Abstract
Integral field unit (IFU) data of the iconic Pillars of Creation in M16 are
presented. The ionisation structure of the pillars was studied in great detail
over almost the entire visible wavelength range, and maps of the relevant
physical parameters, e.g. extinction, electron density, electron temperature,
line-of-sight velocity of the ionised and neutral gas are shown. In agreement
with previous authors, we find that the pillar tips are being ionised and
photo-evaporated by the massive members of the nearby cluster NGC 6611. They
display a stratified ionisation structure where the emission lines peak in a
descending order according to their ionisation energies. The IFU data allowed
us to analyse the kinematics of the photo-evaporative flow in terms of the
stratified ionisation structure, and we find that, in agreement with
simulations, the photo-evaporative flow is traced by a blueshift in the
position-velocity profile. The gas kinematics and ionisation structure have
allowed us to produce a sketch of the 3D geometry of the Pillars, positioning
the pillars with respect to the ionising cluster stars. We use a novel method
to detect a previously unknown bipolar outflow at the tip of the middle pillar
and suggest that it has an embedded protostar as its driving source.
Furthermore we identify a candidate outflow in the leftmost pillar. With the
derived physical parameters and ionic abundances, we estimate a mass loss rate
due to the photo-evaporative flow of 70 M$_ødot$ Myr$^-1$ which yields an
expected lifetime of approximately 3 Myr.
Description
[1504.03323] The Pillars of Creation revisited with MUSE: gas kinematics and high-mass stellar feedback traced by optical spectroscopy
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