Living on the Edge: Supernova Bubble Expands in New Hubble Time-Lapse Movie

Cygnus Loop
Credits: Image: NASA, ESA, Ravi Sankrit (STScI)

Release Images | Release Videos

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Though a doomed star exploded some 20,000 years ago, its tattered remnants continue racing into space at breakneck speeds – and NASA's Hubble Space Telescope has caught the action.

The nebula, called the Cygnus Loop, forms a bubble-like shape that is about 120 light-years in diameter. The distance to its center is approximately 2,600 light-years. The entire nebula has a width of six full Moons as seen on the sky.

Astronomers used Hubble to zoom into a very small slice of the leading edge of this expanding supernova bubble, where the supernova blast wave plows into surrounding material in space. Hubble images taken from 2001 to 2020 clearly demonstrate how the remnant's shock front has expanded over time, and they used the crisp images to clock its speed.

By analyzing the shock's location, astronomers found that the shock hasn't slowed down at all in the last 20 years, and is speeding into interstellar space at over half a million miles per hour – fast enough to travel from Earth to the Moon in less than half an hour. While this seems incredibly fast, it's actually on the slow end for the speed of a supernova shock wave. Researchers were able to assemble a "movie" from Hubble images for a close-up look at how the tattered star is slamming into interstellar space.

"Hubble is the only way that we can actually watch what's happening at the edge of the bubble with such clarity," said Ravi Sankrit, an astronomer at the Space Telescope Science Institute in Baltimore, Maryland. "The Hubble images are spectacular when you look at them in detail. They're telling us about the density differences encountered by the supernova shocks as they propagate through space, and the turbulence in the regions behind these shocks."

A very close-up look at a nearly two-light-year-long section of the filaments of glowing hydrogen shows that they look like a wrinkled sheet seen from the side. "You're seeing ripples in the sheet that is being seen edge-on, so it looks like twisted ribbons of light," said William Blair of the Johns Hopkins University, Baltimore, Maryland. "Those wiggles arise as the shock wave encounters more or less dense material in the interstellar medium." The time-lapse movie over nearly two decades shows the filaments moving against the background stars but keeping their shape.

"When we pointed Hubble at the Cygnus Loop we knew that this was the leading edge of a shock front, which we wanted to study. When we got the initial picture and saw this incredible, delicate ribbon of light, well, that was a bonus. We didn't know it was going to resolve that kind of structure," said Blair.

Blair explained that the shock is moving outward from the explosion site and then it starts to encounter the interstellar medium, the tenuous regions of gas and dust in interstellar space. This is a very transitory phase in the expansion of the supernova bubble where invisible neutral hydrogen is heated to 1 million degrees Fahrenheit or more by the shock wave's passage. The gas then begins to glow as electrons are excited to higher energy states and emit photons as they cascade back to low energy states. Further behind the shock front, ionized oxygen atoms begin to cool, emitting a characteristic glow shown in blue.

The Cygnus Loop was discovered in 1784 by William Herschel, using a simple 18-inch reflecting telescope. He could have never imagined that a little over two centuries later we'd have a telescope powerful enough to zoom in on a very tiny slice of the nebula for this spectacular view.

The Hubble Space Telescope is a project of international cooperation between NASA and ESA. 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.

Source: HubbleSite/News

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About This Release

Credits:

Release: NASA, ESA, Ravi Sankrit (STScI)

Media Contact:

Ray Villard
Space Telescope Science Institute, Baltimore, Maryland

Science Contact

Ravi Sankrit
Space Telescope Science Institute, Baltimore, Maryland

William Blair
Johns Hopkins University, Baltimore, Maryland

Permissions: Content Use Policy

Contact Us: Direct inquiries to the News Team.

Related Links and Documents

Science Paper: The science paper by R. Sankrit et al., PDF (1.81 MB)

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Eta Carinae: Chandra Rewinds Story of Great Eruption of the 1840s

Eta Carinae Time-Lapse: 1999, 2003, 2009, 2014, and 2020
Credit: X-ray: NASA/SAO/GSFC/M. Corcoran et al; HST: NASA/ESA/STScI
Image Processing: NASA/CXC/SAO/L. Frattare, J. Major, N. Wolk

JPEG (61.2 kb) - Large JPEG (1021.8 kb) - Tiff (2.7 MB) - More Images

A Tour of Eta Carinae - More Videos

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A new movie made from over two decades of data from NASA’s Chandra X-ray Observatory shows a famous star system changing with time, as described in our latest press release. Eta Carinae contains two massive stars (one is about 90 times the mass of the Sun and the other is believed to be about 30 times the Sun’s mass).

In the middle of the 19th century, skywatchers observed as Eta Carinae experienced a huge explosion that was dubbed the “Great Eruption.” During this event, Eta Carinae ejected between 10 and 45 times the mass of the Sun. This material became a dense pair of spherical clouds of gas, now called the Homunculus nebula, on opposite sides of the two stars. The Homunculus is clearly seen in a composite image of the Chandra data with optical light from the Hubble Space Telescope (blue, purple, and white).

Eta Carinae (Composite)
Credit: X-ray: NASA/SAO/GSFC/M. Corcoran et al; HST: NASA/ESA/STScI;
Image Processing: NASA/CXC/SAO/L. Frattare, J.Major, N. Wolk

A new time-lapse sequence contains frames of Eta Carinae taken with Chandra from 1999, 2003, 2009, 2014, and 2020. Astronomers used the Chandra observations along with data from ESA’s XMM-Newton to watch as the stellar eruption from about 180 years ago continues to expand into space at speeds up to 4.5 million miles per hour. The two massive stars produce the blue, relatively high energy X-ray source in the center of the ring. They are too close to each other to be seen individually.

A bright ring of X-rays (orange) around the Homunculus nebula was discovered about 50 years ago and studied in previous Chandra work. The new movie of Chandra, plus a deep, summed image generated by adding the data together, reveal important hints about Eta Carinae’s volatile history. This includes the rapid expansion of the ring, and a previously-unknown faint shell of X-rays outside it.

This faint X-ray shell is highlighted in an additional graphic showing the summed image. The image on the left emphasizes the bright X-ray ring, and the image on the right shows the same data but emphasizing the faintest X-rays. The shell is located in between the two contour levels, as labeled.

Eta Carinae (Summed)
Credit:NASA/SAO/GSFC/M. Corcoran et al.

Because the newly discovered outer X-ray shell has a similar shape and orientation to the Homunculus nebula, researchers concluded both structures have a common origin. The idea is that material was blasted away from Eta Carinae well before the 1843 Great Eruption — sometime between 1200 and 1800, based on the motion of clumps of gas previously seen in Hubble Space Telescope data. Later this slower material was lit up in X-rays when the fast blast wave from the Great Eruption tore through space, colliding with and heating the material to millions of degrees to create the bright X-ray ring. The blast wave has now traveled beyond the bright ring.

