Tuesday, March 09, 2021

Most distant quasar with powerful radio jets discovered

Artist’s rendering of quasar P172+18 
 
Wide-field view of the sky around the quasar P172+18

Videos

ESOcast 234 Light: Most distant quasar with powerful radio jets discovered
ESOcast 234 Light: Most distant quasar with powerful radio jets discovered 
 
Zooming-in on the remote quasar P172+18
Zooming-in on the remote quasar P172+18


With the help of the European Southern Observatory’s Very Large Telescope (ESO’s VLT), astronomers have discovered and studied in detail the most distant source of radio emission known to date. The source is a “radio-loud” quasar — a bright object with powerful jets emitting at radio wavelengths — that is so far away its light has taken 13 billion years to reach us. The discovery could provide important clues to help astronomers understand the early Universe.

Quasars are very bright objects that lie at the centre of some galaxies and are powered by supermassive black holes. As the black hole consumes the surrounding gas, energy is released, allowing astronomers to spot them even when they are very far away.

The newly discovered quasar, nicknamed P172+18, is so distant that light from it has travelled for about 13 billion years to reach us: we see it as it was when the Universe was just around 780 million years old. While more distant quasars have been discovered, this is the first time astronomers have been able to identify the telltale signatures of radio jets in a quasar this early on in the history of the Universe. Only about 10% of quasars — which astronomers classify as “radio-loud” — have jets, which shine brightly at radio frequencies [1].

P172+18 is powered by a black hole about 300 million times more massive than our Sun that is consuming gas at a stunning rate. “The black hole is eating up matter very rapidly, growing in mass at one of the highest rates ever observed,” explains astronomer Chiara Mazzucchelli, Fellow at ESO in Chile, who led the discovery together with Eduardo Bañados of the Max Planck Institute for Astronomy in Germany.

The astronomers think that there’s a link between the rapid growth of supermassive black holes and the powerful radio jets spotted in quasars like P172+18. The jets are thought to be capable of disturbing the gas around the black hole, increasing the rate at which gas falls in. Therefore, studying radio-loud quasars can provide important insights into how black holes in the early Universe grew to their supermassive sizes so quickly after the Big Bang.

“I find it very exciting to discover ‘new’ black holes for the first time, and to provide one more building block to understand the primordial Universe, where we come from, and ultimately ourselves,” says Mazzucchelli.

P172+18 was first recognised as a far-away quasar, after having been previously identified as a radio source, at the Magellan Telescope at Las Campanas Observatory in Chile by Bañados and Mazzucchelli. “As soon as we got the data, we inspected it by eye, and we knew immediately that we had discovered the most distant radio-loud quasar known so far,” says Bañados.

However, owing to a short observation time, the team did not have enough data to study the object in detail. A flurry of observations with other telescopes followed, including with the X-shooter instrument on ESO’s VLT, which allowed them to dig deeper into the characteristics of this quasar, including determining key properties such as the mass of the black hole and how fast it’s eating up matter from its surroundings. Other telescopes that contributed to the study include the National Radio Astronomy Observatory's Very Large Array and the Keck Telescope in the US.  

While the team are excited about their discovery, to appear in The Astrophysical Journal, they believe this radio-loud quasar could be the first of many to be found, perhaps at even larger cosmological distances. “This discovery makes me optimistic and I believe — and hope — that the distance record will be broken soon,” says Bañados.

Observations with facilities such as ALMA, in which ESO is a partner, and with ESO’s upcoming Extremely Large Telescope (ELT) could help uncover and study more of these early-Universe objects in detail.

Source: ESO/News


Notes
 
[1] Radio waves that are used in astronomy have frequencies between about 300 MHz and 300 GHz.


More Information

This research is presented in the paper “The discovery of a highly accreting, radio-loud quasar at z=6.82” to appear in The Astrophysical Journal (https://doi.org/10.3847/1538-4357/abe239).

The team is composed of Eduardo Bañados (Max-Planck-Institut für Astronomie [MPIA], Germany, and The Observatories of the Carnegie Institution for Science, USA), Chiara Mazzucchelli (European Southern Observatory, Chile), Emmanuel Momjian (National Radio Astronomy Observatory [NRAO], USA), Anna-Christina Eilers (MIT Kavli Institute for Astrophysics and Space Research, USA), Feige Wang (Steward Observatory, University of Arizona, USA), Jan-Torge Schindler (MPIA), Thomas Connor (Jet Propulsion Laboratory [JPL], California Institute of Technology, USA), Irham Taufik Andika (MPIA and International Max Planck Research School for Astronomy & Cosmic Physics at the University of Heidelberg, Germany), Aaron J. Barth (Department of Physics and Astronomy, University of California, Irvine, USA), Chris Carilli (NRAO and Astrophysics Group, Cavendish Laboratory, University of Cambridge, UK), Frederick Davies (MPIA), Roberto Decarli (INAF Bologna — Osservatorio di Astrofisica e Scienza dello Spazio, Italy), Xiaohui Fan (Steward Observatory, University of Arizona, USA), Emanuele Paolo Farina (Max-Planck-Institut für Astrophysik, Germany), Joseph F. Hennawi (Department of Physics, Broida Hall, University of California, Santa Barbara, USA), Antonio Pensabene (Dipartimento di Fisica e Astronomia, Alma Mater Studiorum, Universita di Bologna, Italy and INAF Bologna), Daniel Stern (JPL), Bram P. Venemans (MPIA), Lukas Wenzl (Department of Astronomy, Cornell University, USA and MPIA) and Jinyi Yang (Steward Observatory, University of Arizona, USA).

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It has 16 Member States: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile and with Australia as a Strategic Partner. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its world-leading Very Large Telescope Interferometer as well as two survey telescopes, VISTA working in the infrared and the visible-light VLT Survey Telescope. Also at Paranal ESO will host and operate the Cherenkov Telescope Array South, the world’s largest and most sensitive gamma-ray observatory. ESO is also a major partner in two facilities on Chajnantor, APEX and ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre Extremely Large Telescope, the ELT, which will become “the world’s biggest eye on the sky”.


