. | . |
Birth of magnetar from colossal collision potentially spotted for first time by Staff Writers Evanston IL (SPX) Nov 16, 2020
Long ago and far across the universe, an enormous burst of gamma rays unleashed more energy in a half-second than the sun will produce over its entire 10-billion-year lifetime. After examining the incredibly bright burst with optical, X-ray, near-infrared and radio wavelengths, a Northwestern University-led astrophysics team believes it potentially spotted the birth of a magnetar. Researchers believe the magnetar was formed by two neutron stars merging, which has never before been observed. The merger resulted in a brilliant kilonova - the brightest ever seen - whose light finally reached Earth on May 22, 2020. The light first came as a blast of gamma-rays, called a short gamma-ray burst. "When two neutron stars merge, the most common predicted outcome is that they form a heavy neutron star that collapses into a black hole within milliseconds or less," said Northwestern's Wen-fai Fong, who led the study. "Our study shows that it's possible that, for this particular short gamma-ray burst, the heavy object survived. Instead of collapsing into a black hole, it became a magnetar: A rapidly spinning neutron star that has large magnetic fields, dumping energy into its surrounding environment and creating the very bright glow that we see." The research has been accepted by The Astrophysical Journal and will be published online later this year. Fong is an assistant professor of physics and astronomy in Northwestern's Weinberg College of Arts and Sciences and a member of CIERA (Center for Interdisciplinary Exploration and Research in Astrophysics). The research involved two undergraduates, three graduate students and three postdoctoral fellows from Fong's laboratory.
'There was a new phenomenon happening' Fong's team quickly realized that something didn't add up. Compared to X-ray and radio observations, the near-infrared emission detected with Hubble was much too bright. In fact, it was 10 times brighter than predicted. "As the data were coming in, we were forming a picture of the mechanism that was producing the light we were seeing," said the study's co-investigator, Tanmoy Laskar of the University of Bath in the United Kingdom. "As we got the Hubble observations, we had to completely change our thought process, because the information that Hubble added made us realize that we had to discard our conventional thinking and that there was a new phenomenon going on. Then we had to figure out about what that meant for the physics behind these extremely energetic explosions."
Magnetic monster "You basically have these magnetic field lines that are anchored to the star that are whipping around at about 1,000 times a second, and this produces a magnetized wind," Laskar explained. "These spinning field lines extract the rotational energy of the neutron star formed in the merger, and deposit that energy into the ejecta from the blast, causing the material to glow even brighter." "We know that magnetars exist because we see them in our galaxy," Fong said. "We think most of them are formed in the explosive deaths of massive stars, leaving these highly magnetized neutron stars behind. However, it is possible that a small fraction form in neutron star mergers. We have never seen evidence of that before, let alone in infrared light, making this discovery special."
Strangely bright kilonova "We only have one confirmed and well-sampled kilonova to date," said Jillian Rastinejad, a co-author of the paper and graduate student in Fong's laboratory. "So it is especially exciting to find a new potential kilonova that looks so different. This discovery gave us the opportunity to explore the diversity of kilonovae and their remnant objects." If the unexpected brightness seen by Hubble came from a magnetar that deposited energy into the kilonova material, then, within a few years, the ejected material from the burst will produce light that shows up at radio wavelengths. Follow-up radio observations may ultimately prove that this was a magnetar, leading to an explanation of the origin of such objects. "Now that we have one very bright candidate kilonova," Rastinejad said, "I'm excited for the new surprises that short gamma-ray bursts and neutron star mergers have in store for us in the future."
Research Report: "The broadband counterpart of the short GRB 2005221 at z = 0.5536: A luminous kilonova or a collimated outflow with a reverse shock"
Hubble sees unexplained brightness from colossal explosion Baltimore MD (SPX) Nov 16, 2020 Long ago and far across the universe, an enormous burst of gamma rays unleashed more energy in a half-second than the Sun will produce over its entire 10-billion-year lifetime. In May of 2020, light from the flash finally reached Earth and was first detected by NASA's Neil Gehrels Swift Observatory. Scientists quickly enlisted other telescopes - including NASA's Hubble Space Telescope, the Very Large Array radio observatory, the W. M. Keck Observatory, and the Las Cumbres Observatory Global Telesc ... read more
|
|
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. |