Monday, September 30, 2024

DECam Confirms that Early-Universe Quasar Neighborhoods are Indeed Cluttered

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Artist Illustration of Early-Universe Quasar Cosmic Neighborhood



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Cosmoview Episode 86: DECam Confirms that Early-Universe Quasar Neighborhoods are Indeed Cluttered
PR Video noirlab2422a
Cosmoview Episode 86: DECam Confirms that Early-Universe Quasar Neighborhoods are Indeed Cluttered

Cosmoview Episodio 86: DECam confirma que los vecindarios de los cuásares del Universo primitivo están realmente abarrotados



New finding with the expansive Dark Energy Camera offers a clear explanation to quasar ‘urban density’-conundrum

Observations using the Dark Energy Camera (DECam) confirm astronomers’ expectation that early-Universe quasars formed in regions of space densely populated with companion galaxies. DECam’s exceptionally wide field of view and special filters played a crucial role in reaching this conclusion, and the observations reveal why previous studies seeking to characterize the density of early-Universe quasar neighborhoods have yielded conflicting results.

Quasars are the most luminous objects in the Universe and are powered by material accreting onto supermassive black holes at the centers of galaxies. Studies have shown that early-Universe quasars have black holes so massive that they must have been swallowing gas at very high rates, leading most astronomers to believe that these quasars formed in some of the densest environments in the Universe where gas was most available. However, observational measurements seeking to confirm this conclusion have thus far yielded conflicting results. Now, a new study using the Dark Energy Camera (DECam) points the way to both an explanation for these disparate observations and also a logical framework to connect observation with theory.

DECam was fabricated by the Department of Energy and is mounted on the U.S. National Science Foundation Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory in Chile, a Program of NSF NOIRLab.

The study was led by Trystan Lambert, who completed this work as a PhD student at Diego Portales University’s Institute of Astrophysical Studies in Chile [1] and is now a postdoc at the University of Western Australia node at the International Centre for Radio Astronomy Research (ICRAR). Utilizing DECam’s massive field of view, the team conducted the largest on-sky area search ever around an early-Universe quasar in an effort to measure the density of its environment by counting the number of surrounding companion galaxies.

For their investigation, the team needed a quasar with a well-defined distance. Luckily, quasar VIK 2348–3054 has a known distance, determined by previous observations with the Atacama Large Millimeter/submillimeter Array (ALMA), and DECam’s three-square-degree field of view provided an expansive look at its cosmic neighborhood. Serendipitously, DECam is also equipped with a narrowband filter perfectly matched for detecting its companion galaxies. “This quasar study really was the perfect storm,” says Lambert. “We had a quasar with a well-known distance, and DECam on the Blanco telescope offered the massive field of view and exact filter that we needed.”

DECam’s specialized filter allowed the team to count the number of companion galaxies around the quasar by detecting a very specific type of light they emit, known as Lyman-alpha radiation. Lyman alpha radiation is a specific energy signature of hydrogen, produced when it is ionized and then recombined during the process of star formation. Lyman-alpha emitters are typically younger, smaller galaxies, and their Lyman-alpha emission can be used as a way to reliably measure their distances. Distance measurements for multiple Lyman-alpha emitters can then be used to construct a 3D map of a quasar’s neighborhood.

After systematically mapping the region of space around quasar VIK J2348-3054, Lambert and his team found 38 companion galaxies in the wider environment around the quasar — out to a distance of 60 million light-years — which is consistent with what is expected for quasars residing in dense regions. However, they were surprised to find that within 15 million light-years of the quasar, there were no companions at all.

This finding illuminates the reality of past studies aimed at classifying early-Universe quasar environments and proposes a possible explanation for why they have turned out conflicting results. No other survey of this kind has used a search area as large as the one provided by DECam, so to smaller-area searches a quasar’s environment can appear deceptively empty.

“DECam’s extremely wide view is necessary for studying quasar neighborhoods thoroughly. You really have to open up to a larger area,” says Lambert. “This suggests a reasonable explanation as to why previous observations are in conflict with one another.”

The team also suggests an explanation for the lack of companion galaxies in the immediate vicinity of the quasar. They postulate that the intensity of the radiation from the quasar may be large enough to affect, or potentially stop, the formation of stars in these galaxies, making them invisible to our observations.

“Some quasars are not quiet neighbors,” says Lambert. “Stars in galaxies form from gas that is cold enough to collapse under its own gravity. Luminous quasars can potentially be so bright as to illuminate this gas in nearby galaxies and heat it up, preventing this collapse.”

Lambert’s team is currently following up with additional observations to obtain spectra and confirm star formation suppression. They also plan to observe other quasars to build a more robust sample size.

“These findings show the value of the National Science Foundation’s productive partnership with the Department of Energy,” says Chris Davis, NSF program director for NSF NOIRLab. “We expect that productivity will be amplified enormously with the upcoming NSF–DOE Vera C. Rubin Observatory, a next-generation facility that will reveal even more about the early Universe and these remarkable objects.”




Notes

[1] This study was made possible through a collaboration between researchers at Diego Portales University and the Max Planck Institute of Astronomy. A portion of this work was funded through a grant by Chile’s National Research and Development Agency (ANID) for collaborations with the Max Planck Institutes.



More information

This research was presented in a paper entitled “A lack of LAEs within 5 Mpc of a luminous quasar in an overdensity at z=6.9: potential evidence of quasar negative feedback at protocluster scales” to appear in Astronomy & Astrophysics. DOI: 10.1051/0004-6361/202449566

The team is composed of Trystan S. Lambert (Universidad Diego Portales, Chile/University of Western Australia, Australia), R.J. Assef (Universidad Diego Portales, Chile), C. Mazzucchelli (Universidad Diego Portales, Chile), E. Bañados (Max Planck Institute of Astronomy, Germany), M. Aravena (Universidad Diego Portales, Chile), F. Barrientos (Pontificia Universidad Católica de Chile, Chile), J. González-López (Las Campanas Observatory, Chile/Universidad Diego Portales, Chile), W. Hu (George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A&M University, USA), L. Infante (Pontificia Universidad Católica de Chile, Chile), S. Malhotra (NASA Goddard Space Flight Center, USA), C. Moya-Sierralta (Pontificia Universidad Católica de Chile, Chile), J. Rhoads (NASA Goddard Space Flight Center, USA), F. Valdes (NSF NOIRLab), J. Wang (University of Science and Technology of China, People’s Republic of China), I.G.B. Wold (Center for Research and Exploration in Space Science and Technology, NASA Goddard Space Flight Center, USA/Catholic University of America, USA), and Z. Zheng (Shanghai Astronomical Observatory, People’s Republic of China).

