Euclid: Early Release Observations – The intracluster light and intracluster globular clusters of the Perseus cluster

We study the intracluster light (ICL) and intracluster globular clusters (ICGCs) in the nearby Perseus galaxy cluster using Euclid's EROs. By modelling the isophotal and iso-density contours, we map the distributions and properties of the ICL and ICGCs out to a radius of 600 kpc ( 1/3 of the virial radius) from the brightest cluster galaxy (BCG). We find that the central 500 kpc of the Perseus cluster hosts 70000±2800 GCs and 1.6×10^12 L_⊙ of diffuse light from the BCG+ICL in the near-infrared H_E. This accounts for 37±6 and ICGCs share a coherent spatial distribution, suggesting a common origin or that a common potential governs their distribution. Their contours on the largest scales (>200 kpc) are offset from the BCG's core westwards by 60 kpc towards several luminous cluster galaxies. This offset is opposite to the displacement observed in the gaseous intracluster medium. The radial surface brightness profile of the BCG+ICL is best described by a double Sérsic model, with 68±4 transition between these components occurs at  50 kpc, beyond which the isophotes become increasingly elliptical and off-centred. The radial ICGC number density profile closely follows the BCG+ICL profile only beyond this 50 kpc radius, where we find an average of 60 GCs per 10^9 M_⊙ of diffuse stellar mass. The BCG+ICL colour becomes increasingly blue with radius, consistent with the stellar populations in the ICL having subsolar metallicities [Fe/H] -0.6. The colour of the ICL, and the specific frequency and luminosity function of the ICGCs suggest that the ICL+ICGCs were tidally stripped from the outskirts of massive satellites with masses of a few ×10^10 M_⊙, with an increasing contribution from dwarf galaxies at large radii.