TY - JOUR
T1 - SPT-CL J0417–4748
T2 - A Deep Chandra Study of a Relaxed Galaxy Cluster without Central Star Formation
AU - Somboonpanyakul, Taweewat
AU - Mantz, Adam B.
AU - Allen, Steven W.
AU - Flores, Anthony M.
AU - Morris, R. Glenn
AU - Stueber, Haley R.
AU - Bleem, Lindsey E.
AU - Floyd, Benjamin
AU - Hlavacek-Larrondo, Julie
AU - Kim, Keunho J.
N1 - Publisher Copyright:
© 2026. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the https://creativecommons.org/licenses/by/4.0/. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
PY - 2026/3/20
Y1 - 2026/3/20
N2 - We present an in-depth Chandra X-ray analysis of the galaxy cluster SPT-CL J0417−4748 (hereafter SPT J0417) at z = 0.58 with a focus on its thermodynamic properties and the apparent absence of central star formation. Utilizing a total Chandra exposure of 103 ks, we find that the large-scale X-ray morphology is consistent with a dynamically relaxed cool-core system. The intracluster medium shows a central density of 0.08 ± 0.01 cm−3, a central pseudoentropy of (Formula presented) 26−5+6keVcm2, and a central cooling time of (Formula presented) 515−75+96 Myr, values typical of massive cool-core clusters. Despite these conditions, no evidence of recent or ongoing star formation is detected in the brightest cluster galaxy (BCG). Spectral energy distribution fitting of Dark Energy Survey photometry indicates that the bulk of the stellar population formed at z ∼ 1.25, with no significant star formation over the past ∼3 Gyr, while optical spectra from Magellan show no [O II] emission. Complementary ASKAP radio and Spitzer infrared data indicate a lack of strong current active galactic nucleus (AGN) activity in the BCG. SPT J0417 exemplifies massive, relaxed cool-core clusters in which cooling and star formation appear almost completely quenched, providing valuable insights into how AGN feedback regulates the long-term thermal balance of the intracluster medium.
AB - We present an in-depth Chandra X-ray analysis of the galaxy cluster SPT-CL J0417−4748 (hereafter SPT J0417) at z = 0.58 with a focus on its thermodynamic properties and the apparent absence of central star formation. Utilizing a total Chandra exposure of 103 ks, we find that the large-scale X-ray morphology is consistent with a dynamically relaxed cool-core system. The intracluster medium shows a central density of 0.08 ± 0.01 cm−3, a central pseudoentropy of (Formula presented) 26−5+6keVcm2, and a central cooling time of (Formula presented) 515−75+96 Myr, values typical of massive cool-core clusters. Despite these conditions, no evidence of recent or ongoing star formation is detected in the brightest cluster galaxy (BCG). Spectral energy distribution fitting of Dark Energy Survey photometry indicates that the bulk of the stellar population formed at z ∼ 1.25, with no significant star formation over the past ∼3 Gyr, while optical spectra from Magellan show no [O II] emission. Complementary ASKAP radio and Spitzer infrared data indicate a lack of strong current active galactic nucleus (AGN) activity in the BCG. SPT J0417 exemplifies massive, relaxed cool-core clusters in which cooling and star formation appear almost completely quenched, providing valuable insights into how AGN feedback regulates the long-term thermal balance of the intracluster medium.
KW - Cool cores (302)
KW - Galaxy clusters (584)
KW - X-ray astronomy (1810)
UR - https://www.scopus.com/pages/publications/105039487664
U2 - 10.3847/1538-4357/ae4727
DO - 10.3847/1538-4357/ae4727
M3 - Article
AN - SCOPUS:105039487664
SN - 0004-637X
VL - 1000
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1
M1 - 42
ER -