Links

Chiara Mazzucchelli
European Southern Observatory
Vitacura, Chile
Email: Chiara.Mazzucchelli@eso.org

Eduardo Bañados
Max-Planck-Institut für Astronomie
Heidelberg, Germany
Email: banados@mpia.de

Bárbara Ferreira
ESO Public Information Officer
Garching bei München, Germany
Cell: +49 151 241 664 00
Email: pio@eso.org

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Monday, March 08, 2021

A blazing nearby super-Earth

Artistic impression of the surface of the newly discovered hot super-Earth Gliese 486b. With a temperature of about 700 Kelvin (430 °C), the astronomers of the CARMENES collaboration expect a Venus-like hot and dry landscape interspersed with glowing lava rivers. Gliese 486b possible has a tenuous atmosphere. © Image: RenderArea

The diagram provides an estimate of the interior compositions of selected exoplanets based on their masses and radii in Earth units. The red marker represents Gliese 486b, and orange symbols depict planets around cool stars like Gliese 486. Grey dots show planets hosted by hotter stars. The coloured curves indicate the theoretical mass-radius relationships for pure water at 700 Kelvin (blue), for the mineral enstatite (orange), for the Earth (green), and pure iron (red). For comparison, the diagram also highlights Venus and the Earth.  © Image: Trifonov et al./MPIA graphics department 
 

The graph illustrates the orbit of a transiting rocky exoplanet like Gliese 486b around its host star. During transit, the planet obscures the stellar disk. Simultaneously, a tiny portion of the starlight passes through the planet’s atmospheric layer. While Gliese 486b continues to orbit, parts of the illuminated hemisphere become visible like lunar phases until the planet vanishes behind the star.  © Image: MPIA graphics department

During the recent two and a half decades, astronomers have discovered thousands of exoplanets made of gas, ice and rock. Only a few of them are Earth-like. However, probing their atmospheres with the currently available instrumentation is challenging at best. Now, astronomers of the CARMENES consortium have published a new study, led by Trifon Trifonov from the Max Planck Institute for Astronomy, which reports the discovery of a hot rocky super-Earth orbiting the nearby red dwarf star Gliese 486. Despite its small separation from the parent star, the planet designated Gliese 486b possibly has retained a part of its original atmosphere. Therefore, Gliese 486b is uniquely suited to examine its atmosphere and interior with the next generation of space-borne and ground-based telescopes. The results are published in the journal Science today.

With the advent of efficient exoplanet-hunting facilities, the numbers of newly discovered worlds outside the Solar System quickly rose to thousands. By combining different observing techniques, astronomers have determined planetary masses, sizes, and even bulk densities, allowing them to estimate their internal composition. The next goal to fully characterize those exoplanets similar to Earth by studying their atmospheres is much more challenging. Especially for rocky planets like Earth, any such atmosphere consists of a thin layer, if it exists at all. As a result, many current atmospheric models of rocky planets remain untested.

Planetary atmospheres must meet specific prerequisites to observe them with next-generation observatories. At a distance of only 26 light-years, scientists of the CARMENES (Calar Alto high-Resolution search for M dwarfs with Exoearths with Near-infrared and optical Échelle Spectrographs) consortium now have found a planet orbiting the red dwarf star Gliese 486 that perfectly satisfies these specifications for rocky planets. The newly discovered planet designated Gliese 486b is a super-Earth with a mass 2.8 times that of our home planet. It is also 30% bigger than Earth. The scientists employed both transit photometry and radial velocity spectroscopy to obtain their results.

“The proximity of this exoplanet is exciting because it will be possible to study it in more detail with powerful telescopes such as the upcoming James Webb Space Telescope and the future Extremely Large Telescopes,” Trifon Trifonov explains. He is a planetary scientist at the Max Planck Institute for Astronomy (MPIA) and lead author of the article that features this discovery.

By calculating the planet’s mean density from the mass and radius measurements, its composition appears similar to Venus and Earth, including a metallic core. Anyone standing on Gliese 486b would feel a gravitational pull that is 70% stronger than what we experience on our world.

Gliese 486b revolves around its host star on a circular trajectory within 1.5 days and at a distance of 2.5 million kilometres. One rotation takes the same amount of time, so one side always faces the star. Although the star Gliese 486 is much fainter and cooler than the Sun, the irradiation is so intense that the planet’s surface heats up to at least 700 Kelvin (approx. 430 °C). In this sense, Gliese 486b’s surface probably looks more like Venus than Earth, with a hot and dry landscape interspersed with glowing lava rivers. However, unlike Venus, Gliese 486b possibly only has a tenuous atmosphere if any. Model calculations may be consistent with both scenarios because stellar irradiation tends to evaporate atmospheres. At the same time, the planet’s gravity helps to retain it. Figuring out the balance of those contributions is difficult.

“The discovery of Gliese 486b was a stroke of luck. A hundred degrees hotter and the planet’s entire surface would be lava. Its atmosphere would consist of vapourised rocks,” José A. Caballero of the Centro de Astrobiología (CSIC-INTA, Spain) and co-author of the paper concludes. “On the other hand, if Gliese 486b were a hundred degrees colder, it would have been unsuitable for follow-up observations.”

The future measurements that the CARMENES team have in mind exploit the orbital orientation, which causes Gliese 486b to cross the surface of the host star from our point of view. Whenever this happens, a tiny fraction of the stellar light shines through the thin atmospheric layer before it reaches Earth. The various compounds absorb light at specific wavelengths, leaving their footprint in the signal. By using spectrographs, the astronomers split up the light according to wavelengths and look for absorption features to derive the atmospheric composition and dynamics. This method is also known as transit spectroscopy.

A second spectroscopic measurement, called emission spectroscopy, is planned when parts of the illuminated hemisphere become visible like lunar phases during Gliese 486b’s orbit until it vanishes behind the star. The spectrum contains information on the bright, hot planetary surface.

“We can hardly wait for the new telescopes to become available,” Trifonov admits. “The results will help us to understand how well rocky planets can hold their atmospheres, what they are made of and how they influence the energy distribution on the planets.”

Both Trifonov and Caballero collaborate in the CARMENES project, whose consortium comprises eleven research institutions in Spain and Germany. Its purpose is to monitor some 350 red dwarf stars for signs of low-mass planets using a spectrograph mounted at the 3.5 m Calar Alto telescope (Spain). This study includes additional spectroscopic measurements to infer Gliese 486b’s mass. The scientists obtained observations with the MAROON-X instrument at the 8.1 m Gemini North telescope (USA) and retrieved archival data from the 10 m Keck telescope (USA) and the ESO 3.6 m telescope (Chile).

Photometric observations to derive the planet’s size stem from the TESS (Transiting Exoplanet Survey Satellite) spacecraft (NASA, USA), the MuSCAT2 (Multicolour Simultaneous Camera for studying Atmospheres of Transiting exoplanets 2) instrument mounted at the 1.52 m Telescopio Carlos Sánchez at Observatorio del Teide (Spain), and the LCOGT (Las Cumbres Observatory Global Telescope), among others.