NSF NOIRLab (U.S. National Science Foundation National Optical-Infrared Astronomy Research Laboratory), the U.S. center for ground-based optical-infrared astronomy, operates the International Gemini Observatory (a facility of NSF, NRC–Canada, ANID–Chile, MCTIC–Brazil, MINCyT–Argentina, and KASI–Republic of Korea), Kitt Peak National Observatory (KPNO), Cerro Tololo Inter-American Observatory (CTIO), the Community Science and Data Center (CSDC), and Vera C. Rubin Observatory (operated in cooperation with the Department of Energy’s SLAC National Accelerator Laboratory). It is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with NSF and is headquartered in Tucson, Arizona. The astronomical community is honored to have the opportunity to conduct astronomical research on I’oligam Du’ag (Kitt Peak) in Arizona, on Maunakea in Hawai‘i, and on Cerro Tololo and Cerro Pachón in Chile. We recognize and acknowledge the very significant cultural role and reverence that these sites have to the Tohono O’odham Nation, to the Native Hawaiian community, and to the local communities in Chile, respectively.




Links



Contacts

Trystan Lambert
Postdoc Scholar
University of Western Australia
Email:
trystanscottlambert@gmail.com

Josie Fenske
Jr. Public Information Officer
NSF NOIRLab
Email:
josie.fenske@noirlab.edu


Sunday, September 29, 2024

In Odd Galaxy, NASA's Webb Finds Potential Missing Link to First Stars

Caption: The galaxy GS-NDG-9422 may easily have gone unnoticed. However, what appears as a faint blur in this James Webb Space Telescope NIRCam (Near-Infrared Camera) image may actually be a groundbreaking discovery that points astronomers on a new path of understanding galaxy evolution in the early universe.

Detailed information on the galaxy’s chemical makeup, captured by Webb’s NIRSpec (Near-Infrared Spectrograph) instrument, indicates that the light we see in this image is coming from the galaxy’s hot gas, rather than its stars. That is the best explanation astronomers have discovered so far to explain the unexpected features in the light spectrum. They think that the galaxy’s stars are so extremely hot (more than 140,000 degrees Fahrenheit, or 80,000 degrees Celsius) that they are heating up the nebular gas, allowing it to shine even brighter than the stars themselves.

The authors of a new study on Webb’s observations of the galaxy think GS-NDG-9422 may represent a never-before-seen phase of galaxy evolution in the early universe, within the first billion years after the big bang. Their task now is to see if they can find more galaxies displaying the same features. Credits: Image: NASA, ESA, CSA, STScI, Alex Cameron (Oxford)



Looking deep into the early universe with NASA’s James Webb Space Telescope, astronomers have found something unprecedented: a galaxy with an odd light signature, which they attribute to its gas outshining its stars. Found approximately one billion years after the big bang, galaxy GS-NDG-9422 (9422) may be a missing-link phase of galactic evolution between the universe’s first stars and familiar, well-established galaxies.

“My first thought in looking at the galaxy’s spectrum was, ‘that’s weird,’ which is exactly what the Webb telescope was designed to reveal: totally new phenomena in the early universe that will help us understand how the cosmic story began,” said lead researcher Alex Cameron of the University of Oxford.

Cameron reached out to colleague Harley Katz, a theorist, to discuss the strange data. Working together, their team found that computer models of cosmic gas clouds heated by very hot, massive stars, to an extent that the gas shone brighter than the stars, was nearly a perfect match to Webb’s observations.

“It looks like these stars must be much hotter and more massive than what we see in the local universe, which makes sense because the early universe was a very different environment,” said Katz, of Oxford and the University of Chicago.

In the local universe, typical hot, massive stars have a temperature ranging between 70,000 to 90,000 degrees Fahrenheit (40,000 to 50,000 degrees Celsius). According to the team, galaxy 9422 has stars hotter than 140,000 degrees Fahrenheit (80,000 degrees Celsius).

The research team suspects that the galaxy is in the midst of a brief phase of intense star formation inside a cloud of dense gas that is producing a large number of massive, hot stars. The gas cloud is being hit with so many photons of light from the stars that it is shining extremely brightly.

In addition to its novelty, nebular gas outshining stars is intriguing because it is something predicted in the environments of the universe’s first generation of stars, which astronomers classify as Population III stars.

“We know that this galaxy does not have Population III stars, because the Webb data shows too much chemical complexity. However, its stars are different than what we are familiar with – the exotic stars in this galaxy could be a guide for understanding how galaxies transitioned from primordial stars to the types of galaxies we already know,” said Katz. At this point, galaxy 9422 is one example of this phase of galaxy development, so there are still many questions to be answered. Are these conditions common in galaxies at this time period, or a rare occurrence? What more can they tell us about even earlier phases of galaxy evolution? Cameron, Katz, and their research colleagues are actively identifying more galaxies to add to this population to better understand what was happening in the universe within the first billion years after the big bang.

“It’s a very exciting time, to be able to use the Webb telescope to explore this time in the universe that was once inaccessible,” Cameron said. “We are just at the beginning of new discoveries and understanding.”

The research paper is published in Monthly Notices of the Royal Astronomical Society.

The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).

About This Release

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Media Contact:

Leah Ramsay
Space Telescope Science Institute, Baltimore, Maryland

Christine Pulliam
Space Telescope Science Institute, Baltimore, Maryland

Permissions: Content Use Policy

Contact Us: Direct inquiries to the News Team.

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Saturday, September 28, 2024

The new and improved IC 1954

A spiral galaxy seen tilted diagonally. It has two large, curling arms that extend from the centre and wrap around. The arms are followed by thick strands of dark reddish dust. The arms and rest of the galaxy’s disc are speckled with glowing patches; some are blue in colour, others are pink, showing gas illuminated by new stars. A faint glow surrounds the galaxy, which lies on a dark, nearly empty background. Credit: ESA/Hubble & NASA, D. Thilker, J. Lee and the PHANGS-HST Team

The spiral galaxy IC 1954, located 45 million light-years from Earth in the constellation Horologium, is the star of this Picture of the Week from the Hubble Space Telescope. It sports a glowing bar in its core, two main majestically winding spiral arms and clouds of dark dust across it. An image of this galaxy was previously released in 2021; this week’s image is entirely new and now includes H-alpha data. The improved coverage of star-forming nebulae, which are prominent emitters of the red H-alpha light, can be seen in the numerous glowing, pink spots across the disc of the galaxy. Interestingly, some astronomers posit that the galaxy’s ‘bar’ is actually an energetic star-forming region that just happens to lie over the galactic centre.

The new data featured in this image come from a programme to extend the cooperation between multiple observatories: Hubble, the infrared James Webb Space Telescope, and the Atacama Large Millimeter/submillimeter Array, a ground-based radio telescope. By surveying IC 1954 and over fifty other nearby galaxies in radio, infrared, optical, and ultraviolet light, astronomers aim to fully trace and reconstruct the path matter takes through stars and the interstellar gas and dust in each galaxy. Hubble’s observing capabilities form an important part of this survey: it can capture younger stars and star clusters when they are brightest at ultraviolet and optical wavelengths, and its H-alpha filter effectively tracks emission from nebulae. The resulting dataset will form a treasure trove of research on the evolution of stars in galaxies, which Webb will build upon as it continues its science operations into the future.