A paper describing these results appeared in The Astrophysical Journal and is available at https://iopscience.iop.org/article/10.3847/1538-4357/ac8f27

The authors of the paper are Michael Corcoran (NASA’s Goddard Space Flight Center), Kenji Hamaguchi (GSFC), Nathan Smith (University of Arizona), Ian Stevens (University of Birmingham, UK), Anthony Moffat (University of Montreal), Noel Richardson (Embry-Riddle Aeronautical University), Gerd Weigelt (Max Planck Institute for Radio Astronomy), David Espinoza-Galeas (The Catholic University of America), Augusto Damineli (University of Sao Paolo, Brazil), and Christopher Russell (Catholic University).

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

Quick Look: Chandra Rewinds Story of Great Eruption of the 1840's

Source: NASA's Chandra X-Ray Observatory

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Visual Description:

This release features composite images and a time-lapse movie of a cosmic explosion that sky watchers have been observing since the middle of the 19th century. About 180 years ago, a huge explosion inside the Eta Carinae star system ejected massive amounts of material in an event dubbed the "Great Eruption". The resulting gas and debris cloud has been expanding ever since.

The time lapse sequence of Chandra observations begins with an image from 1999. Here, a hazy, neon blue ball with a brilliant white core is encircled by a patchy, oblong, orange ring. The blue and white ball shows X-rays from two massive stars, 30 and 90 times the mass of our sun. These stars are too close together to be seen individually. The oblong orange gas ring encircling them is tilted, stretching toward our upper right and lower left.

The time lapse movie progresses with four similar images, containing data from 2003, 2009, 2014, and 2020. As the images flit by, one after the other, the neon blue ball expands, but the white core appears stable. The patches forming the orange ring of gas shift and swell, moving away from the stars inside the blue and white ball.

An additional composite image features optical and X-ray observations of the explosion, inside the expanding orange ring of gas. Here, the explosion is shaped like an hourglass, or peanut shell, with bulbous ends and a narrow middle. The shell is a translucent mauve color, streaked with purple veins. Inside, at the narrow middle, a brilliant white light gleams brightly. The peanut shell shape is tilted, with one bulbous end pointing away from us, toward our upper right, and the other pointing toward us, down to our lower left. This is the same orientation as the orange ring of gas. That indicates that both structures have the same origin: the "Great Eruption", observed about 180 years ago.

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Fast Facts for Eta Carinae (Time-lapse):

Credit: X-ray: NASA/SAO/GSFC/M. Corcoran et al.; Image Processing: L. Frattare, J. Major, N. Wolk (SAO/CXC)
Scale: Image is about 2.2 arcmin (4.8 light-years) across.
Category: Normal Stars & Star Clusters
Coordinates (J2000): RA 10h 45m 04s | Dec -59° 41´ 03"
Constellation: Carina
Observation Dates: 17 observations from Sept 1999 to March 2020
Observation Time: 79 hours 41 minutes (3 days 7 hours 41 minutes)
Obs. ID: 50, 51, 1249, 4455, 9933-9937, 16509, 15731, 15732, 16510, 15733, 16511, 22312, 22313
Instrument: ACIS
References: Corcoran, M. et al, ApJ, 2022, 937, 122. DOI 10.3847/1538-4357/ac8f27
Color Code: X-ray: red, green, and blue
Distance Estimate: About 7,500 light-years

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Study reveals cosmic surprises from the dawn of time

LEDA 2046648
Credit: NASA/ESA

A groundbreaking international study has unveiled remarkable insights into the early evolution of galaxies, shedding light on the fundamental processes that have shaped our universe.

A research team from Denmark and Australia used the extraordinary capabilities of the James Webb Space Telescope to delve back in time billions of years, to the period shortly after the Big Bang when galaxies were first forming.

Study co-author, astrophysicist Associate Professor Claudia Lagos at The University of Western Australia node of the International Centre for Radio Astronomy Research (ICRAR), said researchers found that for more than 12 billion years galaxies followed the same set of rules when it came to the formation rate of stars, as well as their mass and chemical composition.

“It was like the galaxies had a rulebook that they followed – but astonishingly, this cosmic rulebook, appears to have undergone a dramatic rewrite during the universe’s infancy,” Associate Professor Lagos said.

“The most surprising discovery was that ancient galaxies produced far fewer heavy elements than we would have predicted based on what we know from galaxies that formed later.

“In fact their chemical abundance was approximately four times lower than anticipated, based on the fundamental-metallicity relation observed in later galaxies.”

Associate Professor Lagos said the findings challenged previous ideas about how galaxies evolved in the early universe, suggesting that early on galaxies were closely connected to the space around them and influenced by their cosmic neighbourhood.

“What’s most surprising is that the early galaxies continually received new, pristine gas from their surroundings, with the gas influx diluting the heavy elements inside the galaxies, making them less concentrated,” Associate Professor Lagos said.

The discovery challenges existing theories about galaxy evolution and raises questions about the mechanisms at play during the universe’s formative years, opening the door to further exploration about the cosmic processes that influenced the development of early galaxies.

The findings were published in Nature Astronomy.

Source:International Center for Radio Astronomy Research ICRAR/News

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Featured Image: A Rare X-ray Binary in a Starburst Galaxy

An X-ray view of the dwarf starburst galaxy NGC 4214 created from Chandra X-ray Observatory Data
Credit:Adapted from Lin et al. 2023

Ten million light-years from Earth, a tiny galaxy that glitters with new stars houses a rare kind of binary system. The binary, cataloged as CXOU J121538.2+361921 and referred to simply as X-1, is the brightest X-ray point source in its home galaxy. The system’s bright X-ray light is the result of a star having its atmosphere stolen by a compact companion, like a black hole or a neutron star, creating an extremely hot accretion disk. In a recent research article, a team led by Zikun Lin (Key Laboratory of Optical Astronomy, Chinese Academy of Sciences; University of Chinese Academy of Sciences) used data from the Chandra X-ray Observatory and the Hubble Space Telescope to learn more about this unusual system. The Chandra data, shown to the right, allowed the team to confirm that the binary components eclipse each other every 3.6 hours. The Hubble data, shown above, allowed them to identify the optical counterpart of the X-ray binary for the first time: a blazingly hot blue star that is likely a massive, evolved star with powerful winds and a metal-rich atmosphere. In some tens of millions of years, this star and its companion — the team suspects a black hole, though a neutron star can’t yet be ruled out — will lose their orbital energy to gravitational waves and coalesce in a spectacular cosmic explosion.

