By UNIVERSITY OF CALIFORNIA - LOS ANGELES DECEMBER 26, 2022
Thousands of galaxies flood this near-infrared, high-resolution image of galaxy cluster SMACS 0723 captured by the James Webb Space Telescope. A pair of UCLA-led studies demonstrate some of the scientific advances that the telescope is making possible. Credit: NASA, ESA, CSA, STScI
Astrophysicists shed light on how hydrogen fog burned away after the Big Bang.
- UCLA astrophysicists are among the first scientists to use the James Webb Space Telescope to get a glimpse of the earliest galaxies in the universe.
- The studies reveal unprecedented detail about events that took place within the first billion years after the Big Bang.
- The UCLA projects were among a small number selected by NASA to test the capabilities of the Webb telescope.
The earliest galaxies were cosmic fireballs converting gas into stars at breathtaking speeds across their full extent, reports a study led by the University of California, Los Angeles (UCLA) published in a special issue of the Astrophysical Journal.
The research, based on data from the James Webb Space Telescope, is the first study of the shape and structure of those galaxies. It shows that they were nothing like present-day galaxies in which star formation is confined to small regions, such as the constellation of Orion in our own Milky Way galaxy.
“We’re seeing galaxies form new stars at an electrifying pace,” said Tommaso Treu, the study’s lead author, a UCLA professor of physics and astronomy. “Webb’s incredible resolution allows us to study these galaxies in unprecedented detail, and we see all of this star formation occurring within the regions of these galaxies.”
Treu directs the GLASS–JWST Early Release Science Program, whose first results are the subject of the special journal issue. Another UCLA-led study in the issue found that galaxies that formed soon enough after the Big Bang — within less than a billion years — might have begun burning off leftover photon-absorbing hydrogen, bringing light to a dark universe
Guido Roberts-Borsani. Credit: Courtesy of Guido Roberts-Borsani
“Even our very best telescopes really struggled to confirm the distances to such far away galaxies, so we didn’t know whether they rendered the universe transparent or not,” said Guido Roberts-Borsani, a UCLA postdoctoral researcher who led the study. “Webb is showing us that not only can it do the job, but it can do it with astonishing ease. It’s a game changer.”
Those findings are two of many breathtaking discoveries by UCLA astrophysicists who are among the first to peer through a window to the past newly opened by Webb.
Webb is the largest near-infrared telescope in space, and its remarkable resolution offers an unparalleled view of objects so distant that their light takes billions of years to reach Earth. Although those objects have aged by now, light from only their earliest moments has had enough time to travel through the universe to end up on Webb’s detectors. As a result, not only has the Webb functioned as a sort of time machine — taking scientists back to the period shortly after the Big Bang — but the images it’s producing have become a family album, with snapshots of infant galaxies and stars.
Tommaso Treu, Credit: Courtesy of Tommaso Treu
GLASS–JWST was one of 13 Early Release Science projects selected by NASA in 2017 to quickly produce publicly accessible datasets and to demonstrate and test the capabilities of instruments on the Webb.
The project seeks to understand how and when light from the first galaxies burned through the hydrogen fog left over from the Big Bang — a phenomenon and time period called the Epoch of Reionization — and how gas and heavy elements are distributed within and around galaxies over cosmic time. Treu and Roberts-Borsani use three of the Webb’s innovative near-infrared instruments to take detailed measurements of distant galaxies in the early universe.
The Epoch of Reionization is a period that remains poorly understood by scientists. Until now, researchers have not had the extremely sensitive infrared instruments needed to observe galaxies that existed then. Prior to cosmic reionization, the early universe remained devoid of light because ultraviolet photons from early stars were absorbed by the hydrogen atoms that saturated space
Scientists think that sometime within the universe’s first billion years radiation emitted by the first galaxies and possibly by the first black holes caused the hydrogen atoms to lose electrons, or ionize, preventing photons from “sticking” to them and clearing a pathway for the photons to travel across space. As galaxies began to ionize larger and larger bubbles, the universe became transparent and light traveled freely, as it does today, allowing us to view a brilliant canopy of stars and galaxies each night.
