By Eric Steinbring with translation by Stéphanie Côté (Canadian Gemini Office, NRC Herzberg Astronomy & Astrophysics Research Centre)
(Cassiopeia – Winter 2023)
Observatory Status
Both telescopes are now back on sky and busily doing science. As reported in September, Gemini North and South went into shutdown in August due to a cyber-intrusion incident. NOIRLab operations were also impacted more broadly. But operations at Gemini North returned in October, and were soon followed by the South, which had already been scheduled for a maintenance shutdown at that time; it emerged sporting a shiny primary mirror (as did the North in June), now freshly re-coated with their special protected silver. There has been no impact on databases or ongoing operations – although some webpages are still not yet available, and a few web-based community tools require temporary workarounds; those should return to normal soon, too. It can also be happily reported that the 2024A Call for Proposals was unaffected by this incident; over-subscription for Canadian time in the South was higher than usual (in part due to newly offering GHOST, the Gemini High Resolution Optical Spectrograph), plus we broke our own record for student-oriented proposals, with a whopping 76-percent indicating the requested data were for a thesis!
New and Refurbished Instruments
Apart from GHOST being the latest facility instrument, the South’s venerable Gemini Multi-Object Spectrograph (GMOS-S) has also been renewed somewhat; it has had a faulty detector replaced, which has been an ongoing issue. GMOS-S is expected to be fully back for science operations again later in the month. And, likewise, coming back in the North is Altair; the facility adaptive optics (AO) system has been down due to its own electronic issues lately, in part related to its 20-year “vintage”, which is comparable to GMOS. The Gemini North AO (GNAO) system will be Altair’s much-advanced replacement in a few years. In the nearer term, something new in the North is IGRINS-2, the Immersion Grating Infrared Spectrograph near-clone of IGRINS (which is a visiting instrument on the South), undergoing commissioning right now. Judging from past Canadian interest in IGRINS, its northern replacement will likely also prove very popular, perhaps for 2024B; it will joint MAROON-X, the high-resolution optical spectrograph and radial-velocimeter, currently our second-highest-demanded instrument on the North, right after GMOS-N (see below).
Science Both Big and Small
Gemini North and GMOS have lately played a big part in science about “little” things: they were instrumental in capturing the stripped-down remains of more than 100 dwarf galaxies, caught transitioning into ultra-compact dwarf galaxies, objects that fall in that special range of too big to be a star cluster, and yet still much too small to be called a dwarf galaxy. This confirms that many of these objects are likely to be the “fossil” remains of normal dwarf galaxies, but have lost their outer layers (the figure below nicely illustrates that transition for objects in M87; see the article here). “Our results provide the most complete picture of the origin of this mysterious class of galaxy that was discovered nearly 25 years ago,” says NOIRLab astronomer Eric Peng in the Gemini press release, and a co-author on the Nature paper reporting the results with other Canadian co-investigators Pat Côté, Laura Ferrarese, Stephen Gwyn and Joel Roediger (HAA) and Matt Taylor (University of Calgary).
A continuum of galaxies captured at different stages of the transformation process from a dwarf galaxy to an ultra-compact dwarf galaxy (UCD). These objects are located near the supergiant elliptical galaxy M87, the dominant member of the neighboring Virgo Cluster.