By Kerry Hensley

Citation

“On the Short-period Eclipsing High-mass X-Ray Binary in NGC 4214,” Zikun Lin et al 2023 ApJ 954 46. doi:10.3847/1538-4357/ace770

Source: American Astronomical Society/AAS-Nova

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What’s in a name?

SDSS J103512.07+461412.2

A galaxy in the centre of a wide view of space. It is surrounded by a variety of differently-shaped small galaxies. A wide and very flat spiral galaxy, and one star with four prominent diffraction spikes, are noticeable. The galaxy itself is a broad horizontal streak of tiny stars, extending left and right from a dense and bright core of stars in the centre. Credit: ESA/Hubble & NASA, R. Tully

This Hubble Picture of the Week includes the pithily-named galaxy SDSS J103512.07+461412.2, visible in the centre of this image as a dispersed sweep of dust and stars with a denser, brighter core. SDSS J103512.07+461412.2 is located 23 million light-years from Earth in the constellation Ursa Major. The seemingly rambling name is because this galaxy was observed as part of the Sloan Digital Sky Survey (SDSS), a massive survey that began in 2000 with the aim of observing and cataloguing vast numbers of astronomical objects. So far, it has recorded several hundred million astronomical objects.

In the early days of astronomy catalogues, astronomers painstakingly recorded individual objects one by one. As an example, the Messier catalogue includes only 110 objects, identified by the astronomer Charles Messier because they were all getting in the way of his comet-hunting efforts. As the Messier catalogue is so limited, it is sufficient to simply refer to those objects as M1 to M110. In contrast, when a survey as massive in scope as the SDSS is involved, and when huge volumes of data need to be processed in an automated manner, the names assigned to objects need to be both longer, and more informative.

To that end, every SDSS object has a designation that follows the format of: ‘SDSS J’, followed by the right ascension (RA), and then the declination (Dec). RA and Dec define the position of an astronomical object in the night sky. RA is analogous to longitude here on Earth, whilst the Dec corresponds to latitude. To be more exact, RA measures the longitudinal distance of an astronomical object from the point where the celestial equator (the mid-point between the north and south celestial poles) intersects with the ecliptic (the plane in which Earth orbits around the Sun). The entire night sky is then carved into 24 slices, known as ‘hours’, measured eastwards from that starting point (which is designated as zero hour). This means that the RA can be expressed in ‘hours’, ‘minutes’ and ‘seconds’. Dec is the angle north or south of the celestial equator, and is expressed in degrees. The RA and Dec of the objects featured in each Hubble Picture of the Week can be found on the lower right side of the webpage!

Thus, the SDSS J103512.07+461412.2 name simply tells us that the galaxy can be found 10 hours, 35 minutes and 12 seconds east of the zero-hour point on the celestial equator, and just over 46 degrees to the north of the celestial equator. So that lengthy name is really an identifier and a detailed location in one!

Source: ESA/Hubble/powt

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ALMA and James Webb Observe the Most Distant Galaxy Protocluster

Artist's impression of the "metropolitan area" of the protocluster A2744ODz7p9 revealed by the James Webb Space Telescope and ALMA
Credit: NAOJ

Artist's impression of what the "metropolitan area" will become tens of millions of years after the observed time
Credit: NAOJ

The background color image shows a map of the light intensity (redder color shows stronger Emission) in the core region of the protogalactic cluster A2744ODz7p9, acquired with the NIRCam onboard JWST. The size of the image corresponds to about half of the radius of the Milky Way Galaxy. (Left) Contours show the distribution of light emitted by ionized oxygen, obtained with the NIRSpec instrument onboard JWST. 4 galaxies were identified at 13.14 billion light-years away. (Right) Contours show the distribution of dust emission from three of the four galaxies. The white circle in the lower left of the figure indicates the beam size of the ALMA data. Credit: JWST (NASA, ESA, CSA), ALMA (ESO/NOAJ/NRAO), T. Hashimoto et al.

Galaxy formation simulations of the future of the core of A2744z7p9OD. (a) Gas density in a region similar to the proto-cluster A2744z7p9OD at a cosmological age of 689 million years. (b) A zoomed-in view of the core region in (a) corresponding to the region observed by JWST. The color map indicates the light distribution of oxygen ions. (b) to (d) show the evolution of the simulated object: the four galaxies gradually merge and evolve into a larger entity. Credit: T. Hashimoto et al.

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An international collaboration led by Assistant Professor Takuya Hashimoto (University of Tsukuba, Japan) and Researcher Javier Álvarez-Márquez (Spanish Center for Astrobiology) has used the James Webb Space Telescope (JWST) and the Atacama Large Millimeter/submillimeter Array (ALMA) to observe the most distant galaxy protocluster to date, 13.14 billion light-years away1. This profound observation has revealed this protocluster's dense 'metropolitan' core, indicating accelerated galaxy growth. Simulations suggest this region will merge into a singular, massive galaxy in the forthcoming tens of millions of years, offering insights into early galactic birth and evolution.

Studying how individual stars are born and die in galaxies, how new stars are born from remnants of old stars, and how galaxies grow are important themes in astronomy, as they provide insight into our roots in the Universe. Galaxy clusters, one of the most significant structures in the Universe, assemble more than 100 galaxies bound together through mutual gravitational force. Observations of nearby galaxies have shown that the growth of a galaxy depends on its environment in the sense that mature stellar populations are commonly seen in regions where galaxies are densely collected. This is referred to as the "environment effect."

Although the environment effect has been considered an essential piece to understanding galaxy formation and evolution, it is not well known when it was initiated in the history of the Universe. One of the keys to understanding this is to observe the ancestors of galaxy clusters shortly after the birth of the Universe, known as galaxy protoclusters (hereafter protoclusters); these are assemblies of about ten distant galaxies. Fortunately, astronomy allows us to observe the distant Universe as it was in the past. For example, light from a galaxy 13 billion light-years away takes 13 billion years to reach Earth, so what we observe now is what that galaxy looked like 13 billion years ago. However, light that travels 13 billion light-years becomes fainter, so the telescopes that observe it must have high sensitivity and spatial resolution.

The research team first observed the core region of this protocluster using JWST. Using NIRSpec, an instrument that observes spectra at wavelengths ranging from visible to near-infrared, the team made integral field spectroscopy observations that can simultaneously acquire spectra from all locations within the field of view. The team has successfully detected ionized oxygen-ion light ([OIII] 5008 Å) from four galaxies in a quadrangle region measuring 36,000 light-years along a side, which is equivalent to half the radius of the Milky Way galaxy. Based on the redshift of this light (the elongation of the wavelength due to the cosmic expansion), the distance of the four galaxies from the Earth was identified as 13.14 billion light years. "I was surprised when we identified four galaxies by detecting oxygen-ion emission at almost the same distance. The 'candidate galaxies' in the core region were indeed members of the most distant protocluster," says Yuma Sugahara (Waseda/NAOJ), who led the JWST data analysis.