Source: Max Planck Institute for Astronomy

Background information

The team was composed of T. Trifonov (Max-Planck-Institut für Astronomie [MPIA]), J. A. Caballero (Centro de Astrobiología [CAB]), J. C. Morales (Institut de Ciències de l'Espai [ICE] and Institut d’Estudis Espacials de Catalunya [IEEC-CSIC]), A. Seifahrt (The University of Chicago), I. Ribas (ICE/IEEC-CSIC), A. Reiners (Institut für Astrophysik, Georg-August-Universität Göttingen [Uni Göttingen]), J. L. Bean (The University of Chicago), R. Luque (Instituto de Astrofísica de Canarias [IAC] and Universidad de La Laguna [ULL]), H. Parviainen (IAC/ULL), E. Pallé (IAC/ULL), S. Stock (Zentrum für Astronomie der Universität Heidelberg [ZAH]) , M. Zechmeister (The University of Chicago), P. J. Amado (Instituto de Astrofísica de Andalucía [IAA-CSIC]), G. Anglada-Escudé (ICE/IEEC-CSIC), M. Azzaro (Centro Astronómico Hispano-Alemán [CAHA]), T. Barclay (NASA Goddard Space Flight Center, and University of Maryland), V. J. S. Béjar (IAC/ULL), P. Bluhm (ZAH), N. Casasayas-Barris (IAC/ULL), C. Cifuentes (CAB), K. A. Collins (Center for Astrophysics, Harvard & Smithsonian [CfA]), K. I. Collins (George Mason University), M. Cortés-Contreras (CAB), J. de Leon (The University of Tokyo), S. Dreizler (Uni Göttingen), C. D. Dressing (University of California at Berkeley), E. Esparza-Borges (IAC/ULL), N. Espinoza (Space Telescope Science Institute), M. Fausnaugh (Massachusetts Institute of Technology [MIT]), A. Fukui (The University of Tokyo), A. P. Hatzes (Thüringer Landessternwarte Tautenburg), C. Hellier (Keele University), Th. Henning (MPIA), C. E. Henze (NASA Ames Research Center), E. Herrero (ICE/IEEC-CSIC), S. V. Jeffers (Uni Göttingen), J. M. Jenkins (NASA Ames Research Center), E. L. N. Jensen (Swarthmore College), A. Kaminski (ZAH), D. Kasper (The University of Chicago), D. Kossakowski (MPIA), M. Kürster (MPIA), M.Lafarga (ICE/IEEC-CSIC), D. W. Latham (CfA), A. W. Mann (University of North Carolina at Chapel Hill,), K. Molaverdikhani (ZAH), D. Montes (Departamento de Física de la Tierra y Astrofísica & IPARCOS-UCM), B. T. Montet (University of New South Wales), F. Murgas (IAC and Departamento de Astrofísica, ULL), N. Narita (The University of Tokyo, Japan Science and Technology Agency, Astrobiology Center, and IAC), M. Oshagh (IAC and Departamento de Astrofísica, ULL), V. M.Passegger (Universität Hamburg and University of Oklahoma,), D. Pollacco (University of Warwick), S. N. Quinn (CfA), A. Quirrenbach (ZAH), G. R. Ricker (MIT), C. Rodríguez López (IAA), J. Sanz-Forcada (CAB), R. P. Schwarz (Patashnick Voorheesville Observatory), A. Schweitzer (Universität Hamburg), S. Seager (MIT), A. Shporer (MIT), M. Stangret (IAC/ULL), J. Stürmer (Universität Heidelberg), T. G. Tan (MIT), P. Tenenbaum (MIT), J. D. Twicken (SETI Institute and NASA Ames Research), R. Vanderspek (MIT), and J. N. Winn (Princeton University).


Contact

Dr. Trifon Trifonov
Phone:+49 6221 528-443 
Max Planck Institute for Astronomy, Heidelberg

Dr. Markus Nielbock
span style="color: #f1c232;">Press and public relations officer
Phone:+49 6221 528-134
Max Planck Institute for Astronomy, Heidelberg
Mobile: +49 15678 747326


Original Aplication
 
1. T. Trifonov, J. A. Caballero, J. C. Morales et al.
A nearby transiting rocky exoplanet that is suitable for atmospheric investigation
Science (2021)
Source
 


Video  -  A journey to Gliese 486b

This virtual journey to Gliese 486b begins with its position in the night sky. After focusing on the parent star Gliese 486b, the film depicts the measurements. Finally, we fly to the exoplanet Gliese 486b and explore its possible surface, which probably resembles Venus, with a hot and dry landscape interspersed with glowing lava flows. 

Saturday, March 06, 2021

Exploding Stars in Black Hole Disks

This artist’s impression shows a flash of light produced within the accretion disk that surrounds a supermassive black hole. A new study explores whether we could see the signatures produced by exploding stars embedded in these disks. Credit: NASA/JPL-Caltech

The swirling disks of material that surround supermassive black holes are likely home to massive stars, neutron stars, and black holes. A new study explores whether we can detect the signatures of fiery explosions produced by these uniquely situated stars and stellar remnants.

Artist’s illustration of two merging black holes embedded in the gas disk surrounding a supermassive black hole.
Credit: Caltech/R. Hurt (IPAC) 

An Unusual Home

Recently, scientists detected gravitational waves from the merger of unexpectedly large black holes. One proposed explanation — that these monsters grew to their large sizes while embedded within the accretion disk surrounding an even larger supermassive black hole — has piqued interest in studying the evolution of stars hosted within the violent disks of these active galactic nuclei (AGN).

AGN accretion disks are dense, turbulent environments that produce bright, high-energy radiation as disk material spirals inwards toward the black hole. Yet these seemingly hostile surroundings may still host stars that arise either in situ — the gas within accretion disks can become unstable and fragment into self-gravitating clumps that become stars — or are captured from the nuclear star cluster that surrounds an AGN.

Explosive Ends

Once stars form or are trapped in an AGN disk, the dense environment increases the likelihood that the stars pair off into binaries. As disk-hosted stars evolve, some fraction of them should end their lives in spectacular explosions — either as long gamma-ray bursts (GRBs) caused by the deaths of massive stars, or as short GRBs produced when two evolved stellar remnants collide.

The possibility of these relativistic explosions occurring within AGN disks is intriguing. Does the unique environment of the disk influence the explosion? If so, could we expect to see specific, identifiable features from GRBs produced within the disks around supermassive black holes?

A team of scientists led by Rosalba Perna (Stony Brook University and Flatiron Institute) has explored these questions by modeling how the properties of GRB explosions are changed when they occur within disks.

