One possible origin for GRB 211211A, shown in this illustration, is a pair of compact stars merging (bright dots in the center) and emitting jets of radiation (green and purple beams). Heavy elements forming in the clouds of matter surrounding the stars emit light that is known as a kilonova. SAMUELE RONCHINI/GSSI 2022

By Lisa Grossman
8.12.2022

Astronomers have spotted a bright gamma-ray burst that upends previous theories of how these energetic cosmic eruptions occur.

For decades, astronomers thought that GRBs came in two flavors, long and short — that is, lasting longer than two seconds or winking out more quickly. Each type has been linked to different cosmic events. But about a year ago, two NASA space telescopes caught a short GRB in long GRB’s clothing: It lasted a long time but originated from a short GRB source.

“We had this black-and-white vision of the universe,” says astrophysicist Eleonora Troja of the Tor Vergata University of Rome. “This is the red flag that tells us, nope, it’s not. Surprise!”

This burst, called GRB 211211A, is the first that unambiguously breaks the binary, Troja and others report December 7 in five papers in Nature and Nature Astronomy.

Prior to the discovery of this burst, astronomers mostly thought that there were just two ways to produce a GRB. The collapse of a massive star just before it explodes in a supernova could make a long gamma-ray burst, lasting more than two seconds (SN: 10/28/22). Or a pair of dense stellar corpses called neutron stars could collide, merge and form a new black hole, releasing a short gamma-ray burst of two seconds or less.

See full text

An artist's impression of a gamma-ray burst. (ESO/A. Roquette)

12 October 2022
By MICHELLE STARR

Observatories around the world have just detected a colossal flare of extremely energetic radiation described as "record-breaking".

The event, first detected on October 9, was so bright that it was initially confused for an event closer to home. Initially dubbed Swift J1913.1+1946, it was thought to be a brief flash of X-rays from a not-too-distant source. It was only through further analysis that astronomers discovered the true nature of the glow – a gamma-ray burst, one of the most violent explosions in the Universe, now re-named GRB221009A.

Though further away, it was still one of the closest seen yet, just 2.4 billion light-years away. Moreover, this exceptionally bright gamma-ray burst appears to be the most energetic ever detected, coming in at up to 18 teraelectronvolts.

To be clear, though this proximity happens to be 20 times closer than the average long gamma-ray burst, it poses absolutely no danger to life on Earth.

Rather, it's tremendously exciting – an event that could shed new light (pun intended) on these fascinating explosions. Although its closeness makes it appear brighter in our sky, GRB221009A is possibly the most intrinsically bright gamma-ray burst we've ever seen.

See full text

In the new decadal survey, researchers recommend building a planet-hunting space telescope that takes inspiration from a previously proposed mission called HabEx (illustrated). IMAGE COURTESY OF SCOTT GAUDI

By Maria Temming
4 HOURS AGO

The Astronomy and Astrophysics Decadal Survey is basically a sneak preview of the next 10 years of U.S. space science. Every decade, experts assembled by the National Academies of Sciences, Engineering and Medicine collect input from astronomers nationwide to recommend a prioritized list of projects to policy makers and federal agencies. Past to-do lists have been topped by specific big-ticket items, such as the James Webb Space Telescope and the Nancy Grace Roman Space Telescope (SN: 10/6/21; SN: 8/13/10). But this year, astronomers are shaking things up.

The latest decadal survey, which charts the course for U.S. astronomy and astrophysics from 2022 to 2032, recommends that NASA create a new program to develop several major space telescopes at a time. Investing early in multiple mission concepts could curb the risk of individual missions becoming too unwieldy and expensive, according to the report released November 4.

See full text

Scientists spotted an exploding star in one of a pair of galaxies known as the Butterfly galaxies (shown). Observations of that supernova (bright spot in the zoomed-in view) in the hours and days after it went off showed details of the star’s life just before death. NASA, ESA, RYAN FOLEY/UCSC, JOSEPH DEPASQUALE/STSCI

By Emily Conover
NOVEMBER 2, 2021 

A mad scramble to observe the moments after a star’s death is helping scientists understand how the star lived out its last year.

Astronomers reported the exploding star just 18 hours after it flared up on March 31, 2020, in a galaxy about 60 million light-years away from Earth in the Virgo cluster. The supernova occurred in part of the sky already watched by NASA’s Transiting Exoplanet Survey Satellite, which images large portions of the sky every 30 minutes (SN: 1/8/19). And a team of scientists quickly realized that data would track precisely how the eruption brightened over time, making it ideal for further study.

