Chandra X-Ray Observatory Captures Breathtaking New Images

 

The images feature data from the Smithsonian Astrophysical Observatory along with a host of other NASA telescopes including the James Webb Space Telescope, Hubble Space Telescope and more.

Top row:

N79 is a giant region of star formation in the Large Magellanic Cloud, a small satellite neighbor galaxy to the Milky Way. Chandra sees the hot gas created by young stars, which helps astronomers better understand how stars like our Sun formed billions of years ago. [X-rays from Chandra (purple) and infrared data from Webb (blue, grey and gold)]

NGC 2146 is a spiral galaxy with one of its dusty arms obscuring the view of its center from Earth.. X-rays from Chandra reveal double star systems and hot gas being expelled from the galaxy by supernova explosions and strong winds from giant stars. [X-rays from Chandra (pink and purple), optical data from Hubble and the Las Cumbres Observatory in Chile and infrared data from NSF’s Kitt Peak (red, green and blue)]

IC 348 is a star-forming region in our Milky Way galaxy. The wispy structures that dominate the image are interstellar material that reflects light from the cluster’s stars. The point-like sources in Chandra’s X-ray data are young stars forming in the cluster. [X-rays from Chandra (red, green and blue) and Webb infrared data (pink, orange and purple)]

Middle row:

M83, a spiral galaxy similar to the Milky Way, is oriented face-on toward Earth, providing an unobstructed view of its entire structure that is often not possible with galaxies viewed atdifferent angles. Chandra has detected the explosions of stars, or supernovas, and their aftermath across M83. [X-rays from Chandra (red, green and blue) with ground-based optical data (pink, gold and gray)].

M82 is a so-called starburst galaxy where stars are forming at rates tens to hundreds of times higher than normal galaxies. Chandra sees supernovas that produce expanding bubbles of multimillion-degree gas that extend for millions of light-years away from the galaxy's disk. [X-rays from Chandra (purple) with Hubble optical data (red, green, and blue)]

NGC 1068 is a relatively nearby spiral galaxy containing a black hole at its center that is twice as massive as the one in the Milky Ways. Chandra shows a million-mile-per-hour wind is being driven from NGC 1068’s black hole which lights (?) up the center of the galaxy in X-rays. [X-rays from Chandra (blue), radio data from NSF’s VLA radio data (pink), and optical data from Hubble and Webb (yellow, grey and gold)]

Bottom row:

NGC 346 is a young cluster home to thousands of newborn stars. The cluster’s most massive stars createpowerful winds and produce intense radiation. X-rays from Chandra reveal output from massive stars in the cluster and diffuse emission from a supernova remnant, the glowing debris of an exploded star. [X-rays from Chandra (purple) with optical and ultraviolet from Hubble blue, brown and gold)]

IC 1623 is a system where two galaxies are erging. As the galaxies collide, they trigger new bursts of star formation that glow intensely in certain kinds of light which is detected by Chandara and other telescopesThe merging galaxies may also be in the process of forming a supermassive black hole. [X-rays from Chandra (magenta) with Webb infrared data (red, gold and gray)]

Westerlund 1 is the biggest and closest “super” star cluster to Earth. Data from Chandra and other telescopes is helping astronomers delve deeper into this galactic factory where stars are being produced at extraordinarily high rates. Observations from Chandra have uncovered thousands of individual stars pumping out X-ray emission into the cluster. [X-rays from Chandra (pink, blue, purple and orange) with Webb infrared data (yellow, gold and blue) and Hubble optical data (cyan, grey and light yellow)]

NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program. The Smithsonian Astrophysical Observatory's Chandra X-ray Center, part of the Center for Astrophysics | Harvard & Smithsonian, controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.