Schematic illustrating the location of an exploding star in an AGN disk, shown in cross section. Bottom: Illustration of relevant radii in observed GRBs. RIS is the location of internal shocks that usually powers prompt emission, and RES marks the location where the expanding outflow runs into the surrounding medium, powering the afterglow. The relative locations of these radii can change in a dense surrounding environment, leading to different emission signatures. Credit: Perna et al. 2021

Searching for Signatures

Perna and collaborators explore a standard model of a GRB in which prompt emission is produced first as a series of internal shocks are driven by colliding shells of speeding material. The prompt emission is then followed by a long, decaying afterglow as this relativistic outflow is slowed when it plows into the surrounding matter.

The authors show that the properties of the AGN disk environment can change the behavior of both of those emission components. The high density of the disk material can cause a powerful reverse shock to be driven backwards early in the explosion, powering the prompt emission in place of internal shocks. And the later afterglow of the GRB can end up brighter and peaking earlier than is the case for typical GRBs observed in a low-density environment like the interstellar medium.

These features and other signatures identified by Perna and collaborators may help us to determine whether future observed GRBs exploded in typical environments, or instead in the extreme surroundings of an AGN disk. This will help us to better understand how some stars may be evolving in their unusual homes around supermassive black holes.

Citation

“Electromagnetic Signatures of Relativistic Explosions in the Disks of Active Galactic Nuclei,” Rosalba Perna et al 2021 ApJL 906 L7. doi:10.3847/2041-8213/abd319

 

Source: American Astronomical Society/ASS Nova

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Friday, March 05, 2021

Hubble Solves Mystery of Monster Star's Dimming

This zoom into VY Canis Majoris is a combination of Hubble imaging and an artist's impression. The left panel is a multicolor Hubble image of the huge nebula of material cast off by the hypergiant star. This nebula is approximately a trillion miles across. The middle panel is a close-up Hubble view of the region around the star. This image reveals close-in knots, arcs, and filaments of material ejected from the star as it goes through its violent process of casting off material into space. VY Canis Majoris is not seen in this view, but the tiny red square marks the location of the hypergiant, and represents the diameter of the solar system out to the orbit of Neptune, which is 5.5 billion miles across. The final panel is an artist's impression of the hypergiant star with vast convection cells and undergoing violent ejections. VY Canis Majoris is so large that if it replaced the Sun, the star would extend for hundreds of millions of miles, to between the orbits of Jupiter and Saturn. Credit: NASA, ESA, and R. Humphreys (University of Minnesota), and J. Olmsted (STScI).  Releaaed Images

Last year, astronomers were puzzled when Betelguese, the bright red supergiant star in the constellation Orion, dramatically faded, but then recovered. The dimming lasted for weeks. Now, astronomers have turned their sights toward a monster star in the adjoining constellation Canis Major, the Great Dog.

The red hypergiant VY Canis Majoris—which is far larger, more massive, and more violent than Betelgeuse—experiences much longer, dimmer periods that last for years. New findings from NASA's Hubble Space Telescope suggest the same processes that occurred on Betelgeuse are happening in this hypergiant, but on a much grander scale.

"VY Canis Majoris is behaving a lot like Betelgeuse on steroids," explained the study's leader, astrophysicist Roberta Humphreys of the University of Minnesota, Minneapolis.

As with Betelgeuse, Hubble data suggest the answer for why this bigger star is dimming. For Betelgeuse, the dimming corresponded to a gaseous outflow that may have formed dust, which briefly obstructed some of Betelgeuse's light from our view, creating the dimming effect.

"In VY Canis Majoris we see something similar, but on a much larger scale. Massive ejections of material which correspond to its very deep fading, which is probably due to dust that temporarily blocks light from the star," said Humphreys.

The enormous red hypergiant is 300,000 times brighter than our Sun. If it replaced the Sun in our own solar system, the bloated monster would extend out for hundreds of millions of miles, between the orbits of Jupiter and Saturn.

"This star is absolutely amazing. It's one of the largest stars that we know of—a very evolved, red supergiant. It has had multiple, giant eruptions," explained Humphreys.

Giant arcs of plasma surround the star at distances from it that are thousands of times farther away than the Earth is from the Sun. These arcs look like the solar prominences from our own Sun, only on a much grander scale. Also, they're not physically connected to the star, but rather, appear to have been thrown out and are moving away. Some of the other structures close to the star are still relatively compact, looking like little knots and nebulous features.

In previous Hubble work, Humphreys and her team were able to determine when these large structures were ejected from the star. They found dates ranging over the past several hundred years, some as recently as the past 100 to 200 years.

Now, in new work with Hubble, researchers resolved features much closer to the star that may be less than a century old. By using Hubble to determine the velocities and motions of the close-in knots of hot gas and other features, Humphreys and her team were able to date these eruptions more accurately. What they found was remarkable: many of these knots link to multiple episodes in the 19th and 20th centuries when VY Canis Majoris faded to one-sixth its usual brightness.

Unlike Betelgeuse, VY Canis Majoris is now too faint to be seen by the naked eye. The star was once visible but has dimmed so much that it can now only be seen with telescopes.

The hypergiant sheds 100 times as much mass as Betelgeuse. The mass in some of the knots is more than twice the mass of Jupiter. "It's amazing the star can do it," Humphreys said. "The origin of these high mass-loss episodes in both VY Canis Majoris and Betelgeuse is probably caused by large-scale surface activity, large convective cells like on the Sun. But on VY Canis Majoris, the cells may be as large as the whole Sun or larger."

"This is probably more common in red supergiants than scientists thought and VY Canis Majoris is an extreme example," Humphreys continued. "It may even be the main mechanism that's driving the mass loss, which has always been a bit of a mystery for red supergiants."

Though other red supergiants are comparably bright and eject a lot of dust, none of them is as complex as VY Canis Majoris. "So what's special about it? VY Canis Majoris may be in a unique evolutionary state that separates it from the other stars. It's probably this active over a very short period, maybe only a few thousand years. We're not going to see many of those around," said Humphreys.

The star began life as a super-hot, brilliant, blue supergiant star perhaps as much as 35 to 40 times our Sun's mass. After a few million years, as the hydrogen fusion burning rate in its core changed, the star swelled up to a red supergiant. Humphreys suspects that the star may have briefly returned to a hotter state and then swelled back up to a red supergiant stage.

"Maybe what makes VY Canis Majoris so special, so extreme, with this very complex ejecta, might be that it's a second-stage red supergiant," explained Humphreys. VY Canis Majoris may have already shed half of its mass. Rather than exploding as a supernova, it might simply collapse directly to a black hole.

The team's findings appear in the February 4, 2021 edition of The Astronomical Journal.

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, in Washington, D.C.

