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22 Agosto 2019: Every galaxy has a story, and every galaxy has been many others in the past (unlike for humans, this is not purely metaphorical, as galaxies grow via hierarchical assembly). Generally speaking, the most massive galaxies have led the most interesting lives, often within teeming galactic metropolises where they are subject to frequent interactions with assorted neighbors. These interactions influence the structure and motions of the stars, gas, and dark matter that make up the galaxies. They also affect the growth of the supermassive black holes at the galaxies’ centers. Although the detailed life stories of most galaxies will remain forever uncertain, the key thematic elements may be surmised in various ways. A particularly powerful probe of a galaxy’s dynamical structure is called integral field spectroscopy (IFS), which dissects a galaxy’s light at each point within the spectrograph’s field of view. In this way, it is possible to construct a map …

5 Agosto 2019: Jupiter’s volcanic moon Io brought astronomers and geologists together to reveal that this moon’s hot spots fluctuate on unexpected timescales. The team utilized the Gemini North telescope and the W.M. Keck Observatory, both located on Maunakea, Hawaiʻi Island. The Gemini observations, which provided about 80% of the data for the study, employed the high-resolution adaptive optics system ALTAIR combined with the Gemini Near InfraRed Imager and spectrograph (NIRI). The researchers conducted a total of 271 observations between 2013 and 2018 and published their results in the July 2019 issue of The Astronomical Journal and the June 28, 2019 issue Geophysical Research Letters. While whizzing around Jupiter in an elliptical orbit with a period of only 1.8 days, Io’s interior is warmed by the varying pull of Jupiter’s gravity, roughly similar to how the Earth’s moon causes tides on our planet. This “tidal heating” powers Io’s volcanoes. However, the shape of …

25 Julio 2019: By observing a single star orbiting around the supermassive black hole at the center of our Milky Way Galaxy, a team of astronomers have tested Einstein’s one hundred-year-old theory of General Relativity in an unprecedented new regime. Unlike Sir Isaac Newton’s law of gravity, which states that matter pulls on other matter across empty space, General Relativity theory proposes that massive objects like supermassive black holes distort both space and time, which in turn affects the motions of objects around them. The team’s result: “Einstein’s right, at least for now,” said Andrea Ghez at the University of California Los Angeles (UCLA), a co-lead author of the research. Gemini Observatory played an integral part in this research using the Gemini North telescope on Maunakea in Hawai‘i with the Near Infrared Integral Field Spectrometer (NIFS). Using NIFS the team acquired critical spectroscopic observations of the star, known as S0-2, as it orbited …

29 Mayo 2019: To have, or not to have dark matter? That is the question. In early 2018, a team of researchers led by Pieter van Dokkum of Yale University shook up the astrophysics world when they announced that the dwarf, “ultra-diffuse galaxy,” which was referred to by van Dokkum as NGC 1052-DF2, is almost devoid of dark matter. Their report, published in the journal Nature, acknowledged that this conclusion depended on the distance to the galaxy. Nevertheless, the researchers presented evidence in favor of a distance that implied the galaxy was seriously light on dark matter. The problem is that the formation of galaxies without dark matter doesn’t fit most theories of galaxy evolution. If van Dokkum and his team are correct then astrophysicists have some serious explaining to do. The original Gemini summary of the van Dokkum et al. work can be found here. The van Dokkum team has also published …

17 Abril 2019: The Gemini telescopes helped identify low-metallicity stars by gathering medium-resolution spectroscopic GMOS data for 666 bright stars under poor weather conditions. These data provide a unique opportunity to explore the chemical evolution of the Milky Way and look at the enrichment of star-forming gas clouds in the early Universe. Low-metalicity stars (stars with less than 1% of the elements heavier than Hydrogen and Helium than the Sun contains) are the Rosetta Stones of stellar astrophysics. Encoded in the atmosphere of these low-mass, long-lived relics are the signatures of the processes by which the first chemical elements were cooked up, perhaps as early as a few tens of millions of years after the Big Bang. These stars are believed to be the direct descendants of the first stars to be born in the Universe, which were massive and short-lived. Hence, second-generation, low-metallicity stars are the artifacts which help us write the …

6 Febrero 2019: Astronomers using adaptive optics on the 8-meter Gemini North telescope have resolved, for the first time in near-infrared light, a giant elliptical galaxy with a young radio jet down to unprecedented scales. The observations also show how the jets, emanating from a black hole at the center of this galaxy, are heating the interstellar medium, which may have a significant impact on the evolution of the host galaxy. Using adaptive optics (AO) and near-infrared imaging on the 8-meter Gemini North telescope in Hawai‘i, a team of astronomers lead by PhD student Henry Zovaro (The Australian National University) report the discovery of shocked molecular and ionized gas resulting from a jet-driven feedback coming from the center of a compact radio galaxy. The discovery offers important information on how such activity can influence the evolution of its host galaxy. The galaxy, which goes by the name MCG 5-4-18, is a nearby giant …