To learn even more, the team leapt into action, viewing the supernova with a variety of telescopes in the hours and days that followed, even orchestrating a last-minute change of plans for the Hubble Space Telescope. That provided the supernova’s spectrum, an accounting of its light broken up by wavelength, at various moments after the blast.

All that data revealed that in the last year of its life, the star had spewed some of its outer layers into space, researchers report October 26 in Monthly Notices of the Royal Astronomical Society. The amount of material ejected was about 0.23 times the mass of the sun, the team estimates. When the supernova went off, it launched a shock wave that plowed through that material shortly after the explosion, generating light picked up by the telescopes.

See full text

STELLAR SWOON A simulation of a supernova tracks the turmoil in the center of a dying star in the moments after its core collapses. The collapse creates a shock wave (blue line) that travels outward, blasting the star apart. Red colors represent material hurtling outward, blues represent inward motion. The surfaces of the lumpy shapes have equal entropy, which is related to temperature. T. MELSON, H.-T. JANKA AND A. MAREK/ASTROPHYS. J. LETT. 2015

By Emily Conover
FEBRUARY 8, 2017

Almost every night that the constellation Orion is visible, physicist Mark Vagins steps outside to peer at a reddish star at the right shoulder of the mythical figure. “You can see the color of Betelgeuse with the naked eye. It’s very striking, this red, red star,” he says. “It may not be in my lifetime, but one of these days, that star is going to explode.”

With a radius about 900 times that of the sun, Betelgeuse is a monstrous star that is nearing its end. Eventually, it will no longer be able to support its own weight, and its core will collapse. A shock wave from that collapse will speed outward, violently expelling the star’s outer layers in a massive explosion known as a supernova. When Betelgeuse detonates, its cosmic kaboom will create a light show brighter than the full moon, visible even during the daytime. It could happen tomorrow, or a million years from now.

See full text

Engineers work on the James Webb Space Telescope’s primary mirror. The 18 hexagonal mirror segments are made of lightweight yet tough beryllium and coated with a thin layer of gold to boost reflectivity. DESIREE STOVER/NASA

Lisa Grossman
OCTOBER 6, 2021

Delays for the space telescope mean there’ll be more cool science to do

The James Webb Space Telescope has been a long time coming. When it launches later this year, the observatory will be the largest and most complex telescope ever sent into orbit. Scientists have been drafting and redrafting their dreams and plans for this unique tool since 1989.

The mission was originally scheduled to launch between 2007 and 2011, but a series of budget and technical issues pushed its start date back more than a decade. Remarkably, the core design of the telescope hasn’t changed much. But the science that it can dig into has. In the years of waiting for Webb to be ready, big scientific questions have emerged. When Webb was an early glimmer in astronomers’ eyes, cosmological revolutions like the discoveries of dark energy and planets orbiting stars outside our solar system hadn’t yet happened.

“It’s been over 25 years,” says cosmologist Wendy Freedman of the University of Chicago. “But I think it was really worth the wait.”

An audacious plan
Webb has a distinctive design. Most space telescopes house a single lens or mirror within a tube that blocks sunlight from swamping the dim lights of the cosmos. But Webb’s massive 6.5-meter-wide mirror and its scientific instruments are exposed to the vacuum of space. A multilayered shield the size of a tennis court will block light from the sun, Earth and moon.

For the awkward shape to fit on a rocket, Webb will launch folded up, then unfurl itself in space (see below, What could go wrong?).

See full text

Fourteen celestial sources of gamma rays (colored dots in this all-sky map of the Milky Way; yellow indicates bright sources and blue shows dim sources) may come from stars made of antimatter. SIMON DUPOURQUÉ/IRAP

If true, the preliminary find might mean some antimatter survived to the present day

By Maria Temming
APRIL 26, 2021

Fourteen pinpricks of light on a gamma-ray map of the sky could fit the bill for antistars, stars made of antimatter, a new study suggests.

These antistar candidates seem to give off the kind of gamma rays that are produced when antimatter — matter’s oppositely charged counterpart — meets normal matter and annihilates. This could happen on the surfaces of antistars as their gravity draws in normal matter from interstellar space, researchers report online April 20 in Physical Review D.

“If, by any chance, one can prove the existence of the antistars … that would be a major blow for the standard cosmological model,” says Pierre Salati, a theoretical astrophysicist at the Annecy-le-Vieux Laboratory of Theoretical Physics in France not involved in the work. It “would really imply a significant change in our understanding of what happened in the early universe.”