Friday, September 27, 2024

Gargantuan Black Hole Jets Are Biggest Seen Yet

An artist’s illustration of the longest black hole jet system ever observed. Nicknamed Porphyrion after a mythological Greek giant, these jets span roughly 7 megaparsecs, or 23 million light-years. That is equivalent to lining up 140 Milky Way galaxies back-to-back. Porphyrion dates back to a time when our universe was less than half its present age. During this early epoch, the wispy filaments that connect and feed galaxies, known as the cosmic web, were closer together than they are now. Consequently, this colossal jet pair extended across a larger portion of the cosmic web compared to similar jets in our nearby universe. Porphyrion’s discovery thus implies that jets in the early universe may have influenced the formation of galaxies to a greater extent than previously believed. Image credit: E. Wernquist / D. Nelson (IllustrisTNG Collaboration) / M. Oei



The jumbo jets blast hot plasma well beyond their own host galaxy

Maunakea, Hawaiʻi – Astronomers have spotted the biggest pair of black hole jets ever seen, spanning 23 million light-years in total length. That’s equivalent to lining up 140 Milky Way galaxies back to back.

“This pair is not just the size of a solar system, or a Milky Way; we are talking about 140 Milky Way diameters in total,” says Martijn Oei, a Caltech postdoctoral scholar and lead author of the new study. “The Milky Way would be a little dot in these two giant eruptions.”

The study, which includes data from W. M. Keck Observatory on Maunakea, Hawaiʻi, published online today in the journal Nature and will be featured on the cover of the print issue tomorrow, September 19.

The jet megastructure, nicknamed Porphyrion after a giant in Greek mythology, dates to a time when our universe was 6.3 billion years old, or less than half its present age of 13.8 billion years. These fierce outflows—with a total power output equivalent to trillions of suns—shoot out from above and below a supermassive black hole at the heart of a remote galaxy.

Prior to Porphyrion’s discovery, the largest confirmed jet system was Alcyoneus, also named after a giant in Greek mythology. Alcyoneus, which was discovered in 2022 by the same team that found Porphyrion, spans the equivalent of around 100 Milky Ways. For comparison, the well-known Centaurus A jets, the closest major jet system to Earth, spans 10 Milky Ways.

The latest finding suggests that these giant jet systems may have had a larger influence on the formation of galaxies in the young universe than previously believed. Porphyrion existed during an early epoch when the wispy filaments that connect and feed galaxies, known as the cosmic web, were closer together than they are now. That means enormous jets like Porphyrion reached across a greater portion of the cosmic web compared to jets in the local universe.

“Astronomers believe that galaxies and their central black holes co-evolve, and one key aspect of this is that jets can spread huge amounts of energy that affect the growth of their host galaxies and other galaxies near them,” says co-author George Djorgovski, professor of astronomy and data science at Caltech. “This discovery shows that their effects can extend much farther out than we thought.”

Lurking in the Past

To find the galaxy from which Porphyrion originated, the team used the Giant Metrewave Radio Telescope in India along with ancillary data from a project called Dark Energy Spectroscopic Instrument, which operates from Kitt Peak National Observatory in Arizona. The observations pinpointed the home of the jets to a hefty galaxy about 10 times more massive than our Milky Way.

The team then used the Keck Observatory to show that Porphyrion is 7.5 billion light-years from Earth.

“Up until now, these giant jet systems appeared to be a phenomenon of the recent universe,” Oei says. “If distant jets like these can reach the scale of the cosmic web, then every place in the universe may have been affected by black hole activity at some point in cosmic time,” Oei says.

Keck Observatory’s Low Resolution Imaging Spectrometer (LRIS) also revealed that Porphyrion emerged from what is called a radiative-mode active black hole, as opposed to one that is in a jet-mode state. When supermassive black holes become active—in other words, when their immense forces of gravity tug on and heat up surrounding material—they are thought to either emit energy in the form of radiation or jets. Radiative-mode black holes were more common in the young, or distant, universe, while jet-mode ones are more common in the present-day universe.

The fact that Porphyrion came from a radiative-mode black hole came as a surprise because astronomers did not know this mode could produce such huge and powerful jets. What is more, because Porphyrion lies in the distant universe where radiative-mode black holes abound, the finding implies there may be a lot more colossal jets left to be found.


Ongoing Mysteries

How the jets can extend so far beyond their host galaxies without destabilizing is still unclear.

“Martijn’s work has shown us that there isn’t anything particularly special about the environments of these giant sources that causes them to reach those large sizes,” says Hardcastle, who is an expert in the physics of black hole jets. “My interpretation is that we need an unusually long-lived and stable accretion event around the central, supermassive black hole to allow it to be active for so long—about a billion years—and to ensure that the jets keep pointing in the same direction over all of that time. What we’re learning from the large number of giants is that this must be a relatively common occurrence.”

As a next step, Oei wants to better understand how these megastructures influence their surroundings. The jets spread cosmic rays, heat, heavy atoms, and magnetic fields throughout the space between galaxies.

Oei is specifically interested in finding out the extent to which giant jets spread magnetism.

“The magnetism on our planet allows life to thrive, so we want to understand how it came to be,” he says. “We know magnetism pervades the cosmic web, then makes its way into galaxies and stars, and eventually to planets, but the question is: Where does it start? Have these giant jets spread magnetism through the cosmos?”




About LRIS

The Low Resolution Imaging Spectrometer (LRIS) is a very versatile and ultra-sensitive visible-wavelength imager and spectrograph built at the California Institute of Technology by a team led by Prof. Bev Oke and Prof. Judy Cohen and commissioned in 1993. Since then it has seen two major upgrades to further enhance its capabilities: the addition of a second, blue arm optimized for shorter wavelengths of light and the installation of detectors that are much more sensitive at the longest (red) wavelengths. Each arm is optimized for the wavelengths it covers. This large range of wavelength coverage, combined with the instrument’s high sensitivity, allows the study of everything from comets (which have interesting features in the ultraviolet part of the spectrum), to the blue light from star formation, to the red light of very distant objects. LRIS also records the spectra of up to 50 objects simultaneously, especially useful for studies of clusters of galaxies in the most distant reaches, and earliest times, of the universe. LRIS was used in observing distant supernovae by astronomers who received the Nobel Prize in Physics in 2011 for research determining that the universe was speeding up in its expansion.

About W. M. Keck Observatory

The W. M. Keck Observatory telescopes are among the most scientifically productive on Earth. The two 10-meter optical/infrared telescopes atop Maunakea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometers, and world-leading laser guide star adaptive optics systems. Some of the data presented herein were obtained at Keck Observatory, which is a private 501(c) 3 non-profit organization operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the Native Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.


Thursday, September 26, 2024

NASA's Chandra Finds Galaxy Cluster That Crosses the Streams

 
Zwicky 8338
Credit X-ray: NASA/CXC/Xiamen Univ./C. Ge; Optical: DESI collaboration; Image Processing: NASA/CXC/SAO/N. Wolk




Astronomers using NASA’s Chandra X-ray Observatory have found a galaxy cluster has two streams of superheated gas crossing one another. This result shows that crossing the streams may lead to the creation of new structure.

