Gravitational Lensing Archives

December 21, 2023December 21, 2023 by Evan Gough

Webb Sees a Supernova Go Off in a Gravitationally Lensed Galaxy – for the Second Time

NASA’s James Webb Space Telescope has spotted a multiply-imaged supernova in a distant galaxy designated MRG-M0138. Image Credit: NASA, ESA, CSA, STScI, Justin Pierel (STScI) and Andrew Newman (Carnegie Institution for Science).

Nature, in its infinite inventiveness, provides natural astronomical lenses that allow us to see objects beyond the normal reach of our telescopes. They’re called gravitational lenses, and a few years ago, the Hubble Space Telescope took advantage of one of them to spot a supernova explosion in a distant galaxy.

Now, the JWST has taken advantage of the same lens and found another supernova in the same galaxy.

December 19, 2023December 19, 2023 by Evan Gough

Can Webb Find the First Stars in the Universe?

The Universe’s very first stars had an important job. They formed from the primordial elements created by the Big Bang, so they contained no metals. It was up to them to synthesize the first metals and spread them out into the nearby Universe.

The JWST has made some progress in finding the Universe’s earliest galaxies. Can it have the same success when searching for the first stars?

November 11, 2023November 11, 2023 by Matt Williams

An Epic Collaboration Between Hubble and JWST

This panchromatic view of galaxy cluster MACS0416 was created by combining infrared observations from the NASA/ESA/CSA James Webb Space Telescope with visible-light data from the NASA/ESA Hubble Space Telescope. Credit: NASA/ESA/CSA/STScI

In 2012, as part of the MAssive Cluster Survey (MACS), the Hubble Space Telescope (HST) discovered a pair of colliding galaxy clusters (MACS0416) that will eventually combine to form an even bigger cluster. Located about 4.3 billion light-years from Earth, the MACS0416 cluster contains multiple gravitational lenses that allow astronomers to look back in time and view galaxies as they appeared when the Universe was young. In a new collaboration that symbolizes the passing of the torch, the venerable Hubble and the James Webb Space Telescope (JWST) teamed up to conduct an extremely detailed study of MACS0416.

November 4, 2023November 13, 2023 by Matt Williams

Civilizations Could Use Gravitational Lenses to Transmit Power From Star to Star

A new study shows how Solar Gravitational Lenses (SGLs) could be used to beam power from one system to another.. Credit: NASA/ESA

In 1916, famed theoretical physicist Albert Einstein put the finishing touches on his Theory of General Relativity, a geometric theory for how gravity alters the curvature of spacetime. The revolutionary theory remains foundational to our models of how the Universe formed and evolved. One of the many things GR predicted was what is known as gravitational lenses, where objects with massive gravitational fields will distort and magnify light coming from more distant objects. Astronomers have used lenses to conduct deep-field observations and see farther into space.

In recent years, scientists like Claudio Maccone and Slava Turyshev have explored how using our Sun as a Solar Gravity Lens (SGL) could have tremendous applications for astronomy and the Search for Extratterstiral Intelligence (SETI). Two notable examples include studying exoplanets in extreme detail or creating an interstellar communication network (a “galactic internet”). In a recent paper, Turyshev proposes how advanced civilizations could use stellar gravitational lenses to transmit power from star to star – a possibility that could have significant implications in our search for technosignatures.

September 7, 2023September 7, 2023 by Brian Koberlein

The Most Distant Galactic Field Lines Ever Seen

Mapping of the magnetic field in the distant 9io9 galaxy. Credit: ALMA (ESO/NAOJ/NRAO)/J. Geach et al.

The galaxies in our local Universe all have magnetic fields. Galactic magnetic fields can be generated by ionized gas within a galaxy, and these same magnetic fields affect the evolution of galaxies. But while modern galaxies have magnetic fields, did early ones? Astronomers are still trying to understand how galactic magnetic fields arise in young galaxies, but this can be a challenge without observational data. Now a team using data from the Atacama Large Millimeter/submillimeter Array (ALMA) has observed the magnetic field of a galaxy when the Universe was just 2.5 billion years old. The galaxy is known as 9io9. It takes 11 billion years for its light to reach us, making it the most distant galaxy for which we have observed a magnetic field.

