Primordial Helium Research at the Large Binocular Telescope

A recent news story from Gonzaga University reports on research by Gonzaga Professor Erik Aver using the Large Binocular Telescope to study the primordial helium abundance. The work, conducted in collaboration with Richard Pogge at Ohio State University and Evan Skillman at the University of Minnesota, was recently awarded major support through a grant of $755k from the National Science Foundation.

The study will make use of LBT spectra of more than 40 metal-poor galaxies analyzed with advanced methods to measure a value for the primordial helium abundance with an uncertainty of approximately 0.5%. The resulting increase in precision will be significant as a constraint on proposed scenarios for extending the standard model of particle physics. 

Dual and Lensed Active Galactic Nuclei at Sub-arcsecond Separations Revealed through HST and LBT Observations

A recent study led by Filippo Mannucci (INAF/Osservatorio Astrofisico di Arcetri) reported observations by the Large Binocular Telescope and Hubble Space Telescope confirming candidates for multiple supermassive black holes at small angular separation.

These objects, identified as active galactic nuclei based on the radiative signature of matter accreting onto the central compact object, were selected as potential multiple systems based on measurements from the Gaia satellite suggesting the presence of more than one peak in the light distribution seen on the sky. The LBT and HST delivered high angular resolution images allowing the sources to be seen as distinct pairs or multiple sources for the first time.

Dual supermassive black holes are of interest as candidates for merging systems that will ultimately spiral together while releasing huge amounts of energy in gravitational waves. Models tracing the formation and development of galaxies, along with their central black holes, predict the occurrence of such mergers as they evolve over cosmic time.

Multiple systems can alternatively represent images of a single active galactic nucleus, produced through the bending of light by a massive object at intermediate distance, through a process known as gravitational lensing. Gravitational lenses provide a novel means for tracing the distribution of dark matter and measuring cosmological parameters.

The LBT measurements made use of the LUCI1 infrared camera assisted by the SOUL implementation of natural guide-star, single conjugate adaptive optics.

The results are published in Mannucci et al. (2022),Nature Astronomy, 6, 1185

LBT Observations Confirm Exoplanet Candidates Identified by Gaia

The Gaia spacecraft, designed to map the three-dimensional structure of our Galaxy, has provided a rich database of precision measurements enabling other types of science, most recently the discovery of exoplanets orbiting target stars. In a recent report by Aviad Panahi (Tel Aviv University) and collaborators, Gaia photometry was used for the first time to identify candidate exoplanet transit events, signaled by a dip in a star’s brightness as an orbiting planet passes along our line of sight and covers a part of the stellar disk.

Confirmation that the temporary dimming was the result of an orbiting exoplanet was obtained for two sources, with spectra from the Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) on the Large Binocular Telescope. The data acquired over multiple epochs provide sensitive measures of the star’s radial velocity (i.e. speed of motion along our line of sight) which oscillates over time as the star is pulled by the gravity of an orbiting planet.

The LBT data enable estimation of the planets’ mass which in both cases resembles that of Jupiter. However, the newly discovered exoplanets orbit in close proximity to their parent stars, with periods of only 3 – 4 days, resulting in surface temperatures in excess of 1000 K. The discovery of these “hot jupiters” is an important demonstration of the potential for Gaia to extend the census of extrasolar planets.

The study findings are reported in Panahi et al. 2022, Astronomy & Astrophysics, 663, A101

A weird star produced the fastest nova on record

A team of users of the Large Binocular Telescope has recorded the fastest nova ever. They hope to find answers to not only the nova’s many baffling traits, but to larger questions about our solar system and the universe.

Astronomers are buzzing after observing the fastest nova ever recorded. The unusual event drew scientists’ attention to an even more unusual star. As they study it, they may find answers to not only the nova’s many baffling traits, but to larger questions about the chemistry of our solar system, the death of stars and the evolution of the universe.

The research team, led by Arizona State University Regents Professor Sumner Starrfield, Professor Charles Woodward from University of Minnesota and Research Scientist Mark Wagner from The Ohio State University, co-authored a report published in the Research Notes of the American Astronomical Society.

 A nova is a sudden explosion of bright light from a two-star system. Every nova is created by a white dwarf — the very dense leftover core of a star — and a nearby companion star. Over time, the white dwarf draws matter from its companion, which falls onto the white dwarf. The white dwarf heats this material, causing an uncontrolled reaction that releases a burst of energy. The explosion shoots the matter away at high speeds, which we observe as visible light.

The bright nova usually fades over a couple of weeks or longer. On June 12, 2021, the nova V1674 Hercules burst so bright that it was visible to the naked eye — but in just over one day, it was faint once more. It was like someone flicked a flashlight on and off.

Nova events at this level of speed are rare, making this nova a precious study subject.

“It was only about one day, and the previous fastest nova was one we studied back in 1991, V838 Herculis, which declined in about two or three days,” says Starrfield, an astrophysicist in ASU’s School of Earth and Space Exploration.

As the astronomy world watched V1674 Hercules, other researchers found that its speed wasn’t its only unusual trait. The light and energy it sends out is also pulsing like the sound of a reverberating bell.

