Gravitational Lensing Archives

May 3, 2023May 5, 2023 by Matt Williams

Gravitational Lensing is Helping to Nail Down Dark Matter

Using the gravitational lensing technique, a team was able to examine how light from distant quasar was affected by intervening small clumps of dark matter. Credit: NASA/ESA/D. Player (STScI)

According to the most widely-accepted cosmological model, the majority of the mass in our Universe (roughly 85%) consists of “Dark Matter.” This elusive, invisible mass is theorized to interact with “normal” (or “visible”) matter through gravity alone and not electromagnetic fields, neither absorbing nor emitting light (hence the name “dark”). The search for this matter is ongoing, with candidate particles including Weakly-Interacting Massive Particles (WIMPs) or ultralight bosons (axions), which are at opposite extremes of the mass scale and behave very differently (in theory).

This matter’s existence is essential for our predominant theories of gravity (General Relativity) and particle physics (The Standard Model) to make sense. Otherwise, we may need to radically rethink our theories on how gravity behaves on the largest of scales (aka. Modified Gravity). However, according to new research led by the University of Hong Kong (HKU), the study of “Einstein Rings” could bring us a step closer to understanding Dark Matter. According to their paper, the way Dark Matter alters the curvature of spacetime leaves signatures that suggest it could be made up of axions!

April 27, 2023April 27, 2023 by Brian Koberlein

Gravitational Waves From Pulsars Could Be Used to Probe the Interior of the Sun

A solar flare, as it appears in extreme ultra-violet light. Some stars emit superflares similar to this, but many times brighter and stronger than those from the Sun. Credit: NASA/SFC/SDO

Gravitational wave astronomy is still in its early stages. So far it has focused on the most energetic and distinct sources of gravitational waves, such as the cataclysmic mergers of black holes and neutron stars. But that will change as our gravitational telescopes improve, and it will allow astronomers to explore the universe in ways previously impossible.

April 5, 2023April 5, 2023 by Matt Williams

This JWST Image Shows Gravitational Lensing at its Finest

. Credit: ESA/Webb, NASA & CSA, J. Rigby

One of the more intriguing aspects of the cosmos, which the James Webb Space Telescope (JWST) has allowed astronomers to explore, is the phenomenon known as gravitational lenses. As Einstein’s Theory of General Relativity describes, the curvature of spacetime is altered by the presence of massive objects and their gravity. This effect leads to objects in space (like galaxies or galaxy clusters) altering the path light travels from more distant objects (and amplifying it as well). By taking advantage of this with a technique known as Gravitational Lensing, astronomers can study distant objects in greater detail.

Consider the image above, the ESA’s picture of the month acquired by the James Webb Space Telescope (JWST). The image shows a vast gravitational lens caused by SDSS J1226+2149, a galaxy cluster located roughly 6.3 billion light-years from Earth in the constellation Coma Berenices. The lens these galaxies created greatly amplified light from the more distant Cosmic Seahorse galaxy. Combined with Webb‘s incredible sensitivity, this technique allowed astronomers to study the Cosmic Seahorse in the hopes of learning more about star formation in early galaxies.

April 3, 2023April 3, 2023 by Matt Williams

Astronomers Think They've Found One of the Biggest Black Holes Ever Seen

Artist's impression of an ultramassive black hole (UBH). Credit: ESA/Hubble/DSS/Nick Risinger/N. Bartmann

In 1931, Indian-American physicist Subrahmanyan Chandrasekhar proposed a resolution to Einstein’s Theory of General Relativity that postulated the existence of black holes. By 1972, astronomers obtained the first conclusive evidence that these objects existed in our Universe. Observations of quasars and the center of the Milky Way also revealed that most massive galaxies have supermassive black holes (SMBHs) at their cores. Since then, the study of black holes has revealed that these objects vary in size and mass, ranging from micro black holes (MBHs) and intermediate black holes (IMBHs) to SMBHs.

Using astronomical simulations and a technique known as Gravitational Lensing, an international team of astrophysicists detected what could be the largest black hole ever observed. This ultramassive black hole (UMBH) has a mass roughly 30 billion times that of our Sun and is located near the center of the Abell 1201 galaxy cluster, roughly 2.7 billion light-years from Earth. This is the first time a black hole has been found using Gravitational Lensing, and it could enable studies that look farther into space to find black holes and deepen our understanding of their size and scale.