In addition, the research team paid attention to the archival ALMA data, which had already been acquired for this region. The data captures radio emission from cosmic dust in these distant galaxies. As a result of analyses, they detected dust emissions from three of the four galaxies. This is the first detection of dust emission in member galaxies of a protocluster this far back in time. Cosmic dust in galaxies is thought to be supplied by supernova explosions at the end of the evolution of massive stars in the galaxies, which provide the material for new stars. Therefore, large amounts of dust in a galaxy indicate that many of the first-generation stars in the galaxy have already completed their lives and that the galaxy is growing. Professor Luis Colina (Centro de Astrobiología (CAB, CSIC-INTA)) describes the significance of the results: "Emission from cosmic dust was not detected in member galaxies of the protocluster outside the core region. The results indicate that many galaxies are clustered in a small region and that galaxy growth is accelerated, suggesting that environmental effects existed only ~700 million years after the Big Bang."

Furthermore, the research team conducted a galaxy formation simulation to theoretically test how the four galaxies in the core region formed and evolved. The results showed that a region of dense gas particles existed around 680 million years after the Big Bang, and that four galaxies are formed, similar to the observed core region. To follow the evolution of these four galaxies, the simulation calculated physical processes such as the kinematics of stars and gas, chemical reactions, star formation, and supernovae. The simulations showed that the four galaxies merge and evolve into a single larger galaxy within a few tens of millions of years, which is a short time scale in the evolution of the Universe. "We successfully reproduced the properties of the galaxies in the core region owing to the high spatial resolution of our simulations and the large number of galaxy samples we have. In the future, we would like to explore the formation mechanism of the core region and its dynamical properties in more detail," says Yurina Nakazato, a graduate student at the University of Tokyo, who analyzed the simulation data.

Javier Álvarez-Márquez (Spanish Center for Astrobiology) says, "We will conduct more sensitive observations of the protocluster A2744z7p9OD with ALMA to see if there are any galaxies that were not visible with the previous sensitivity. We will also apply the JWST and ALMA observations, which have proven to be very powerful, to more protoclusters to elucidate the growth mechanism of galaxies, and to explore our roots in the Universe."

Source: ALMA (Atacama Large Millimeter/submillimeter Array)/Press Release

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Additional Information

These results have been accepted for publication in The Astrophysical Journal Letters as "Reionization and the ISM/Stellar Origins with JWST and ALMA (RIOJA): The core of the highest redshift galaxy overdensity confirmed by NIRSpec/JWST" on August 30, 2023, and will be published in the journal.

The research team members are Takuya Hashimoto (University of Tsukuba), Javier Álvarez-Márquez (Centro de Astrobiología (CAB), CSIC-INTA), Yoshinobu Fudamoto (Chiba University), Luis Colina (Centro de Astrobiología (CAB), CSIC-INTA), Akio K. Inoue (Waseda University), Yurina Nakazato (University of Tokyo), Daniel Ceverino (Universidad Autonoma de Madrid/CIAFF), Naoki Yoshida (University of Tokyo, Kavli IPMU), Luca Costantin (Centro de Astrobiología (CAB), CSIC-INTA), Yuma Sugahara (Waseda University/NAOJ), Alejandro Crespo Gómez (Centro de Astrobiología (CAB), CSIC-INTA), Carmen Blanco-Prieto (Centro de Astrobiología (CAB), CSIC-INTA), Ken Mawatari (University of Tsukuba), Santiago Arribas (Centro de Astrobiología (CAB), CSIC-INTA), Rui Marques-Chaves (University of Geneva), Miguel Pereira-Santaella (Instituto de Física Fundamental (IFF), CSIC), Tom J.L.C. Bakx (Chalmers University of Technology), Masato Hagimoto (Nagoya University), Takeshi Hashigaya (Kyoto University), Hiroshi Matsuo (NAOJ/SOKENDAI), Yoichi Tamura (Nagoya University), Mitsutaka Usui (University of Tsukuba), Yi W. Ren (Waseda University)

This text is based on the original Press Release by the National Astronomical Observatory of Japan (NAOJ), an ALMA partner on behalf of East Asia.

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of the European Organisation for Astronomical Research in the Southern Hemisphere (ESO), the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science and Technology Council (NSTC) in Taiwan and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI).

ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

Scientific Paper

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Notes:

The redshift of this object was z = 7.88. Based on this, calculating the distance using the latest cosmological parameters (H0 = 67.7 km/s/Mpc, Ωm = 0.3111, ΩΛ = 0.6899) yields 13.14 billion light years. The distance for A2744z7p9OD was first determined by the team of Takahiro Morishita (California Institute of Technology).

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A Fast Radio Burst Reveals Foreground Galaxy Clusters

Artist's impression of a fast radio burst traveling from its source in a distant galaxy to an observed on Earth. Along this path, the burst passes through the halo of another galaxy, which affects the radio signal. Credit: ESO/M. Kornmesser; CC BY 4.0

The repeating fast radio burst FRB 20190520B traveled through an unusually large amount of matter on its journey to Earth. Could unidentified galaxy clusters in the billions of light-years that separate us from the burst’s source explain why?

The signal from the first fast radio burst ever detected. The highest frequencies arrive first, and the lower frequencies follow. Credit: Wikipedia user Psr1909; CC BY-SA 4.0

An Astrophysical Mystery

Fast radio bursts are among the most mysterious events in the universe. Most of these powerful, milliseconds-long radio blips occur just once, each burst an astronomical flash in the pan that leaves researchers puzzling over its origin. In rare cases, fast radio bursts repeat, giving us a clue that at least some sources of these mysterious bursts survive the event.

Snapshot of an interactive figure showing the locations of the newly identified galaxy clusters relative to FRB 20190520B’s location.  You can interact with this figure here. Credit: Lee et al. 2023

Surveying a Superlative Burst

The dispersion measure of the repeating fast radio burst FRB 20190520B is more than twice as large as expected given its distance. This unusually high value caught the attention of a team led by Khee-Gan Lee (Kavli Institute for the Physics and Mathematics of the Universe), which is carrying out the Fast Radio Burst (FRB) Line-of-sight Ionization Measurement From Lightcone AAOmega Mapping survey, or FLIMFLAM. This survey aims to map the distribution of luminous matter in the universe by searching for galaxy groups that are revealed by fast radio bursts.