Source: Harvard-Smithsonian Center for Astrophysics (CfA)/News

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Media Contact:

Megan Watzke
Chandra X-Ray Observatory
mwatzke@cfa.harvard.edu

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Image Credits:

NGC 2146: X-ray: NASA/CXC/SAO; Optical: NASA/ESA/STScI and NOIRLab/NSF/AURA; Infrared: NSF/NOAO/KPNO; Image Processing: NASA/CXC/SAO/L. Frattare

IC 348: X-ray: NASA/CXC/SAO; Infrared: NASA/ESA/CSA/STScI; Image Processing: NASA/CXC/SAO/J. Major

M83: X-ray: NASA/CXC/SAO; Optical: NASA/ESA/AURA/STScI, Hubble Heritage Team, W. Blair (STScI/Johns Hopkins University) and R. O'Connell (University of Virginia); Image Processing: NASA/CXC/SAO/L. Frattare

M82: X-ray: NASA/CXC/SAO; Optical/IR: NASA/ESA/STScI; Image Processing: NASA/CXC/SAO/J. Major

NGC 1068: X-ray: NASA/CXC/SAO; Optical/IR: NASA/ESA/CSA/STScI (HST and JWST); Radio: NSF/NRAO/VLA; Image Processing: NASA/CXC/SAO/J. Schmidt and N. Wolk

NGC 346: X-ray: NASA/CXC/SAO; Optical/IR: NASA/ESA/CSA/STScI (HST and JWST); Radio: NSF/NRAO/VLA; Image Processing: NASA/CXC/SAO/J. Schmidt and N. Wolk

IC 1623: X-ray: NASA/CXC/SAO; IR: NASA/ESA/CSA/STScI; Image Processing: NASA/CXC/SAO/L. Frattare and J. Major

Westerlund 1: X-ray: NASA/CXC/SAO; Optical: NASA/ESA/STScI; IR: NASA/ESA/CSA/STScI; Image Processing: NASA/CXC/SAO/L. Frattare

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Zooming in on a supermassive black hole in action

An image of the spiral galaxy NGC 1068 (Messier 77) obtained by the European Southern Observatory’s (ESO) Very Large Telescope (VLT). The galaxy has a distance of 14.4 Mpc (47 million light-years) and is one of the nearest galaxies with an active galactic nucleus. © ESO

A new type of observation reveals what makes the cores of active galaxies glow

Using the Large Binocular Telescope Interferometer, a team of astronomers led by scientists from the Max Planck Institute for Astronomy (MPIA) and the University of Arizona (UofA) has disentangled the sources of infrared radiation near the supermassive black hole at the centre of the galaxy NGC 1068. They discovered that the surrounding dusty wind is heated by the hot central accretion disk and shocks generated by a collimated gas jet. These findings and additional features support the unified model of active galactic nuclei, which explains their varying appearances.

Active galactic nuclei (AGN) are supermassive black holes at the centre of certain galaxies. When these black holes attract matter, a quickly rotating disk of hot gas forms, releasing enormous amounts of energy before plunging into the black hole. Such AGN belong to the most energetic phenomena observed in space. As a result, they also influence processes occurring in their host galaxies. The details are a field of ongoing research.

A team around former MPIA student Jacob Isbell, now a postdoc at the Steward Observatory of the University of Arizona, aimed the Large Binocular Telescope (LBT) at the galaxy NGC 1068, also known as Messier 77, to study the minute details in its centre at thermal infrared wavelengths. This galaxy is one of the nearest with an AGN. The observations had the proper spatial resolution to focus on the components emitting this kind of radiation. The results are now published in Nature Astronomy.

An optical image of the spiral galaxy NGC 1068 (Messier 77) overlaid with an insert with the image obtained by the Large Binocular Telescope Interferometer (LBTI) at thermal infrared wavelengths (8.7 micrometres). The false-colour image depicts the brightness variation of mostly warm dust surrounding the supermassive black hole in the centre of that galaxy. By comparing the image with previous observations at various wavelengths, the researchers identified the hot and bright disk of gas and dust and the collimated gas jet as their heat sources. The components identified in the image confirm the unified model of active galactic nuclei. © ESO / J. Isbell (UofA, MPIA) / MPIA

Disentangling the AGN components

The bright, hot disk surrounding the supermassive black hole emits an enormous amount of light that drives the dust apart as if the individual grains were tiny sails – a phenomenon known as radiation pressure. The images revealed the glowing dust, a warm, outflowing wind caused by that mechanism, which was heated by the hot central disk.