See full text

NASA image

By Ashley Strickland, CNN | Posted - Dec. 7, 2020

The two largest planets in our solar system are coming closer together than they have been since the Middle Ages, and it's happening just in time for Christmas.

So, there are some things to look forward to in the final month of 2020.

On the night of Dec. 21, the winter solstice, Jupiter and Saturn will appear so closely aligned in our sky that they will look like a double planet. This close approach is called a conjunction.

"Alignments between these two planets are rather rare, occurring once every 20 years or so, but this conjunction is exceptionally rare because of how close the planets will appear to one another," said Rice University astronomer and professor of physics and astronomy Patrick Hartigan in a statement.

"You'd have to go all the way back to just before dawn on March 4, 1226, to see a closer alignment between these objects visible in the night sky."

See full text

See also a beautiful webpage from University of Exeter

© Jeremy Sanders, Hermann Brunner and the eSASS team (MPE); Eugene Churazov, Marat Gilfanov (on behalf of IKI)

By Jonathan Amos

BBC Science Correspondent

Behold the hot, energetic Universe.
A German-Russian space telescope has just acquired a breakthrough map of the sky that traces the heavens in X-rays.
The image records a lot of the violent action in the cosmos - instances where matter is being accelerated, heated and shredded.
Feasting black holes, exploding stars, and searingly hot gas.
The data comes from the eRosita instrument mounted on Spektr-RG.
This orbiting telescope was launched in July last year and despatched to an observing position some 1.5 million km from Earth. Once commissioned and declared fully operational in December, it was left to slowly rotate and scan the depths of space.
eRosita's first all-sky data-set, represented in the image at the top of this page, was completed only last week. It records over a million sources of X-rays.
"That's actually pretty much the same number as had been detected in the whole history of X-ray astronomy going back 60 years. We've basically doubled the known sources in just six months," said Kirpal Nandra, who heads the high-energy astrophysics group at the Max Planck Institute for Extraterrestrial Physics (MPE) in Garching, Germany.
"The data is truly stunning and I think what we're doing here will revolutionise X-ray astronomy," he told BBC News.

See full text

See also Max-Planck webpage

A bright radio burst generated by a magnetar (one illustrated) in our galaxy hints that similar objects are responsible for at least some of the fast radio bursts in other galaxies, which have puzzled astronomers for over a decade. L. CALÇADA/ESO

High-energy event nearby could help explain mystery signals from distant galaxies

By Maria Temming

Astronomers think they’ve spotted the first example of a superbright blast of radio waves, called a fast radio burst, originating within the Milky Way.

Dozens of these bursts have been sighted in other galaxies — all too far away to see the celestial engines that power them (SN: 2/7/20). But the outburst in our own galaxy, detected simultaneously by two radio arrays on April 28, was close enough to see that it was generated by a highly magnetic neutron star called a magnetar.

That observation is a smoking gun that magnetars are behind at least some of the extragalactic fast radio bursts, or FRBs, that have defied explanation for over a decade (SN: 7/25/14). Researchers describe the magnetar’s radio burst online at arXiv.org on May 20 and May 21.

“When I first heard about it, I thought, ‘No way. Too good to be true,’” says Ben Margalit, an astrophysicist at the University of California, Berkeley, who wasn’t involved in the observations. “Just, wow. It’s really an incredible discovery.”

 See full text

You may have a look also in a recent TAT paper  

The Australian Square Kilometre Array Pathfinder helped detect the universe's missing matter.(Supplied: Kirsten Gottschalk, COMET)

28.05.2020

By science, technology and environment reporter Michael Slezak and the Specialist Reporting Team's Penny

After an intergalactic search lasting more than two decades, an Australian-led team of scientists say they have finally found the universe's "missing matter", solving a mystery that has long stumped astronomers.

Since the mid-90s, scientists have been trying to locate half of the universe's ordinary matter. They believed it was out there because of clues left over from the Big Bang, but it had never been seen.

"What we're talking about here is what scientists call baryonic matter, which is the normal stuff that you and I are made of," said Associate Professor Jean-Pierre Macquart, from the Curtin University node of the International Centre for Radio Astronomy Research.

Astronomy is full of missing stuff. Most of the universe is understood to be "dark matter" and "dark energy", which nobody has ever directly seen. But even more of a mystery for astronomers was that they couldn't find about half the ordinary matter in the universe.

