the Gemini South telescope, combined with
archival multi-band mid-infrared images obtained using T-ReCS (Thermal-Region Camera
Spectrograph) on Gemini South. The stellar
supercluster, identified as the nucleus and kinematic center of molecular gas rotation, is almost coincident with the symmetry center of
the galaxy’s inner bar. This infrared core (IRC)
is also the primary source of the starburstdriven outflow. Both the IRC and the nuclear
disk are offset with respect to the galaxy’s
stellar bulge, which implies that the central
gas reservoir and new star formation are decoupled from older galactic structure.
The complete results are published in The Astrophysical Journal, and more information
with detailed images is posted on the Gemini
website.
Discovery of a z ~ 6 Quasar:
Rethinking Reioniation Sources
in the Early Universe
Korea’s first result as a limited Gemini partner,
the discovery of a faint quasar at a redshift of
z ~ 6, sheds new light on the sources of reionization energy about a billion years after the
Big Bang.
Ionizing the neutral atoms of the intergalactic
medium requires significant sources of ener-
gy, from either galaxies’ stars or their accreting central black holes (as quasars). The new
discovery, however, ultimately suggests that
quasars do not contribute significantly.
In this work, the team began with the Infrared
Medium-Deep Survey, based on data from
Maunakea telescopes including the United
Kingdom Infrared Telescope and the CanadaFrance-Hawai‘i Telescope. Color selection revealed high-redshift quasar candidates, and
observations of this newly-discovered quasar
using the Gemini Multi-Object Spectrograph
on Gemini South confirm its redshift and
identity spectroscopically (Figure 2).
This single source and six additional candidates from the same survey are consistent
with limited contributions to reionization
from the faint end of the quasar luminosity
function; thus, 90% or more of the ionizing
flux must come from other sources.
This is the first Korean publication as part
of the Gemini Partnership, and was led by
Yongjung Kim (Seoul National University),
Myungshin Im (Principal Investigator; Seoul
National University), and colleagues. A translation of the Korean press release is posted on
the Gemini website, and the full publication
appears in The Astrophysical Journal Letters.
Figure 2.
This GMOS-S spectrum
of the newly-discovered
z~6 quasar confirms its
identity and redshift.
8
GeminiFocus
January 2016