JWST's PEARLS

Welcome to the public website for the JWST “Prime Extragalactic Areas for Reionization and Lensing Science” (“PEARLS”) project!

The main goal of PEARLS is to study the epoch of galaxy assembly, AGN growth, and First Light using the James Webb Space Telescope (JWST) . This 110 hour GTO program  (#1176 and 2738) is lead by JWST Interdisciplinary Scientist Rogier Windhorst, from Arizona State University, in collaboration with a team of astronomers from around the world.

PEARLS uses NIRCam to survey three prime extragalactic survey areas including two at the North Ecliptic Pole (NEP), seven gravitationally lensing clusters, two high redshift proto-clusters, and the iconic backlit VV 191 galaxy system to map its dust attenuation. PEARLS also includes NIRISS spectra for one of the NEP fields and NIRSpec spectra of two high-redshift quasars. Three fields, JWST NEP Time-Domain Field (TDF), the IRAC Dark Field (IDF), and two lensing clusters, will be observed in up to four epochs over a year, to find faint variable objects such as weak AGN, high-redshift supernovae, and cluster caustic transits. Both NEP fields have sightlines through our Galaxy, providing significant numbers of very faint brown dwarfs whose proper motions can be studied. Observations from the first spoke in the NEP TDF are public. We designed PEARLS to be of lasting benefit to the community.

Full observing details for the programs can be found at Program Information: #1176 and Program Information: #2738.

Recent Highlights

Webb Researchers Discover Lensed Supernova, Confirm Hubble Tension

Measuring the Hubble constant, the rate at which the universe is expanding, is an active area of research among astronomers around the world who analyze data from both ground- and space- based observatories. Now, researchers are using an independent method of measurement to further improve the precision of the Hubble constant — gravitationally lensed supernovae. Brenda Frye from the University of Arizona, and a team of many researchers from different institutions around the world, are leading this effort after Webb’s discovery of three points of light in the direction of a distant and densely populated cluster of galaxies.

“It all started with one question by the team: ‘What are those three dots that weren’t there before? Could that be a supernova?’ The points of light, not visible in 2015 Hubble imaging of the same cluster, were obvious when the images of PLCK G165.7+67.0 arrived on Earth from Webb’s PEARLS program. The team notes the question was the first to pop to mind for good reason: ‘The field of G165 was selected for this program due to its high rate of star formation of more than 300 solar masses per year, an attribute that correlates with higher supernova rates.’

“Trifold supernova images are special: The time delays, supernova distance, and gravitational lensing properties yield a value for the Hubble constant or H0 (pronounced H-naught). The supernova was named SN H0pe since it gives astronomers hope to better understand the universe’s changing expansion rate.

In an effort to explore SN H0pe further, the PEARLS-Clusters team obtained JWST Director's Discretionary Time observations. In parallel, data were acquired at the MMT, a 6.5-meter telescope on Mt. Hopkins, and the Large Binocular Telescope on Mt. Graham, both in Arizona. In analyzing both observations, our team was able to confirm that SN H0pe is anchored to a background galaxy, well behind the cluster, that existed 3.5 billion years after the big bang.

The team reports the value for the Hubble constant as 75.4 kilometers per second per megaparsec, plus 8.1 or minus 5.5. [One parsec is equivalent to 3.26 light-years distance.] This is only the second measurement of the Hubble constant by this method, and the first time using a standard candle. The PEARLS program lead investigator remarked, ‘This is one of the great Webb discoveries, and is leading to a better understanding of this fundamental parameter of our universe. Our team’s results are impactful: The Hubble constant value matches other measurements in the local universe, and is somewhat in tension with values obtained when the universe was young. Webb observations in Cycle 3 will improve on the uncertainties, allowing more sensitive constraints on H0.”

For more details, see the Oct 1 2024 NASA Webb press release!

