. 24/7 Space News .
STELLAR CHEMISTRY
NASA's Fermi Spots a Supernova's 'Fizzled' Gamma-ray Burst
by Francis Reddy for GSFC News
Greenbelt MD (SPX) Jul 27, 2021

file illustration only

On Aug. 26, 2020, NASA's Fermi Gamma-ray Space Telescope detected a pulse of high-energy radiation that had been racing toward Earth for nearly half the present age of the universe. Lasting only about a second, it turned out to be one for the record books - the shortest gamma-ray burst (GRB) caused by the death of a massive star ever seen.

GRBs are the most powerful events in the universe, detectable across billions of light-years. Astronomers classify them as long or short based on whether the event lasts for more or less than two seconds. They observe long bursts in association with the demise of massive stars, while short bursts have been linked to a different scenario.

"We already knew some GRBs from massive stars could register as short GRBs, but we thought this was due to instrumental limitations," said Bin-bin Zhang at Nanjing University in China and the University of Nevada, Las Vegas. "This burst is special because it is definitely a short-duration GRB, but its other properties point to its origin from a collapsing star. Now we know dying stars can produce short bursts, too."

Named GRB 200826A, after the date it occurred, the burst is the subject of two papers published in Nature Astronomy on Monday, July 26. The first, led by Zhang, explores the gamma-ray data. The second, led by Tomas Ahumada, a doctoral student at the University of Maryland, College Park and NASA's Goddard Space Flight Center in Greenbelt, Maryland, describes the GRB's fading multiwavelength afterglow and the emerging light of the supernova explosion that followed.

"We think this event was effectively a fizzle, one that was close to not happening at all," Ahumada said. "Even so, the burst emitted 14 million times the energy released by the entire Milky Way galaxy over the same amount of time, making it one of the most energetic short-duration GRBs ever seen."

When a star much more massive than the Sun runs out of fuel, its core suddenly collapses and forms a black hole. As matter swirls toward the black hole, some of it escapes in the form of two powerful jets that rush outward at almost the speed of light in opposite directions. Astronomers only detect a GRB when one of these jets happens to point almost directly toward Earth.

Each jet drills through the star, producing a pulse of gamma rays - the highest-energy form of light - that can last up to minutes. Following the burst, the disrupted star then rapidly expands as a supernova.

Short GRBs, on the other hand, form when pairs of compact objects - such as neutron stars, which also form during stellar collapse - spiral inward over billions of years and collide. Fermi observations recently helped show that, in nearby galaxies, giant flares from isolated, supermagnetized neutron stars also masquerade as short GRBs.

GRB 200826A was a sharp blast of high-energy emission lasting just 0.65 second. After traveling for eons through the expanding universe, the signal had stretched out to about one second long when it was detected by Fermi's Gamma-ray Burst Monitor. The event also appeared in instruments aboard NASA's Wind mission, which orbits a point between Earth and the Sun located about 930,000 miles (1.5 million kilometers) away, and Mars Odyssey, which has been orbiting the Red Planet since 2001. ESA's (the European Space Agency's) INTEGRAL satellite observed the blast as well.

All of these missions participate in a GRB-locating system called the InterPlanetary Network (IPN), for which the Fermi project provides all U.S. funding. Because the burst reaches each detector at slightly different times, any pair of them can be used to help narrow down where in the sky it occurred. About 17 hours after the GRB, the IPN narrowed its location to a relatively small patch of the sky in the constellation Andromeda.

Using the National Science Foundation-funded Zwicky Transient Facility (ZTF) at Palomar Observatory, the team scanned the sky for changes in visible light that could be linked to the GRB's fading afterglow.

"Conducting this search is akin to trying to find a needle in a haystack, but the IPN helps shrink the haystack," said Shreya Anand, a graduate student at Caltech and a co-author on the afterglow paper. "Out of more than 28,000 ZTF alerts the first night, only one met all of our search criteria and also appeared within the sky region defined by the IPN."

Within a day of the burst, NASA's Neil Gehrels Swift Observatory discovered fading X-ray emission from this same location. A couple of days later, variable radio emission was detected by the National Radio Astronomy Observatory's Karl Jansky Very Large Array in New Mexico. The team then began observing the afterglow with a variety of ground-based facilities.

Observing the faint galaxy associated with the burst using the Gran Telescopio Canarias, a 10.4-meter telescope at the Roque de los Muchachos Observatory on La Palma in Spain's Canary Islands, the team showed that its light takes 6.6 billion years to reach us. That's 48% of the universe's current age of 13.8 billion years.

