The Hubble Ultra Deep Field Image (see description on the right, below)

The Hubble Ultra Deep Field Image
(10,000 galaxies in an area 1% of the apparent size of the moon -- see description on the right, below)

Wednesday, October 11, 2023

2023 October

 

AEA Astronomy Club Newsletter                        

October  2023

 

Contents


AEA Astronomy Club News & Calendar p.1
Video(s) & Picture(s) of the Month p. 3
Astronomy News p. 14
General Calendar p. 23

    Colloquia, lectures, mtgs. p. 23
    Observing p. 24

Useful Links p. 26
About the Club p. 27

Club News & Calendar.

Club Calendar

 

Club Meeting Schedule: --

 

7 Sept      AEA Astronomy Club Meeting     TBD – Great Courses video        Teams

 

5 Oct        AEA Astronomy Club Meeting     TBD – Great Courses video        Teams

 

AEA Astronomy Club meetings are now on 1st  Thursdays at 11:30 am.  Virtual meetings on Teams until further notice.  When live meetings resume, our preferred room has been A1/1735, when we can reserve it. 

 

Club News:   .

 

Annular solar eclipse Oct. 14 (% of disk area eclipsed – 0.90 is annular:  Albuquerque 0.90,  Houston 0.85, Colorado Springs 0.81, Los Angeles 0.70)

 


 

The club’s Meade LX-200 10” telescope & accessories need a new home – contact Alex Ellis.

 

Congratulations and thanks to our new Vice President, Alexandra Gruson!

 

2023 AEA Astronomy Club Dues

• The new Treasurer, Eric Belle, will be sending out a request for 2023 Dues, it is recognized that this request is being sent out 3 months late

• We will attempt to set up an electronic method of dues payment; once the proposed method has been approved by the officers, an email will be sent out to the membership along with a request to pay 2023 Dues.

·         To be counted on the club roster for group membership in the Astronomical League, you need to renew.

2024 Eclipse --   An update from the 2024 solar eclipse committee (Mark Clayson, Marilee Wheaton, Judy Kerner,Mai Lee, Melissa Jolliff, Nahum Melamed):

 

6 months ahead of the eclipse, Marilee & Mark have noted that lowest airfares from L.A. to San Antonio have begun to rise from earlier research – lower priced fares have been taken.  Here is the status of room reservations in our block of rooms as of Oct. 2 (all with sofabeds also) at the 2 adjacent properties:

 

Property 1:

Studio king suites 13 of 30

2 bedroom suites 2 of 5

 

Property 2:

Double queens 2 of 10

King rooms 4 of 5

 

Marilee Wheaton has the link & phone to make reservations.  It is within an hour drive of Kerrville and Fredericksburg – two options on centerline for observing.  If you would like more information about the hotels & available rooms, the link and phone to reserve a room as well as preliminary travel & car rental research and observing plans, contact Marilee Wheaton at Marilee.wheaton@aero.org ,  310-874-5480.

 

We are still pursuing options for reserving an observing site – leaning now towards Fredericksburg rather than Kerrville, as the latter has been adopted by NASA for one of their 3 sites.  Looking at schools, parks, commercial & private properties.  There are designated public viewing sites, but we’d like to find a private one to avoid crowds and parking issues.  We do have a new club member working remotely from San Antonio – Alexandra Olano – who has offered to check out sites for us.

 

It is expected that all people making reservations be members of the club in 2024.  And, as with Mt. Wilson observing trips, we ask that all family members/friends accompanying them also join the club for 2024, as they will also be receiving benefits of the club (arrangements, equipment, photos, expertise, and possibly eclipse glasses and T-shirt).  Violations are subject to cancellation of room reservations, if membership is not finalized by Dec. 31, 2023.

 

Also, please let Marilee know of your anticipated travel plan – driving or flying.  We need to know who’s driving and may be able to take some of our club equipment for observing and photographing the eclipse. 

Contact Jason Fields if interested in joining him for an observing night with his 20” Dobs – per recent emails.