17 Diciembre 2018: Extremely high-resolution speckle observations by Gemini South deliver critical details on a star (or stars) lying in the apparent path of remnants from the early formation of our Solar System. In early March of 2017 the outer Solar System object Orcus, and its one known satellite Vanth, were on an apparent collision course with a star – at least that’s the way it appeared from our perspective on Earth. Original calculations showed that Orcus would pass in front of a relatively bright star and temporarily block the star’s light. However, later refinements to the calculations revealed that the shadow of Vanth would trace a path across the Earth’s surface. These events, known as occultations, are only visible from a thin swath on Earth’s surface and calculations have small uncertainties due to observations of the orbits and estimates of the objects’ size. But even with these uncertainties, what happened surprised astronomers. …

15 Diciembre 2018: Gemini Observatory announces the opportunity for new Large and Long Programs, with observations beginning in the 2019B semester. Letters of Intent to propose a new Large and Long Program are due February 4, 2019. Completed Proposals are due April 1, 2019.

16 Octubre 2018: Thanks to two allocations of Director’s Discretionary Time and a successful Fast-Turnaround program, an international team (including Gemini Emeritus Astronomer Tom Geballe, who wrote this summary on behalf of the team) used Gemini North/GNIRS to follow the evolution of the near-infrared spectrum of the core-collapse supernova 2017eaw (ccSN 2017eaw) over three semesters. The data obtained from this relatively nearby event may help us to better understand the existence of dusty galaxies in the early, much more distant Universe. One of the unexpected discoveries in studies of the very early Universe is that many high redshift galaxies are “dusty.” These dusty galaxies exist as recently as several hundred million to a billion years after the Big Bang. The origin of this dust is somewhat of a mystery, because stars with masses similar to the Sun, which constitute the vast majority of stars in a galaxy, would not have evolved to the …

19 Septiembre 2018: Multi-conjugate adaptive optics technology at Gemini South reveals that young galaxies, with large amounts of star formation, and actively growing central black holes, were relatively compact in the 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. Such galaxies have hundreds of times the infrared luminosity of a normal galaxy such as the Milky Way. 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 …

27 Agosto 2018: Using the Gemini North telescope in Hawai`i, an international team of astronomers from Brazil, Italy, the Netherlands, and the UK has discovered the most distant radio galaxy to date, at 12.5 billion light years, when the Universe was just 7% of its current age. The team used spectroscopic data from the Gemini Multi-Object Spectrograph (GMOS-N) to measure a redshift of z = 5.72 for the radio galaxy identified as TGSS J1530+1049. This is the largest redshift of any known radio galaxy. The redshift of a galaxy tells astronomers its distance because galaxies at greater distances move away from us at higher speeds, and this motion causes the galaxy's light to shift farther into the red. Because light has a finite speed and takes time to reach us, more distant galaxies are also seen at earlier times in the history of the Universe. The study was led by graduate students Aayush …

17 Julio 2018: Scientists announced the discovery of 12 new moons orbiting the planet Jupiter, including one that bucks the trend by orbiting in the opposite direction from others of its ilk. Gemini observations confirmed this jovian oddball, dubbed Valetudo, after the great-granddaughter of the god Jupiter. The Gemini director’s discretionary observations were made using the Gemini Multi-Object Spectrograph (GMOS) on the Gemini North telescope atop of Hawaii’s Maunakea. Read more about this discovery in the Association of Universities for Research in Astronomy (AURA) press release that follows. Scientists using National Science Foundation Observatories find 12 new moons of Jupiter Sometimes you find something you weren’t even looking for. A team of scientists led by Carnegie’s Scott S. Sheppard, during a search to find very distant Solar System objects, just announced the discovery of twelve new moons orbiting Jupiter. The moons were first found in the spring of 2017 when the team was …

9 Julio 2018: The frustrating search for intermediate mass black holes is advancing thanks to Gemini observations of a “belch” which escaped when a black hole devoured a star. The black hole powering the blast weighed in at a few tens of thousand solar masses and is quite possibly a missing link between supermassive and stellar mass black holes. After 10 years of searching, an international team of astronomers used Gemini South, and space-based telescopes, to probe a luminous X-ray outburst unlike any seen before. The outburst was unusual because it appears to be the result of a “tidal disruption event” (TDE), in which a massive black hole slurps up an entire star, but this particular event did not occur within the center of a galaxy, where the most massive black holes reside. In their investigation, the researchers measured the mass of the black hole that powered the outburst and found it was …

31 Mayo 2018: A new study using Gemini data reveals that the ratio of binary stars in Kepler’s K2 exoplanet host stars is similar to that found elsewhere in our neighborhood of the Milky Way. According to lead author Dr. Rachel Matson of NASA’s Ames Research Center, “While we have known that about 50% of all stars are binary, to confirm a similar ratio in exoplanet host stars helps set some important constraints on the formation of potential exoplanets seen by Kepler.” Until recently, astronomers generally focused on single exoplanet host stars, believing that planets form primarily around lone stars like our Sun. However, the research led by Matson, who’s team observed 206 star systems, demonstrates that the influence of a neighboring star does not appear to deter planet formation. The presence of a very close neighboring star produces enormous collateral effects on a planetary system, possibly ejecting planets into interstellar space, or …