August 19, 2023August 19, 2023 by Brian Koberlein

A New Way to Measure the Expansion Rate of the Universe: Redshift Drift

Cosmological redshift depends upon a galaxy's distance. Credit: NASA/JPL-Caltech/R. Hurt (Caltech-IPAC)

In 1929 Edwin Hubble published the first solid evidence that the universe is expanding. Drawing upon data from Vesto Slipher and Henrietta Leavitt, Hubble demonstrated a correlation between galactic distance and redshift. The more distant a galaxy was, the more its light appeared shifted to the red end of the spectrum. We now know this is due to cosmic expansion. Space itself is expanding, which makes distant galaxies appear to recede away from us. The rate of this expansion is known as the Hubble parameter, and while we have a good idea of its value, there is still a bit of tension between different results.

July 26, 2023July 26, 2023 by Brian Koberlein

A Gamma Ray Burst Lasted So Long it Triggered a Satellite Twice

An artist's depiction of a gamma-ray burst's relativistic jet full of very-high-energy photons breaking out of a collapsing star. Credit: DESY, Science Communication Lab

Gamma Ray Bursts (GRBs) are the most powerful astrophysical phenomena in the universe. For a span of seconds to a few minutes, they can be the most powerful high-energy event in the sky, shining across billions of light years. But recently astronomers detected a GRB that lasted more than a thousand seconds, with two blasts of gamma rays that triggered the Fermi Gamma Ray Burst Monitor. It’s such a strange cosmic event that astronomers aren’t sure what caused it, but they do have a possible idea.

July 4, 2023July 4, 2023 by Brian Koberlein

Gravitational Waves Can Be Gravitationally Lensed, and This Could Provide Another Way to Measure the Expansion of the Universe

A simulation of merging black holes. Credit: NASA's Goddard Space Flight Center/Scott Noble

Gravitational waves don’t travel through space and time. They are ripples in the fabric of spacetime itself. This is why they are so difficult to detect. We can only observe them by closely watching how objects bent and stretched within spacetime. But despite their oddness, gravitational waves behave in many of the same ways as light, and astronomers can use that fact to study cosmic expansion.

June 18, 2023June 18, 2023 by Matt Williams

Astronomers See the Same Supernova Four Times Thanks to a Gravitational Lens

A gravitational lens caused by a galaxy in the foreground leading to an "Einstein Cross." Credit: NASA/ESA/STScI

Measuring cosmic distances is challenging, and astronomers rely on multiple methods and tools to do it – collectively referred to as the Cosmic Distance Ladder. One particularly crucial tool is Type Ia supernovae, which occur in binary systems where one star (a white dwarf) consumes matter from a companion (often a red giant) until it reaches the Chandrasekhar Limit and collapses under its own mass. As these stars blow off their outer layers in a massive explosion, they temporarily outshine everything in the background.

In a recent study, an international team of researchers led by Ariel Goobar of the Oskar Klein Centre at Stockholm University discovered an unusual Type Ia supernova, SN Zwicky (SN 2022qmx). In an unusual twist, the team observed an “Einstein Cross,” an unusual phenomenon predicted by Einstein’s Theory of General Relativity where the presence of a gravitational lens in the foreground amplifies light from a distant object. This was a major accomplishment for the team since it involved observing two very rare astronomical events that happened to coincide.

May 17, 2023May 17, 2023 by Brian Koberlein

Astronomers Have a New Way to Measure the Expansion of the Universe

Multiple observations of the Refsdal supernova. Credit: Kelly,et al

The cosmos is expanding at an ever-increasing rate. This cosmic acceleration is caused by dark energy, and it is a central aspect of the evolution of our universe. The rate of cosmic expansion can be expressed by a cosmological constant, commonly known as the Hubble constant, or Hubble parameter. But while astronomers generally agree this Hubble parameter exists, there is some disagreement as to its value.