The team spectroscopically determined the distances to galaxies in the field of view surrounding FRB 20190520B’s location and used a group-finding algorithm to identify galaxy groups and clusters. They found multiple galaxy groups in the field of view, including two galaxy clusters that lie directly between us and FRB 20190520B. By using models to estimate the masses of these galaxies and their halos, Lee’s team determined how much these intervening galaxy clusters contributed to the burst’s dispersion measure.

A Revised Estimate

Based on FRB 20190520B’s extremely high dispersion measure, previous research estimated its host galaxy’s dispersion to be the highest of any known fast radio burst, a fact that has been difficult to reconcile with other observations of the galaxy. Now, with the new estimate of the foreground galaxies’ contribution, FRB 20190520B’s host galaxy has been assigned a more moderate value that aligns with its observational properties. This study demonstrates that even when focusing closely on a single fast radio burst, it’s still important to zoom out and consider the big picture!

Citation

“The FRB 20190520B Sight Line Intersects Foreground Galaxy Clusters,” Khee-Gan Lee et al 2023 ApJL 954 L7. doi:10.3847/2041-8213/acefb5

By Kerry Hensley

Source: American Astronomical Society/AAS-Nova

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NASA’s Webb Finds Carbon Source on Surface of Jupiter’s Moon Europa

Europa (NIRCam Image)
Credits: Science: NASA, ESA, CSA, Gerónimo Villanueva (NASA-GSFC), Samantha K Trumbo (Cornell University)
Image Processing: Gerónimo Villanueva (NASA-GSFC), Alyssa Pagan (STScI)

Europa Carbon Dioxide Distribution (NIRCam and NIRSpec IFU Image) Credits: Science: NASA, ESA, CSA, Gerónimo Villanueva (NASA-GSFC), Samantha K Trumbo (Cornell University)
Image Processing: Gerónimo Villanueva (NASA-GSFC), Alyssa Pagan (STScI)

Release Images

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Jupiter’s moon Europa is one of a handful of worlds in our solar system that could potentially harbor conditions suitable for life. Previous research has shown that beneath its water-ice crust lies a salty ocean of liquid water with a rocky seafloor. However, planetary scientists had not confirmed if that ocean contained the chemicals needed for life, particularly carbon.

Astronomers using data from NASA’s James Webb Space Telescope have identified carbon dioxide in a specific region on the icy surface of Europa. Analysis indicates that this carbon likely originated in the subsurface ocean and was not delivered by meteorites or other external sources. Moreover, it was deposited on a geologically recent timescale. This discovery has important implications for the potential habitability of Europa’s ocean.

“On Earth, life likes chemical diversity – the more diversity, the better. We’re carbon-based life. Understanding the chemistry of Europa’s ocean will help us determine whether it’s hostile to life as we know it, or if it might be a good place for life,” said Geronimo Villanueva of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, lead author of one of two independent papers describing the findings.

“We now think that we have observational evidence that the carbon we see on Europa’s surface came from the ocean. That's not a trivial thing. Carbon is a biologically essential element,” added Samantha Trumbo of Cornell University in Ithaca, New York, lead author of the second paper analyzing these data.

NASA plans to launch its Europa Clipper spacecraft, which will perform dozens of close flybys of Europa to further investigate whether it could have conditions suitable for life, in October 2024.

A Surface-Ocean Connection

Webb finds that on Europa’s surface, carbon dioxide is most abundant in a region called Tara Regio – a geologically young area of generally resurfaced terrain known as “chaos terrain.” The surface ice has been disrupted, and there likely has been an exchange of material between the subsurface ocean and the icy surface.

“Previous observations from the Hubble Space Telescope show evidence for ocean-derived salt in Tara Regio,” explained Trumbo. “Now we’re seeing that carbon dioxide is heavily concentrated there as well. We think this implies that the carbon probably has its ultimate origin in the internal ocean.”

“Scientists are debating how much Europa’s ocean connects to its surface. I think that question has been a big driver of Europa exploration,” said Villanueva. “This suggests that we may be able to learn some basic things about the ocean’s composition even before we drill through the ice to get the full picture.”

Both teams identified the carbon dioxide using data from the integral field unit of Webb’s Near-Infrared Spectrograph (NIRSpec). This instrument mode provides spectra with a resolution of 200 x 200 miles (320 x 320 kilometers) on the surface of Europa, which has a diameter of 1,944 miles, allowing astronomers to determine where specific chemicals are located.

Carbon dioxide isn’t stable on Europa’s surface. Therefore, the scientists say it’s likely that it was supplied on a geologically recent timescale – a conclusion bolstered by its concentration in a region of young terrain.

“These observations only took a few minutes of the observatory’s time,” said Heidi Hammel of the Association of Universities for Research in Astronomy, a Webb interdisciplinary scientist leading Webb’s Cycle 1 Guaranteed Time Observations of the solar system. “Even with this short period of time, we were able to do really big science. This work gives a first hint of all the amazing solar system science we’ll be able to do with Webb.”

Searching for a Plume

Villanueva’s team also looked for evidence of a plume of water vapor erupting from Europa’s surface. Researchers using NASA’s Hubble Space Telescope reported tentative detections of plumes in 2013, 2016, and 2017. However, finding definitive proof has been difficult.

The new Webb data shows no evidence of plume activity, which allowed Villanueva’s team to set a strict upper limit on the rate of material potentially being ejected. The team stressed, however, that their non-detection does not rule out a plume.

“There is always a possibility that these plumes are variable and that you can only see them at certain times. All we can say with 100% confidence is that we did not detect a plume at Europa when we made these observations with Webb,” said Hammel.

These findings may help inform NASA’s Europa Clipper mission, as well as ESA’s (European Space Agency’s) upcoming Jupiter Icy Moons Explorer (JUICE ).

The two papers will be published in Science on September 21

The James Webb Space Telescope is the world's premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.

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About This Release Credits

Media Contact:

Ann Jenkins
Space Telescope Science Institute, Baltimore, Maryland

Christine Pulliam
Space Telescope Science Institute, Baltimore, Maryland

Science: Gerónimo Villanueva (NASA-GSFC), Samantha K Trumbo (Cornell University)

Permissions: Content Use Policy

Contact Us: Direct inquiries to the News Team.

Source: NASA's James Webb Space Telescope/News

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Astronomers reveal cosmic ribbon around rare galaxy

NGC 4632

Image Credit: J. English (U.Manitoba), with support of N. Deg (Queen’s U.) and the WALLABY team; CSIRO/ASKAP radio telescope, NAOJ/Subaru Telescope

CSIRO’s ASKAP radio telescope on Wajarri Yamaji Country in Western Australia.
Credit: CSIRO/A.Cherney

Associate Professor Barbara Catinella

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International astronomers using a telescope owned and operated by CSIRO, Australia’s national science agency, have revealed a galaxy wrapped in a cosmic ‘ribbon’.