Simultaneously, farther out, much material is way brighter than it should have been if it was illuminated only by the bright accretion disk. By comparing the new images to past observations at various wavelengths, the researchers tied this finding to a collimated jet of hot gas emanating from the disk centre. While blasting through the galaxy, it hits and heats clouds of molecular gas and dust, leading to the unexpected bright infrared signal. Such jets are particularly bright at radio wavelengths when interacting with gas and particles in the environment around the supermassive black holes.

Altogether, the result confirms the so-called unified model of AGN. It promotes a configuration of a supermassive black hole in the centre of a galaxy, which attracts and collects gas and dust from the surrounding host galaxy, accumulating in an inner bright and hot disk. In addition, an outer, larger structure of cooler, outflowing material obstructs the view. Finally, a powerful gas jet is ejected from the centre. Different components are exposed to the observer, depending on the viewing angle. Although the observed features vary significantly between objects, the unified model proposes that those variations derive from intrinsically similar configurations of structures around the supermassive black hole, powering the AGN phenomenon.

View from the dome of the Large Binocular Telescope (LBT) through the open dome doors. In the foreground are the two large primary mirrors with the support structure for the secondary mirrors. © Marc-André Besel & Wiphu Rujopakarn

LBT – A precursor of future segmented-mirror telescopes

The LBT is located on Mount Graham, northeast of Tucson, USA, and operates its two 8.4-metre mirrors independently of each other, essentially functioning like two separate telescopes mounted side by side and aligned in parallel. MPIA is a member of the LBT Corporation via the LBT-Beteiligungsgesellschaft (holding company), which supplies 25% of all operations funding.

Combining the light from both mirrors, the LBT becomes an imaging interferometer (LBTI), allowing for approximately three times higher resolution observations than would be possible with each mirror on its own. To stabilize this high-resolution imaging machine, LBTI regularly deploys the OVMS+ vibration control system developed under MPIA leadership by MPIA’s Jörg-Uwe Pott to enable these challenging observations of distant galaxies. This imaging technique has been successfully employed to study volcanoes on the surface of Jupiter’s moon Io. The Jupiter results encouraged the researchers to use the interferometer to look now at an AGN.

“The AGN within the galaxy NGC 1068 is especially bright, so it was the perfect opportunity to test this method,” Isbell said. “These are the highest resolution direct images of an AGN taken so far.” In this context, direct images mean, they contain all faint and diffuse radiation from the structures observed. In contrast, images from other interferometers, such as the Very Large Telescope Interferometer (VLTI), are reconstructed from computations interpolating the missing imaging information.

Combining both mirrors produces images directly on the detector, very much like telescopes with segmented mirrors do, such as the James Webb Space Telescope, as well as the future 25-metre Giant Magellan Telescope (GMT) and the upcoming 39-metre Extremely Large Telescope (ELT), both being built in Chile. This way, Isbell and his collaborators produced the first ELT-like images of an AGN. As a result, the LBTI observations resolved individual features of up to 20 light-years at a distance of 47 million light-years. Previously, the various processes were blended due to low resolution, but now it is possible to view their individual impact.

A test for future observations

The study shows that the environments of AGN can be complex. The new findings help us understand the intricate ways in which AGN interact with their host galaxies. By probing distant galaxies in the early universe, when the galaxies were still young, we cannot achieve the same level of detail. Therefore, these results are like a local analogue.

“This type of imaging can be used on any astronomical object,” Isbell said. “We’ve already started looking at disks around stars and very large, evolved stars, which have dusty envelopes around them.”

Additional information

The MPIA team involved in this study comprised Jacob W. Isbell (now Steward Observatory, The University of Arizona, Tucson, USA) and Jörg-Uwe Pott.

Other researchers included Steve Ertel (Steward Observatory and Large Binocular Telescope Observatory, The University of Arizona, Tucson, USA), Gerd Weigelt (Max Planck Institute for Radio Astronomy, Bonn, Germany), and Marko Stalevski (Astronomical Observatory, Belgrade, Serbia and Sterrenkundig Observatorium, Universiteit Gent, Belgium).

