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Gemini e-Newscast #111

September 26, 2018

In This e-Newscast:

Dr. Jennifer Lotz Appointed Gemini Observatory Director

The Association of Universities for Research in Astronomy (AURA) announces the appointment of Dr. Jennifer Lotz as the next Director of the Gemini Observatory. Dr. Lotz begins a five-year appointment as Gemini Director starting October 1, 2018. Previously, Dr. Lotz held the position of associate astronomer at the Space Telescope Science Institute (STScI).

“I’m excited by the science at the twin Gemini telescopes right now and by the opportunity to help Gemini Observatory make the most of its full potential,” said Dr. Lotz. “Gemini is truly poised to lead the way in high spatial resolution imaging, spectroscopy and rapid response astronomy.” Dr. Lotz also stated that the position attracted her because of Gemini’s reputation as a flexible and nimble observatory. “Gemini is able to uniquely study time-dependent phenomena ranging from small Solar System bodies to distant gravitational wave sources. Given the synergies of Gemini’s strengths with the other astronomical facilities coming on-line in the next few years, this is a particularly exciting time for the Observatory,” she added. See the full press release.

GeMS “SERVS” Up Sharp Views of Young Galaxies in Early Universe

A team of astronomers led by Dr. Mark Lacy (National Radio Astronomy Observatory, USA) used advanced adaptive optics on the Gemini South telescope in Chile to obtain high-resolution near-infrared images of three fields from the Spitzer Extragalactic Representative Volume Survey (SERVS). Their sample includes several ultra-luminous infrared galaxies (ULIRGs) which the Herschel Space Observatory found to be undergoing large bursts of star formation within the first few billion years of the Big Bang.

The high-resolution GeMS images reveal that the ULIRGs have messy, irregular structures indicating that they are the product of recent galactic interactions and mergers. Lacy explains, “The fact that the disturbed morphologies of these galaxies persist into the infrared suggests that their appearance is not dominated by clumpy extinction from dust, but reflects the irregular distribution of stellar light.” Dust is highly effective at obscuring ultraviolet and blue light, but effects red and infrared light less. “These GeMS observations help reveal the physical mechanisms by which massive galaxies evolve into the objects we see today,” added Lacy. See the full press release.
GeMS/GSAOI K-band image of one of the three fields targeted from the Spitzer Extragalactic Representative Volume Survey. The insets show detailed views of several distant galaxies in this field.

Gemini Observatory to Advance Adaptive Optics and Multi-messenger Astronomy with NSF Award

Gemini recently received a multi-million dollar award from the National Science Foundation (NSF) to enhance its role in the era of “multi-messenger astronomy” and future facilities like the James Webb Space Telescope. The new funding will be used in part to develop automated systems to trigger follow-up observations within minutes of discover and quickly deliver science-ready data to astronomers, through automated data processing pipelines. The award will fund the development of an advanced multi-conjugate AO system for high-resolution studies in the spatial domain, which includes a new, modern AO system for Gemini North. Gemini will work with visiting instrument teams including Gemini InfraRed Multi-Object Spectrograph (GIRMOS) and the community to build a new imager and provide additional instruments for the new AO system. See the full press release.

GMOS-S Bubbles No More - The Proof

In the previous e-Newscast we reported on the completion of the remedial work to resolve the issue of air bubbles that over time had developed on some of the oil interfaces between optical lenses of the Gemini Multi-Object Spectrograph at Gemini South (GMOS-S). This work required disassembly of the instrument which a somewhat risky intervention. Now, the instrument is back on sky and we have verified that all is well as the images shown here prove.

The first set (top) of daytime images, making use of the “pinhole camera” configuration using the dome lights as the illumination source, bring to sharp focus the bubbles in the optical system of the instrument. The image on the left was taken before and the one on the right after the intervention. Disregard the overall stripe pattern which is due to the primary mirror cover, but look at the effects of the bubbles at the bottom of the field of view on the left image that are completely gone in the image on the right.

The second snapshot shows a g' band image on sky, on the left reduced with a twilight flat field taken before the intervention, and on the right with a twilight flat field taken after the intervention. As you can see the intensity gradients at the bottom are gone now, and the flat fielding is substantially improved, putting an end to a long-standing difficulty with imaging data reduction.
Top images: The pre-intervention image on the left shows the clear presence of the air bubbles at the bottom of the image, while the image at the top-right, after the intervention, reveals the absence of bubbles. The change in rotation is due to the Cassegrain Rotator being rotated by 90 degrees between the images, the detector keeps the same orientation.
Bottom images: This comparison shows that flat field data now work correctly (right), while older data results in an uneven background (left).


TOPTICA Laser Update

Progress continues with the installation of the new Gemini North TOPTICA fiber laser. With the old Lockheed Martin Coherent Technologies laser removed we were able to begin modifying the telescope to accept the new laser and began preparations to install it in June. The addition of new equipment high on the telescope requires additional counterbalance weights for the telescope. These weights were designed and added in sequence so that the installation of the laser components, including the Gemini North Enclosure System for TOPTICA (GNEST) and the Electronics Cabinet (EC), would maintain telescope balance throughout. We conducted our first on-sky propagation at zenith on August 31st remotely from the Hilo Base Facility and as this issue goes to e-press we continue preparing for commissioning.
Gemini senior optical technician Clayton Ah Hee (left, foreground) and summit crew member John Randrup prepare GNEST for installation onto the telescope.
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