Researchers have discovered an enormous, comet-like tail of hot gas — spanning over 1.6 million light-years long — trailing behind a galaxy within the galaxy cluster called Zwicky 8338 (Z8338 for short). This tail, spawned as the galaxy had some of its gas stripped off by the hot gas it is hurtling through, has split into two streams.

This is the second pair of tails trailing behind a galaxy in this system. Previously, astronomers discovered a shorter pair of tails from a different galaxy near this latest one. This newer and longer set of tails was only seen because of a deeper observation with Chandra that revealed the fainter X-rays.

Tails in Zwicky 8338
Credit: X-ray: NASA/CXC/Xiamen Univ./C. Ge; Optical: DESI collaboration; 
Image Processing: NASA/CXC/SAO/N. Wolk)

Astronomers now have evidence that these streams trailing behind the speeding galaxies have crossed one another. Z8338 is a chaotic landscape of galaxies, superheated gas, and shock waves (akin to sonic booms created by supersonic jets) in one relatively small region of space. These galaxies are in motion because they were part of two galaxy clusters that collided with each other to create Z8338.

This new composite image shows this spectacle. X-rays from Chandra (represented in purple) outline the multimillion-degree gas that outweighs all of the galaxies in the cluster. The Chandra data also shows where this gas has been jettisoned behind the moving galaxies. Meanwhile an optical image from the Dark Energy Survey from the Cerro Tololo Inter-American Observatory in Chile shows the individual galaxies peppered throughout the same field of view.

The original gas tail discovered in Z8338 is about 800,000 light-years long and is seen as vertical in this image (see the labeled version). The researchers think the gas in this tail is being stripped away from a large galaxy as it travels through the galaxy cluster. The head of the tail is a cloud of relatively cool gas about 100,000 light-years away from the galaxy it was stripped from. This tail is also separated into two parts.

The team proposes that the detachment of the tail from the large galaxy may have been caused by the passage of the other, longer tail. Under this scenario, the tail detached from the galaxy because of the crossing of the streams.

The results give useful information about the detachment and destruction of clouds of cooler gas like those seen in the head of the detached tail. This work shows that the cloud can survive for at least 30 million years after it is detached. During that time, a new generation of stars and planets may form within it.

The Z8338 galaxy cluster and its jumble of galactic streams are located about 670 million light-years from Earth. A paper describing these results appeared in the Aug. 8, 2023, issue of the Monthly Notices of the Royal Astronomical Society and is available online at: https://academic.oup.com/mnras/article/525/1/1365/7239302.

NASA's Marshall Space Flight Center manages the Chandra program. The Smithsonian Astrophysical Observatory's Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.





Visual Description:

This release features a composite image of two pairs of hot gas tails found inside a single galaxy cluster. The image is presented both labeled and unlabeled, with color-coded ovals encircling the hot gas tails.

In both the labeled and unlabeled versions of the image, mottled purple gas speckles a region of space dotted with distant flecks of red and white. Also present in this region of space are several glowing golden dots. These dots are individual galaxies that together form the cluster Zwicky 8338.

To our right of center is a glowing golden galaxy with a mottled V shaped cloud of purple above it. Yellow labels identify the two arms of the V as tails trailing behind the hurtling galaxy below.

To our left of center is another golden galaxy, this one surrounded by purple gas. Behind it, opening toward our right in the shape of a widening V lying on its side, are two more mottled purple clouds. Labeled in white, these newly-discovered gas tails are even larger than the previously discovered tails labeled in yellow. These tails, which overlap with the galaxy on our right, are over 1.6 million light-years long.



Fast Facts for Zwicky 8338:

Scale: Image is about 20 arcmin (3.8 million light-years) across.
Category:Groups & Clusters of Galaxies, Normal Galaxies & Starburst Galaxies
Coordinates (J2000): RA 18h 11m 01.6s | Dec +49° 54´ 42.2"
Constellation: Hercules
Observation Dates: 3 observations from Jan 04 2013 to Dec 27 2016
Observation Time: 19 hours 20 minutes
Obs. ID: 15163, 18281, 19978
Instrument: ACIS
References: Ge, C. et al, 2023, MNRAS, 525, 1365; arXiv:2308.00328
Color Code: X-ray: purple; Optical: red, green, and blue.
Distance Estimate: About 670 million light-years


Wednesday, September 25, 2024

NASA's Webb Provides Another Look Into Galactic Collisions

Arp 107 (NIRCam and MIRI Image)
Credits: Image: NASA, ESA, CSA, STScI

Credits: Image: NASA, ESA, CSA, STScI

Arp 107 (Compass Image)
Credits: Image: NASA, ESA, CSA, STScI



Smile for the camera! An interaction between an elliptical galaxy and a spiral galaxy, collectively known as Arp 107, seems to have given the spiral a happier outlook thanks to the two bright “eyes” and the wide semicircular “smile.” The region has been observed before in infrared by NASA’s Spitzer Space Telescope in 2005, however NASA’s James Webb Space Telescope displays it in much higher resolution. This image is a composite, combining observations from Webb’s MIRI (Mid-Infrared Instrument) and NIRCam (Near-Infrared Camera).

NIRCam highlights the stars within both galaxies and reveals the connection between them: a transparent, white bridge of stars and gas pulled from both galaxies during their passage. MIRI data, represented in orange-red, shows star-forming regions and dust that is composed of soot-like organic molecules known as polycyclic aromatic hydrocarbons. MIRI also provides a snapshot of the bright nucleus of the large spiral, home to a supermassive black hole.

The spiral galaxy is classified as a Seyfert galaxy, one of the two largest groups of active galaxies, along with galaxies that host quasars. Seyfert galaxies aren’t as luminous and distant as quasars, making them a more convenient way to study similar phenomena in lower energy light, like infrared.

This galaxy pair is similar to the Cartwheel Galaxy, one of the first interacting galaxies that Webb observed. Arp 107 may have turned out very similar in appearance to the Cartwheel, but since the smaller elliptical galaxy likely had an off-center collision instead of a direct hit, the spiral galaxy got away with only its spiral arms being disturbed.

The collision isn’t as bad as it sounds. Although there was star formation occurring before, collisions between galaxies can compress gas, improving the conditions needed for more stars to form. On the other hand, as Webb reveals, collisions also disperse a lot of gas, potentially depriving new stars of the material they need to form.

Webb has captured these galaxies in the process of merging, which will take hundreds of millions of years. As the two galaxies rebuild after the chaos of their collision, Arp 107 may lose its smile, but it will inevitably turn into something just as interesting for future astronomers to study.

Arp 107 is located 465 million light-years from Earth in the constellation Leo Minor.

The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).




About This Release

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Matthew Brown
Space Telescope Science Institute, Baltimore, Maryland

Christine Pulliam
Space Telescope Science Institute, Baltimore, Maryland

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Contact Us: Direct inquiries to the News Team.


Tuesday, September 24, 2024

Fireworks at Closest Approach: Repeated X-ray Flares from a Young Binary System

Two young protostars in a cosmic tango that brings them within 10 stellar radii every two weeks. This artist’s illustration of the DQ Tau system shows the intense fireworks that occur every fortnight as these two swiftly moving stars are ever, ever getting back together. Image credit: NASA/JPL-Caltech/R. Hurt (IPAC).

