The Scientific Era of JWST is Upon Us

by Adam Hadhazy

Kavli astrophysics institutes researchers react to the first images from the long-heralded JWST

Credits: NASA, ESA, CSA, and STScI

The Author

Adam Hadhazy

The wait is over! Last month, scientists working with JWST, triumphantly released to the public the first images snapped by the next-generation celestial observatory. Those first images captured familiar objects like the Carina Nebula, but in high-resolution detail never before obtainable, as well as some of the tiniest, most distant galaxies on record—and that's just the beginning. JWST's origins go back to the 1990s, and the instrument suffered many setbacks during its building and testing phases before finally launching in December 2021. The biggest telescope ever put into space, JWST had to undergo a nerve-wracking, yet all but flawless deployment and commissioning. Now with JWST fully operational and on the job, many Kavli astrophysics institute-affiliated researchers will be delighted at the observational windfalls the telescope will deliver. The Kavli Foundation profiled some of those researchers in the "Looking Ahead to JWST" series of stories last year, and upon the news of the first JWST images, Kavli institute members offered fresh comments. Over at the Kavli Institute for Cosmological Physics (KICP) at the University of Chicago, Wendy Freedman said in a news story, "The detail in these JWST images is simply spectacular" and "it's as if we are putting on eyeglasses and suddenly seeing fine detail for the first time." Meanwhile, Risa Wechsler at the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) at Stanford University said in a Q&A that her reaction to the first images was "Awe. Pure awe." Wechsler also commented that after seeing the first image, "I was so excited that I didn't sleep very well" because she "woke up thinking about these tiny, wonderful galaxies and anticipating what we will learn and what else we can do with this telescope." Once again, JWST is to blame for some sleepless nights, though this time around, the insomnia is from sheer scientific enthusiasm, rather than testing mishaps and budget overruns. Watch this space for more exciting news from JWST!

Stunningly bright cosmic blast captured in its earliest moments

The astronomical art of possible origins of MUSSES2020J. (upper) An event where a star is tidally disrupted by a massive black hole (BH). The disrupted material creates a tail (red) that traces the path of the stellar orbit. The disrupted material starts accreting to the BH around the pericenter, producing a powerful wind (white) that results in a rapidly brightening transient phenomenon. (left) A neutron star with very strong magnetic field (Magnetar) ejects two jets, which provides energy for brightness of a supernova. (right) A pulsational pair-instability supernova (PPISN) forms circumstellar matter (purple) before the explosion, and its ejected materials in the explosion (green) collides with the circumstellar matter. This collision provides energy for rapid brightening of the supernova. (Credit: Kavli IPMU)

One of the newest kids on the astrophysical block is the fast blue optical transient, or FBOT. These bright, energetic blasts of light on the blue part of the visible spectrum (versus the low-energy red part) have captured scientists' attention in recent years. Now researchers at the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) at Tokyo University are reporting the earliest-ever detection of such a transient, meaning key data have been collected because the transient had not already been fading by the time astronomers discovered it and got a good look instrumentally. The research team saw the object intensify in brightness more so than supernovae—the explosions of massive stars—and with similarly startling intensity as a celebrated blast seen in 2018 and nicknamed "the Cow". The research propose calling FBOTs with these properties fast blue ultraluminous transients, or FBUTs. The hope is with more identifications, the origin of these FBOT and FBUT events—perhaps from rare supernovae or even from stars shredded by black hole encounters—will be uncovered.

Longest repeating fast radio burst may at last reveal the source objects for these events

Although not as newfound as FBOTs, fast radio bursts, or FRBs, have only been on the astrophysical scene since their initial discovery in 2007. Astronomers have started to get a pretty good bead on what FRBs might be, with hundreds on record now and more coming all the time thanks to the Canadian Hydrogen Intensity Mapping Experiment, or CHIME, which is custom-built to nab FRBs. Among CHIME's latest quarry: the longest-lasting and most clearly periodic fast radio burst spotted yet. Reported by researchers at the Massachusetts Institute of Technology's Kavli Institute for Astrophysics and Space Research (MKI), the new FRB lasts up to three seconds, which is far longer than the usual millisecond duration of FRBs, and there is a 0.2-second repeating burst pattern within that few-second window. This signature strongly points to the handful of known, high-energy, repeating sources in the universe as the new FRB's ultimate progenitor. These sources are pulsars and magnetars, the remnants of massive stars compressed to extreme densities and which spin rapidly, shooting out beams of radiation periodically.

New dark matter hunter now on the prowl

The most sensitive dark matter detector of its kind yet, LUX-ZEPLIN (LZ) has officially been started up. Its research team has reported that the device is operational and has already set a new limit on postulated dark matter particles called WIMPs. Dark matter looms as one of the biggest questions in all of astrophysics, with numerous lines of evidence suggesting that 5/6ths of the universe's matter is in some form that only interacts via the force of gravity with the remaining 1/6th of ordinary matter we can observe. WIMPs, or weakly interacting massive particles, are a theoretically well-supported candidate particle, but searches to date have been fruitless. The hope is that LZ finally can bring home a detection via its next-generation sensors monitoring an ultrapure detection medium of 10 tonnes of liquid xenon, surrounded by shielding water, all placed deep underground in South Dakota to further protect the experiment from confounding radiation. Members of the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) at Stanford University are heavily involved in LZ and helped build, test, and operationalize the experiment.

Lifting the veil on the earliest stars

Peering back to when the first stars formed poses many challenges, not least of which is seeing through the fog-like clouds of hydrogen gas that permeated the young Universe. The signals from those primordial stars, which reach us as radio waves, are all but drowned out by stronger, nearer sources of radio waves, including from here on Earth. At the Kavli Institute for Cosmology, Cambridge (KICC), researchers are developing a novel wideband, multi-antenna radio astronomy method that takes in more data than conventional radio astronomy observations. This method will help in statistically isolating the faint signals of early stars forming amidst that sea of stronger radio noise, and effectively allow us to see through the veil of hydrogen clouds in the early universe.

Parsing the architecture of the universe with AI-assisted programs

Running simulations of structure formation in the cosmos usually requires big, expensive chunks of time on supercomputers. To help get around this issue, Kavli IPMU researchers have developed a software program that they trained through artificial intelligence to quickly make predictions about why the universe looks the way it does. Encouragingly, when the researchers compared their program's model's predictions to real observational datasets, the model's results independently and strongly corresponded to our broad understanding of the universe's composition. In this cosmological "standard model," matter and (predominantly) dark matter make up about 30% of mass-energy the cosmos, and dark energy the remaining 70%. The researchers plan to apply the program to other cosmological datasets to see if new insights can be efficiently drawn about the universe's composition and evolution.