This is based on our articles:

• JWST Spectroscopy of SN H0pe: Classification and Time Delays of a Triply-imaged Type Ia Supernova at z = 1.78

• JWST Photometric Time-Delay and Magnification Measurements for the Triply-Imaged Type Ia “Supernova H0pe” at z = 1.78

• The JWST Discovery of the Triply-imaged Type Ia “Supernova H0pe” and Observations of the Galaxy Cluster PLCK G165.7+67.0′

• Spectroscopy of the supernova H0pe host galaxy at redshift 1.78

• Birds of a Feather: Resolving Stellar Mass Assembly With JWST/NIRCam in a Pair of Kindred z=2 Dusty Star-forming Galaxies Lensed by the PLCK G165.7+67.0 Cluster

• SN H0pe: The First Measurement of H0 from a Multiply-Imaged Type Ia Supernova, Discovered by JWST

NASA’s Webb, Hubble Combine to Create Most Colorful View of Universe

NASA’s James Webb Space Telescope and Hubble Space Telescope have united to study an expansive galaxy cluster known as MACS0416. The resulting panchromatic image combines visible and infrared light to assemble one of the most comprehensive views of the universe ever taken. Located about 4.3 billion light-years from Earth, MACS0416 is a pair of colliding galaxy clusters that will eventually combine to form an even bigger cluster.

The image reveals a wealth of details that are only possible to capture by combining the power of both space telescopes. It includes a bounty of galaxies outside the cluster and a sprinkling of sources that vary over time, likely due to gravitational lensing – the distortion and amplification of light from distant background sources.

This cluster was the first of a set of unprecedented, super-deep views of the universe from an ambitious, collaborative Hubble program called the Frontier Fields, inaugurated in 2014. Hubble pioneered the search for some of the intrinsically faintest and youngest galaxies ever detected. Webb’s infrared view significantly bolsters this deep look by going even farther into the early universe with its infrared vision.

“We are building on Hubble’s legacy by pushing to greater distances and fainter objects,” said Rogier Windhorst of Arizona State University, principal investigator of the PEARLS program (Prime Extragalactic Areas for Reionization and Lensing Science), which took the Webb observations.

For more details, see the Nov 9 2023 NASA Webb press release!

This is based on our articles

• "JWST’s PEARLS: Mothra, a new kaiju star at z = 2.091 extremely magnified by MACS0416, and implications for dark matter models" Jose M. Diego et al. 2023 A&A 679 A23. DOI 10.1051/0004-6361/202347556

• "JWST's PEARLS: Transients in the MACS J0416.1-2403 Field" Haojing Yan et al. 2023 Accepted for publication in ApJS. DOI 10.48550/arXiv.2307.07579 

Webb Spotlights Gravitational Arcs in ‘El Gordo’ Galaxy Cluster

A new image of the galaxy cluster known as “El Gordo” is revealing distant and dusty objects never seen before, and providing a bounty of fresh science. The infrared image, taken by NASA’s James Webb Space Telescope, displays a variety of unusual, distorted background galaxies that were only hinted at in previous Hubble Space Telescope images. El Gordo is a cluster of hundreds of galaxies that existed when the universe was 6.2 billion years old, making it a “cosmic teenager.” It’s the most massive cluster known to exist at that time. (“El Gordo” is Spanish for the “Fat One.”)

In our El Gordo images we have studied galaxies such as “El Anzuelo” (The Fishhook), “La Flaca” (the Thin One), a single red giant star nicknamed Quyllur, and many ultra-diffuse galaxies. For more details, see the Aug 2 2023 NASA Webb, ESA Webb, ASU, UofA and Chandra press releases!

This is based on our articles

• "JWST’s PEARLS: A new lens model for ACT-CL J0102−4915, “El Gordo,” and the first red supergiant star at cosmological distances discovered by JWST", J. M. Diego et al. 2023 A&A 672, A3. DOI 10.1051/0004-6361/202245238

• "The JWST PEARLS View of the El Gordo Galaxy Cluster and of the Structure It Magnifies" Brenda L. Frye et al. 2023 ApJ 952 81. DOI 10.3847/1538-4357/acd929

• "PEARLS: Low Stellar Density Galaxies in the El Gordo Cluster Observed with JWST" Timothy Carleton et al. 2023 Accepted for publication in ApJ. DOI 10.48550/arXiv.2303.04726 

• "Are JWST/NIRCam color gradients in the lensed z=2.3 dusty star-forming galaxy El Anzuelo due to central dust attenuation or inside-out galaxy growth?" Patrick S. Kamieneski et al. 2023 Accepted for publication in ApJ. DOI 10.48550/arXiv.2303.05054 

The public data and mosaics for El Gordo can be found on our Data Products page. 

