Figure 2.
Environmental Effect?
The Importance of Our Results
We are currently working on more Gemini data
of other UV sources in H I tails of several interacting systems –– searching for any environmental evidence that may be decisive factors
in the formation of TDGs or/and stellar clusters.
Some preliminary results show that compact
groups of galaxies may be more conducive to
TDG formation (or better said, TDG survival)
than pairs and mergers. This argument agrees
with the simulations by Bournaud and Duc
(2006) where specific conditions, such as low
impact velocity (v < 250 kilometers per second), prograde encounters and mass ratios up
to 4:1 may lead to TDG formation. Compact
groups might harbor these conditions besides
the possibility that group potential may be
able to drive TDGs away from the nearby proximity of their progenitor galaxies.
The fate of these newly discovered objects is
still unknown. Whether these systems will become independent entities is not clear. It will
depend on several parameters, such as the distance to the parent galaxies and total masses.
TDGs, for instance, might grow into dwarf galaxies and become part of the interacting system. But they might also fall into bigger galaxies and be torn apart.
December2012
GALEX NUV-band image
of the H I tidal tail of
NGC 2782. NUV-band
image of the entire
target is shown in the
upper-left corner. Topright: Gemini r-band
image of the tail. The
numbered circles (4
arcsecond radius) show
the detected regions.
The contours represent
the H I distribution
taken from Smith
(1994). Bottom images:
close-up of the detected
regions (left-hand
side: NUV-band image;
right-hand side: r-band
image). The Gemini
r-band image resolved
the UV detections in
several smaller stellar
clusters, as exemplified
in the lowest six panels.
The white rectangles
over regions 5, 6, and 7
indicate, approximately,
the position of the slit
in the spectroscopic
observation.
Stellar clusters may also be tidally shredded
and become sparse stars in the intergalactic
medium; they might also become the progenitors of globular clusters and stay as part of the
final merging system. Independently of what
the future holds for these systems, when they
are young, they contain massive stars which
will explode as supernovae as they evolve. Because the masses of these systems are low, the
GeminiFocus
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