This press release is based on the one published by the University of Arizona.

Source: Max Planck Institute for Astronomy/Press Releases

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Contacts:

Dr. Markus Nielbock
Press and outreach officer
+49 6221 528-134
pr@mpia.de
MPIA press department
Max Planck Institute for Astronomy, Heidelberg, Germany

Dr. Jacob W. Isbell
jwisbell@arizona.edu
Jacob Isbell / UofA
Steward Observatory, The University of Arizona, Tucson, AZ, USA

Dr. Jörg-Uwe Pott
+49 6221 528-202
jpott@mpia.de
Jörg-Uwe Pott / MPIA
Max Planck Institute for Astronomy, Heidelberg, Germany

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Original publication

Jacob W. Isbell, S. Ertel, J.-U. Pott et al.
Direct imaging of active galactic nucleus outflows and their origin with the 23 m Large Binocular Telescope
Nature Astronomy (2025)

Source | DOI

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Video

The Unified Model of active galactic nuclei
Credit: ESO/L. Calçada and M. Kornmesser

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Links

Nature Astronomy embargo policy
Ring of cosmic dust hides a supermassive black hole in Active Galactic Nucleus

February 16, 2022
Image of warm dust emission from the heart of an active galactic nucleus shows a ring-like structure that obscures the black hole

more

 

 

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Astronomers Discover Magnetic Loops Around Supermassive Black Hole

Artist concept of NGC1068, featuring its powerful black hole and accretion disc, and never before seen polarization in water masers outside of our galaxy. Credit: NSF/AUI/NSF NRAO/S.Dagnello - Hi-Res File

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For the first time, astronomers using the High Sensitivity Array — a multi-facility network supported by the U.S. National Science Foundation National Radio Astronomy Observatory — have observed evidence of magnetic filaments in the accretion disk surrounding a nearby galaxy’s supermassive black hole

NGC 1068 is a well-known, relatively nearby, bright galaxy with a supermassive black hole at its center. Despite its status as a popular target for astronomers, however, its accretion disk is obscured by thick clouds of dust and gas. A few light-years in diameter, the outer accretion disk is dotted by hundreds of distinct water maser sources that hinted for decades at deeper structures. Masers are distinct beacons of electromagnetic radiation that shine in microwave or radio wavelengths; in radio astronomy, water masers observed at a frequency of 22 GHz are particularly useful because they can shine through much of the dust and gas that obscures optical wavelengths.

Led by astronomer Jack Gallimore of Bucknell University, an international team of astronomers and students set out to observe NGC 1068 with twin goals in mind: astrometric mapping of the galaxy’s radio continuum and measurements of polarization for its water masers. “NGC 1068 is a bit of a VIP among active galaxies,” says co-author C. M. Violette Impellizzeri. “It is unusually powerful, with a black hole and an edge-on accretion disk. And because it is so nearby, it has been really, really well-studied in detail.” Gallimore and his team set out to look at NGC 1068 in a completely new way, however.

Observations of this nature relied upon the recently upgraded High Sensitivity Array (HSA), which consists of the NSF NRAO telescopes at the Karl G. Jansky Very Large Array, the Very Long Baseline Array, and the Green Bank Telescope networked together and fully supported by NSF NRAO. By measuring the polarization of water masers as well as the continuum of radio emissions from NGC 1068, the team generated a map revealing the compact radio source now known as NGC 1068* as well as mysterious extended structures of more faint emissions.

Mapping the astrometric distribution of NGC 1068 and its water masers revealed that they are spread along filaments of structure. “It really came out in these new observations, that these filaments of maser spots line up like beads on a string,” Gallimore summarized. The team was stunned to see that there’s a clear offset — a displacement angle — between the radio continuum showing the structures at the galaxy’s core and the locations of the masers themselves. “The configuration is unstable, so we are probably observing the source of a magnetically-launched outflow.”