DQ Tau is a unique binary system. Approximately 650 light-years away in the Taurus constellation, DQ Tau consists of two young stars still in the process of forming. The protostars have not yet ignited hydrogen burning in their cores (the fusion process that heats mature stars). Instead, they are glowing as they evolve from their natal form (diffuse clouds of gas) and are heated by this gravitational collapse. Each is half the mass of the Sun and currently twice its radius, dancing in a highly elongated orbit which has them plunging in towards each other every 15.8 days. At closest approach in this violent cosmic tango, the separation between the two stars is exceptionally small, only 8-10 stellar radii. Characteristic of this early phase, the protostars in DQ Tau harbor strong magnetic fields on their surfaces. Also, like most protostars, the DQ Tau system is surrounded by a disk in which planets are also forming. Understanding planet formation, including how the intense flares characteristic of protostars affect disk heating and chemistry, are areas of active research.

DQ Tau provides an exceptional laboratory for such studies. Like clockwork, the DQ Tau system brightens at closest approach. While large X-ray flares in young stars are generally rare and unpredictable (as on our own star, the Sun), the presence of the predictable X-ray super-flares and outbursts in DQ Tau enables synchronized studies of these cosmic fireworks. Like tourists at Yellowstone National Park timing their visit to Old Faithful Geyser, astronomers can plan ahead, coordinating telescopes to jointly investigate these intense flares and understand how they affect the protoplanetary disk. X-ray flares come as the protostar magnetospheres collide, while the lower energy optical and ultraviolet flares also come from accretion of material onto the young stars. Infrared and radio studies probe the changing temperature and chemistry of the protoplanetary disk.

In a recent paper published in the Astrophysical Journal, scientists led by Konstantin Getman at Pennsylvania State University report on new observations of a single orbit of DQ Tau in July and August 2022 using the NuSTAR, Swift, and Chandra X-ray telescopes. NuSTAR accesses higher energy X-rays, while Swift and Chandra access lower energy X-rays. The observations indicate that most of the X-ray emission is from interactions of the magnetospheres of these young stars at closest approach. In a process similar to what is seen on our own Sun, magnetic field collisions and reconnections produce strong high-energy X-ray emission. This heats the surrounding region to high temperature, detectable as thermal emission in the lower energy X-rays. Notably, however, flares on our Sun occur among coronal magnetic loops much smaller than the star, with sizes of 1000 to 10,000 km. In contrast, the DQ Tau super-flares occur on spatial scales a thousand times larger, corresponding to approximately 10 million km or tens of stellar radii. The current study is part of a broader campaign using additional ground-based telescopes to investigate the influence of DQ Tau’s stellar radiation on the chemistry within its surrounding disk.


Monday, September 23, 2024

Huge gamma-ray burst collection ‘rivals 250-year-old Messier catalogue’

Gamma-ray bursts (like the one depicted in this artist’s impression) are the most violent explosions in the Universe, releasing more energy than the Sun would in 10 billion years. 
Credit: NASA/Swift/Cruz deWilde
Licence type: Attribution (CC BY 4.0)



Hundreds of gamma-ray bursts (GRBs) have been recorded as part of an enormous global effort so extensive it "rivals the catalogue of deep-sky objects created by Messier 250 years ago", astronomers say.

GRBs are the most violent explosions in the Universe, releasing more energy than the Sun would in 10 billion years. They occur when either a massive star dies or two neutron stars merge.

The explosions are so formidable that if one were to erupt within a distance of 1,000 light-years from Earth – which is predicted to happen every 500 million years – the blast of radiation could damage our ozone layer and have devastating consequences for life. However, the chances of such an event occurring any time soon are extremely low.

First observed almost six decades ago, GRBs also have the potential to help us better understand the history of our Universe, from its earliest stars to how it looks today.

The latest research recorded 535 GRBs – the nearest of which was 77 million light-years from Earth – from 455 telescopes and instruments across the world.

It was led by Professor Maria Giovanna Dainotti, of the National Astronomical Observatory of Japan, and has been published today in the Monthly Notices of the Royal Astronomical Society.

The researchers likened their collection to the 110 deep-sky objects catalogued by the French astronomer Charles Messier in the 18th century. To this day the catalogue continues to provide astronomers – both professional and amateur – with a range of easy-to-find objects in the night sky.

"Our research enhances our understanding of these enigmatic cosmic explosions and showcases the collaborative effort across nations," said Professor Dainotti.

"The result is a catalogue akin to the one created by Messier 250 years ago, which classified deep-sky objects observable at that time."

It has been hailed by co-author Professor Alan Watson, of the National Autonomous University of Mexico, as a "great resource" that could help "push the frontiers of our knowledge forward".

This animation models a gamma-ray burst called GRB 080319B, detected by NASA's Swift satellite in 2008. It shows jets of particles and gamma radiation being emitted in opposite directions as a massive star collapses, first a narrow beam (white) and then a wider one (purple). Credit: NASA/Swift/Cruz deWilde. Download Videos and Images

Professors Watson and Dainotti were part of a team of more than 50 scientists who meticulously studied how GRB light reaches Earth over several weeks and, in some cases, even months after the explosion. The result, they say, is the largest catalogue ever assembled of GRBs observed in optical wavelengths with measured distances.

It includes 64,813 photometric observations collected over 26 years, with notable contributions from the Swift satellites, the RATIR camera, and the Subaru Telescope.

What the team found particularly interesting about their findings was that nearly a third of the GRBs recorded (28 per cent) did not change or evolve as the light from the explosions travelled across the cosmos.

Co-author Dr Rosa Becerra, of the University of Tor Vergata in Rome, said this suggests that some of the most recent GRBs behave in exactly the same way as those which occurred billions of years ago.

Such a finding is at odds with the big picture commonly seen in the Universe, where objects have continuously evolved from the Big Bang.

Professor Dainotti added: "This phenomenon could indicate a very peculiar mechanism for how these explosions occur, suggesting that the stars linked to GRBs are more primitive than those born more recently.

"However, this hypothesis still needs more investigation."

On the other hand, for the few GRBs where this optical evolution matches the X-ray evolution, a more straightforward explanation is possible.

"Specifically, we are observing an expanding plasma composed of electrons and positrons that cools over time, and like a hot iron rod radiating redder and redder light as it cools, we do see a transition of the emission mechanism," said fellow researcher Professor Bruce Gendre, of the University of the Virgin Islands.

"In this case, this mechanism may be linked to the magnetic energy that powers these phenomena."

The researchers now want the astronomical community to help expand their GRB compilation further. They have made the data accessible through a user-friendly web app and have called on their peers to add to it, ideally by sharing findings in the same format.

"Adopting a standardised format and units, potentially linked to the International Virtual Observatory Alliance protocols, will enhance the consistency and accessibility of the data in this field," Professor Gendre said.

"Once the data are secured, additional population studies will be conducted, triggering new discoveries based on the statistical analysis of the current work."