We need volunteers to help with:

 

·         Installing our new software on our tablet & laptop

·         Populating our club Sharepoint site with material & links to the club’s Aerowiki & Aerolink materials – Kaly Rangarajan has volunteered to help with this

·         Arranging future club programs

·         Managing club equipment & library (Kelly Gov volunteered to help with the library, Sam has a fair chunk of the equipment)

Astronomy Video(s) & Picture(s) of the Month

(generally from Astronomy Picture of the Day, APOD: http://apod.nasa.gov/apod/archivepix.html)

From Jay Landis: 

While I was taking data for the Tulip Nebula, the other part of the night I was taking data on the Wizard nebula.  This nebula is approximately 8,500 light years away in the constellation Cepheus. The total integration time for the data for this target was 61 hours 51 minutes through six different filters.  I used red, green, and blue for natural color stars.  I used narrowband filters (6nm bandpass) for the primary nebula data.  The filters were H-alpha (656nm), Sulphur-II (672nm), and Oxygen-III (501nm).  The color palette used was SHO or SII for red, Ha for green, and OIII for blue.

Enjoy the wonder.

Clear skies to everyone


 

VIDEO: A Ring of Fire Sunrise Solar Eclipse  https://www.youtube.com/watch?v=UJfpqSj7cCs&t=118s


Video Credit: Colin Legg & Geoff SimsMusic: Peter Nanasi

Explanation: What's rising above the horizon behind those clouds? It's the Sun. Most sunrises don't look like this, though, because most sunrises don't include the Moon. In the early morning of 2013 May 10, however, from Western Australia, the Moon was between the Earth and the rising Sun. At times, it would be hard for the uninformed to understand what was happening. In an annular eclipse, the Moon is too far from the Earth to block the entire Sun, and at most leaves a ring of fire where sunlight pours out around every edge of the Moon. The featured time-lapse video also recorded the eclipse through the high refraction of the Earth's atmosphere just above the horizon, making the unusual rising Sun and Moon appear also flattened. As the video continues, the Sun continues to rise, while the Sun and Moon begin to separate. The next annular solar eclipse will occur in less than three weeks. On Saturday, October 14, a ring of fire will be visible through clear skies from a thin swath crossing both North and South America.

 

VIDEO:  HESS Telescopes Explore the High-Energy Sky https://apod.nasa.gov/apod/ap230906.html
Video Credit & Copyright: Jeff Dai (TWAN), H.E.S.S. Collaboration;
Music: Ibaotu catalog number 1044988 (Used with permission)

Explanation: They may look like modern mechanical dinosaurs, but they are enormous swiveling eyes that watch the sky. The High Energy Stereoscopic System (H.E.S.S.) Observatory is composed of four 12-meter reflecting-mirror telescopes surrounding a larger telescope housing a 28-meter mirror. They are designed to detect strange flickers of blue light -- Cherenkov radiation --emitted when charged particles move slightly faster than the speed of light in air. This light is emitted when a gamma ray from a distant source strikes a molecule in Earth's atmosphere and starts a charged-particle showerH.E.S.S. is sensitive to some of the highest energy photons (TeV) crossing the universe. Operating since 2003 in Namibia, H.E.S.S. has searched for dark matter and has discovered over 50 sources emitting high energy radiation including supernova remnants and the centers of galaxies that contain supermassive black holes. Pictured in June, H.E.S.S. telescopes swivel and stare in time-lapse sequences shot in front of our Milky Way Galaxy and the Magellanic Clouds -- as the occasional Earth-orbiting satellite zips by.

 

HH 211: Jets from a Forming Star
Credit: NASAESACSAWebb; Processing: Tom Ray (DIAS Dublin)

Explanation: Do stars always create jets as they form? No one is sure. As a gas cloud gravitationally contracts, it forms a disk that can spin too fast to continue contracting into a protostar. Theorists hypothesize that this spin can be reduced by expelling jets. This speculation coincides with known Herbig-Haro (HH) objects, young stellar objects seen to emit jets -- sometimes in spectacular fashionPictured is Herbig-Haro 211, a young star in formation recently imaged by the Webb Space Telescope (JWST) in infrared light and in great detail. Along with the two narrow beams of particles, red shock waves can be seen as the outflows impact existing interstellar gas. The jets of HH 221 will likely change shape as they brighten and fade over the next 100,000 years, as research into the details of star formation continues.

 

 

The Red Sprite and the Tree Credit & Copyright: Maxime Villaeys

Explanation: The sprite and tree could hardly be more different. To start, the red sprite is an unusual form of lightning, while the tree is a common plant. The sprite is far away -- high in Earth's atmosphere, while the tree is nearby -- only about a football field away. The sprite is fast -- electrons streaming up and down at near light's speed, while the tree is slow -- wood anchored to the ground. The sprite is bright -- lighting up the sky, while the tree is dim -- shining mostly by reflected light. The sprite was fleeting -- lasting only a small fraction of a second, while the tree is durable -- living now for many years. Both however, when captured together, appear oddly similar in this featured composite image captured early this month in France as a thunderstorm passed over mountains of the Atlantic Pyrenees.