HSA measurements of the polarization of these water masers revealed striking evidence of magnetic fields. “No one has ever seen polarization in water masers outside of our galaxy,” Gallimore emphasized. Similar to the looping structures seen on our Sun’s surface as prominences, the polarization pattern of these water masers clearly indicates that magnetic fields are also at the root of these light-year-scale structures as well. “Looking at the filaments, and seeing that the polarization vectors are perpendicular to them, that’s the key to confirming that they are magnetically driven structures. It’s exactly what you’d expect to see,” Gallimore summarizes.

Previous studies of the region hinted at patterns usually associated with magnetic fields, but such conclusions remained beyond the reach of observing technology until recently. “Only the HSA has the combination of resolution and sensitivity needed to map out magnetic fields using polarized light,” says Gallimore. Impellizzeri adds, “There have been a lot of upgrades that the NSF NRAO facilities have undergone. All of the telescopes have had significant improvements. And so one of the reasons we decided that it was worth redoing these observations, instead of just going back to the archive, was that we knew we would get much better data now.”

Their findings reveal evidence of a compact central radio source (the galaxy’s supermassive black hole), clear polarization of the water masers indicating structure within NGC 1068’s magnetic fields, and spectacular extended features across the continuum of radio frequencies. Together, these findings indicate that magnetic fields are the underlying drivers of these phenomena.

Plenty of mysteries remain, however. Within the radio continuum map, for instance, there is a diffuse, faint protrusion that the team nicknamed “the foxtail,” which extends northward from the central region.

Gallimore says, “We said to ourselves, when we set out to do this, ‘let’s see if we can really push the limits and get a good continuum as well as polarization data.’ And both of those goals succeeded. With the NSF NRAO High Sensitivity Array, we detected water megamaser polarization for the first time, and we also made a really amazing continuum map that we’re still trying to wrap our minds around.”

About NRAO

The National Radio Astronomy Observatory (NRAO) and the Green Bank Observatory (GBO) are major facilities of the U.S. National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

Source: National Radio Astronomy Observatory (NRAO)/News

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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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Contacts:

Nicolás Lira
Education and Public Outreach Coordinator
Joint ALMA Observatory, Santiago - Chile
Phone: +56 2 2467 6519
Cel: +56 9 9445 7726
Email: nicolas.lira@alma.cl

Naoko Inoue
EPO officer, ALMA Project
National Astronomical Observatory of Japan (NAOJ)
Email: naoko.inoue@nao.ac.jp

Bárbara Ferreira
ESO Public Information Officer
Garching bei München, Germany
Phone: +49 89 3200 6670
Email: pio@eso.org

Jill Malusky
Public Information Officer
NRAO
Phone: +1 304-456-2236
Email: jmalusky@nrao.edu

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Supermassive black hole caught hiding in a ring of cosmic dust

PR Image eso2203a

Galaxy Messier 77 and close-up view of its active centre 

 

PR Image eso2203b

A close-up view of Messier 77’s active galactic nucleus

 

PR Image eso2203c

Dazzling galaxy Messier 77

 

PR Image eso2203d

Artist’s impression of the active galactic nucleus of Messier 77

 

PR Image eso2203e

The active galaxy Messier 77 in the constellation of Cetus 

 

PR Image eso2203f

Wide-field image of the sky around Messier 77

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Video

PR Video eso2203b

Artist’s animation of the active galactic nucleus of Messier 77 

 

PR Video eso2203c

The Unified Model of active galactic nuclei

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The European Southern Observatory’s Very Large Telescope Interferometer (ESO’s VLTI) has observed a cloud of cosmic dust at the centre of the galaxy Messier 77 that is hiding a supermassive black hole. The findings have confirmed predictions made around 30 years ago and are giving astronomers new insight into “active galactic nuclei”, some of the brightest and most enigmatic objects in the universe.

Active galactic nuclei (AGNs) are extremely energetic sources powered by supermassive black holes and found at the centre of some galaxies. These black holes feed on large volumes of cosmic dust and gas. Before it is eaten up, this material spirals towards the black hole and huge amounts of energy are released in the process, often outshining all the stars in the galaxy.

Astronomers have been curious about AGNs ever since they first spotted these bright objects in the 1950s. Now, thanks to ESO’s VLTI, a team of researchers, led by Violeta Gámez Rosas from Leiden University in the Netherlands, have taken a key step towards understanding how they work and what they look like up close. The results are published today in Nature.

