Kpc X - Ray Tail in the Cluster a 3627

We present the discovery of a 70 kpc X-ray tail behind the small late-type galaxy ESO 137-001 in the nearby, hot (T=6.5 keV) merging cluster A3627, from both Chandra and XMM-Newton observations. The tail has a length-to-width ratio of ∼ 10. It is luminous (L 0.5−2keV ∼ 10 41 ergs s −1), with a temperature of ∼ 0.7 keV and an X-ray M gas of ∼ 10 9 M ⊙ (∼ 10% of the galaxy's stellar mass). We interpret this tail as the stripped interstellar medium of ESO 137-001 mixed with the hot cluster medium, when this blue galaxy is being converted into a gas-poor galaxy. Three X-ray point sources are detected in the axis of the tail, which may imply active star formation in the tail. The straightness and narrowness of the tail also implies that the ICM turbulence is not strong on scales of 20-70 kpc. 1. introduction The intracluster medium (ICM) has long been proposed to play a vital role in shaping the properties of cluster galaxies, especially through stripping cold galactic material. Ram-pressure stripping is likely an important factor for galaxy transformation in rich environments (e.g., Gunn & Gott 1972; Quilis, Moore & Bower 2000). Radio observations have long revealed an HI deficiency in cluster galaxies, which indicates stripping (e.g., Giovanelli & Haynes 1985). In X-rays, the stripped tails of late-type galaxies only began to be revealed by Chandra and XMM-Newton data (Wang et al. 2004; Sun & Vikhlinin 2005, SV05 hereafter; Machacek et al. 2005). Recently we carried out a systematic analysis of the X-ray thermal coro-nae of ∼ 200 galaxies in 25 nearby (z < 0.05) hot (kT > 3 keV) clusters (Sun et al. in prep.). During our analysis , we found an X-ray tail in A3627, which is apparently associated with the late-type galaxy ESO 137-001. The narrowness and length of the tail makes it the most dramatic X-ray stripped tail of a galaxy to date. A3627 is a nearby massive galaxy cluster in the core of the Great Attractor. Kraan-Korteweg et al. (1996) found, in a deep imaging and spectroscopic survey for galaxies behind the Milky Way, that A3627 (at a Galactic latitude of-7.2 •) is an extremely rich cluster rivaling Coma and Perseus in mass and galactic content. A major cluster merger is implied by the earlier X-ray observations from ROSAT and ASCA that reveal a southeast-northwest cluster elongation (Fig. …