 

Comet Schwassmann-Wachmann 3 Fragments
Credit: NASAESA, H. Weaver (JHU / APL), M. Mutchler and Z. Levay (STScI)

Explanation: Periodic comet 73P/Schwassmann-Wachmann 3 has broken up at least twice. A cosmic souffle of ice and dust left over from the early solar system, this comet was first seen to split into several large pieces during the close-in part of its orbit in 1995. However, in the 2006 passage, it disintegrated into dozens of fragments that stretched several degrees across the sky. Since comets are relatively fragile, stresses from heat, gravity and outgassing, for example, could be responsible for their tendency to break up in such a spectacular fashion when they near the hot Sun. The Hubble Space Telescope recorded, in 2006, the featured sharp view of prolific Fragment B, itself trailing a multitude of smaller pieces, each with its own cometary coma and tail. The picture spans over 3,000 kilometers at the comet's distance of 32 million kilometers from planet Earth.

The Large Cloud of Magellan
Image Credit & CopyrightChris Willocks / Telescope.Live

Explanation: The 16th century Portuguese navigator Ferdinand Magellan and his crew had plenty of time to study the southern sky during the first circumnavigation of planet Earth. As a result, two fuzzy cloud-like objects easily visible to southern hemisphere skygazers are known as the Clouds of Magellan, now understood to be satellite galaxies of our much larger, spiral Milky Way galaxy. About 160,000 light-years distant in the constellation Dorado, the Large Magellanic Cloud is seen in this sharp galaxy portrait. Spanning about 15,000 light-years or so, it is the most massive of the Milky Way's satellite galaxies and is the home of the closest supernova in modern times, SN 1987A. The prominent patch above center is 30 Doradus, also known as the magnificent Tarantula Nebula, a giant star-forming region about 1,000 light-years across.

NGC 4632: Galaxy with a Hidden Polar Ring
Credit: Jayanne English (U. Manitoba), Nathan Deg (Queen's University) & WALLABY SurveyIDIA/VislabCSIRO/ASKAPNAOJ/Subaru Telescope; Text: Jayanne English (U. Manitoba)

Explanation: Galaxy NGC 4632 hides a secret from optical telescopes. It is surrounded by a ring of cool hydrogen gas orbiting at 90 degrees to its spiral disk. Such polar ring galaxies have previously been discovered using starlight. However, NGC 4632 is among the first in which a radio telescope survey revealed a polar ring. The featured composite image combines this gas ring, observed with the highly sensitive ASKAP telescope, with optical data from the Subaru telescope. Using virtual reality, astronomers separated out the gas in the main disk of the galaxy from the ring, and the subtle color gradient traces its orbital motion. Why do polar rings exist? They could be material pulled from one galaxy as it gravitationally interacts with a companion. Or hydrogen gas flows along the filaments of the cosmic web and accretes into a ring around a galaxy, some of which gravitationally contracts into stars.

NGC 7331 and Beyond
Image Credit & CopyrightIan Gorenstein

Explanation: Big, beautiful spiral galaxy NGC 7331 is often touted as an analog to our own Milky Way. About 50 million light-years distant in the northern constellation Pegasus, NGC 7331 was recognized early on as a spiral nebula and is actually one of the brighter galaxies not included in Charles Messier's famous 18th century catalog. Since the galaxy's disk is inclined to our line-of-sight, long telescopic exposures often result in images that evokes a strong sense of depth. The effect is further enhanced in this sharp image by galaxies that lie beyond the gorgeous island universe. The most prominent background galaxies are about one tenth the apparent size of NGC 7331 and so lie roughly ten times farther away. Their close alignment on the sky with NGC 7331 occurs just by chance. Lingering above the plane of the Milky Way, this striking visual grouping of galaxies is known to some as the Deer Lick Group.





Back from Bennu
Image Credit: NASA/Keegan Barber

Explanation: Back from asteroid 101955 Bennu, a 110-pound, 31-inch wide sample return capsule rests in a desert on planet Earth in this photo, taken at the Department of Defense Utah Test and Training Range near Salt Lake City last Sunday, September 24. Dropped off by the OSIRIS-Rex spacecraft, the capsule looks charred from the extreme temperatures experienced during its blistering descent through Earth's dense atmosphere. OSIRIS-Rex began its home-ward journey from Bennu in May of 2021. Delivered to NASA’s Johnson Space Center in Houston on September 25, the capsule's canister is expected to contain an uncontaminated sample of about a half pound (250 grams) of Bennu's loosely packed regolith. Working in a new laboratory designed for the OSIRIS-REx mission, scientists and engineers will complete the canister disassembly process, and plan to unveil the sample of the near-Earth asteroid in a broadcast event on October 11.