Contact

Media Contacts:
Ann Jenkins / Ray Villard
Space Telescope Science Institute, Baltimore, Maryland
410-338-4488 / 410-338-4514
jenkins@stsci.edu / villard@stsci.edu 

Science Contact:

Roberta Humphreys
University of Minnesota, Minneapolis, Minnesota
roberta@umn.edu

Related Links  

  

Source: HubbleSite/News

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Thursday, March 04, 2021

Extinct atom reveals the long-kept secrets of the solar system

The unstable atom 92Nb, which has long since disappeared, provides information about the beginnings of our solar system.
Illustration: Makiko K. Haba


Using the extinct niobium-​92 atom, ETH researchers have been able to date events in the early solar system with greater precision than before. The study concludes that supernova explosions must have taken place in the birth environment of our sun.

If an atom of a chemical element has a surplus of protons or neutrons, it becomes unstable. It will shed these additional particles as gamma radiation until it becomes stable again. One such unstable isotope is niobium-​92 (92Nb), which experts also refer to as a radionuclide. Its half-​life of 37 million years is relatively brief, so it went extinct shortly after the formation of the solar system. Today, only its stable daughter isotope, zirconium-​92 (92Zr), bears testimony to the existence of 92Nb.

Yet scientists have continued to make use of the extinct radionuclide in the form of the 92Nb-92Zr chronometer, with which they can date events that took place in the early solar system some 4.57 billion years ago.

Use of the 92Nb-92Zr chronometer has hitherto been limited by a lack of precise information regarding the amount of 92Nb that was present at the birth of the solar system. This compromises its use for dating and determining the production of these radionuclides in stellar environments.

Meteorites hold the key to the distant past

Now a research team from ETH Zurich and the Tokyo Institute of Technology (Tokyo Tech) has greatly improved this chronometer. The researchers achieved this improvement by means of a clever trick: they recovered rare zircon and rutile minerals from meteorites that were fragments of the protoplanet Vesta. These minerals are considered to be the most suitable for determing 92Nb, because they give precise evidence of how common 92Nb was at the time of the meteorite's formation. Then, with the uranium-​lead dating technique (uranium atoms that decay into lead), the team calculated how abundant 92Nb was at the time the solar system’s formation. By combining the two methods, the researchers succeeded in considerably improving the precision of the 92Nb-92Zr chronometer.

“This improved chronometer is thus a powerful tool for providing precise ages for the formation and development of asteroids and planets – events that happened in the first tens of millions of years after the formation of the solar system,” says Maria Schönbächler, Professor at the Institute of Geochemistry and Petrology at ETH Zurich, who led the study.

Supernova released niobium-92

Now that the researchers know more precisely how abundant 92Nb was at the very beginnings of our solar system, they can determine more accurately where these atoms were formed and where the material that makes up our sun and the planets originated.

The research team’s new model suggests that the inner solar system, with the terrestrial planets Earth and Mars, is largely influenced by material ejected by Type Ia supernovae in our Milky Way galaxy. In such stellar explosions, two orbiting stars interact with each other before exploding and releasing stellar material. In contrast, the outer solar system was fed primarily by a core-​collapse supernova – probably in the stellar nursery where our sun was born –, in which a massive star collapsed in on itself and exploded violently.

Reference  Releated Articles

Haba MK, Lai Y-J, Wotzlaw J-F, Yamaguchi A, Lugaro M, Schönbächler M. Precise initial abundance of Niobium-​92 in the Solar System and implications for p-​process nucleosynthesis. PNAS February 23, 2021 118 (8) e2017750118. DOI: 10.1073/pnas.2017750118

Releated Articles

By:  Peter Rüegg

Source:  ETH Zurich /News


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Wednesday, March 03, 2021

Hoinga: The largest supernova remnant ever discovered with X-rays

Cut-out of the first SRG/eROSITA all-sky survey. The Hoinga supernova remnant is marked. The large bright source in the lower quadrant of the image is from the supernova remnant “Vela” with “Pupis-A”. The image colours are correlated with the energies of the detected X-ray photons. Red represents the 0.3-0.6 keV energy range, green 0.6-1.0 keV and blue 1.0-2.3 keV. © SRG/eROSITA

Close-up of the Hoinga supernova remnant as seen in the first eROSITA all-sky survey. Photons to produce this 7.5 x 7.5 degrees image were colour-coded according to their energy (red for energies 0.2 - 0.7 keV, green for 0.7 - 1.2 keV, blue for 1.2 - 2.4 keV). Almost the entire X-ray emission from the remnant is observed at energies between 0.2 - 0.7 keV. The image was smoothed to better enhance the visibility of the diffuse X-ray emission. © SRG/eROSITA, MPE

Composite image of Hoinga taken at 1.4 GHz and 2.3 GHz by the CHIPASS and SPASS radio surveys. The blue colour is arbitrary; fore- and background sources were removed from the images to increase the visibility of the diffuse radio emission from the supernova remnant. Credit: CHIPASS/SPASS/N. Hurley-Walker, ICRAR-Curtin (Radio)

Composite X-ray and radio image of Hoinga (see also Fig.2 and Fig.3). The X-rays discovered by eROSITA are emitted by the hot debris of the exploded progenitor, whereas the radio antennae detect synchrotron emission from relativistic electrons, which are decelerated at the outer remnant layer. Credit: eROSITA/MPE (X-ray), CHIPASS/SPASS/N. Hurley-Walker, ICRAR-Curtin (Radio)

In the first all-sky survey by the eROSITA X-ray telescope onboard SRG, astronomers at the Max Planck Institute for Extraterrestrial Physics have identified a previously unknown supernova remnant, dubbed “Hoinga”. The finding was confirmed in archival radio data and marks the first discovery of a joint Australian-eROSITA partnership established to explore our Galaxy using multiple wavelengths, from low-frequency radio waves to energetic X-rays. The Hoinga supernova remnant is very large and located far from the galactic plane – a surprising first finding – implying that the next years might bring many more discoveries

Massive stars end their lives in gigantic supernova explosions when the fusion processes in their interiors no longer produce enough energy to counter their gravitational collapse. But even with hundreds of billions of stars in a galaxy, these events are pretty rare. In our Milky Way, astronomers estimate that a supernova should happen on average every 30 to 50 years. While the supernova itself is only observable on a timescale of months, their remnants can be detected for about 100 000 years. These remnants are composed of the material ejected by the exploding star at high velocities and forming shocks when hitting the surrounding interstellar medium.