Roberts-Borsani’s finding that galaxies formed faster and earlier than previously thought could confirm that they were the culprits of cosmic reionization. The study also confirms the distances to two of the farthest galaxies known using a new technique that allows astronomers to probe the beginning of cosmic reionization.
For more on this research, see Webb Draws Back the Curtains on an Undiscovered Universe.
References:
“Early Results From GLASS-JWST. XII: The Morphology of Galaxies at the Epoch of Reionization” by T.Treu, A.Calabro, M.Castellano, N.Leethochawalit, E.Merlin, A.Fontana, L.Yang, T.Morishita, M.Trenti, A.Dressler, C.Mason, D.Paris, L.Pentericci, G.Roberts-Borsani, B.Vulcani, K.Boyett, M.Bradac, K.Glazebrook, T.Jones, D.Marchesini, S.Mascia, T.Nanayakkara, P.Santini, V.Strait, E.Vanzella and X.Wang, Astrophysical Journal.
arXiv:2207.13527
“Early Results from GLASS-JWST. I: Confirmation of Lensed z = 7 Lyman-break Galaxies behind the Abell 2744 Cluster with NIRISS” by Guido Roberts-Borsani, Takahiro Morishita, Tommaso Treu, Gabriel Brammer, Victoria Strait, Xin Wang, Marusa Bradac, Ana Acebron, Pietro Bergamini, Kristan Boyett, Antonello Calabró, Marco Castellano, Adriano Fontana, Karl Glazebrook, Claudio Grillo, Alaina Henry, Tucker Jones, Matthew Malkan, Danilo Marchesini, Sara Mascia, Charlotte Mason, Amata Mercurio, Emiliano Merlin, Themiya Nanayakkara, Laura Pentericci, Piero Rosati, Paola Santini, Claudia Scarlata, Michele Trenti, Eros Vanzella, Benedetta Vulcani and Chris Willott, 18 October 2022, Astrophysical Journal Letters.
DOI: 10.3847/2041-8213/ac8e6e
Webb Space Telescope Makes Stunning Discovery: Unveils Previously Shrouded Newborn Stars
By RICE UNIVERSITY DECEMBER 25, 2022
Astronomers from Rice University and other organizations dug deep into the data from this near-infrared image, one of the first taken by NASA’s James Webb Space Telescope. The image shows a star-forming region in the constellation Carina known as the Cosmic Cliffs. Many newborn stars in such regions are shrouded in thick clouds of dust. Webb’s infrared camera penetrated the dust, allowing astronomers to discover telltale signs of two dozen infant stars that hadn’t been previously detected. Credit: Image courtesy of NASA, ESA, CSA and STScI
Webb’s infrared camera peers through dust clouds, enabling discovery.
Rice University astronomer Megan Reiter and colleagues took a “deep dive” into one of the first images from NASA’s James Webb Space Telescope and were rewarded with the discovery of telltale signs from two dozen previously unseen young stars about 7,500 light years from Earth.
The research, which was published in the December issue of the Monthly Notices of the Royal Astronomical Society, offers a glimpse of what astronomers will find with Webb’s near-infrared camera. The instrument is designed to peer through clouds of interstellar dust that have previously blocked astronomers’ view of stellar nurseries, especially those that produce stars similar to Earth’s sun.
Reiter, an assistant professor of physics and astronomy, and co-authors from the California Institute of Technology, the University of Arizona, Queen Mary University in London and the United Kingdom’s Royal Observatory in Edinburgh, Scotland, analyzed a portion of Webb’s first images of the Cosmic Cliffs, a star-forming region in a cluster of stars known as NGC 3324.
Matter flows away from the poles of newborn stars in fast-moving columns that plow through nebular clouds. Gas and dust pile up in front of these outflows, forming waves called “bow shocks” in much the same way that bow waves form at the leading edge of seagoing ships. This false-color infrared image from the James Webb Space Telescope shows bow shocks of molecular hydrogen (red) streaming away from newborn stars in a star-forming region called the Cosmic Cliffs in the southern constellation Carina. Credit: Image courtesy of NASA, ESA, CSA and STScI
“What Webb gives us is a snapshot in time to see just how much star formation is going on in what may be a more typical corner of the universe that we haven’t been able to see before,” said Reiter, who led the study.