Tagging Bennu
Image Credit: OSIRIS-RExUniversity of ArizonaNASAGoddard Scientific Visualization Studio

Explanation: The OSIRIS-REx spacecraft's arm reached out and touched asteroid 101955 Bennu on October 20, 2020, after a careful approach to the small, near-Earth asteroid's boulder-strewn surface. Dubbed a Touch-And-Go (TAG) sampling event, the 30 centimeter wide sampling head (TAGSAM) appears to crush some of the rocks in this close-up recorded by the spacecraft's SamCam. The image was snapped just after surface contact some 321 million kilometers from planet Earth. One second later, the spacecraft fired nitrogen gas from a bottle to blow a substantial amount of Bennu's regolith into the sampling head, collecting the loose surface material. And now, nearly three years later, on Sunday, September 24, that sample of asteroid Bennu is scheduled to arrive on planet Earth. The sample return capsule will be dropped off by the OSIRIS-Rex spacecraft as it makes a close flyby of Earth. Twenty minutes after the drop-off, the spacecraft will fire its thrusters to divert past Earth and continue on to orbit near-Earth asteroid 99942 Apophis.

 

STEVE and Milky Way Cross over Rural Road
Image Credit & Copyright: Theresa Clarke

Explanation: Not every road ends in a STEVE. A week ago, a sky enthusiast's journey began with a goal: to photograph an aurora over Lake Huron. Driving through rural OntarioCanada, the forecasted sky show started unexpectedly early, causing the photographer to stop before arriving at the scenic Great Lake. Aurora images were taken toward the north -- but over land, not sea. While waiting for a second round of auroras, a peculiar band of light was noticed to the west. Slowly, the photographer and friends realized that this western band was likely an unusual type of aurora: a Strong Thermal Emission Velocity Enhancement (STEVE). Moreover, this STEVE was putting on quite a show: appearing intertwined with the central band of our Milky Way Galaxy while intersecting the horizon just near the end of the country road. After capturing this cosmic X on camera, the photographer paused to appreciate the unexpected awesomeness of finding extraordinary beauty in an ordinary setting.

 

 

 

Astronomy News:

(generally from ScienceDaily.com or ScienceNews.org)

 

Book Reviews:  “‘Simulating the Cosmos’ and ‘The Universe in a


 Box’ Review: Big Picture” (the Wall Street Journal)

 

https://www.wsj.com/arts-culture/books/simulating-the-cosmos-and-the-universe-in-a-box-review-big-picture-9c8533b0?st=hg25mb6lr6sn506&reflink=desktopwebshare_permalink

 

JWST’s hunt for distant galaxies keeps turning up surprises

Galaxies in the early universe are bigger, brighter and more mature than expected

 

 

Scientists at the University of Texas at Austin search for distant galaxies in the first deep field image taken by the James Webb Space Telescope, released in July 2022.

NOLAN ZUNK/UNIV. OF TEXAS AT AUSTIN

When Brant Robertson saw a new measurement of the distance to a familiar galaxy, he laughed out loud.

For more than a decade, the galaxy had been a contender for the most distant ever observed. In 2012, Robertson and colleagues used data from the Hubble Space Telescope to show that the galaxy’s light had shone across the universe from about 13.3 billion years ago — less than 400 million years into the universe’s existence.

Not everyone believed it. “We got a lot of flak,” recalls Robertson, an astrophysicist at the University of California, Santa Cruz. “It seemed too implausible that it was at such a great distance.” It felt like he was going around claiming to have seen the Loch Ness monster.

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But in September, the James Webb Space Telescope, JWST for short, aimed its massive mirror and sensitive spectrograph at the same galaxy and showed that Robertson and his colleagues were right. The galaxy’s light is indeed incredibly old, dating to just 390 million years after the Big Bang. It was like someone had drained the lake, and the monster was sitting there at the bottom.

And this galactic Nessie is not alone. So far, in its first year of observations, JWST has turned up thousands of distant galaxies dating to the early universe, many more than astronomers had expected. Some of those galaxies are brighter, more massive or more mature than astronomers would have thought. They are now scratching their heads trying to explain how the galaxies could have grown up so fast.

