1. Molecular Hydrogen in the outer filaments surrounding NGC 1275 Nina Hatch CS Crawford, RM Johnstone, AC Fabian IOA, Cambridge

2. Central Cluster Galaxy Emission-line nebulae Emission line nebulae are found surrounding ~27% of CCG Bright and extended structure Cowie et al 1983 Conselice et al 2001 Only find emission line nebulae if cluster has a short radiative cooling time and bright centrally peaked x-ray emission

3. Perseus: 200ks Chandra Fabian et al 03

4. Unsharped mask of X-ray image of Perseus cluster Fabian et al, 2003

5. NGC1275/Perseus cluster in Hα Conselice et al 2001

9. Edge et al, 2002 Similar line ratios found in outer filaments as in the nucleus – indicating similar ionising mechanism

10. Velocity shear across lower filaments ~ 175km/s

11. Velocity shift relative to nucleus

12. Ionisation Mechanisms Excitation source of optical filaments still uncertain -short cooling time → gas continually ionised - Soft X-ray/Hα indicate filaments radiate predominantly in optical → soft x-rays do not ionise Possible mechanisms UV photoionisation from nearby stars -likely to be dominant mechanism in Eastern knot shocks conduction from hot ICM Will analyse line ratios using CLOUDY

13. Summary Detection of molecular hydrogen ~ 25kpc from CCG, deeply embedded within hot ICM Velocity shift between outer filaments and central nebula and within filaments Spectra indicate different ionisation mechanisms acting on filaments