0 keV energy range. We conduct a redshift survey of member galaxies and find that the line-of-sight relative velocity between the two subclusters is 76±364 km/s. We use publicly available hydrodynamic simulations to show that it cannot be a head-on merger, that it is observed ≈395--560 Myr after pericenter, and that the viewing angle must be one that foreshortens the apparent subcluster separation by a factor ≈2.