Located in the southern constellation Carina, NGC 3324 hosts several well-known regions of star formation that astronomers have studied for decades. Many details from the region have been obscured by dust in images from the Hubble Space Telescope and other observatories. Webb’s infrared camera was built to see through dust in such regions and to detect jets of gas and dust that spew from the poles of very young stars.
Reiter and colleagues focused their attention on a portion of NGC 3324 where only a few young stars had previously been found. By analyzing a specific infrared wavelength, 4.7 microns, they discovered two dozen previously unknown outflows of molecular hydrogen from young stars. The outflows range in size, but many appear to come from protostars that will eventually become low-mass stars like Earth’s sun.
“The findings speak both to how good the telescope is and to how much there is going on in even quiet corners of the universe,” Reiter said.
Rice University astronomer Megan Reiter led a “deep dive” study of the earliest images from the James Webb Space Telescope. The research revealed telltale signs of two dozen previously uncataloged young stars in the star cluster NGC 3324 in the constellation Carina. Credit: Jeff Fitlow/Rice University
Within their first 10,000 years, newborn stars gather material from the gas and dust around them. Most young stars eject a fraction of that material back into space via jets that stream out in opposite directions from their poles. Dust and gas pile up in front of the jets, which clear paths through nebular clouds like snowplows. One vital ingredient for baby stars, molecular hydrogen, gets swept up by these jets and is visible in Webb’s infrared images.
“Jets like these are signposts for the most exciting part of the star formation process,” said study co-author Nathan Smith of the University of Arizona. “We only see them during a brief window of time when the protostar is actively accreting.”
The accretion period of early star formation has been especially difficult for astronomers to study because it is fleeting — usually just a few thousand years in the earliest portion of a star’s multimillion-year childhood.
Study co-author Jon Morse of the California Institute of Technology said jets like those discovered in the study “are only visible when you embark on that deep dive — dissecting data from each of the different filters and analyzing each area alone.
“It’s like finding buried treasure,” Morse said.
Reiter said the size of the Webb telescope also played a role in the discovery.
“It’s just a huge light bucket,” Reiter said. “That lets us see smaller things that we might have missed with a smaller telescope. And it also gives us really good angular resolution. So we get a level of sharpness that allows us to see relatively small features, even in faraway regions.”
For more on this research, see Webb Pierces Through Dust Clouds to Unveil Young Stars in Early Stages of Formation.
Reference: “Deep diving off the ‘Cosmic Cliffs’: previously hidden outflows in NGC 3324 revealed by JWST” by Megan Reiter, Jon A Morse, Nathan Smith, Thomas J Haworth, Michael A Kuhn and Pamela D Klaassen, 4 October 2022, Monthly Notices of the Royal Astronomical Society.
DOI: 10.1093/mnras/stac2820
The Webb Space Telescope program is led by NASA in partnership with the European Space Agency (ESA) and the Canadian Space Agency (CSA). The telescope’s science and mission operations are led by the Space Telescope Science Institute (STScI) in Baltimore.
The research was supported by NASA (NAS 5-0312, NAS 5–26555), STScI and a Dorothy Hodgkin Fellowship from the UK’s Royal Society.
Webb Space Telescope Captures North Ecliptic Pole – Studded With Galactic Diamonds
By SPACE TELESCOPE SCIENCE INSTITUTE DECEMBER 24, 2022
A swath of sky measuring 2% of the area covered by the full moon was imaged with Webb’s Near-Infrared Camera (NIRCam) in eight filters and with Hubble’s Advanced Camera for Surveys (ACS) and Wide-Field Camera 3 (WFC3) in three filters that together span the 0.25 – 5-micron wavelength range. This image represents a portion of the full PEARLS field, which will be about four times larger. Thousands of galaxies over an enormous range in distance and time are seen in exquisite detail, many for the first time. Light from the most distant galaxies has traveled almost 13.5 billion years to reach us. Because this image is a combination of multiple exposures, some stars show additional diffraction spikes. This representative-color image was created using Hubble filters F275W (purple), F435W (blue), and F606W (blue); and Webb filters F090W (cyan), F115W (green), F150W (green), F200W (green), F277W (yellow), F356W (yellow), F410M (orange), and F444W (red). Credit: NASA, ESA, CSA, A. Pagan (STScI) & R. Jansen (ASU). Science: R. Jansen, J. Summers, R. O’Brien, and R. Windhorst (Arizona State University); A. Robotham (ICRAR/UWA); A. Koekemoer (STScI); C. Willmer (UofA); and the PEARLS team
NASA’s James Webb Space Telescope has captured one of the first medium-deep wide-field images of the cosmos, featuring a region of the sky known as the North Ecliptic Pole. The image, which accompanies a paper published on December 14 in the Astronomical Journal, is from the Prime Extragalactic Areas for Reionization and Lensing Science (PEARLS) GTO program.
