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We present results from a mosaic of nine Chandra observations of
M86 and the surrounding field. We detect three main diffuse
components: the Virgo ICM at ~2.4 keV, the extended halo of M86 at
~1.2 keV, and the cooler central and stripped gas of M86 at
~0.8 keV. 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.
Based on the morphology and temperature structure of the tail, 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 presently known.
The total gas mass in the plume (7x108 Msun) and tail (1x109 Msun) is about three 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, as
suggested by optical isophotes. 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 with respect to M87), its position
relative to the Virgo cluster, and the orientation of the tail tightly constrain its orbital
parameters.
The data are inconsistent with a radial orbit, and imply
inner and outer turning radii of ri ~ 300 kpc and
ro > 8.8 Mpc, indicating that M86 is, at best, only weakly bound to the
Virgo cluster.
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