Every 501 seconds, there’s a wobble that observers can see in both visible light waves and X-rays. A year after its explosion, the nova is still showing this wobble, and it seems it’s been going on for even longer. Starrfield and his colleagues have continued to study this quirk.

“The most unusual thing is that this oscillation was seen before the outburst, but it was also evident when the nova was some 10 magnitudes brighter,” says Wagner, who is also the head of science at the Large Binocular Telescope Observatory being used to observe the nova. “A mystery that people are trying to wrestle with is what’s driving this periodicity that you would see it over that range of brightness in the system.”

The team also noticed something strange as they monitored the matter ejected by the nova explosion — some kind of wind, which may be dependent on the positions of the white dwarf and its companion star, is shaping the flow of material into space surrounding the system.

This illustration shows an intermediate polar system, a type of two-star system that the research team thinks V1674 Hercules belongs to.  A flow of gas from the large companion star impacts an accretion disk before flowing along magnetic field lines onto the white dwarf.    Credit: Illustration by Mark Garlick. 

Though the fastest nova is (literally) flashy, the reason it’s worth further study is that novae can tell us important information about our solar system and even the universe as a whole.

A white dwarf collects and alters matter, then seasons the surrounding space with new material during a nova explosion. It’s an important part of the cycle of matter in space. The materials ejected by novae will eventually form new stellar systems. Such events helped form our solar system as well, ensuring that Earth is more than a lump of carbon.

 “We're always trying to figure out how the solar system formed, where the chemical elements in the solar system came from,” Starrfield says. “One of the things that we're going to learn from this nova is, for example, how much lithium was produced by this explosion. We're fairly sure now that a significant fraction of the lithium that we have on the Earth was produced by these kinds of explosions.”

Sometimes a white dwarf star doesn’t lose all of its collected matter during a nova explosion, so with each cycle, it gains mass. This would eventually make it unstable, and the white dwarf could generate a type 1a supernova, which is one of the brightest events in the universe. Each type 1a supernova reaches the same level of brightness, so they are known as standard candles.

“Standard candles are so bright that we can see them at great distances across the universe. By looking at how the brightness of light changes, we can ask questions about how the universe is accelerating or about the overall three-dimensional structure of the universe,” Woodward says. “This is one of the interesting reasons that we study some of these systems.”

Additionally, novae can tell us more about how stars in binary systems evolve to their death, a process that is not well understood. They also act as living laboratories where scientists can see nuclear physics in action and test theoretical concepts.

The nova took the astronomy world by surprise. It wasn’t on scientists’ radar until an amateur astronomer from Japan, Seidji Ueda, discovered and reported it.

MODS1 & MODS2, the pair of LBTO multi-object double spectrographs used by the team, seen while the telescope is pointed at horizon. Photo credit: Rick Pogge.

Citizen scientists play an increasingly important role in the field of astronomy, as does modern technology. Even though it is now too faint for other types of telescopes to see, the team is still able to monitor the nova thanks to the Large Binocular Telescope’s wide aperture and its observatory’s other equipment, including its pair of multi-object double spectrographs (MODS) and exceptional PEPSI high resolution spectrograph.

They plan to investigate the cause of the outburst and the processes that led to it, the reason for its record-breaking decline, the forces behind the observed wind, and the cause of its pulsing brightness.

AN UNEXPECTED GAMMA RAY BURST

An international group led by INAF researchers have confirmed that the gamma-ray burst GRB 200826A, which lasted less than two seconds – typical of short bursts – is associated with the explosion of a massive star, which is typical of long gamma-ray bursts. The study, involving also several universities and research institutes in Italy, is primarily based on data collected with the Large Binocular Telescope in Arizona, USA. The observations made the first ever use of adaptive optics to observe a supernova associated with a gamma-ray burst. 

Announcing the new Director of the Large Binocular Telescope

The Large Binocular Telescope Observatory, one of the largest and most advanced optical telescopes in the world, is proud to announce the appointment of its new Director, Prof. Joseph Shields, who will assume the position effective June 06, 2022.

Prof. Joseph Shields

Dr. Shields is currently Vice President for Research & Creative Activity and Dean of the Graduate College and the former Chair of the Department of Physics & Astronomy at  Ohio University.

Dr. Shields received his bachelors degree from the University of Kansas and his PhD in Astronomy from the University of California at Berkeley. He held a postdoctoral appointment at the Ohio State University and a Hubble Fellowship at the University of Arizona prior to joining the faculty at Ohio University. In his research, Shields studies the physics  of  supermassive black holes in galaxies, using both ground-based and space-based observatories. He is also interested  in the interstellar medium, star formation,  and supernovae. He is an author on more than 110 papers in the peer-reviewed literature, and served for four years as a Scientific Editor of the Astrophysical Journal.

The LBT Board of Directors appointed Prof. Shields to serve as the Observatory’s new director following an extensive international search.