3 Mayo 2018: Astronomers using data from both of the Gemini Multi-Object Spectrographs (GMOS - North and South) measured the motions of stars within a sample of 32 massive elliptical cluster galaxies and found the stellar motions inconsistent with these galaxies’ solitary cousins. The galaxies chosen are known as brightest cluster galaxies (BCGs) because they are the brightest members of large galaxy clusters. The international team of astronomers obtained Gemini spectra to find the relative velocities of stars within each galaxy and then determine the central stellar velocity dispersions and radial dispersion profiles for each galaxy. “This is similar to what we see in our own Solar System with the different velocities of the planets around the Sun,” said John Blakeslee, Gemini Observatory's Head of Science. “We use the planets’ velocities to determine our Solar System’s mass distribution and it is also how we know the Sun’s mass accurately.” The researchers discovered a …

19 Febrero 2018: By measuring the brightness of about a dozen stars, lingering just outside of our galaxy, a team of astronomers believe they have solved a nearby intergalactic mystery. The researchers exposed the identities of three ultra-faint dwarf galaxy candidates using the Gemini South telescope. The team reports that the objects appear to be loose clusters of stars, not dwarf galaxies as some had previously believed. This finding has profound ramifications on the quantity of cold dark matter around our Milky Way and, by implication, other galaxies. Using the Gemini Multi-Object Spectrograph (GMOS) at the Gemini South telescope in Chile, an international research team led by Dr. Blair C. Conn of the Australian National University studied three ultra-faint dwarf galaxy candidates, and found they were not as expected. The three ultra-faint dwarf galaxy suspects, DES1, Eridanus III, and Tucana V, located in the vicinity of the Magellanic Clouds, were studied using a …

12 Enero 2018: The Core-collapse Supernova Rate Problem, or the fact that we don’t see as many core-collapse supernovae as we would expect, has a solution, thanks to research using the Gemini South telescope. The research team concludes that the majority of core collapse supernovae, exploding in luminous infrared galaxies, have previously not been found due to dust obscuration and poor spatial resolution. Core-collapse supernovae are spectacular explosions that mark the violent deaths of massive stars. An international team of astronomers, led by PhD student Erik Kool of Macquarie University in Australia, used laser guide star imaging on the Gemini South telescope to study why we don’t see as many of these core-collapse supernovae as expected. The study began in 2015 with the Supernova UNmasked By InfraRed detection (SUNBIRD) project which has shown that dust obscuration and limited spatial resolution can explain the small number of detections to date. In this, the first …

18 Diciembre 2017: Using the Gemini South telescope, researchers extracted spectra from extremely faint optical sources which they determined are nurseries of massive stars around an elliptical galaxy. Indeed, the sources were so faint that they were previously undetected and only revealed using ~4 hour exposures with the Gemini Multi-Object Spectrograph (GMOS). It is speculated that the nurseries formed as the result of a past galactic merger. Using a novel observational technique, called Multi-Slit Imaging Spectroscopy (MSIS) a team, lead by Fernanda Urrutia (Universidad de La Serena and Gemini Observatory), found a new generation of star clusters around the elliptical galaxy, NGC 2865. “The main result of our work is that we were able to detect all the clusters of massive stars around this elliptical galaxy,” said Urrutia. “Elliptical galaxies normally don’t have enough gas to form massive stars, thus we did not expect to observe star formation inside the galaxy, much less …

29 Noviembre 2017: Gemini observations played a critical role in research by scientists at the University of Washington in their quest to identify an object which appears to be “photobombing” the Andromeda Galaxy. The researchers determined that rather than being a binary star system within the neighboring Andromeda Galaxy, as previously thought, the object is really a distant galaxy containing a supermassive black hole binary – a pair of black holes orbiting each other very closely within the galaxy’s core. “The Gemini spectroscopic observations revealed the true nature of this puzzling object as a background galaxy with an active nucleus,” said Gemini’s Chief Scientist John Blakeslee. “Careful analysis of the extreme velocities seen in the spectra then led the team to suspect that the supermassive black hole in the galaxy’s center is actually a tightly bound binary.” Observations by NASA’s Chandra X-ray Observatory first cast suspicion that things weren’t as simple as they …

22 Septiembre 2017: Gemini astronomer Tom Geballe describes his recent infrared spectroscopic observations of a mysterious quintuplet of stars. Each of these stars is embedded in its own cocoon of dust in a cluster of massive stars near the center of the Milky Way. The research, using the Gemini Near Infrared Spectrograph (GNIRS) and Near-infrared Integral Field Spectrometer (NIFS) on the Gemini North telescope, confirms that four of the five stars are evolved massive stars which have expelled their outer hydrogen layers, and are rapidly approaching the explosive ends of their relatively short lives. Until this work astronomers were unable to detect the stars inside the cocoons and thereby directly discern their natures. The existence of this Infrared Quintuplet is yet another illustration of the effects of high densities of massive stars in some clusters and of the extreme conditions at the very heart of our galaxy. Most objects in the center of …