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| Paper: |
Investigating the Properties of Molecular Gas in Merger Remnants |
| Volume: |
499, Revolution in Astronomy with ALMA: The Third Year |
| Page: |
143 |
| Authors: |
Ueda, J.; Merger Remnant CO Study Team |
| Abstract: |
Major mergers are widely believed to provide a way
to form spheroid-dominated early-type galaxies.
Contrary to this scenario,
recent simulations that include more realistic gas physics have shown
that some mergers will remerge as disk-dominated late-type galaxies,
forming extended molecular gas disks.
In order to look for observational evidence of extended gas disks in merger remnants,
we have conducted a <1 kpc resolution CO imaging study of 37 local merger remnants
using new and archival interferometric maps.
Among the sources with robust CO detection,
80% of the sources show kinematical signatures of rotating molecular gas disks in their velocity fields,
and about half of the sources have gas disks that are extended relative to the stellar component,
possibly forming a late-type galaxy with a central stellar bulge.
On the other hand, the rest (54%) of the sources have gas disks
that are more compact than the K-band effective radius.
Comparing the properties of molecular gas of the merger remnants
to those of early-type and late-type galaxies,
most of the sources show similar properties to early-type galaxies
and they are likely to become early-types.
We also find that sources with extended molecular gas disks
and large gas mass fractions are likely to become late-type galaxies,
unless there are further mechanisms which transport molecular gas toward the central regions.
These results suggest observationally that merging events reprocess them
into a mixture of types including early-types and late-types. |
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