About 300 such supernova remnants are known today – much less than the estimated 1200 that should be observable throughout our home Galaxy. So, either astrophysicists have misunderstood the supernova rate or a large majority has been overlooked so far. An international team of astronomers are now using the all-sky scans of the eROSITA X-ray telescope to look for previously unknown supernova remnants. With temperatures of millions of the degrees, the debris of such supernovae emits high-energy radiation, i.e. they should show up in the high-quality X-ray survey data.

“We were very surprised that the first supernova remnant popped up straight away,” says Werner Becker at the Max Planck Institute for Extraterrestrial Physics. “Hoinga” is the largest supernova remnant ever discovered in X-rays. With a diameter of about 4.4 degrees, it covers an area about 90 times bigger than the size of the full Moon. “Moreover, it lies very far off the galactic plane, which is very unusual,” he adds. Most previous searches for supernova remnants have concentrated on the disk of our galaxy, where star formation activity is highest and stellar remnants therefore should be more numerous, but it seems that many supernova remnants have been overlooked by this search strategy.

After the astronomers found the object in the eROSITA all-sky data, they turned to other resources to confirm its nature. Hoinga is – although barely – visible also in data taken by the ROSAT X-ray telescope 30 years ago, but nobody noticed it before due to its faintness and its location at high galactic latitude. However, the real confirmation came from radio data, the spectral band where 90% of all known supernova remnants were found so far.

“We went through archival radio data and it had been sitting there, just waiting to be discovered,” marvels Natasha Walker-Hurley, from the Curtin University node of the International Centre for Radio Astronomy Research in Australia. “The radio emission in 10-year-old surveys clearly confirmed that Hoinga is a supernova remnant, so there may be even more of these out there waiting for keen eyes.”

The eROSITA X-ray telescope will perform a total of eight all-sky surveys and is about 25 times more sensitive than its predecessor ROSAT. Both observatories were designed, build and are operated by the Max Planck Institute for Extraterrestrial Physics. The astronomers expected to discover new supernova remnants in its X-ray data over the next few years, but they were surprised to identify one so early in the programme. Combined with the fact that the signal is already present in decades-old data, this implies that many supernova remnants might have been overlooked in the past due to low-surface brightness, being in unusual locations or because of other nearby emission from brighter sources. 

Together with upcoming radio surveys, the eROSITA X-ray survey shows great promise for finding many of the missing supernova remnants, helping to solve this long-standing astrophysical mystery.



Notes:

1. The name Hoinga for the supernova remnant was chosen in honour of the first author’s hometown: Hoinga was the medieval name of Bad Hönningen am Rhein.

2. On 11 June 2020, the eROSITA telescope completed its first survey of the entire X-ray sky. Launched on 13 July 2019 on-board the SRG spacecraft and now orbiting the second Lagrange point of the Earth-Sun-system, the telescope is in continuous scanning mode. eROSITA is the primary instrument aboard SRG, a joint Russian-German science mission supported by the Russian Space Agency (Roskosmos), in the interests of the Russian Academy of Sciences represented by its Space Research Institute (IKI), and the Deutsches Zentrum für Luft- und Raumfahrt (DLR). The development and construction of the eROSITA X-ray instrument was led by the Max Planck Institute for Extraterrestrial Physics (MPE), with contributions from the Dr. Karl Remeis Observatory Bamberg, the University of Hamburg Observatory, the Leibniz Institute for Astrophysics Potsdam (AIP), and the Institute for Astronomy and Astrophysics of the University of Tübingen, with the support of DLR and the Max Planck Society. The Argelander Institute for Astronomy of the University of Bonn and the Ludwig-Maximilians-Universität Munich also participated in the science preparation for eROSITA.



Contacts

Dr. Werner Becker
scientist
+49 (0)89 30000-3588
+49 (0)89 30000-3569

Dr. Hannelore Hämmerle
press officer
+49 (0)89 30000-3980
+49 (0)89 30000-3569


Original Publication 

1. W. Becker, N. Hurley-Walker, Ch. Weinberger, L. Nicastro, M. G. F. Mayer, A. Merloni, J. Sanders
Hoinga - A Supernova Remnant Discovered in the SRG/eROSITA All-Sky Survey eRASS1
A&A, Accepted: 12 February 2021
Source / DOI

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Tuesday, March 02, 2021

Hubble Looks at a ‘Black Eye’ Galaxy

NGC 4826
Hi-res image

This image taken with the NASA/ESA Hubble Space Telescope features NGC 4826 — a spiral galaxy located 17 million light-years away in the constellation of Coma Berenices (Berenice’s Hair). This galaxy is often referred to as the “Black Eye” or “Evil Eye” galaxy because of the dark band of dust that sweeps across one side of its bright nucleus.

NGC 4826 is known by astronomers for its strange internal motion. The gas in the outer regions of this galaxy and the gas in its inner regions are rotating in opposite directions, which might be related to a recent merger. New stars are forming in the region where the counter-rotating gases collide. 

This galaxy was first discovered in 1779 by the English astronomer Edward Pigott. 

Text credit: European Space Agency (ESA)
Image credit: ESA/Hubble & NASA, J. Lee and the PHANGS-HST Team; Acknowledgment: Judy Schmidt

Media contact:

Claire Andreoli
NASA's Goddard Space Flight Center
301-286-1940
claire.andreoli@nasa.gov

Editor: Lynn Jenner
 
Source: NASA/Solar System and Beyond

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Sunday, February 28, 2021

New study suggests supermassive black holes could form from dark matter

Artist’s impression of a spiral galaxy embedded in a larger distribution of invisible dark matter, known as a dark matter halo (coloured in blue). Studies looking at the formation of dark matter haloes have suggested that each halo could harbour a very dense nucleus of dark matter, which may potentially mimic the effects of a central black hole, or eventually collapse to form one.Credit: ESO / L. Calçada.  Licence type:  Attribution (CC BY 4.0)

A new theoretical study has proposed a novel mechanism for the creation of supermassive black holes from dark matter. The international team find that rather than the conventional formation scenarios involving ‘normal’ matter, supermassive black holes could instead form directly from dark matter in high density regions in the centres of galaxies. The result has key implications for cosmology in the early Universe, and is published in Monthly Notices of the Royal Astronomical Society.

Exactly how supermassive black holes initially formed is one of the biggest problems in the study of galaxy evolution today. Supermassive black holes have been observed as early as 800 million years after the Big Bang, and how they could grow so quickly remains unexplained.

Standard formation models involve normal baryonic matter – the atoms and elements that that make up stars, planets, and all visible objects – collapsing under gravity to form black holes, which then grow over time. However the new work investigates the potential existence of stable galactic cores made of dark matter, and surrounded by a diluted dark matter halo, finding that the centres of these structures could become so concentrated that they could also collapse into supermassive black holes once a critical threshold is reached.

