# Detection of the Stellar Intracluster Medium in Perseus (Abell 426)

## TL;DR

This study uses Hubble Space Telescope data to detect and analyze intracluster globular clusters in the Perseus galaxy cluster, revealing a large population extending far from the center and providing insights into their distribution and properties.

## Contribution

First detection and measurement of intracluster globular clusters in Perseus, estimating their abundance and analyzing their properties in relation to central galaxies.

## Key findings

- Intragalactic GCs extend at least 500 kpc from Perseus center.
- Estimated total IGCs in Perseus are around 50,000 or more.
- GC populations in NGC 1272 and NGC 1275 show bimodal color distributions.

## Abstract

Hubble Space Telescope photometry from the ACS/WFC and WFPC2 cameras is used to detect and measure globular clusters (GCs) in the central region of the rich Perseus cluster of galaxies. A detectable population of Intragalactic GCs is found extending out to at least 500 kpc from the cluster center. These objects display luminosity and color (metallicity) distributions that are entirely normal for GC populations. Extrapolating from the limited spatial coverage of the HST fields, we estimate very roughly that the entire Perseus cluster should contain ~50000 or more IGCs, but a targetted wide-field survey will be needed for a more definitive answer. Separate brief results are presented for the rich GC systems in NGC 1272 and NGC 1275, the two largest Perseus ellipticals. For NGC 1272 we find a specific frequency S_N = 8, while for the central giant NGC 1275, S_N ~ 12. In both these giant galaxies, the GC colors are well matched by bimodal distributions, with the majority in the blue (metal-poor) component. This preliminary study suggests that Perseus is a prime target for a more comprehensive deep imaging survey of Intragalactic GCs.