But to prove this short burst came from a collapsing star, the researchers also needed to catch the emerging supernova.

"If the burst was caused by a collapsing star, then once the afterglow fades away it should brighten again because of the underlying supernova explosion," said Leo Singer, a Goddard astrophysicist and Ahumada's research advisor. "But at these distances, you need a very big and very sensitive telescope to pick out the pinpoint of light from the supernova from the background glare of its host galaxy."

To conduct the search, Singer was granted time on the 8.1-meter Gemini North telescope in Hawaii and the use of a sensitive instrument called the Gemini Multi-Object Spectrograph. The astronomers imaged the host galaxy in red and infrared light starting 28 days after the burst, repeating the search 45 and 80 days after the event. They detected a near-infrared source - the supernova - in the first set of observations that could not be seen in later ones.

The researchers suspect that this burst was powered by jets that barely emerged from the star before they shut down, instead of the more typical case where long-lasting jets break out of the star and travel considerable distances from it. If the black hole had fired off weaker jets, or if the star was much larger when it began its collapse, there might not have been a GRB at all.

The discovery helps resolve a long-standing puzzle. While long GRBs must be coupled to supernovae, astronomers detect far greater numbers of supernovae than they do long GRBs. This discrepancy persists even after accounting for the fact that GRB jets must tip nearly into our line of sight for astronomers to detect them at all.

The researchers conclude that collapsing stars producing short GRBs must be marginal cases whose light-speed jets teeter on the brink of success or failure, a conclusion consistent with the notion that most massive stars die without producing jets and GRBs at all. More broadly, this result clearly demonstrates that a burst's duration alone does not uniquely indicate its origin.


Related Links
Fermi Gamma-ray Space Telescope

Stellar Chemistry, The Universe And All Within It


Thanks for being there;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Monthly Supporter
$5+ Billed Monthly


paypal only
SpaceDaily Contributor
$5 Billed Once


credit card or paypal


STELLAR CHEMISTRY
Galactic gamma ray bursts predicted last year show up right on schedule
Berkeley CA (SPX) Jul 14, 2021
Magnetars are bizarre objects - massive, spinning neutron stars with magnetic fields among the most powerful known, capable of shooting off brief bursts of radio waves so bright they're visible across the universe. A team of astrophysicists has now found another peculiarity of magnetars: They can emit bursts of low energy gamma rays in a pattern never before seen in any other astronomical object. It's unclear why this should be, but magnetars themselves are poorly understood, with dozens of ... read more

Comment using your Disqus, Facebook, Google or Twitter login.



Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

STELLAR CHEMISTRY
Space station mishap caused orbiting lab to rotate 1 1/2 times, NASA says

What you need to know about Starliner's Test-2

Nauka Module incident caused by software failure

Progress 77 and Pirs undocked from Station

STELLAR CHEMISTRY
Boeing postpones Starliner capsule launch attempt over valve issue

Finding the cause of a fatal problem in rocket engine combustors

German startups launch mini-rocket challenge to SpaceX and co.

Rocket tanks of carbon fibre reinforced plastic proven possible

STELLAR CHEMISTRY
Earthly rocks point way to water hidden on Mars

Helicopter scouts ridge area for Perseverance

Clays, not water, are likely source of Martian lakes

Zhurong marks 1st anniversary since launch with dune exploration

STELLAR CHEMISTRY
China's space propaganda blitz endures at slick new planetarium

Shanxi company helps astronauts keep fit in space

How Chinese astronauts stay healthy in space

China's five-star red flag flies proudly on red planet

STELLAR CHEMISTRY
Next batch of OneWeb satellites set to launch August 20

Iridium granted trio of regulatory approvals in Japan

Inmarsat unveils the communications network of the future

Space company in search for professionals

STELLAR CHEMISTRY
Experiment bound for Space Station turns down the heat

World's first commercial re-programmable satellite blasts into space

Upgrades to NASA's Space Communications Infrastructure Pave the Way to Higher Data Rates

Metallic glass gears up for 'Cobots,' Coatings, and More

STELLAR CHEMISTRY
Astronomers show how planets form in binary systems without getting crushed

Galileo Project to search for ET artifacts in galactic space

From the sun to the stars: A journey of exoplanet discovery begins

ALMA images moon-forming disk around alien world

STELLAR CHEMISTRY
Juno joins Japan's Hisaki satellite and Keck Observatory to solve "energy crisis" on Jupiter

Hubble finds first evidence of water vapor on Ganymede

NASA Awards Launch Services Contract for the Europa Clipper Mission

Juno tunes into Jovian radio triggered by Jupiter's volcanic moon Io









The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.