“We are excited to welcome Joe and look forward to working with him to maintain the prominent position of LBT as a world-class astronomical facility,” stated Adriano Fontana, Chair of the LBT Board of Directors. “Joe has a unique combination of astronomical experience, scientific vision and managerial capabilities that make him the perfect match for LBT. Joe will build on the unique role of LBT in fostering new astronomical discoveries and the development of cutting-edge observational techniques associated with adaptive optics and interferometry.“

In accepting the Director position, Shields commented: “I am pleased and honoured to have the opportunity to lead the talented LBTO staff during the observatory’s next phase as a pioneer in the realm of extremely large optical telescopes.  The LBT has a storied history and vibrant future in technological innovation and astronomical discovery, enabled by the distinctive expertise of its partner institutions.”

The LBT Board of Directors also extended its appreciation to Dr. Christian Veillet, who successfully led the Observatory during the last ten years, completing the installation and commissioning of the initial suite of scientific instruments.

LBT is a unique astronomical facility. Located on Mt. Graham in southeast Arizona, at an elevation of 3200m/10000 ft, the LBT has  two 8.4m (27.5 feet) mirrors  side-by-side like a pair of binoculars for a combined collecting area of a single 11.8m (38.7 feet) telescope. This unique design gives it the capabilities of a 23-m (75.5 feet) telescope in some observing modes, making it the first of the next-generation extremely large telescopes.

The LBT is an international collaboration among institutions in the United States, Italy and Germany. LBT Corporation partners are: The University of Arizona on behalf of the Arizona Board of Regents; Istituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft, Germany, representing the Max-Planck Society, The Leibniz Institute for Astrophysics Potsdam, and Heidelberg University; The Ohio State University, representing OSU, University of Notre Dame, University of Minnesota and University of Virginia.

Near-Earth Asteroid Might be a Lost Fragment of the Moon

 A team of UArizona-led researchers think that the near-Earth asteroid Kamo`oalewa might actually be a miniature moon.

A near-Earth asteroid named Kamo`oalewa could be a fragment of our moon, according to a new paper published in Nature Communications Earth and Environment by a team of astronomers led by the University of Arizona.

Kamo`oalewa is a quasi-satellite – a subcategory of near-Earth asteroids that orbit the sun but remain relatively close to Earth. Little is known about these objects because they are faint and difficult to observe. Kamo`oalewa was discovered by the PanSTARRS telescope in Hawaii in 2016, and the name – found in a Hawaiian creation chant – alludes to an offspring that travels on its own. The asteroid is roughly the size of a Ferris wheel – between 150 and 190 feet in diameter – and gets as close as about 9 million miles from Earth.

Due to its orbit, Kamo`oalewa can only be observed from Earth for a few weeks every April. Its relatively small size means that it can only be seen with one of the largest telescopes on Earth. Using the UArizona-managed Large Binocular Telescope on Mount Graham in southern Arizona, a team of astronomers led by planetary sciences graduate student Ben Sharkey found that Kamo`oalewa's pattern of reflected light, called a spectrum, matches lunar rocks from NASA's Apollo missions, suggesting it originated from the moon.

The team can't yet be sure how it may have broken loose. The reason, in part, is because there are no other known asteroids with lunar origins.

"I looked through every near-Earth asteroid spectrum we had access to, and nothing matched," said Sharkey, the paper's lead author.

The debate over Kamo`oalewa's origins between Sharkey and his adviser, UArizona associate professor Vishnu Reddy, led to another three years of hunting for a plausible explanation.

"We doubted ourselves to death," said Reddy, a co-author who started the project in 2016. After missing the chance to observe it in April 2020 due to a COVID-19 shutdown of the telescope, the team found the final piece of the puzzle in 2021.

"This spring, we got much needed follow-up observations and went, 'Wow it is real,'" Sharkey said. "It's easier to explain with the moon than other ideas."

Kamo`oalewa's orbit is another clue to its lunar origins. Its orbit is similar to the Earth's, but with the slightest tilt. Its orbit is also not typical of near-Earth asteroids, according to study co-author Renu Malhotra, a UArizona planetary sciences professor who led the orbit analysis portion of the study.

"It is very unlikely that a garden-variety near-Earth asteroid would spontaneously move into a quasi-satellite orbit like Kamo`oalewa's," she said. "It will not remain in this particular orbit for very long, only about 300 years in the future, and we estimate that it arrived in this orbit about 500 years ago," Malhotra said. Her lab is working on a paper to further investigate the asteroid's origins.

An artist impression of Earth quasi-satellite Kamo`oalewa near the Earth-Moon system. Astronomers using the Large Binocular Telescope have shown that it might be a lost fragment of the moon.
Credit: Addy Graham/University of Arizona

Kamo`oalewa is about 4 million times fainter than the faintest star the human eye can see in a dark sky.

"These challenging observations were enabled by the immense light gathering power, of the twin 8.4-meter telescopes of the Large Binocular Telescope," said study co-author Al Conrad, a staff scientist with the telescope.

The study also included data from the Lowell Discovery Telescope in Flagstaff, Arizona. Other co-authors on the paper include Olga Kuhn, Christian Veillet, Barry Rothberg and David Thompson from the Large Binocular Telescope; Audrey Thirouin from Lowell Observatory and Juan Sanchez from the Planetary Science Institute in Tucson. The research was funded by NASA's Near-Earth Object Observations Program.