“Medium-deep” refers to the faintest objects that can be seen in this image, which are about 29th magnitude (1 billion times fainter than what can be seen with the unaided eye), while “wide-field” refers to the total area that will be covered by the program, about one-twelfth the area of the full moon. The image is comprised of eight different colors of near-infrared light captured by Webb’s Near-Infrared Camera (NIRCam), augmented with three colors of ultraviolet and visible light from the Hubble Space Telescope
“I was blown away by the first PEARLS images.” — Rolf Jan
This beautiful color image unveils in unprecedented detail and to exquisite depth a universe full of galaxies to the furthest reaches, many of which were previously unseen by Hubble or the largest ground-based telescopes, as well as an assortment of stars within our own Milky Way galaxy. The NIRCam observations will be combined with spectra obtained with Webb’s Near-Infrared Imager and Slitless Spectrograph (NIRISS), allowing the team to search for faint objects with spectral emission lines, which can be used to estimate their distances more accurately.
We asked members of the PEARLS team that created this image to share their thoughts and reactions while analyzing this field:
“For over two decades, I’ve worked with a large international team of scientists to prepare our Webb science program,” said Rogier Windhorst, Regents Professor at Arizona State University (ASU) and PEARLS principal investigator. “Webb’s images are truly phenomenal, really beyond my wildest dreams. They allow me to measure the number density of galaxies shining to very faint infrared limits and the total amount of light they produce.”
“I was blown away by the first PEARLS images,” agreed Rolf Jansen, Research Scientist at ASU and a PEARLS co-investigator. “Little did I know, when I selected this field near the North Ecliptic Pole, that it would yield such a treasure trove of distant galaxies, and that we would get direct clues about the processes by which galaxies assemble and grow. I can see streams, tails, shells, and halos of stars in their outskirts, the leftovers of their building blocks.”
“The stunning image quality of Webb is truly out of this world.” — Anton Koekemoer
“The Webb images far exceed what we expected from my simulations in the months prior to the first science observations,” said Jake Summers, a research assistant at ASU. “Looking at them, I was most surprised by the exquisite resolution. There are many objects that I never thought we would actually be able to see, including individual globular clusters around distant elliptical galaxies, knots of star formation within spiral galaxies, and thousands of faint galaxies in the background.”
“The diffuse light that I measured in front of and behind stars and galaxies has cosmological significance, encoding the history of the universe,” said Rosalia O’Brien, a graduate research assistant at ASU. “I feel very lucky to start my career right now. Webb’s data is like nothing we have ever seen, and I’m really excited about the opportunities and challenges it offers.”
“I spent many years designing the tools to find and accurately measure the brightnesses of all objects in the new Webb PEARLS images, and to separate foreground stars from distant galaxies,” says Seth Cohen, a research scientist at ASU and a PEARLS co-investigator. “The telescope’s performance, especially at the shortest near-infrared wavelengths, has exceeded all my expectations, and allowed for unplanned discoveries.”
“The stunning image quality of Webb is truly out of this world,” agreed Anton Koekemoer, research astronomer at STScI, who assembled the PEARLS images into very large mosaics. “To catch a glimpse of very rare galaxies at the dawn of cosmic time, we need deep imaging over a large area, which this PEARLS field provides.”
“I hope that this field will be monitored throughout the Webb mission, to reveal objects that move, vary in brightness, or briefly flare up,” said Rolf. Added Anton: “Such monitoring will enable the discovery of time-variable objects like distant exploding supernovae and bright accretion gas around black holes in active galaxies, which should be detectable to larger distances than ever before.”
