Mark Lacy, Kristina Nyland, and Susan Ridgway
GeMS Delivers the Sharpest
View of the Visible Light from
Distant Galaxies
We recently used GeMS/GSAOI observations to make some of the
first ≈ 0.1-arcsecond-resolution observations in the near-infrared
of extragalactic fields exceeding 1.5 arcminutes in size. The unique
capabilities of GeMS have allowed us to study the size evolution of
distant galaxies in the rest-frame optical/near-infrared. In particular
we have focused on z ~ 1-3 ultraluminous infrared galaxies, finding
signs of recent merger activity, including a rare candidate triple active
galactic nucleus. Our observations give us an indication of what the
James Webb Space Telescope will be
able to deliver in a few years.
Figure 1.
The GSAOI image of the
ES1C field. Objects of
interest are shown as
insets, each measuring 6
arcseconds on a side. The
red circles indicate the
stars used to determine
the PSF in the field, and
the blue circles show
those used as natural
guide stars for the
adaptive optics system
(one is off the image).
The most massive galaxies seen today started
life as some of the first structures to form in the
early Universe, then grew both in mass and size
through mergers and the accretion of further mate-
rial. Along that evolutionary journey, most of them
went through episodes of violent activity, including
powerful starburst and quasar events. Today, most
of them are quiescent in nature, with star forma-
tion having largely stopped, and active galactic nu-
clei (AGN) reduced to a very low level. Their story is
therefore rich in astrophysical phenomena, offering
us insights into what drives, and, ultimately, what
stops the formation of galaxies.
October 2018
GeminiFocus
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