Media contacts:

Sam Tonkin
Royal Astronomical Society
Mob: +44 (0)7802 877 700

press@ras.ac.uk

Dr Robert Massey
Royal Astronomical Society
Mob: +44 (0)7802 877 699

press@ras.ac.uk

Science contacts:

Professor Maria Dainotti
Mob: +81 (0)80 3082 1978

mariagiovannadainotti@yahoo.it



Further information

The new study 'An optical gamma-ray burst catalogue with measured redshift PART I: Data release of 535 gamma-ray bursts and colour evolution', Professor Maria Giovanna Dainotti et al., has been published in Monthly Notices of the Royal Astronomical Society.



Notes for editors

About the Royal Astronomical Society

TThe Royal Astronomical Society (RAS), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science.

The RAS organises scientific meetings, publishes international research and review journals, recognises outstanding achievements by the award of medals and prizes, maintains an extensive library, supports education through grants and outreach activities and represents UK astronomy nationally and internationally. Its more than 4,000 members (Fellows), a third based overseas, include scientific researchers in universities, observatories and laboratories as well as historians of astronomy and others.

The RAS accepts papers for its journals based on the principle of peer review, in which fellow experts on the editorial boards accept the paper as worth considering. The Society issues press releases based on a similar principle, but the organisations and scientists concerned have overall responsibility for their content.


Sunday, September 22, 2024

The Search for the First Stars to Light Up the Universe

An artist's impression of the first stars in the universe going supernova.
Credit:
NAOJ, CC BY 4.0

Title: A Hide-and-Seek Game: Looking for Population III Stars During the Epoch of Reionization Through the HeIIλ1640 Line
Authors: Alessandra Venditti et al.
First Author’s Institution: Sapienza University of Rome
Status: Published in ApJL



The Dawn of the Universe

A long time ago, in a galaxy far, far away… the very first stars lit up the universe, ending the cosmic dark ages and ushering in the cosmic dawn. In our current best model of the universe, this happened around 13.4 billion years ago, around 100 million years after the Big Bang. Finding evidence of these very first stars, also called Population III (Pop III) stars, is one of the ultimate treasure hunts in astronomy, and one that JWST was specifically designed for.

These Pop III stars were formed from highly pristine gas, i.e., from clouds that are almost exclusively hydrogen and helium (the lightest elements in the periodic table). It’s these first stars that then began to form and release heavier elements, and after many billions of years of star formation, the universe today is a lot more chemically evolved. However, some pockets of pristine gas reservoirs are predicted to hang around even after cosmic dawn, meaning that Pop III stars could still exist as late as 12.5 billion years ago (which corresponds to a redshift of z = 6).

The authors of today’s article carry out a very interesting experiment to predict just how many Pop III stars we might be able to find at these later times (at redshifts of z = 6–10, which correspond to ~12.5–13 billion years ago). The first important question they address is how we even go about finding these stars.

Oh Look, a Clue!

Formation within a pristine environment is a key characteristic of Pop III stars, and it actually helps us find them. Thanks to their hydrogen-rich composition, Pop III stars are theorised to be much more massive than modern stars and capable of powering very energetic (hard) radiation fields. With this huge amount of energy, they are able to double ionise the helium in the surrounding gas, which then causes emission of the helium-II recombination line at 1640 Angstroms. This emission line is therefore a great clue for finding Pop III stars!

We can even predict how many Pop III systems should exist at each point in time and how strong this emission line should be. To do this, the authors use the dustyGadget cosmological simulations. Essentially, they simulate the evolution of a universe of a certain size (volume) and include as much physics as possible (for example, star formation recipes). These simulations are currently the largest-volume simulations that also include models for Pop III stars. In the top panels of Figure 1, you can see how many Pop III systems exist in the simulations as a function of stellar mass and at different redshifts (different points in cosmic history), indicated by the solid grey line.

Figure 1: Top panels: Number density of Pop III systems expected at a given redshift in haloes within a given range of stellar mass. The total number density is shown as a solid grey line, while the numbers observable by JWST NIRSpec Integral Field Unit (IFU) are shown by the golden lines and those observable through NIRSpec Multi-Object Spectroscopy (MOS) by the brown lines. The solid/dashed line style refers to the best-/worst-case observations. Bottom panels: The fraction of Pop III stars missed in JWST/NIRSpec observations. The authors find that a significant number of Pop III systems can be overlooked by JWST. Credit: Venditti et al. 2024

The downside is that this emission is faint and difficult to observe, so next the authors need to consider the capabilities of our current best instrument (JWST).

Is JWST up to the Task?

JWST hosts a variety of instruments, and for this work we are mainly interested in the NIRSpec Integral Field Unit and the NIRSpec Multi-Object Spectroscopy modes. We can make a pretty good estimate of just how capable these instruments are at detecting helium-II 1640 by calculating their sensitivity limits, i.e., how strong does the emission need to be for us to detect it? The authors calculate the sensitivity limits of these instruments for a variety of observing times and set ups. They then compare the sensitivity limit to the predicted emission line strength of the simulated Pop III systems to work out how many of those systems they would be able to observe (coloured lines in top panels) and what fraction are missed (bottom panels).

These results indicate that only the brightest Pop III systems (within the most massive haloes) can be observed. Very low-luminosity systems might be missed even with ~50-hour exposures. However, there’s still hope! Even with these limitations, the authors predict that more than 400 Pop III systems could be discovered within current JWST surveys — although spectroscopic follow-ups would be necessary to identify them.

Overall, today’s article makes some very exciting predictions about finding Population III stars using JWST, which would help astronomers understand the very first light in the universe.

Original astrobite edited by Nathalie Korhonen Cuestas.




About the author, Lucie Rowland:

I’m a first-year PhD student at Leiden Observatory in the Netherlands, studying massive, star-forming galaxies in the early universe with ALMA and JWST. It’s a really exciting time to be interested in astronomy, so I hope to make groundbreaking new research more accessible!



Editor’s Note: Astrobites is a graduate-student-run organization that digests astrophysical literature for undergraduate students. As part of the partnership between the AAS and astrobites, we occasionally repost astrobites content here at AAS Nova. We hope you enjoy this post from astrobites; the original can be viewed at astrobites.org.


A wobble from Mars could be sign of dark matter, MIT study finds

An artist’s illustration depicts a primordial black hole (at left) flying past, and briefly “wobbling” the orbit of Mars (at right), with the sun in the background. MIT scientists say such a wobble could be detectable by today’s instruments. Credit: Image by Benjamin Lehmann, using SpaceEngine @ Cosmographic Software LLC.



Watching for changes in the Red Planet’s orbit over time could be new way to detect passing dark matter.

In a new study, MIT physicists propose that if most of the dark matter in the universe is made up of microscopic primordial black holes — an idea first proposed in the 1970s — then these gravitational dwarfs should zoom through our solar system at least once per decade. A flyby like this, the researchers predict, would introduce a wobble into Mars’ orbit, to a degree that today’s technology could actually detect.

Such a detection could lend support to the idea that primordial black holes are a primary source of dark matter throughout the universe.

