TY - JOUR
T1 - Discovery of a possible splashback feature in the intracluster light of MACS J1149.5+2223
AU - Gonzalez, Anthony H.
AU - George, Tyler
AU - Connor, Thomas
AU - Deason, Alis
AU - Donahue, Megan
AU - Montes, Mireia
AU - Zabludoff, Ann I.
AU - Zaritsky, Dennis
N1 - Funding Information:
AHG thanks Yannick Bahe for providing information on the axial ratios of the BCG and ICL in the C-EAGLE simulations. The authors also thank the anonymous referee for thoughtful comments that improved the manuscript. Thiswork is based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555. Support for Program number 15308 was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555. The work of TC was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA.
Publisher Copyright:
© 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.
PY - 2021/10/1
Y1 - 2021/10/1
N2 - We present an analysis of the intracluster light (ICL) in the Frontier Field Cluster MACS J1149.5+2223 (z = 0.544), which combines new and archival Hubble WFC3/IR imaging to provide continuous radial coverage out to 2.8 Mpc from the brightest cluster galaxy (BCG). Employing careful treatment of potential systematic biases and using data at the largest radii to determine the background sky level, we reconstruct the surface brightness profile out to a radius of 2 Mpc. This radius is the largest to which the ICL has been measured for an individual cluster. Within this radius, we measure a total luminosity of 1.5 × 1013 L⊙ for the BCG plus ICL. From the profile and its logarithmic slope, we identify the transition from the BCG to ICL at r ∼70 kpc. Remarkably, we also detect an apparent inflection in the profile centred in the 1.2-1.7 Mpc (0.37-0.52 r200m) radial bin, a signature of an infall caustic in the stellar distribution. Based upon the shape and strength of the feature, we interpret it as potentially being at the splashback radius, although the radius is smaller than theoretical predictions. If this is the splashback radius, then it is the first such detection in the ICL and the first detection of the splashback radius for an individual cluster. Similar analyses should be possible with the other Frontier Field clusters, and eventually with clusters observed by the Euclid and Roman missions.
AB - We present an analysis of the intracluster light (ICL) in the Frontier Field Cluster MACS J1149.5+2223 (z = 0.544), which combines new and archival Hubble WFC3/IR imaging to provide continuous radial coverage out to 2.8 Mpc from the brightest cluster galaxy (BCG). Employing careful treatment of potential systematic biases and using data at the largest radii to determine the background sky level, we reconstruct the surface brightness profile out to a radius of 2 Mpc. This radius is the largest to which the ICL has been measured for an individual cluster. Within this radius, we measure a total luminosity of 1.5 × 1013 L⊙ for the BCG plus ICL. From the profile and its logarithmic slope, we identify the transition from the BCG to ICL at r ∼70 kpc. Remarkably, we also detect an apparent inflection in the profile centred in the 1.2-1.7 Mpc (0.37-0.52 r200m) radial bin, a signature of an infall caustic in the stellar distribution. Based upon the shape and strength of the feature, we interpret it as potentially being at the splashback radius, although the radius is smaller than theoretical predictions. If this is the splashback radius, then it is the first such detection in the ICL and the first detection of the splashback radius for an individual cluster. Similar analyses should be possible with the other Frontier Field clusters, and eventually with clusters observed by the Euclid and Roman missions.
KW - galaxies: clusters: general
KW - galaxies: evolution
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U2 - 10.1093/mnras/stab2117
DO - 10.1093/mnras/stab2117
M3 - Article
AN - SCOPUS:85115200702
VL - 507
SP - 963
EP - 970
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 1
ER -