By making extraordinarily detailed observations of the centre of the galaxy Messier 77, also known as NGC 1068, Gámez Rosas and her team detected a thick ring of cosmic dust and gas hiding a supermassive black hole. This discovery provides vital evidence to support a 30-year-old theory known as the Unified Model of AGNs.

Astronomers know there are different types of AGN. For example, some release bursts of radio waves while others don’t; certain AGNs shine brightly in visible light, while others, like Messier 77, are more subdued. The Unified Model states that despite their differences, all AGNs have the same basic structure: a supermassive black hole surrounded by a thick ring of dust.

According to this model, any difference in appearance between AGNs results from the orientation at which we view the black hole and its thick ring from Earth. The type of AGN we see depends on how much the ring obscures the black hole from our view point, completely hiding it in some cases.

Astronomers had found some evidence to support the Unified Model before, including spotting warm dust at the centre of Messier 77. However, doubts remained about whether this dust could completely hide a black hole and hence explain why this AGN shines less brightly in visible light than others.

“The real nature of the dust clouds and their role in both feeding the black hole and determining how it looks when viewed from Earth have been central questions in AGN studies over the last three decades,” explains Gámez Rosas. “Whilst no single result will settle all the questions we have, we have taken a major step in understanding how AGNs work.”

The observations were made possible thanks to the Multi AperTure mid-Infrared SpectroScopic Experiment (MATISSE) mounted on ESO’s VLTI, located in Chile’s Atacama Desert. MATISSE combined infrared light collected by all four 8.2-metre telescopes of ESO’s Very Large Telescope (VLT) using a technique called interferometry. The team used MATISSE to scan the centre of Messier 77, located 47 million light-years away in the constellation Cetus.

“MATISSE can see a broad range of infrared wavelengths, which lets us see through the dust and accurately measure temperatures. Because the VLTI is in fact a very large interferometer, we have the resolution to see what’s going on even in galaxies as far away as Messier 77. The images we obtained detail the changes in temperature and absorption of the dust clouds around the black hole,” says co-author Walter Jaffe, a professor at Leiden University.

Combining the changes in dust temperature (from around room temperature to about 1200 °C) caused by the intense radiation from the black hole with the absorption maps, the team built up a detailed picture of the dust and pinpointed where the black hole must lie. The dust — in a thick inner ring and a more extended disc — with the black hole positioned at its centre supports the Unified Model. The team also used data from the Atacama Large Millimeter/submillimeter Array, co-owned by ESO, and the National Radio Astronomy Observatory’s Very Long Baseline Array to construct their picture.

“Our results should lead to a better understanding of the inner workings of AGNs,” concludes Gámez Rosas. “They could also help us better understand the history of the Milky Way, which harbours a supermassive black hole at its centre that may have been active in the past.”  

The researchers are now looking to use ESO’s VLTI to find more supporting evidence of the Unified Model of AGNs by considering a larger sample of galaxies.

Team member Bruno Lopez, the MATISSE Principal Investigator at the Observatoire de la Côte d’Azur in Nice, France, says: “Messier 77 is an important prototype AGN and a wonderful motivation to expand our observing programme and to optimise MATISSE to tackle a wider sample of AGNs."

ESO’s Extremely Large Telescope (ELT), set to begin observing later this decade, will also aid the search, providing results that will complement the team’s findings and allow them to explore the interaction between AGNs and galaxies.

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More Information

This research was presented in the paper “Thermal imaging of dust hiding the black hole in the Active Galaxy NGC 1068” (doi: 10.1038/s41586-021-04311-7) to appear in Nature.