According to the model this could have happened much more quickly than other proposed formation mechanisms, and would have allowed supermassive black holes in the early Universe to form before the galaxies they inhabit, contrary to current understanding.

Carlos R. Argüelles, the researcher at Universidad Nacional de La Plata and ICRANet who led the investigation comments: “This new formation scenario may offer a natural explanation for how supermassive black holes formed in the early Universe, without requiring prior star formation or needing to invoke seed black holes with unrealistic accretion rates.”

Another intriguing consequence of the new model is that the critical mass for collapse into a black hole might not be reached for smaller dark matter halos, for example those surrounding some dwarf galaxies. The authors suggest that this then might leave smaller dwarf galaxies with a central dark matter nucleus rather than the expected black hole. Such a dark matter core could still mimic the gravitational signatures of a conventional central black hole, whilst the dark matter outer halo could also explain the observed galaxy rotation curves.

“This model shows how dark matter haloes could harbour dense concentrations at their centres, which may play a crucial role in helping to understand the formation of supermassive black holes,” added Carlos.

“Here we’ve proven for the first time that such core–halo dark matter distributions can indeed form in a cosmological framework, and remain stable for the lifetime of the Universe.”

The authors hope that further studies will shed more light on supermassive black hole formation in the very earliest days of our Universe, as well as investigating whether the centres of non-active galaxies, including our own Milky Way, may play host to these dense dark matter cores.

Source: Royal Astronomical Society (RAS)/News


Media Contacts:

Dr Morgan Hollis
Royal Astronomical Society
Mob: +44 (0)7802 877 700
press@ras.ac.uk

Dr Robert Massey
Royal Astronomical Society
Mob: +44 (0)7802 877 699
press@ras.ac.uk

Science contacts

Dr Carlos R. Argüelles
Facultad de Ciencias Astronómicas y Geofísicas
Universidad Nacional de La Plata
Buenos Aires
Argentina
carguelles@fcaglp.fcaglp.unlp.edu.ar 



Further information

The new work appears in, “On the formation and stability of fermionic dark matter haloes in a cosmological framework”, Carlos R Argüelles, Manuel I Díaz, Andreas Krut, and Rafael Yunis, Monthly Notices of the Royal Astronomical Society (2020), in press (DOI: 10.1093/mnras/staa3986).

A copy of the paper is available from: https://doi.org/10.1093/mnras/staa3986

The institutions participating in the research were Universidad Nacional de La Plata, the National Research Council of Science and Technology, the International Center for Relativistic Astrophysics Network, and Buenos Aires National University. 

Notes for editors

The Royal Astronomical Society (RAS), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science. The RAS organises scientific meetings, publishes international research and review journals, recognises outstanding achievements by the award of medals and prizes, maintains an extensive library, supports education through grants and outreach activities and represents UK astronomy nationally and internationally. Its more than 4,400 members (Fellows), a third based overseas, include scientific researchers in universities, observatories and laboratories as well as historians of astronomy and others.

The RAS accepts papers for its journals based on the principle of peer review, in which fellow experts on the editorial boards accept the paper as worth considering. The Society issues press releases based on a similar principle, but the organisations and scientists concerned have overall responsibility for their content.

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Saturday, February 27, 2021

Big galaxies steal star-forming gas from their smaller neighbours

An artist’s impression showing the increasing effect of ram-pressure stripping in removing gas from galaxies, sending them to an early death. Credit: ICRAR, NASA, ESA, the Hubble Heritage Team (STScI/AURA)

Large galaxies are known to strip the gas that occupies the space between the stars of smaller satellite galaxies.

In research published today, astronomers have discovered that these small satellite galaxies also contain less ‘molecular’ gas at their centres.

Molecular gas is found in giant clouds in the centres of galaxies and is the building material for new stars. Large galaxies are therefore stealing the material that their smaller counterparts need to form new stars.

Lead author Dr Adam Stevens is an astrophysicist based at UWA working for the International Centre for Radio Astronomy Research (ICRAR) and affiliated to the ARC Centre of Excellence in All Sky Astrophysics in 3 Dimensions (ASTRO 3D).

Dr Stevens said the study provides new systematic evidence that small galaxies everywhere lose some of their molecular gas when they get close to a larger galaxy and its surrounding hot gas halo.

“Gas is the lifeblood of a galaxy,” he said.

“Continuing to acquire gas is how galaxies grow and form stars. Without it, galaxies stagnate.

“We’ve known for a long time that big galaxies strip ‘atomic’ gas from the outskirts of small galaxies.

“But, until now, it hadn’t been tested with molecular gas in the same detail.”

ICRAR-UWA astronomer Associate Professor Barbara Catinella said galaxies don’t typically live in isolation.

“Most galaxies have friends,” she says.

“And when a galaxy moves through the hot intergalactic medium or galaxy halo, some of the cold gas in the galaxy is stripped away.

“This fast-acting process is known as ram pressure stripping.”

Two viewing angles of a galaxy undergoing ram-pressure stripping in the IllustrisTNG simulation. Each column shows matter of a different form in the galaxy and its immediate surroundings. From left to right: (1) atomic gas; (2) molecular gas; (3) all gas; (4) stars; and (5) dark matter. Credit: Adam Stevens/ICRAR. Hi-res image

The research was a global collaboration involving scientists from the University of Maryland, Max Planck Institute for Astronomy, University of Heidelberg, Harvard-Smithsonian Center for Astrophysics, University of Bologna and Massachusetts Institute of Technology.

Molecular gas is very difficult to detect directly.

The research team took a state-of-the-art cosmological simulation and made direct predictions for the amount of atomic and molecular gas that should be observed by specific surveys on the Arecibo telescope in Puerto Rico and the IRAM 30-meter telescope in Spain.

They then took the actual observations from the telescopes and compared them to their original predictions.

The two were remarkably close.

Fly-through of galaxies having their gas stripped in the IllustrisTNG simulation.

Big galaxies steal star-forming gas from their smaller neighbours from ICRAR on Vimeo.

Associate Professor Catinella, who led the Arecibo survey of atomic gas, says the IRAM 30-meter telescope observed the molecular gas in more than 500 galaxies.

“These are the deepest observations and largest sample of atomic and molecular gas in the local Universe,” she says.

“That’s why it was the best sample to do this analysis.”

The team’s finding fits with previous evidence that suggests satellite galaxies have lower star formation rates.

Dr Stevens said stripped gas initially goes into the space around the larger galaxy.

“That may end up eventually raining down onto the bigger galaxy, or it might end up just staying out in its surroundings,” he said.

