Chandra’s View of the Ram Pressure Stripped Galaxy M86

Abstract

We present results from a mosaic of nine Chandra observations of M86 and the surrounding field. We detect three main diffuse components: the Virgo intracluster medium (ICM), the extended halo of M86, and the cooler central and stripped gas of M86. The most striking feature is a long tail of emission, which consists of a plume ~4' north of M86 and two main extensions emanating from the plume. We conclude that it is formed by ram pressure stripping of M86 as it falls into the Virgo Cluster and interacts with the Virgo ICM, in agreement with earlier work. The tail is 150 kpc in projection, and a simple estimate gives a lower limit on the true length of the tail of 380 kpc, making this the longest ram pressure stripped tail currently known. The total gas mass in the plume (~7 × 108 M☉) and tail (~1 × 109 M☉) is about 3 times that in the core of M86, which supports the scenario where most of the gas was stripped rapidly and recently. The projected position of the plume can be understood if M86 has an aspherical potential. Ram pressure stripping from an aspherical potential can also explain the split "double tails" seen in M86 and in other Virgo Cluster galaxies in the field. The large line-of-sight velocity of M86 (1550 km s−1 with respect to M87), its position relative to the Virgo Cluster, and the orientation of the tail tightly constrain its orbital parameters.