The research, led by Dr Nathan Deg and Dr Kristine Spekkens from Queen’s University Canada and co- authored by CSIRO’s Professor Bärbel Koribalski, presents a stunning image of a galaxy called NGC 4632 that is 56 million light years from Earth.

It’s been identified as a potential polar ring galaxy, which are some of the most spectacular types of galaxies in the Universe, and among the most mysterious.

Detected using CSIRO’s ASKAP radio telescope on Wajarri Yamaji Country in Western Australia, the galaxy features a ring of gas that can only be seen at radio wavelengths. The ring is orbiting the galaxy at right angles to its spiral disk, like a parcel wrapped in a ribbon of cosmic gas, dust and stars. Dr Nathan Deg co-authored the paper published today in Monthly Notices of the Royal Astronomical Society.

“The findings suggest that one to three per cent of nearby galaxies may have gaseous polar rings, which is much higher than suggested by optical telescopes. Polar ring galaxies might be more common than previously thought,” Dr Deg said.

“While this is not the first time astronomers have observed polar ring galaxies, NGC 4632 is the first observed with ASKAP and there may be many more to come,”

Professor Koribalski said the WALLABY survey aims to observe the whole southern sky using ASKAP to detect and visualise the gas distribution in hundreds of thousands of galaxies.

“NGC 4632 is one of two polar ring galaxies we’ve identified from 600 galaxies that were mapped in our first small WALLABY survey.

“Using ASKAP over coming years we expect to reveal more than 200,000 hydrogen-rich galaxies, among them many more unusual galaxies like these ones with polar rings,” Professor Koribalski said.

Why polar rings exist is still a puzzle to astronomers. One possible explanation is that their stellar rings, which appear blended with gas clouds, are shredded material from a passing galaxy.

Another possibility is that hydrogen gas flows along the filaments of the cosmic web and accretes into a ring around a galaxy, possibly forming stars during this process

Associate Professor Barbara Catinella, from ICRAR’s UWA node, is WALLABY Co-Principal Investigator and co-author on the paper.

“One of the most exciting outcomes of a large survey such as WALLABY, which will scan most of the Southern sky to carry out the largest census of neutral atomic hydrogen ever done, is discovering the unexpected,” she says.

“These unusual galaxies with beautiful gas rings are perfect examples of this.”

In the future, polar ring galaxies can also be used to deepen our understanding of the universe, with potential applications in dark matter research. It is possible to use polar rings to probe the shape of dark matter of the host galaxy, which could lead to new clues about the mysterious properties of the elusive substance.

Over 25 global collaborators from Canada, Australia, South Africa, Ecuador, Burkina Faso, Germany, China, and beyond worked together to analyse data from the first WALLABY survey collected using ASKAP and processed by the Pawsey Supercomputing Research Centre in Western Australia.

ASKAP is part of CSIRO’s Australia Telescope National Facility. It is also a precursor to the international SKA telescopes currently being built in Australia and South Africa.

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

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Signs of (Pre-)Life: Can JWST Detect Conditions for the Formation of Earth-Like Life on Distant Planets?

Artist's impression of K2-18b, the first habitable-zone exoplanet known to have water vapor in its atmosphere.
Credit: ESA/Hubble, M. Kornmesser

Title: Prebiosignature Molecules Can Be Detected in Temperate Exoplanet Atmospheres with JWST
Authors: A. B. Claringbold et al.
First Author’s Institution: University of Cambridge
Status: Published in AJ

The search for life in the universe has always been a driving force for interest in and development of astronomy and the space sciences. Far from tales of little green men and aliens on Mars, today’s scientific investigations into extraterrestrial life usually involve trying to find the traces that life leaves behind in the light that we receive from the stars. This could be evidence of alien transmissions, structures, technology, or intelligence — “technosignatures” — or evidence of molecules or other indicators of the existence of life, regardless of its intelligence — “biosignatures.”

Given many arguments and discussions about the rarity of life in the cosmos, however, many consider it prudent to search not only for these signatures but also for prebiosignatures — molecules in planetary atmospheres that correspond not to the current existence of life, but to the conditions in which life (organic chemistry, in particular) arose on Earth. These include molecules created by volcanism, ultraviolet radiation, or even lightning. Given what we currently understand about how proteins and RNA came to be on our planet, searching for signs of these molecules may help us find the precursors for life elsewhere in the universe.

The authors of today’s article wish to test the sensitivity of JWST to detecting traces of these prebiosignature molecules in the atmospheres of various kinds of exoplanets. To do this, they use atmospheric models to simulate what the transmission spectra of different exoplanets would look like and test whether JWST’s instruments can recover the prebiosignatures from within the simulated data.

Molecular Mission

The authors focused their analysis on a selection of prebiosignature atmospheric molecules informed by a series of origin scenarios for life. The particular molecules chosen were hydrogen cyanide (HCN), sulfur dioxide (SO2), hydrogen sulfide (H2S), cyanoacetylene (HC3N), carbon monoxide (CO), methane (CH4), acetylene (C2H2), ammonia (NH3), nitric oxide (NO), and formaldehyde (CH2O).

In order to detect these molecules in the atmospheres of distant planets, scientists use a technique called transmission spectroscopy. Essentially, when a planet crosses in front of its star (or “transits”) from our point of view, some light from the host star passes through the planet’s atmosphere. Specific wavelengths of this light are absorbed by molecules in the atmosphere, leaving a telltale “fingerprint” of said molecules’ existence in the spectrum of light we observe. All the molecules chosen happen to have spectral signatures in the infrared, which JWST’s instruments can measure.

Wonderful Worlds

To carry out their investigation, the authors first simulated transmission spectra for a particular set of planets, using models of different types of atmospheres as a background. For the best possible chance of atmospheric detection and characterization, the authors elected to model planets whose atmospheres are rich in hydrogen and helium, have a low mean molecular weight, and are orbiting a smaller star.

Specifically, the authors modeled five different types of possible worlds (Table 1 and Figure 1): a “Hycean” world (an ocean planet with a hydrogen atmosphere), an “ultrareduced volcanic” world (active volcanism with hydrogen- and nitrogen-rich outgassing), a “post-impact” world (a planet recently impacted by another planetary body) at two different times after the collision, a super-Earth planet with a thin hydrogen envelope, and a model that simulates the early conditions on Earth, based on TRAPPIST-1e. This final model is not a light, hydrogen-rich atmosphere, but it’s an important one to study given the history of life’s evolution on our planet. All planets are assumed to be orbiting an M-dwarf star for consistency.