 

Studying Maisie’s Galaxy, which dates to about 400 million years after the Big Bang, helped astronomers gain confidence in distance estimates derived from initial JWST data.S. FINKELSTEIN ET AL/ARXIV.ORG 2022 (CC BY 4.0)

 

A lot of the extreme distances still need to be confirmed, but initial evidence suggests there’s reason to believe that many, if not most, of the galaxies really are that far away.

“I was expecting to find some galaxies at this [distance]. Some people were pessimistic; I wasn’t,” says Steven Finkelstein, an astrophysicist at the University of Texas at Austin. “But I was not this optimistic. I thought, ‘Yeah, yeah, we know what we’re going to see.’ And I was wrong.”

The Hubble Space Telescope’s distant galaxies

For longtime galaxy hunters, JWST’s bounty may feel like déjà vu. In the 1990s, Hubble took a long, deep look at an apparently blank patch of sky, just to see what was there. The result was thousands of galaxies, some captured as they looked when the universe was only a billion years old.

Those galaxies looked mature, like they had already been through multiple rounds of supernova explosions and star formation. Thus, they were not the first to form in the universe, astronomers realized. The first galaxies must date even further back.

The hunt for those original galaxies was part of the motivation for building JWST, says astrophysicist Erica Nelson of the University of Colorado Boulder. “The reason we have JWST is, they launched Hubble and saw that the things in the early universe were very evolved,” she says. “They were like, ‘Wow! There are galaxies way earlier than we thought’ ” — even further back in time than Hubble can see.

Hubble wasn’t designed to see all the way back to the universe’s beginning. The telescope is sensitive to ultraviolet, visible and near-infrared wavelengths of light. But by the time light from the universe’s early days reaches us, it has stretched all the way into infrared wavelengths that are longer than Hubble’s (or human) eyes can see. That’s because the universe is expanding; everything in it is moving away from everything else. And as light sources move away from us, their light stretches — the wavelengths of light grow longer, or redder.

Related Stories

1.   

SPACE

Light leaking from a distant galaxy hints at a cosmic makeover’s origins

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2.   

ASTRONOMY

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ASTRONOMY

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The amount of stretching of that light, known as the redshift, is astronomers’ proxy for cosmic distance and age. The present-day universe is at redshift zero. A redshift of 1 corresponds to about 6 billion years after the Big Bang. A redshift of 4 is about 1.5 billion years after the Big Bang, and so on.

In 1995, redshift 4 was the furthest back that Hubble could detect. Over the next 20 years, upgrades to the telescope and new observing techniques pushed the frontier back to redshift 7, which corresponds to 800 million years after the Big Bang. In 2012, the galaxy that Robertson studied appeared at a possible, though at the time unconfirmed, redshift of 11.9. Later, a galaxy called GN-z11 clocked in at a redshift of 11.1, or 400 million years after the Big Bang.

These tantalizing discoveries set off a search for even more distant galaxies. “This has kind of become a game in extragalactic astronomy, where everyone wants to find the highest redshift, most distant galaxy,” astrophysicist Jeyhan Kartaltepe of the Rochester Institute of Technology in New York said in April in Minneapolis at an American Physical Society meeting. “Become the new record holder, right? It’s fun.”

By 2016, when GN-z11 was discovered, the hunt had stalled. Astronomers had wrung everything they could out of existing technology.

“It really requires JWST to push to even earlier times,” Kartaltepe said, “which we need to understand the very beginnings of galaxy formation.”

 

The JWST Advanced Deep Extragalactic Survey, or JADES, scanned a swath of sky (shown) that has turned up hundreds of galaxies that appear to date to within 650 million years of the Big Bang (reddish dots are the most distant galaxies).NASA, ESA, CSA, M. ZAMANI/ESA AND WEBB

 

Why astronomers want to find early galaxies

The quest to find the earliest galaxies is about more than just bragging rights. These galaxies could shed light on a key event in the universe’s infancy called reionization.

In the beginning, there was the Big Bang. After that initial cataclysm, the universe continued to expand and cool. After about 372,000 years, it had cooled enough for electrons and protons to combine into hydrogen atoms. That made the universe transparent to most light less energetic than a particular ultraviolet wavelength — including visible light — for the first time. But with no stars around, the cosmos stayed dark, entering what astronomers call the dark ages.

Sometime during these dark ages, the first stars formed and began to clump together into galaxies with the help of an invisible and still mysterious material known as dark matter. The universe began to fill with starlight. Eventually, something else changed: Roughly 200 million years after the Big Bang, the cosmic veil blocking UV light, as well as more energetic X-rays and gamma rays, lifted as hydrogen atoms everywhere, now much more dispersed than they once were, lost their electrons.

