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.

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The Second Most Energetic Cosmic Ray Ever Found

An example of a cosmic-ray extensive air shower recorded by the Subaru Telescope. The highlighted tracks, which are mostly aligned in similar directions, show the shower particles induced from a high-energy cosmic ray. Credit: NAOJ/Hyper Suprime-Cam (HSC) Collaboration

“Oh My God,” someone must have said in 1991 when researchers detected the most energetic cosmic ray ever to strike Earth. Those three words were adopted as the name for the phenomenon: the Oh-My-God particle. Where did it come from?

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An Amateur Astronomer Discovered One-of-a-Kind Supernova Remnant

PA 30 imaged in O III on Sept 6, 2013 by KPNO from Ritter et al (2021) (left) and in S II from Fesen et al (2023) (right).

In 2013, amateur astronomer Dana Patchick was looking through images from the Wide-field Infrared Survey Explorer archive and discovered a diffuse, circular object near the constellation of Cassiopeia. He found this apparent nebula was interesting because it was bright in the infrared portion of the spectrum, but virtually invisible in the colors of light visible to our eyes. Dana added this item to the database of the Deep Sky Hunters amateur astronomers group, believing it was a planetary nebula – the quiet remnant of stars in mass similar to the sun. He named it PA 30.

However, professional astronomers who picked it up from there realized that this object is far more than it first seemed. It is, they now believe, the remnant of a lost supernova observed in 1181. And an extremely rare type at that.

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This Dark Nebula Hides an Enormous Star

Stars forming in this dark nebula, named G35.2-0.7N, are particularly massive and many of them will explode as supernovae. Image Credit: ESA/Hubble & NASA, R. Fedriani, J. Tan

The birth of a star is a spectacular event that plays out behind a veil of gas and dust. It’s a detailed process that takes millions of years to play out. Once a star leaves its protostar stage behind and begins its life of fusion, the star’s powerful radiative output blows the veil away.

But before then, astrophysicists are at a disadvantage.

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A Machine Learning Algorithm Finds its First Supernova

Plenty of recent mainstream news articles have touted AI’s ability to assist in the process of scientific discovery. But most of them predicted that it could take years or even decades to see the full effect. Astronomy seems ahead of the curve, though, with the announcement of a new AI system developed by researchers at Northwestern University and elsewhere that can now autonomously detect and classify supernovae.

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Colliding Neutron Stars Could Help Measure the Expansion of the Universe

Artist's impression of two neutron stars colliding, known as a "kilonova" event. Credits: Elizabeth Wheatley (STScI)

According to some in the astrophysical community, there has been something of a “Crisis in Cosmology” in recent years. Though astronomers are all aware that the Universe is in a state of expansion, there has been some inconsistency when measuring the rate of it (aka. the Hubble Constant). This issue arises from the Cosmic Distance Ladder, where astronomers use different methods to measure relative distances over longer scales. This includes making local distance estimates using parallax measurements, nearby variable stars, and supernovae (“standard candles”).

They also conduct redshift measurements of the Cosmic Microwave Background (CMB), the relic radiation left over from the Big Bang, to determine cosmological distances. The discrepancy between these two methods is known as the “Hubble Tension,” and astronomers are eager to resolve it. In a recent study, an international team of astrophysicists from the Niels Bohr Institute suggested a novel method for measuring cosmic expansion. They argue that by observing colliding neutron stars (kilonovae), astronomers can relieve the tension and obtain consistent measurements of the Hubble Constant.

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Astronomers Have Been Watching a Supernova’s Debris Cloud Expand for Decades with Hubble

This is a Hubble image of a very small region of the Cygnus Loop, a supernova remnant. The image shows a small part of the leading edge of the expanding bubble. Image Credit: NASA, ESA, Ravi Sankrit (STScI)

Twenty thousand years ago, a star in the constellation Cygnus went supernova. Like all supernovae, the explosion released a staggering amount of energy. The explosion sent a powerful shockwave into the surrounding space at half a million miles per hour, and it shows no signs of slowing down.

For twenty years, the Hubble Space Telescope has been watching some of the action.

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Supernovae Struck the Earth 3 Million and 7 Million Years Ago

X-ray image of the Tycho supernova, also known as SN 1572, located between 8,000 and 9,800 light-years from Earth. Its core collapse could result in a neutron star or a black hole, depending on final mass. (Credit: X-ray: NASA/CXC/RIKEN & GSFC/T. Sato et al; Optical: DSS)
X-ray image of the Tycho supernova, also known as SN 1572, located between 8,000 and 9,800 light-years from Earth. Its core collapse could result in a neutron star or a black hole, depending on final mass. (Credit: X-ray: NASA/CXC/RIKEN & GSFC/T. Sato et al; Optical: DSS)

A recent study examines how the Earth was hit by blasts from supernovae (plural form of supernova (SN)) that occurred 3 million years ago (Mya) and 7 Mya with the goal of ascertaining the distances of where these blasts originated. Using the live (not decaying) radioactive isotope 60-Fe, which is produced from supernovae, a team of researchers at the University of Illinois was able to determine the approximate astronomical distances to the blasts, which they refer to as Pliocene Supernova (SN Plio, 3 Mya) and the Miocene Supernova (SN Mio, 7 Mya).

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This 3D Simulation of a Supernova Needed 5 Million Hours of Supercomputing

The three-dimensional simulation of the exotic supernova reveals the turbulent structures generated during the material ejection in the explosion. Through three-dimensional simulations, scientists gain deeper insights into the physical processes of peculiar supernova explosions and can explain the observed phenomena and characteristics of these extraordinary supernovae. Credit: Ke-Jung Chen/ASIAA.

When the largest stars in the Universe run out of fuel, they detonate as supernovae, collapsing inward and leaving behind a neutron star, black hole, or just wholly vaporizing. What’s happening inside the unfolding explosion is difficult to understand, and especially so for so-called exotic supernovae, the rarest and brightest types of stellar explosions.

To better understand the dynamics of these rare supernovae, astronomers are using powerful supercomputers to simulate the process. After years of real-world research and millions of hours of supercomputer computing time, researchers have completed the first ever high-definition, 3D hydrodynamic simulation of exotic supernovae.

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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.

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