“This unique field is designed to be observable with Webb 365 days per year, so its time-domain legacy, area covered, and depth reached can only get better with time,” concluded Rogier.
About the Authors
- Rogier Windhorst is a Regents Professor in the School of Earth and Space Exploration (SESE) of the Arizona State University (ASU). He serves as one of six Webb Interdisciplinary Scientists worldwide, and is the principal investigator of the Prime Extragalactic Areas for Reionization and Lensing Science (PEARLS) program (program IDs 1176, 2738). The PEARLS team consists of nearly 100 scientists spread across 18 time zones worldwide.
- Rolf Jansen is a research scientist at ASU/SESE and PEARLS co-investigator. He selected the Webb North Ecliptic Pole Time Domain Field and led its development as a new community field for time-domain science with Webb, including the design of the NIRCam observations. He also is principal investigator of the Hubble images used in this color composite.
- Seth Cohen is a research scientist at ASU/SESE and a PEARLS co-investigator. He led software development and photometric calibration, and generated object catalogs for this field.
- Jake Summers is a research assistant at ASU/SESE, responsible for processing, organizing, and distributing the PEARLS data to the team, including the generation of initial mosaics and color composites.
- Rosalia O’Brien is a graduate research assistant at ASU/SESE, responsible for measuring diffuse light, and for reprocessing the Hubble images.
- Anton Koekemoer is a research astronomer at STScI, responsible for the astrometric alignment and combination of individual NIRCam detector images into the final PEARLS mosaics.
- Aaron Robotham is a professor at the University of Western Australia’s ICRAR, and was responsible for the detector-level post-processing of the NIRCam data.
- Christopher Willmer is a research astronomer at the University of Arizona’s Steward Observatory. A member of the NIRCam team, he helped develop the Webb North Ecliptic Pole Time Domain Field, and constructed camera artifacts templates.
Reference: “JWST PEARLS. Prime Extragalactic Areas for Reionization and Lensing Science: Project Overview and First Results” by Rogier A. Windhorst, Seth H. Cohen, Rolf A. Jansen, Jake Summers, Scott Tompkins, Christopher J. Conselice, Simon P. Driver, Haojing Yan, Dan Coe, Brenda Frye, Norman Grogin, Anton Koekemoer, Madeline A. Marshall, Rosalia O’Brien, Nor Pirzkal, Aaron Robotham, Russell E. Ryan Jr., Christopher N. A. Willmer, Timothy Carleton, Jose M. Diego, William C. Keel, Paolo Porto, Caleb Redshaw, Sydney Scheller, Stephen M. Wilkins, S. P. Willner, Adi Zitrin, Nathan J. Adams, Duncan Austin, Richard G. Arendt, John F. Beacom, Rachana A. Bhatawdekar, Larry D. Bradley, Tom Broadhurst, Cheng Cheng, Francesca Civano, Liang Dai, Hervé Dole, Jordan C. J. D’Silva, Kenneth J. Duncan, Giovanni G. Fazio, Giovanni Ferrami, Leonardo Ferreira, Steven L. Finkelstein, Lukas J. Furtak, Hansung B. Gim, Alex Griffiths, Heidi B. Hammel, Kevin C. Harrington, Nimish P. Hathi, Benne W. Holwerda, Rachel Honor, Jia-Sheng Huang, Minhee Hyun, Myungshin Im, Bhavin A. Joshi, Patrick S. Kamieneski, Patrick Kelly, Rebecca L. Larson, Juno Li, Jeremy Lim, Zhiyuan Ma, Peter Maksym, Giorgio Manzoni, Ashish Kumar Meena, Stefanie N. Milam, Mario Nonino, Massimo Pascale, Andreea Petric, Justin D. R. Pierel, Maria del Carmen Polletta, Huub J. A. Röttgering, Michael J. Rutkowski, Ian Smail, Amber N. Straughn, Louis-Gregory Strolger, Andi Swirbul, James A. A. Trussler, Lifan Wang, Brian Welch, J. Stuart B. Wyithe, Min Yun, Erik Zackrisson, Jiashuo Zhang, and Xiurui Zhao, 14 December 2022, The Astronomical Journal.
DOI: 10.3847/1538-3881/aca163