“Given decades of precision telemetry, scientists know the distance between Earth and Mars to an accuracy of about 10 centimeters,” says study author David Kaiser, professor of physics and the Germeshausen Professor of the History of Science at MIT. “We’re taking advantage of this highly instrumented region of space to try and look for a small effect. If we see it, that would count as a real reason to keep pursuing this delightful idea that all of dark matter consists of black holes that were spawned in less than a second after the Big Bang and have been streaming around the universe for 14 billion years.”

Kaiser and his colleagues report their findings today in the journal Physical Review D. The study’s co-authors are lead author Tung Tran ’24, who is now a graduate student at Stanford University; Sarah Geller ’12, SM ’17, PhD ’23, who is now a postdoc at the University of California at Santa Cruz; and MIT Pappalardo Fellow Benjamin Lehmann.

Beyond particles

Less than 20 percent of all physical matter is made from visible stuff, from stars and planets, to the kitchen sink. The rest is composed of dark matter, a hypothetical form of matter that is invisible across the entire electromagnetic spectrum yet is thought to pervade the universe and exert a gravitational force large enough to affect the motion of stars and galaxies.

Physicists have erected detectors on Earth to try and spot dark matter and pin down its properties. For the most part, these experiments assume that dark matter exists as a form of exotic particle that might scatter and decay into observable particles as it passes through a given experiment. But so far, such particle-based searches have come up empty.

In recent years, another possibility, first introduced in the 1970s, has regained traction: Rather than taking on a particle form, dark matter could exist as microscopic, primordial black holes that formed in the first moments following the Big Bang. Unlike the astrophysical black holes that form from the collapse of old stars, primordial black holes would have formed from the collapse of dense pockets of gas in the very early universe and would have scattered across the cosmos as the universe expanded and cooled.

These primordial black holes would have collapsed an enormous amount of mass into a tiny space. The majority of these primordial black holes could be as small as a single atom and as heavy as the largest asteroids. It would be conceivable, then, that such tiny giants could exert a gravitational force that could explain at least a portion of dark matter. For the MIT team, this possibility raised an initially frivolous question.

“I think someone asked me what would happen if a primordial black hole passed through a human body,” recalls Tung, who did a quick pencil-and-paper calculation to find that if such a black hole zinged within 1 meter of a person, the force of the black hole would push the person 6 meters, or about 20 feet away in a single second. Tung also found that the odds were astronomically unlikely that a primordial black hole would pass anywhere near a person on Earth.

Their interest piqued, the researchers took Tung’s calculations a step further, to estimate how a black hole flyby might affect much larger bodies such as the Earth and the moon.

“We extrapolated to see what would happen if a black hole flew by Earth and caused the moon to wobble by a little bit,” Tung says. “The numbers we got were not very clear. There are many other dynamics in the solar system that could act as some sort of friction to cause the wobble to dampen out.”

Close encounters

To get a clearer picture, the team generated a relatively simple simulation of the solar system that incorporates the orbits and gravitational interactions between all the planets, and some of the largest moons.

“State-of-the-art simulations of the solar system include more than a million objects, each of which has a tiny residual effect,” Lehmann notes. “But even modeling two dozen objects in a careful simulation, we could see there was a real effect that we could dig into.”

The team worked out the rate at which a primordial black hole should pass through the solar system, based on the amount of dark matter that is estimated to reside in a given region of space and the mass of a passing black hole, which in this case, they assumed to be as massive as the largest asteroids in the solar system, consistent with other astrophysical constraints.

“Primordial black holes do not live in the solar system. Rather, they’re streaming through the universe, doing their own thing,” says co-author Sarah Geller. “And the probability is, they’re going through the inner solar system at some angle once every 10 years or so.”

Given this rate, the researchers simulated various asteroid-mass black holes flying through the solar system, from various angles, and at velocities of about 150 miles per second. (The directions and speeds come from other studies of the distribution of dark matter throughout our galaxy.) They zeroed in on those flybys that appeared to be “close encounters,” or instances that caused some sort of effect in surrounding objects. They quickly found that any effect in the Earth or the moon was too uncertain to pin to a particular black hole. But Mars seemed to offer a clearer picture.

The researchers found that if a primordial black hole were to pass within a few hundred million miles of Mars, the encounter would set off a “wobble,” or a slight deviation in Mars’ orbit. Within a few years of such an encounter, Mars’ orbit should shift by about a meter — an incredibly small wobble, given the planet is more than 140 million miles from Earth. And yet, this wobble could be detected by the various high-precision instruments that are monitoring Mars today.

If such a wobble were detected in the next couple of decades, the researchers acknowledge there would still be much work needed to confirm that the push came from a passing black hole rather than a run-of-the-mill asteroid.

“We need as much clarity as we can of the expected backgrounds, such as the typical speeds and distributions of boring space rocks, versus these primordial black holes,” Kaiser notes. “Luckily for us, astronomers have been tracking ordinary space rocks for decades as they have flown through our solar system, so we could calculate typical properties of their trajectories and begin to compare them with the very different types of paths and speeds that primordial black holes should follow.”

To help with this, the researchers are exploring the possibility of a new collaboration with a group that has extensive expertise simulating many more objects in the solar system.

“We are now working to simulate a huge number of objects, from planets to moons and rocks, and how they’re all moving over long time scales,” Geller says. “We want to inject close encounter scenarios, and look at their effects with higher precision.”

“It’s a very neat test they’ve proposed, and it could tell us if the closest black hole is closer than we realize,” says Matt Caplan, associate professor of physics at Illinois State University, who was not involved in the study. “I should emphasize there’s a little bit of luck involved too. Whether or not a search finds a loud and clear signal depends on the exact path a wandering black hole takes through the solar system. Now that they’ve checked this idea with simulations, they have to do the hard part — checking the real data.”

This work was supported in part by the U.S. Department of Energy and the U.S. National Science Foundation, which includes an NSF Mathematical and Physical Sciences postdoctoral fellowship.

Jennifer Chu | MIT News



Saturday, September 21, 2024

NSF–DOE Rubin Observatory’s Unparalleled Vision Will Revolutionize Multi-Messenger Astronomy

PR Image noirlab2421a
Artist’s Illustration of Multi-Messenger Event




Vera C. Rubin Observatory will unite coordinated observations of cosmic phenomena using the four messengers of the Universe

Photons, neutrinos, cosmic rays and gravitational waves all carry information about the Universe. Multi-messenger astronomy brings together these four signals to investigate astronomical events from multiple cosmic perspectives. With its sensitive camera and suite of filters, NSF–DOE Vera C. Rubin Observatory will increase the population of known multi-messenger sources by obtaining crucial color information and localizing events for follow-up observations by other telescopes.

Astronomy has always relied on light to convey information about the Universe. But capturing photons is no longer the only technique scientists have for studying astronomical phenomena. Subatomic particles, such as neutrinos and those that are delivered in the form of cosmic rays, as well as gravitational waves — ripples in the fabric of space-time — are also messengers. Multi-messenger astronomy aims to combine the information from more than one of these signals to give researchers a deeper understanding of some of the most extreme events in the Universe. NSF–DOE Vera C. Rubin Observatory will soon contribute to this emerging field by using its powerful camera and wide field of view to find faint multi-messenger sources and point other telescopes in the right direction for follow-up observations.