But in most cases, the little galaxy is doomed to merge with the larger one anyway.

“Often they only survive for one to two billion years and then they’ll end up merging with the central one,” Dr Stevens said.

“So it affects how much gas they’ve got by the time they merge, which then will affect the evolution of the big system as well.

“Once galaxies get big enough, they start to rely on getting more matter from the cannibalism of smaller galaxies.”

Original Publication:

‘Molecular hydrogen in IllustrisTNG galaxies: carefully comparing signatures of environment with local CO & SFR data’, published in Monthly Notices of the Royal Astronomical Society on February 23rd, 2021.   Click here for the paper

Contacts:

Dr Adam Stevens (ICRAR / ASTRO 3D / UWA)

Ph: +61 8 6488 7627                E: Adam.Stevens@icrar.org

Associate Professor Barbara Catinella (ICRAR / UWA)

Ph: +61 8 6488 7760                E: Barbara.Catinella@icrar.org

Kirsten Gottschalk (Media Contact, ICRAR)

Ph: +61 438 361 876               E: Kirsten.Gottschalk@icrar.org

Jess Reid (Media Contact, University of Western Australia)

Ph: +61 8 6488 6876                E: Jess.Reid@uwa.edu.au

 

 Source: International Centre for Radio Astronomy Research (ICRAR)/News

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Friday, February 26, 2021

Supernova 1987A: Reclusive Neutron Star May Have Been Found in Famous Supernova

Supernova 1987A
Credit: Chandra (X-ray): NASA/CXC/Univ. di Palermo/E. Greco;
Illustration: INAF-Osservatorio Astronomico di Palermo/Salvatore Orlando

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Astronomers have found evidence for the existence of a neutron star at the center of Supernova 1987A (SN 1987A), which scientists have been seeking for over three decades. As reported in our latest press release, SN 1987A was discovered on February 24, 1987. The panel on the left contains a 3D computer simulation, based on Chandra data, of the supernova debris from SN 1987A crashing into a surrounding ring of material. The artist's illustration (right panel) depicts a so-called pulsar wind nebula, a web of particles and energy blown away from a pulsar, which is a rotating, highly magnetized neutron star. Data collected from NASA's Chandra X-ray Observatory and NuSTAR in a new study support the presence of a pulsar wind nebula at the center of the ring. 

If this result is upheld by future observations, it would confirm the existence of a neutron star in SN 1987A, the collapsed core that astronomers expect would be present after the star exploded. The pulsar would also be the youngest one ever found. 

NuSTAR and Chandra images of Supernova 1987A

When a star explodes, it collapses onto itself before the outer layers are blasted into space. The compression of the core turns it into an extraordinarily dense object, with the mass of the Sun squeezed into an object only about 10 miles across. Neutron stars, as they were dubbed because they are made nearly exclusively of densely packed neutrons, are laboratories of extreme physics that cannot be duplicated here on Earth. Some neutron stars have strong magnetic fields and rotate rapidly, producing a beam of light akin to a lighthouse. Astronomers call these objects "pulsars," and they sometimes blow winds of charged particles that can create pulsar wind nebulas.

With Chandra and NuSTAR, the team found relatively low-energy X-rays from the supernova debris crashing into surrounding material. The team also found evidence of high-energy particles, using NuSTAR's ability to detect higher-energy X-rays.

 There are two likely explanations for this energetic X-ray emission: either a pulsar wind nebula, or particles being accelerated to high energies by blast wave of the explosion. The latter effect doesn't require the presence of a pulsar and occurs over much larger distances from the center of the explosion.

The latest X-ray study supports the case for the pulsar wind nebula on a couple of fronts. First, the brightness of the higher energy X-rays remained about the same between 2012 and 2014, while the radio emission increased. This goes against expectations in the scenario of energetic particles in the explosion debris. Next, authors estimate it would take almost 400 years to accelerate the electrons up to the highest energies seen in the NuSTAR data, which is over ten times older than the age of the remnant.

The Chandra and NuSTAR data also support a 2020 result from the Atacama Large Millimeter Array (ALMA) that provided possible evidence for the structure of a pulsar wind nebula in the radio band. While this "blob" had other potential explanations, its identification as a pulsar wind nebula could be substantiated with the new X-ray data.

The center of SN 1987A is surrounded by gas and dust. The authors used state-of-the-art simulations to understand how this material would absorb X-rays at different energies, enabling more accurate interpretation of the X-ray spectrum, that is, the spread of X-rays over wavelength. This enables them to estimate what the spectrum of the central regions of SN 1987A is without the obscuring material.

A paper describing these results is being published this week in The Astrophysical Journal and a preprint is available online. The authors of the paper are Emanuele Greco and Marco Miceli (University of Palermo in Italy), Salvatore Orlando, Barbara Olmi and Fabrizio Bocchino (Palermo Astronomical Observatory, a National Institute for Astrophysics, or INAF, research facility); Shigehiro Nagataki and Masaomi Ono (Astrophysical Big Bang Laboratory, RIKEN in Japan); Akira Dohi (Kyushu University in Japan), and Giovanni Peres (University of Palermo).

NASA's Marshall Space Flight Center manages the Chandra program. The Smithsonian Astrophysical Observatory's Chandra X-ray Center controls science from Cambridge Massachusetts and flight operations from Burlington, Massachusetts.

NuSTAR is a Small Explorer mission led by Caltech and managed by NASA's Jet Propulsion Laboratory for the agency's Science Mission Directorate in Washington. NuSTAR was developed in partnership with the Danish Technical University and the Italian Space Agency (ASI). The spacecraft was built by Orbital Sciences Corporation in Dulles, Virginia (now part of Northrop Grumman). NuSTAR's mission operations center is at UC Berkeley, and the official data archive is at NASA's High Energy Astrophysics Science Archive Research Center. ASI provides the mission's ground station and a mirror archive. JPL is a division of Caltech.

Quick Look: Supernova 1987A Pulsar Wind Nebula



Fast facts for Supernova 1987A:

Category:  Supernovas & Supernova Remnants
Coordinates (J2000): RA 05h 35m 28.30s | Dec -69° 16´ 11.10"
Constellation:  Dorado
Observation Date: 7 pointings between Mar 2012 and Sept 2014
Observation Time: 95 hours 30 minutes (3 days 23 hours 30 minutes)
Obs. ID: 13735, 14417, 14697-14698, 15809-15810, 17415
Instrument:  ACIS
Also Known As: Supernova 1987A
References: Greco, E., et al., 2021, ApJ Letters (accepted)  arXiv:2101.0929
Distance Estimate About 168,000 light years

Source: NASA's Chandra X-ray Observatory

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