See full text

The CHIME radio telescope in British Columbia (pictured) found that a repeating source of radio waves from deep space has a brief window of activity about every 16 days.
CHIME COLLABORATION

By Christopher Crockett
FEBRUARY 7, 2020

A blast of radio waves from deep space appears to be on a 16-day cycle

A periodic flurry of radio waves from some unknown object in deep space could help astronomers figure out what’s triggering similar radio bursts in other galaxies.

Since 2007, researchers have cataloged over 100 fast radio bursts, or FRBs, coming from every direction in the sky. But it’s unknown what causes these radio bursts. Only 10 have been seen to repeat (SN: 8/14/19), and none of those had exhibited any sort of steady tempo — until now.

One of the known repeaters has a relatively brief window of activity about every 16 days, researchers report January 28 at arXiv.org. That means something about the source or its environment is reliably controlling the burst activity, a potential clue to the true nature of these enigmatic objects.

See full text

Virginia Trimble at the University of California, Irvine, where she has been on the faculty since 1971. (Monica Almeida for Quanta Magazine)

Elizabeth Landau  November 11, 2019

How a young celebrity became one of the first female astronomers at Caltech, befriended Richard Feynman, and ended up the world’s foremost chronicler of the science of the night sky.

Beginning in 1991, Virginia Trimble read every single astronomy article published in 23 different journals. She would then write an annual “year in review” article, which astronomers everywhere used as a window into the rest of the field at large. Her characteristic dry humor came through even in the first installment: “Science, notoriously, progresses amoeba-like, thrusting out pseudopods in unpredictable directions and dragging in the rest of the body after or, occasionally, retreating in disorder.” She stopped in 2007, in part because, with online publishing, there were just too many articles to read.

This endeavor and others have given Trimble a perspective on the past half-century of astronomy that few others could claim.

Stardom was part of Trimble’s early years, and not just because she attended Hollywood High School. In 1962, while still an undergraduate at the University of California, Los Angeles, she achieved her first small measure of fame when Life magazine published an article about her titled “Behind a Lovely Face, a 180 I.Q.” Then in 1963, she became Miss Twilight Zone, the face of a publicity campaign to promote the popular sci-fi show with Rod Serling.

In college she immersed herself in the other kind of stars — the ones in the broader universe — and went on to become one of the first women to earn a doctorate in astrophysics at the California Institute of Technology. While she was there, she befriended Richard Feynman, who paid her $5.50 an hour to pose as a model.

See full text

Centaurus A, an elliptical galaxy 13 million light-years from Earth, hosts a group of dwarf satellite galaxies co-rotating in a narrow disk, a distribution not predicted by dark-matter-influenced cosmological models. Credit: Christian Wolf and the SkyMapper team / Australian National University

February 1, 2018, University of California, Irvine

An international team of astronomers has determined that Centaurus A, a massive elliptical galaxy 13 million light-years from Earth, is accompanied by a number of dwarf satellite galaxies orbiting the main body in a narrow disk. In a paper published today in Science, the researchers note that this is the first time such a galactic arrangement has been observed outside the Local Group, home to the Milky Way.

"The significance of this finding is that it calls into question the validity of certain cosmological models and simulations as explanations for the distribution of host and satellite galaxies in the universe," said co-author Marcel Pawlowski, a Hubble Fellow in the Department of Physics & Astronomy at the University of California, Irvine.
He said that under the lambda cold dark matter model, smaller systems of stars should be more or less randomly scattered around their anchoring galaxies and should move in all directions. Yet Centaurus A is the third documented example, behind the Milky Way and Andromeda, of a "vast polar structure" in which satellite dwarves co-rotate around a central galactic mass in what Pawlowski calls "preferentially oriented alignment."

See full text

An artist’s impression of a supernova explosion. Until now, stellar explosions have been considered singular events. Illustration: Courtesy of the European Southern Observatory/M. Kornmesser.

Star has exploded in ‘fatal’ supernovae multiple times since 1954 – and is the first star astronomers have witnessed doing so

Astronomers have spotted a “zombie star” that refused to die when massive explosions that are normally considered fatal rocked the heavenly body.

The star, which lies half a billion light years away in the constellation of the Great Bear, has exploded multiple times since 1954, but may finally be on its way to the cosmic graveyard.

It is the first time astronomers have seen the same star explode over and over. Until now stellar explosions, or supernovae, have been considered singular events, the dazzling death throes of stars that have burned up all their fuel.

See full text