March 2, 2023March 2, 2023 by Laurence Tognetti

JWST Sees the Same Supernova Three Times in an Epic Gravitational Lens

JWST image with three smaller insets displaying three lensed images comprised of a single background galaxy up close. Supernova candidate AT 2022riv (middle image with parallel lines) is the oldest image, followed by two subsequent images ~320 days after the first image (bottom) and ~1000 days after the first image (top). Neither of the two subsequent images have the supernova present. (Credit: ESA/Webb, NASA & CSA, P. Kelly)

The NASA/European Space Agency (ESA)/Canadian Space Agency (CSA) James Webb Space Telescope (JWST) mission continues to dazzle and amaze with every image it beams back to Earth, and a recent observation depicting not one, not two, but three images of the same galaxy has been no different, as they proudly tweeted on February 28, 2023.

February 16, 2023February 16, 2023 by Andy Tomaswick

The Mass of a Single Star (other than the Sun) has Been Directly Measured for the First Time

How do you measure an object’s weight from a distance? You could guess at its distance and therefore derive its size. Maybe you could further speculate about its density, which would eventually lead to an estimated weight. But these are far from the exact empirical studies that astrophysicists would like to have when trying to understand the weight of stars. Now, for the first time ever, scientists have empirically discovered the weight of a distant single star, and they did so using gravitational lensing.

February 16, 2023February 16, 2023 by Matt Williams

Webb Sees Three Galaxy Clusters Coming Together to Form a Megacluster

Pandora's Cluster, imaged by the UNCOVER project using the JWST. Credit: Credits: NASA/ESA/CSA, I. Labbe/R. Bezanson/ Alyssa Pagan (STScI)

As the successor to the venerable Hubble Space Telescope, one of the main duties of the James Webb Space Telescope has been to take deep-field images of iconic cosmic objects and structures. The JWST’s next-generation instruments and improved resolution provide breathtakingly detailed images, allowing astronomers to learn more about the cosmos and the laws that govern it. The latest JWST deep-field is of a region of space known as Abell 7244 – aka. Pandora’s Cluster – where three galaxy clusters are in the process of coming together to form a megacluster.

January 26, 2023January 26, 2023 by Evan Gough

Astronomers Pin Down the Age of the Most Distant Galaxy: Seen 367 Million Years After the Big Bang

The radio telescope array ALMA has pin-pointed the exact cosmic age of a distant JWST-identified galaxy, GHZ2/GLASS-z12, at 367 million years after the Big Bang. Image Credit: NASA / ESA / CSA / T. Treu, UCLA / NAOJ / T. Bakx, Nagoya U. Licence type Attribution (CC BY 4.0)

Staring off into the ancient past with a $10 billion space telescope, hoping to find extraordinarily faint signals from the earliest galaxies, might seem like a forlorn task. But it’s only forlorn if we don’t find any. Now that the James Webb Space Telescope has found those signals, the exercise has moved from forlorn to hopeful.

But only if astronomers can confirm the signals.

December 21, 2022December 21, 2022 by Evan Gough

Webb Stares Deeply Into the Universe, Showing How Galaxies Assemble

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. Image Credit: SCIENCE: NASA, ESA, CSA, Rolf A. Jansen (ASU), Jake Summers (ASU), Rosalia O'Brien (ASU), Rogier Windhorst (ASU), Aaron Robotham (UWA), Anton M. Koekemoer (STScI), Christopher Willmer (University of Arizona), JWST PEARLS Team IMAGE PROCESSING: Rolf A. Jansen (ASU), Alyssa Pagan (STScI)

The James Webb Space Telescope is delivering a deluge of images and data to eager scientists and other hungry-minded people. So far, the telescope has shown us the iconic Pillars of Creation like we’ve never seen them before, the details of very young stars as they grow inside their dense cloaks of gas, and a Deep Field that’s taken over from the Hubble’s ground-breaking Deep Field and Ultra Deep Field images. And it’s only getting started.

True to its main science objectives, the JWST has peered back in time to the Universe’s earliest galaxies looking for clues to how they assemble and evolve.

October 28, 2022October 28, 2022 by Brian Koberlein

JWST Sees the Same Galaxy From Three Different Angles Thanks to a Gravitational Lens

This illustration shows how gravitational lensing works. The gravity of a large galaxy cluster is so strong, it bends, brightens and distorts the light of distant galaxies behind it. The scale has been greatly exaggerated; in reality, the distant galaxy is much further away and much smaller. Credit: NASA, ESA, L. Calcada

One of the great tragedies of the night sky is that we will never travel to much of what we see. We may eventually travel to nearby stars, and even distant reaches of our galaxy, but the limits of light speed and cosmic expansion make it impossible for us to travel beyond our local group. So we can only observe distant galaxies, and we can only observe them from our home in the universe. You might think that means we can only see one face of those galaxies, but thanks to the James Webb Space Telescope that isn’t entirely true.