The team is composed of Violeta Gámez Rosas (Leiden Observatory, Leiden University, Netherlands [Leiden]), Jacob W. Isbell (Max Planck Institute for Astronomy, Heidelberg, Germany [MPIA]), Walter Jaffe (Leiden), Romain G. Petrov (Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, France [OCA]), James H. Leftley (OCA), Karl-Heinz Hofmann (Max Planck Institute for Radio Astronomy, Bonn, Germany [MPIfR]), Florentin Millour (OCA), Leonard Burtscher (Leiden), Klaus Meisenheimer (MPIA), Anthony Meilland (OCA), Laurens B. F. M. Waters (Department of Astrophysics/IMAPP, Radboud University, the Netherlands; SRON, Netherlands Institute for Space Research, the Netherlands), Bruno Lopez (OCA), Stéphane Lagarde (OCA), Gerd Weigelt (MPIfR), Philippe Berio (OCA), Fatme Allouche (OCA), Sylvie Robbe-Dubois (OCA), Pierre Cruzalèbes (OCA), Felix Bettonvil (ASTRON, Dwingeloo, the Netherlands [ASTRON]), Thomas Henning (MPIA), Jean-Charles Augereau (Univ. Grenoble Alpes, CNRS, Institute for Planetary sciences and Astrophysics, France [IPAG]), Pierre Antonelli (OCA), Udo Beckmann (MPIfR), Roy van Boekel (MPIA), Philippe Bendjoya (OCA), William C. Danchi (NASA Goddard Space Flight Center, Greenbelt, USA), Carsten Dominik (Anton Pannekoek Institute for Astronomy, University of Amsterdam, The Netherlands [API]), Julien Drevon (OCA), Jack F. Gallimore (Department of Physics and Astronomy, Bucknell University, Lewisburg, Pennsylvania, USA), Uwe Graser (MPIA), Matthias Heininger (MPIfR), Vincent Hocdé (OCA), Michiel Hogerheijde (Leiden; API), Josef Hron (Department of Astrophysics, University of Vienna, Austria), Caterina M.V. Impellizzeri (Leiden), Lucia Klarmann (MPIA), Elena Kokoulina (OCA), Lucas Labadie (1st Institute of Physics, University of Cologne, Germany), Michael Lehmitz (MPIA), Alexis Matter (OCA), Claudia Paladini (European Southern Observatory, Santiago, Chile [ESO-Chile]), Eric Pantin (Centre d'Etudes de Saclay, Gif-sur-Yvette, France), Jörg-Uwe Pott (MPIA), Dieter Schertl (MPIfR), Anthony Soulain (Sydney Institute for Astronomy, University of Sydney, Australia [SIfA]), Philippe Stee (OCA), Konrad Tristram (ESO-Chile), Jozsef Varga (Leiden), Julien Woillez (European Southern Observatory, Garching bei München, Germany [ESO]), Sebastian Wolf (Institute for Theoretical Physics and Astrophysics, University of Kiel, Germany), Gideon Yoffe (MPIA), and Gerard Zins (ESO-Chile).

MATISSE was designed, funded and built in close collaboration with ESO, by a consortium composed of institutes in France (J.-L. Lagrange Laboratory — INSU-CNRS — Côte d’Azur Observatory — University of Nice Sophia-Antipolis), Germany (MPIA, MPIfR and University of Kiel), the Netherlands (NOVA and University of Leiden), and Austria (University of Vienna). The Konkoly Observatory and Cologne University have also provided some support in the manufacture of the instrument.

The European Southern Observatory (ESO) enables scientists worldwide to discover the secrets of the Universe for the benefit of all. We design, build and operate world-class observatories on the ground — which astronomers use to tackle exciting questions and spread the fascination of astronomy — and promote international collaboration in astronomy. Established as an intergovernmental organisation in 1962, today ESO is supported by 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’s headquarters and its visitor centre and planetarium, the ESO Supernova, are located close to Munich in Germany, while the Chilean Atacama Desert, a marvellous place with unique conditions to observe the sky, hosts our telescopes. ESO operates three observing sites: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its 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. Together with international partners, ESO operates APEX and ALMA on Chajnantor, two facilities that observe the skies in the millimetre and submillimetre range. At Cerro Armazones, near Paranal, we are building “the world’s biggest eye on the sky” — ESO’s Extremely Large Telescope. From our offices in Santiago, Chile we support our operations in the country and engage with Chilean partners and society.