 

“We know there was a transition where the hydrogen was reionized somehow,” Robertson says. Thanks to observations with Hubble and other telescopes, “we think galaxies are very likely the agents of that process,” he says. Light from the youngest, most massive stars in those early galaxies might have knocked electrons off atoms in the hydrogen gas between galaxies. “But how that process unfolds, we have relatively little information on,” Robertson says.

JWST can help fill in those details. Taking a census of the galaxies that were around during the era of reionization could help illuminate how it got started.

And so, astronomers were giddy with excitement when JWST launched on Christmas Day in 2021 and started collecting data about six months later. The first images were unveiled with great fanfare on July 12, 2022 (SN: 8/13/22, p. 30). But astronomers had to wait until the next day to download the rest of the data the telescope had acquired while getting up and running.

“We knew, somewhere, on some computer, our photons were sitting there, waiting for us to see them,” Kartaltepe said. “As soon as the data were released in July, we jumped on it and started analyzing.”

Astronomers sifted through the images like a cosmic Where’s Waldo, picking the reddest-looking candidate galaxies out of the pack.

Extremely distant candidates popped out quickly. In several different regions of the sky, JWST found little red dots corresponding to galaxies that appeared to be at astonishing redshifts: 10, 13, even 17. Some of the galaxies seemed small and dim, as expected. But others looked big and bright, suggesting they were heftier than astronomers would expect for such early galaxies.

“These galaxies, they’re just at phenomenal distances. It’s a little hard to swallow,” Robertson said in June in Cambridge, Mass., at the JWST First Light Conference. “But it’s really important to actually confirm the distances to these very, very distant galaxies, and then learn about their properties.”

The most distant galaxy ever confirmed

Most of the cosmic distances reported for JWST galaxies so far have been preliminary estimates based on data from the telescope’s cameras. The cameras scan broad areas of sky and use filters to let in certain wavelengths of light. These filters allow astronomers to estimate “photometric” redshifts.

But to know for sure how far away a galaxy really is, astronomers need to use JWST’s spectrograph. A redshift calculated from a galaxy’s full spectrum of light uses 1,000 data points compared with a photometric redshift’s seven data points.

“Until we have spectra, nothing is ironclad,” Nelson says.

As part of a project called the JWST Advanced Deep Extragalactic Survey, or JADES, Robertson and colleagues collected spectra for four galaxies with photometric redshifts higher than 10 — likely close to the beginning of the era of reionization. One of the galaxies was the one Robertson studied in 2012. The distance of that galaxy, now known as JADES-GS-z11-0, was downgraded a bit, from a redshift of 11.9 to 11.58. But with one of the other galaxies, the team claimed a new record for most distant galaxy ever confirmed, with a redshift of 13.2, just 325 million years after the Big Bang.

The spectra the team analyzed were detailed enough to reveal some properties of the galaxies, Robertson and colleagues reported in April in Nature Astronomy. They’re all about a hundredth the size and mass of the Milky Way, but they are forming stars at a comparable rate — a lot of stars for galaxies this small. All those newborn stars produce a lot of ionizing radiation, meaning it’s possible these galaxies could be some of the earliest agents of reionization, Robertson says.

JADES has since reported about 700 more galaxies whose photometric redshifts place them at redshift 8 or greater, or less than 650 million years after the Big Bang, Robertson said at the June First Light meeting. Those galaxies’ distances still need to be confirmed, but the sheer numbers are amazing. “We’re really in a remarkable age,” Robertson said.

Trusting JWST’s measurements

The huge galaxy haul raises another question: How many of them are likely to be at such great distances?

A potential record-breaking galaxy called CEERS-93316 is a cautionary tale. The galaxy was identified in JWST images taken for the Cosmic Evolution Early Release Science, or CEERS, survey. Those images put the galaxy at a photometric redshift of 16.4, or just 240 million years after the Big Bang.

“That was higher redshift than we expected to see with CEERS,” says Finkelstein, the survey’s lead researcher. CEERS was designed to practice using JWST in its different observing modes and give astronomers some data to play with, not necessarily to set new records.

In its first chunk of data, CEERS contained a surprising number of apparently high-redshift galaxies. So Finkelstein and colleagues asked the director of the Space Telescope Science Institute in Baltimore, which operates JWST, for some extra telescope time to chase down the spectra of CEERS-93316, as well as a galaxy that Finkelstein had found with a photometric redshift of about 12. He named that galaxy Maisie’s Galaxy in honor of his daughter, because he found it on her ninth birthday. (Maisie didn’t mind that her dad had to work that day — “I got other birthday presents,” she says, though she did wish her galaxy was the potential record holder.)

