JWST NIRSpec Archives

April 12, 2024April 12, 2024 by Evan Gough

The Brightest Gamma Ray Burst Ever Seen Came from a Collapsing Star

This artist's visualization of GRB 221009A shows the narrow relativistic jets (emerging from a central black hole) that gave rise to the gamma-ray burst (GRB) and the expanding remains of the original star ejected via the supernova explosion. Credit: Aaron M. Geller / Northwestern / CIERA / IT Research Computing and Data Services

After a journey lasting about two billion years, photons from an extremely energetic gamma-ray burst (GRB) struck the sensors on the Neil Gehrels Swift Observatory and the Fermi Gamma-Ray Space Telescope on October 9th, 2022. The GRB lasted seven minutes but was visible for much longer. Even amateur astronomers spotted the powerful burst in visible frequencies.

It was so powerful that it affected Earth’s atmosphere, a remarkable feat for something more than two billion light-years away. It’s the brightest GRB ever observed, and since then, astrophysicists have searched for its source.

December 11, 2023December 14, 2023 by Matt Williams

Why Was it Tricky to Know the Distances to Galaxies JWST Was Seeing?

Obtaining accurate redshift measurements is a challenge, even with telescopes like Webb. Credit: NASA

One of the chief objectives of the James Webb Space Telescope (JWST) is to study the formation and evolution of the earliest galaxies in the Universe, which emerged more than 13 billion years ago. To this end, scientists must identify galaxies from different cosmological epochs to explore how their properties have changed over time. This, in turn, requires precise dating techniques so astronomers are able to determine when (in the history of the Universe) an observed galaxy existed. The key is to measure the object’s redshift, which indicates how long its light has been traveling through space.

This is the purpose of the Cosmic Evolution Early Release Science Survey (CEERS), a collaborative research group that analyzes Webb data to learn more about galactic evolution. These galaxies are known as “high-redshift,” meaning that their light emissions are redshifted all the way into the infrared spectrum. Galaxies that existed ca. 13 billion years ago can only be observed in the near-infrared spectrum, which is now possible thanks to Webb’s Near-Infrared Camera (NIRCam). Even so, obtaining accurate redshift measurements from such distant galaxies is a very tricky, and requires advanced techniques.

November 23, 2023November 23, 2023 by Evan Gough

Adolescent Galaxies are Incandescent and Contain Unexpected Elements

Light from 23 distant galaxies, identified with red rectangles in the Hubble Space Telescope image at the top, were combined to capture incredibly faint emission from eight different elements, which are labelled in the JWST spectrum at the bottom. Although scientists regularly find these elements on Earth, astronomers rarely, if ever, observe many of them in distant galaxies, especially nickel. Image Credit: Aaron M. Geller, Northwestern, CIERA + IT-RCDS

If the Universe has adolescent galaxies, they’re the ones that formed about 2 to 3 billion years after the Big Bang. New research based on the James Webb Space Telescope shows that these teenage galaxies are unusually hot. Not only that, but they contain some unexpected chemical elements. The most surprising element found in these galaxies is nickel.

November 6, 2023November 9, 2023 by Matt Williams

Supermassive Black Holes Shut Down Star Formation During Cosmic Noon

Artist’s impression of a quasar. These all have supermassive black holes at their hearts. Credit: NOIRLab/NSF/AURA/J. da Silva

Since it became operational almost two years ago, the James Webb Space Telescope (JWST) has produced countless breathtaking images of the Universe and enabled fresh insights into how it evolved. In particular, the telescope’s instruments are optimized for studying the cosmological epoch known as Cosmic Dawn, ca. 50 million to one billion years after the Big Bang when the first stars, black holes, and galaxies in the Universe formed. However, astronomers are also getting a better look at the epoch that followed, Cosmic Noon, which lasted from 2 to 3 billion years after the Big Bang.

During this time, the first galaxies grew considerably, most stars in the Universe formed, and many galaxies with supermassive black holes (SMBHs) at their centers became incredibly luminous quasars. Scientists have been eager to get a better look at galaxies dated to this period so they can see how SMBHs affected star formation in young galaxies. Using near-infrared data obtained by Webb, an international team of astronomers made detailed observations of over 100 galaxies as they appeared 2 to 4 billion years after the Big Bang, coinciding with Cosmic Noon.

October 30, 2023October 30, 2023 by Evan Gough

JWST Searches for Planets in the Fomalhaut System

This image shows Fomalhaut, the star around which the newly discovered planet orbits. Fomalhaut is much hotter than our Sun, 15 times as bright, and lies 25 light-years from Earth. It is blazing through hydrogen at such a furious rate that it will burn out in only one billion years, 10% the lifespan of our star. The field of view is 2.7 x 2.9 degrees.

The Fomalhaut system is nearby in astronomical terms, and it’s also one of the brightest stars in the night sky. That means astronomers have studied it intensely over the years. Now that we have the powerful James Webb Space Telescope the observations have intensified.

The Fomalhaut system has a confounding and complex dusty disk, including a dusty blob. The blob has been the subject of an ongoing debate in astronomy. Can the JWST see through its complexity and find answers to the systems unanswered questions?

October 25, 2023October 26, 2023 by Nancy Atkinson

After DART Smashed Into Dimorphos, What Happened to the Larger Asteroid Didymos?

NASA’s DART mission (Double Asteroid Redirection Test) slammed into asteroid Dimorphos in September 2022, changing its orbital period. Ground and space-based telescopes turned to watch the event unfold, not only to study what happened to the asteroid, but also to help inform planetary defense efforts that might one day be needed to mitigate potential collisions with our planet.

Astronomers have continued to observe and study Dimorphos, well past the impact event. However, Dimorphos is the smaller asteroid in this binary system, and is just a small moon orbiting the larger asteroid Didymos.

The James Webb Space Telescope (JWST) is the only telescope capable of visually distinguishing between the two closely orbiting asteroids. Now, astronomers have made follow-on observations on the system with JWST to see what happened to Didymos after the dust cleared.