Rubin Observatory is jointly funded by the U.S. National Science Foundation (NSF) and the U.S. Department of Energy, Office of Science (DOE/SC). It is a Program of NSF NOIRLab, which, along with SLAC National Accelerator Laboratory, will jointly operate Rubin.

Multi-messenger astronomy is an enhanced way of studying cosmic events that are predicted to emit more than one type of signal, such as stellar explosions, actively feeding black holes, and collisions between compact objects, to name just a few. Each messenger communicates unique information about the physical processes and energies involved. When a single source is observed using multiple signals the data can be combined to reach a deeper level of insight. “The result is more than the sum of its parts,” says Raffaella Margutti, associate professor at the University of California at Berkeley.

In addition to conducting a massive study of the southern sky called the Legacy Survey of Space and Time (LSST), Rubin will also perform ‘Target of Opportunity’ observations in quick response to alerts of potential multi-messenger sources. As the fastest-slewing large telescope in the world, Rubin can point to targets in as little as three minutes. Such observations will provide crucial information about an event’s optical — meaning wavelengths detectable by the human eye — properties, which in turn helps localize the event for follow-up by other telescopes.

However, in order to coordinate multiple telescopes capable of detecting the different types of messengers, scientists have to know where to look. Signals such as gravitational waves and neutrinos can point scientists in the general direction of a source, but in order to pinpoint its exact location you need light. This is where Rubin, equipped with the largest and most sensitive camera ever built for astronomy and astrophysics, will shine.

Margutti, whose studies focus specifically on finding the electromagnetic counterparts to gravitational wave events, explains, “Gravitational wave observatories can only tell you ‘look at this large area and search for something very faint.’ But you don't know exactly where to look.” Furthermore, the distance at which current observatories are capable of detecting gravitational waves can be far beyond the limit of what they can detect with photons, making it hard to observe an event with both messengers.

With its deep and wide capabilities, Rubin will help mitigate both of these challenges. “Rubin wins twice,” says Margutti. “Its strong light-collecting power and ability to scan large sections of sky mean it’s very sensitive to faint optical signals, like those we would be seeking from a gravitational wave source.”

So far only one multi-messenger gravitational wave event has been observed: a merger between two neutron stars that sent both space-time ripples and photons careening across the cosmos. Other events predicted to emit more than one messenger are black hole-neutron star and black hole-black hole mergers. “I would be super excited if we found photons coming from these types of mergers,” says Margutti. “Rubin is uniquely positioned to confirm or expand on the types of mergers that produce light.”

Rubin’s ability to detect faint sources will also be a game changer for studying neutrinos. Robert Stein, California Institute of Technology postdoctoral scholar, explains: “In neutrino science there are many different types of possible sources, but existing optical telescopes are only able to see the brightest, most unusual ones.” Based on the number of neutrinos arriving at detectors here on Earth, scientists believe there to be a vast population of neutrino sources at varying distances throughout the Universe. However, given the limits of existing telescopes, Stein estimates that only 5–10% of them are also detectable with photons. By bringing myriad faint sources to light for the very first time, Rubin could increase that to 50%.

“Neutrino science is in its infancy, so our list of possible sources is still emerging,” says Stein. “In ten or fifteen years we will likely discover that events we’ve already known about are also neutrino source populations.”

Margutti and Stein are both confident that the overarching power of Rubin in the era of multi-messenger astronomy will be in uncovering the unexpected. As it covers vast swaths of the southern hemisphere sky, there’s no telling what Rubin’s unparalleled vision is going to reveal. “The best use of Rubin is as a discovery machine,” says Margutti. Stein echoes a similar sentiment, saying, “I hope to learn what new types of sources we should investigate next. If Rubin could give us that clarity, and I believe it will, that would be amazing.”




More information

The NSF–DOE Rubin Observatory is a joint initiative of the U.S. National Science Foundation (NSF) and the Department of Energy (DOE). Its primary mission is to carry out the Legacy Survey of Space and Time, providing an unprecedented data set for scientific research supported by both agencies. Rubin is operated jointly by NSF NOIRLab and SLAC National Accelerator Laboratory (SLAC). NOIRLab is managed for NSF by the Association of Universities for Research in Astronomy (AURA) and SLAC is operated for DOE by Stanford University. France provides key support to the construction and operations of Rubin Observatory through contributions from CNRS/IN2P3. Additional contributions from a number of international organizations and teams are acknowledged.

The U.S. National Science Foundation (NSF) is an independent federal agency created by Congress in 1950 to promote the progress of science. NSF supports basic research and people to create knowledge that transforms the future.

NSF NOIRLab (U.S. National Science Foundation National Optical-Infrared Astronomy Research Laboratory), the U.S. center for ground-based optical-infrared astronomy, operates the International Gemini Observatory (a facility of NSF, NRC–Canada, ANID–Chile, MCTIC–Brazil, MINCyT–Argentina, and KASI–Republic of Korea), Kitt Peak National Observatory (KPNO), Cerro Tololo Inter-American Observatory (CTIO), the Community Science and Data Center (CSDC), and Vera C. Rubin Observatory (in cooperation with DOE’s SLAC National Accelerator Laboratory). It is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with NSF and is headquartered in Tucson, Arizona. The astronomical community is honored to have the opportunity to conduct astronomical research on I’oligam Du’ag (Kitt Peak) in Arizona, on Maunakea in Hawai‘i, and on Cerro Tololo and Cerro Pachón in Chile. We recognize and acknowledge the very significant cultural role and reverence that these sites have to the Tohono O’odham Nation, to the Native Hawaiian community, and to the local communities in Chile, respectively.

SLAC National Accelerator Laboratory is a vibrant multiprogram laboratory that explores how the Universe works at the biggest, smallest, and fastest scales and invents powerful tools used by scientists around the globe. With research spanning particle physics, astrophysics and cosmology, materials, chemistry, bio- and energy sciences and scientific computing, SLAC helps solve real-world problems and advance the interests of the nation.

SLAC is operated by Stanford University for the U.S. Department of Energy’s Office of Science. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time.



Links



Contacts

Raffaella Margutti
Associate Professor
University of California Berkeley
Email:
rmargutti@berkeley.edu

Robert Stein
Postdoctoral Scholar
California Institute of Technology
Email:
rdstein@caltech.edu

Bob Blum
Director for Operations
Vera C. Rubin Observatory / NSF NOIRLab
Tel: +1 520-318-8233
Email:
bob.blum@noirlab.edu

Željko Ivezić
Director of Rubin Construction
Professor of Astronomy, University of Washington / AURA
Tel: +1-206-403-6132
Email:
ivezic@uw.edu

Josie Fenske
Jr. Public Information Officer
NSF NOIRLab
Email:
josie.fenske@noirlab.edu

Manuel Gnida
Head of External Communications
SLAC National Accelerator Laboratory
Tel: +1 650-926-2632 (office)
Cell: +1 415-308-7832 (cell)
Email:
mgnida@slac.stanford.edu