These and other versions  of these images are available from http://lambda.la.asu.edu/jwst/pr22/ 

Webb, Hubble Team Up to Trace Interstellar Dust Within a Galactic Pair

We got more than we bargained for by combining data from NASA’s James Webb Space Telescope and NASA’s Hubble Space Telescope! Webb’s new data allowed us to trace the light that was emitted by the bright white elliptical galaxy, through the winding spiral galaxy – and identify the effects of interstellar dust in the spiral galaxy. This image of galaxy pair VV 191 includes near-infrared light from Webb, and ultraviolet and visible light from Hubble. See our press release on NASA's JWST blog here!

This is based on our article "Webb's PEARLS: dust attenuation and gravitational lensing in the backlit-galaxy system VV 191", by Bill Keel & the PEARLS team, accepted for publication in ApJ and available at this ADS Link.

For details on our papers, see Papers.

A full list of PEARLS team papers can be found in this ADS library. 

PEARLS Targets

Galaxy Cluster Lenses:

• MACS0416-24 (3 epochs) 

• Abell 2744

• MACS1149+22

• ACT0102-49 (El Gordo) 

• PLCK G165+67

• GAMA 100033

• RXC J1212+27 = Abell 1489 

JWST GTO_ERS cluster lensing observations.pptx (Powerpoint)

Backlit Galaxy:

• VV 191 

Blank Fields:

• North Ecliptic Pole (NEP) (4 epochs)

• IRAC Dark Field

• WFC3 ERS

z > 1 Galaxy Clusters / Protoclusters

• PLCK G191+62 (z = 2.5)

• TN J1338-1942 (z = 4.1) 

z=6 Quasars:

• SDSS J0005-0006

• NDWFS 1426+3254

For data access, see our Data Products page

Team Members

Core team (PIs, CoIs and 'Builders'):
Rogier Windhorst, Seth Cohen, Rolf Jansen, Jake Summers, Jordan D'Silva,  Scott Tompkins, Christopher Conselice, Simon Driver, Haojing Yan, Dan Coe, Brenda Frye, Norman Grogin, Anton Koekemoer, Madeline Marshall, Mario Nonino, Rafael Ortiz III, Nor Pirzkal, Aaron Robotham, Russell E Ryan Jr, and Christopher Willmer

Current members (In alphabetical order):
Nathan J Adams, Duncan Austin, John F. Beacom, Rachana A. Bhatawdekar, Larry D. Bradley, Cheng Cheng, Liang Dai, Jose M Diego, Hervé Dole, Kenneth J Duncan, Giovanni G. Fazio, Giovanni Ferrami, Leonardo Ferreira, Steven L. Finkelstein, Lukas J. Furtak, Hansung Gim, Kevin C. Harrington, Nimish P. Hathi, Jia-Sheng Huang, Minhee Hyun, Bhavin A Joshi, Patrick S. Kamieneski, William C. Keel, Patrick Kelly, Rebecca L Larson, Juno J. Li, Zhiyuan Ma, Peter Maksym, Giorgio Manzoni, Ashish Kumar Meena, Rosalia D O'Brien, Justin D.R. Pierel, Maria del Carmen Polletta, Huub Rottgering, Ian Smail, Amber N Straughn, Louis-Gregory Strolger, James A. A. Trussler, Lifan Wang, Brian Welch, Stephen M. Wilkins, Steven P. Willner, J. Stuart B. Wyithe, Jiawen Yang, Min Yun, Erik Zackrisson, Jiashuo Zhang, and Adi Zitrin