Table 1: Ratios of molecules in each atmospheric model.
Credit: Claringbold et al. 2023

Figure 1: Simulated transmission spectra for each atmospheric model tested, with important spectral lines labeled.
Credit: Claringbold et al. 2023

Having generated the model transmission spectra, the authors simulated realistic noise that JWST would observe in the data given the M-dwarf star and JWST’s various spectroscopic instruments. Afterward, they performed a series of Bayesian detection tests to attempt to retrieve individual molecule abundances from their data. The overall goal of this analysis is an order-of-magnitude estimate of how abundant these molecules would have to be in exoplanet atmospheres in order for JWST to detect them, assuming a “modest amount” of observation time (around five transits or less) dedicated to each exoplanet.

Rousing Results

The authors find that for the model Hycean world, all prebiosignatures are detectable with JWST’s instruments. The hydrogen-rich super-Earth also has very good detectability, despite having the atmosphere with the smallest scale height (the “higher” the atmosphere extends, the more light passes through its molecules, and thus the stronger the signal received on Earth). The ultrareduced volcanic world, while it has a large scale height like the Hycean world, generally has worse detection thresholds due to strongly absorbing CH4 and HCN in its atmosphere. The post-impact planets have the highest scale height, and thus are the best suited for detection, with low thresholds for the prebiosignature molecules. Finally, prebiosignatures in the early Earth model were very difficult to detect with a low number of transits — while some molecules became detectable within 5–10 transits, others require somewhere between 40 and 100, which might be prohibitively long.

Given the models and method of analysis used, the authors note that these results are optimistic at best and may not correspond to real observational thresholds. Features such as clouds and atmospheric haze can increase the detectability threshold for different spectral features by hundreds or thousands of times, possibly rendering them undetectable.

Furthermore, a realistic retrieval method (where there is uncertainty in the atmospheric composition or planetary properties of the exoplanet being observed) may affect the detected abundances of trace molecules. That being said, the authors’ attempts to simulate such an analysis show that the primary prebiosignatures are still well detected within an order of magnitude of the previous results.

The key conclusion of this article is that in the case of light atmospheres and optimal target planets/systems, the detection of prebiosignatures and exploration of the origin of life is well within the capabilities of JWST. As such, a wealth of data on planetary atmospheres is absolutely within the capabilities of the telescope, and detections of said molecules could very well make the news in the years to come.

Original astrobite edited by William Balmer.

Source: American Astronomical Society/AAS-Nova

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Editor’s Note: Astrobites is a graduate-student-run organization that digests astrophysical literature for undergraduate students. As part of the partnership between the AAS and astrobites, we occasionally repost astrobites content here at AAS Nova. We hope you enjoy this post from astrobites; the original can be viewed at astrobites.org.

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About the author, Aldo Panfichi:

Hello! I’m currently finishing up my Master’s degree in Physics at the Pontificia Universidad Católica del Peru in Lima, Peru, writing a thesis project related to asteroids. I previously got my BSc in Astronomy and Astrophysics at the University of Chicago. In my free time, I like spending time with my friends (and my dogs!), going swimming in the summer, and cozying up inside in the winter, playing games or reading science fiction.

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A peculiar proceeding

Arp 107

A pair of merging galaxies. The galaxy on the left has a large, single spiral arm curving out from the core and around to below it, with very visible glowing dust and gas. The right galaxy has a bright core but only a bit of very faint material. A broad curtain of gas connects the two galaxies’ cores and hangs beneath them. A few small stars and galaxies are scattered around the black background. Credit: ESA/Hubble & NASA, J. Dalcanton

This Hubble Picture of the Week — taken using NASA/ESA Hubble Space Telescope’s Advanced Camera for Surveys (ACS) — shows Arp 107, a celestial object that comprises a pair of galaxies in the midst of a collision. The larger galaxy (in the left of this image) is an extremely energetic galaxy type known as a Seyfert galaxy, which house active galactic nuclei at their cores. Seyfert galaxies are notable because despite the immense brightness of the active core, radiation from the entire galaxy can be observed. This is evident in this image, where the spiraling whorls of the whole galaxy are readily visible. The smaller companion is connected to the larger by a tenuous-seeming ‘bridge’, composed of dust and gas. The colliding galactic duo lie about 465 million light-years from Earth.

Arp 107 is part of a catalogue of 338 galaxies known as the Atlas of Peculiar Galaxies, which was compiled in 1966 by Halton Arp. It was observed by Hubble as part of an observing programme that specifically sought to fill in an observational ‘gap’, by taking limited observations of members of the Arp catalogue. Part of the intention of the observing programme was to provide the public with images of these spectacular and not-easily-defined galaxies, and as such, it has provided a rich source for Hubble Pictures of the Week. In fact, several recent releases, including this one and this one, have made use of observations from the same observing programme.

Source: ESA/Hubble/potw

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Dancing with Black Holes: ALMA's Deep Dive into Active Galactic Nucleus's Stellar Orchestra

The central region of the spiral galaxy NGC 1068, as observed by ALMA overlay the Hubble Space Telescope image, has a fascinating distribution of hydrogen cyanide isotopes (H13CN) shown in yellow, cyanide radicals (CN) shown in red, and carbon monoxide isotopes (13CO) shown in blue. H13CN is concentrated solely in the center of the active galactic nucleus. However, CN not only appears in the center and the large-scale ring-shaped gas structure, but also exhibits a structure extending from the center towards the northeast (upper left) and southwest (lower right), which is believed to be caused by the jet emanating from the supermassive black hole. Credit: ALMA (ESO/NAOJ/NRAO), NASA/ESA Hubble Space Telescope, T. Nakajima et al.

Diagram illustrating the machine learning-based classification of molecular distribution patterns. It reveals a structure (in blue) where a specific type of molecular gas extends in two directions from the circumnuclear disk (approximately represented by the white dot at the center) toward the northeast (upper left) and southwest (lower right). Credit: ALMA (ESO/NAOJ/NRAO), T. Saito et al.

Schematic representation of the molecular gas distribution structure in the bipolar region, classified as distinct from the circumnuclear disk through machine learning (the same model is shown from a different perspective in Figure 3). Credit: ALMA (ESO/NAOJ/NRAO), T. Saito et al.

Schematic diagram illustrating the location of the bipolar jet and galactic disk emanating from the supermassive black hole at the galaxy's center, along with the resulting outflow of molecular gas from a side view. Credit: ALMA (ESO/NAOJ/NRAO), T. Saito et al.