When the spectral data came through, Finkelstein’s colleague Pablo Arrabal Haro, an astrophysicist at the National Science Foundation’s NOIRLab, based in Tucson, worked through the weekend to write up results before anyone else.

CEERS-93316’s 16.4 redshift turned out to be wrong. The galaxy was actually at a redshift of 4.9, putting it 1.2 billion years after the Big Bang — practically modern compared with some of JWST’s other finds.

The galaxy’s photometric redshift was so high because of a weird coincidence. Light streaming from hydrogen in the galaxy was redshifted such that it looked like it jumped in brightness at a wavelength suggestive of the huge distance. But when the full spectrum came in, that single jump was revealed to be several separate peaks, suggesting a smaller redshift.

Maisie’s Galaxy, however, is almost as distant as the photometric redshift implied, Arrabal Haro and colleagues reported in a paper posted in March to arXiv.org. And in an April paper posted to arXiv.org, the team reported spectra for more than 30 other galaxies with redshifts of roughly between 8 and 10. So photometric redshift estimates are generally reliable, Finkelstein says.

 

Timeline of early galaxies

JWST has detected many galaxies from the early universe (a few are shown on this timeline). These galaxies could shed light on reionization, the process that ended the cosmic dark ages, when the universe was shrouded in darkness. Some of these galaxies, the “universe breakers,” appear to be more massive than theory can explain.

 

JWST: ESA; BACKGROUND: NASA, ESA, P. OESCH AND B. ROBERTSON/UNIV. OF CALIFORNIA, SANTA CRUZ, A. FEILD/STSCI, ADAPTED BY C. CHANG

“Although we have this notable failure case, that’s a pathological case,” he says. It’s “not devastating.”

That’s good news for JWST’s observing schedule: Astronomers won’t have to follow up with the full spectrum for every distant galaxy. They can believe that most of the redshifts are legit and save the extra effort of taking the full spectrum for the really interesting ones. “It is exciting that the photometric redshifts tend to hold up,” Robertson says. “It gives us some hope that some of these really distant things could be real.”

 

Distant galaxies too bright to explain

Another outcome of JWST analyses so far is that there are more bright galaxies around redshift 10 than expected. Galaxy brightness is an indicator of galaxy mass, and thus star abundance. The brighter the galaxy, the more stars it must have to produce all that light.

Galaxies are born in halos of dark matter, whose gravity pulls in and concentrates ordinary matter. Cosmologists know from simulations and theory how many dark matter halos the universe would have had when the first galaxies formed. They also have a decent idea of how massive those halos were in the universe’s first 500 million years and how much of that mass ended up in the form of hydrogen and helium, the raw material for making stars. Theoretically, if all that gas turned into stars, the largest a galaxy could get would be about 10 billion times the mass of the sun.

In reality, researchers expect early galaxies to be much less massive, because modern galaxies never convert all their gas into stars.

JWST has not turned up any galaxy near the theoretical upper limit. But it has found many more hefty early galaxies than predicted. The confirmed JADES galaxies weigh in at about 100 million solar masses, just 330 million years after the Big Bang. Some of the CEERS galaxies seem to have over a billion suns’ worth of stars as early as 450 million years after the Big Bang. Two galaxies discovered in another JWST survey, called COSMOS-Web, appear to be about 5 billion solar masses as early as 350 million years after the Big Bang, astronomer Caitlin Casey of the University of Texas at Austin said at the June First Light meeting.

“With these massive beacons, you can test the limits of how fast you can assemble that much matter in the short time between the Big Bang and the time that we’re observing them in,” she says.

What astronomers find from these galaxies could point to where our existing understanding of galaxy formation is wrong. Or researchers might discover that some of the galaxies’ light doesn’t come directly from stars but instead from the ionized gas in between stars that are actively forming, Casey says. That would mean the galaxies aren’t actually as massive as they look.

Finding out how early galaxies were put together is the first step to understanding our own galaxy, Robertson says. “That’s ultimately what drives a lot of galaxy formation research, is trying to understand how our home, the thing that’s important to us, the place that we live, came to be,” he says. “We’re never going to complete that full story without looking at how galaxies at redshift 10 were put together…. That’s the starting place for how we got here.”

Breaking the universe … or not

One set of galaxies has sparked debate over not just galaxy formation, but the theoretical foundations of the universe itself.