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Unraveling the cosmic ballet, researchers harness the power of ALMA to illuminate the intricate interplay between supermassive black holes and the birth and death of stars in NGC 1068

Using the Atacama Large Millimeter/submillimeter Array (ALMA), an international research team led by Toshiki Saito from the National Astronomical Observatory of Japan (NAOJ) and Taku Nakajima from Nagoya University, Japan, delved into the mysteries of NGC 1068 (M77), an active galactic nucleus approximately 51.4 million light-years from Earth, located in the direction of the constellation Cetus. The primary aim was to gain comprehensive insights into the two-dimensional distribution of interstellar molecular gas in the 3 mm wavelength band.

Through advanced machine learning 1 techniques, the researchers analyzed the chemical properties of the active galactic nucleus to decode the physical states they represent. Their exploration led to a remarkable discovery: a significant outflow of molecular gas, potentially birthed by a bipolar jet expelled from a supermassive black hole at the galaxy's core. This outflow appears to stem from a shock wave zone where the jet interacts with the galactic disk, subsequently escalating surrounding temperatures.

This fervent jet activity near the galactic heart seems to be rewriting the very fabric of the molecular gas - the foundational building blocks for stars. In doing so, it could be hampering the emergence of new stars. This revelation paints a vivid picture of the dynamic choreography at play in the core of NGC 1068, offering valuable insights into the multifaceted relationship between supermassive black holes and the evolution of galaxies.

Many galaxies harbor an active supermassive black hole at their center. This colossal entity acts as a prodigious engine, emitting vast quantities of energy, giving birth to what is termed an Active Galactic Nucleus (AGN). Comprehending how this galactic nucleus, powered by the immense black hole, influences neighboring interstellar material, especially its role in either fast-tracking or impeding the genesis of new stars, is pivotal for understanding galaxy evolution. However, the dense cloaks of gas and dust often shroud the central regions of AGNs, posing challenges for even the most potent telescopes in the optical and infrared wavelength bands. But ALMA's ability to observe longer wavelengths like millimeter and submillimeter waves, which are less prone to dust absorption, grants it a distinctive edge. This capability allows for an unobstructed gaze into the inner sanctum of the galactic nucleus.

The study recalls previous efforts in observing the central core region of NGC 1068 (M77), especially between 2007 and 2012 when observations utilized the 45-meter radio telescope at the Nobeyama Radio Observatory (NRO) of NAOJ. While those efforts bore fruit, revealing the presence of various molecules, they fell short of providing a granular view of the distribution of molecular gas and structural nuances surrounding the central core due to the limitations in spatial resolution.

Now, under the leadership of Assistant Professor Toshiki Saito of the NAOJ ALMA Project and Assistant Professor Taku Nakajima, the international research collective has transcended previous limitations by employing ALMA for a line survey close to NGC 1068's central core. This approach, enriched by ALMA's inherent properties, allowed for a clear imaging of key structures within the galaxy. Among the notable observations, the team successfully conducted an 'imaging line survey' that visualized the distribution of all detected molecules without any frequency bias.

The insights gleaned from this endeavor are manifold. Not only did the researchers identify 23 significant molecular emission lines, but they also observed stark differences in molecular concentration in various parts of the galaxy. For instance, while the inner sanctum, directly under the influence of the supermassive black hole, displayed heightened concentrations of certain molecules, others, previously believed to be abundant, were less prevalent when observed through ALMA's high-resolution lens.

The observations gathered through this study hold profound implications. The patterns suggest that the black hole's sway heats molecular gas to soaring temperatures, potentially propelled by shock waves. Delving deeper into this phenomenon, the team uncovered a distinct structure wherein a certain type of molecular gas expands in two directions. This configuration, analyzed using machine learning techniques, aligns with the bipolar jet emerging from a supermassive black hole, as revealed in prior studies.

The impact of these jets and outflows is vast. Accompanied by powerful shock waves, they radiate intense ultraviolet and X-rays, creating environments that are hostile to typical interstellar molecules, the quintessential building blocks of stars. Thus, the destruction of these molecules near the galactic center, where they significantly influence star formation, could effectively halt the birth of new celestial entities. This groundbreaking study offers the first chemical-evidence-backed argument that a galaxy's central supermassive black hole might thwart its evolutionary trajectory.

Reflecting on the journey leading to these revelations, Toshiki Saito notes, “Initially, observing molecules in the vicinity of such a jet was considered challenging due to their destruction. However, thanks to ALMA's high sensitivity, high resolution, and the PCA technique 2, we successfully detected the molecular gas outflow associated with the jet and elucidated its chemical properties. This discovery that the supermassive black hole's activity at the galaxy's center hinders its growth is of great significance.” Taku Nakajima encapsulates the endeavor, stating, “Using astrochemistry to investigate the properties of celestial objects is a strong point of Japanese research groups. This marks the first imaging line survey of an AGN that provides insights into the extreme environment at the galaxy's center. We've demonstrated that the combination of line survey observations with ALMA and machine learning analysis is highly effective for comprehending the physical and chemical properties of active galaxies.”

Source: ALMA (Atacama Large Millimeter/submillimeter Array)/Press Releases

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Additional Information

These works were supported by NAOJ ALMA Scientific Research grants No. 2017-06B, 2018-09B, 2020-15A, 2021-18A, and JSPS KAKENHI grants (JP15K05031, JP17H06130, JP18K13577, JP20H00172, JP20H01951, JP21K03632, JP21K03634, JP21K03547, JP22H04939).

One observational result was published by Saito et al. as “AGN-driven Cold Gas Outflow of NGC 1068 Characterized by Dissociation-sensitive Molecules” in The Astrophysical Journal on August 23, 2022 (DOI: 10.3847/1538-4357/ac80ff), and another was done as an online paper on September 14, 2023 and will be published by Nakajima et al. “Molecular Abundance of the Circumnuclear Region Surrounding an Active Galactic Nucleus in NGC 1068 based on Imaging Line Survey in the 3-mm Band with ALMA” in The Astrophysical Journal (DOI: 10.3847/1538-4357/ace4c7).

This text is based on the original Press Release by the National Astronomical Observatory of Japan (NAOJ), an ALMA partner on behalf of East Asia.

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of the European Organisation for Astronomical Research in the Southern Hemisphere (ESO), the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science and Technology Council (NSTC) in Taiwan and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI).

ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

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Notes

1. Machine learning is a subset of artificial intelligence that enables computers to improve their performance on a task through experience. It involves feeding algorithms with data and allowing them to learn patterns or make predictions without being explicitly programmed for each specific outcome.

2. Principal component analysis (PCA) is a popular technique for analyzing large datasets containing a high number of dimensions/features per observation, increasing the interpretability of data while preserving the maximum amount of information, and enabling the visualization of multidimensional data.

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