In February, Nelson and colleagues reported six galaxies spotted with CEERS that seem to have grown so big, so fast that they directly challenge the standard theory of how structure forms in the universe (SN: 3/25/23, p. 14). These galaxies have photometric redshifts between about 7 and 9, meaning they grew up in the first 800 million years of the universe. But their stellar masses appear to rival or exceed that of the Milky Way, about 60 billion solar masses.

Nelson affectionately calls them the “universe breakers.” Nothing that massive should have been able to form that fast, she says. “As soon as we saw it, we were like, this is bananas.”

Barely enough ordinary matter is even believed to have existed back then to create the universe breakers, says astrophysicist Mike Boylan-Kolchin of the University of Texas at Austin. Regions where budding galaxies formed would have had to turn all their atoms into stars.

Six distant galaxies (red dots, above) spotted by the Cosmic Evolution Early Release Science, or CEERS, survey appear to be too massive for standard cosmological theories to explain, though one of these “universe breakers” (top row, middle image) is not as distant as originally thought.NASA, ESA, CSA, I. LABBÉ/SWINBURNE UNIV. OF TECHNOLOGY; IMAGE PROCESSING: G. BRAMMER/COSMIC DAWN CENTER/NIELS BOHR INSTITUTE/UNIV. OF COPENHAGEN

 

“We have this reservoir of atoms,” he says. “Almost every single one of them has to be in stars or in galaxies” if the universe breakers are for real. “If these observations and their interpretation is correct … it’s very hard to accommodate them in our current models,” he says.

Over the last few months, theorists have come up with several ways to explain the universe breakers. One of the most dramatic options would be to add some extra dark energy, the mysterious substance that drives the universe to expand faster and faster, to the early universe, which would speed up all sorts of cosmic processes.

“That would go in the right direction here, in the sense that there’d be bigger reservoirs [of atoms] and maybe more of them at earlier times,” Boylan-Kolchin says. “These early dark energy models do predict faster evolution of structure at early times.”

More mundane options include super-compact early galaxies that could have converted all their gas into stars before the oldest stars had a chance to go supernova and blow it away. Such efficient star formation could explain the universe breakers without breaking the universe, physicist Avishai Dekel of the Hebrew University in Jerusalem and colleagues suggested in a paper published May 25 in the Monthly Notices of the Royal Astronomical Society.

And there’s still the question of whether the universe breakers’ masses and distances will hold up. A spectrum of one of them has already revealed it to be a galaxy at redshift 5.6 with an actively feeding black hole creating extra light — so not a universe breaker after all.

JWST’s second observing cycle began in July, and Nelson will take spectra of the rest of the universe breakers to find out if they are truly abounding with stars, filled with black holes or something else.

Meanwhile, another group of astronomers will test JWST’s limits, hunting for galaxies at redshift 15 or greater. So by the telescope’s second birthday next summer, there may be new distance records.

Editor's Note:

 

This story was updated on September 26, 2023, to clarify that the initial formation of hydrogen atoms after the Big Bang caused the universe to become transparent to certain wavelengths of light while remaining opaque to others. It was also updated to correct the definition of "cosmic dark ages."

A version of this article appears in the August 12, 2023 issue of Science News.

CITATIONS

K.N. Hainline et alThe cosmos in its infancy: JADES galaxy candidates at z>8 in GOODS-S and GOODS-N. arxiv: 2306.02468. Submitted June 4, 2023.

A. Dekel et alEfficient formation of massive galaxies at cosmic dawn by feedback-free starbustsMonthly Notices of the Royal Astronomical Society. Published online May 25, 2023. doi: 10.1093/mnras/stad1557.

P. Arrabal Haro et alSpectroscopic confirmation of CEERS NIRCam-selected galaxies at ~ 8–10. arxiv: 2304.05378. Submitted April 11, 2023.

B.E. Robertson et al. Identification and properties of intense star-forming galaxies at redshifts z>10Nature Astronomy. Published online April 4, 2023. doi:10.1038/s41550-023-01921-1.

P. Arrabal Haro et alSpectroscopic verification of very luminous galaxy candidates in the early universe. arxiv: 2303.15431. Submitted March 27, 2023.

Ivo Labbé et alA population of red candidate massive galaxies ~600 Myr after the Big BangNature. Published online February 22, 2023. doi:10.1038/s41586-023-05786-2.

 

Lisa Grossman is the astronomy writer. She has a degree in astronomy from Cornell University and a graduate certificate in science writing from University of California, Santa Cruz. She lives near Boston.

 

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