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Contacts:

Violeta Gámez Rosas
Leiden University
Leiden, the Netherlands
Tel: +31 71 527 5737
Email: gamez@strw.leidenuniv.nl

Walter Jaffe
Leiden University
Leiden, the Netherlands
Tel: +31 71 527 5737
Email: jaffe@strw.leidenuniv.nl

Bruno Lopez
MATISSE Principal Investigator
Observatoire de la Côte d’ Azur, Nice, France
Tel: +33 4 92 00 30 11
Email: Bruno.Lopez@oca.eu

Romain Petrov
MATISSE Project Scientist
Observatoire de la Côte d’ Azur, Nice, France
Tel: +33 4 92 00 30 11
Email: Romain.Petrov@oca.eu

Bárbara Ferreira
ESO Media Manager
Garching bei München, Germany
Tel: +49 89 3200 6670
Cell: +49 151 241 664 00
Email: press@eso.org

Source: ESO/News

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Mini-Jet found near Milk Way's Supermassive Black Hole

This is a composite view of X-rays, molecular gas, and warm ionized gas near the galactic center. The graphic of a translucent, vertical white fan is added to show the suggested axis of a mini-jet from the supermassive black hole at the galaxy’s heart. The orange-colored features are of glowing hydrogen gas. One such feature, at the top tip of the jet is interpreted as a hydrogen cloud that has been hit by the outflowing jet. The jet scatters off the cloud into tendrils that flow northward. Farther down near the black hole are X-ray observations of superheated gas colored blue and molecular gas in green. These data are evidence that the black hole occasionally accretes stars or gas clouds, and ejects some of the superheated material along its spin axis. Credits: Science: NASA, ESA, Gerald Cecil (UNC-Chapel Hill). Image Precessing:Joseph DePasquale (STScI)

This schematic is based on multiwavelength observations of a suspected jet from the massive black hole at the center of our Milky Way galaxy. The wide view shows our galaxy edge-on, with two huge bubbles of plasma glowing in gamma-rays and X-rays. These are evidence for an explosive outburst from the black hole about 2 million years ago. Probing deep into the galaxy's core (inset), astronomers using the Hubble Space Telescope have captured a glowing cloud of hydrogen near the black hole. The interpretation is that the cloud is being hit by a narrow, columnated jet of material that was blasted out of the black hole merely 2,000 years ago. The black hole is still active, but on a smaller scale of energy output than previously known outbursts. When the jet slams into the hydrogen knot the outflow scatters into octopus-like tendrils that continue along a trajectory out of our galaxy. Credits: Illustration: NASA, ESA, Gerald Cecil (UNC-Chapel Hill), Dani Player (STScI)

The nearby barred-spiral galaxy NGC 1068 serves as a proxy for helping astronomers understand the fireworks taking place at the center of our Milky Way galaxy, driven by eruptions from a supermassive black hole. Because we live inside the Milky Way, much of our view of the galaxy’s center is blocked by intervening clouds of gas and dust. But, looking 45 million light-years away at NGC 1068 gives astronomers a birds-eye view of similar black hole outbursts. The inset Hubble Space Telescope image resolves hydrogen clouds as small as 10 light-years across within 150 light-years of the core. The clouds are glowing because they are caught in a "searchlight" of radiation beamed out of the galaxy's black hole, which is larger and more active than the black hole in the heart of our galaxy. Credits: Science: NASA, ESA, Alex Filippenko (UC Berkeley), William Sparks (STScI), Luis C. Ho (KIAA-PKU), Matthew A Malkan (UCLA), Alessandro Capetti (STScI). Image Processing: Alyssa Pagan (STScI).  Release Images

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Our Milky Way's central black hole has a leak. This supermassive black hole looks like it still has the vestiges of a blowtorch-like jet dating back several thousand years. NASA's Hubble Space Telescope hasn't photographed the phantom jet but has helped find circumstantial evidence that it is still pushing feebly into a huge hydrogen cloud and then splattering, like the narrow stream from a hose aimed into a pile of sand.

This is further evidence that the black hole, with a mass of 4.1 million Suns, is not a sleeping monster but periodically hiccups as stars and gas clouds fall into it. Black holes draw some material into a swirling, orbiting accretion disk where some of the infalling material is swept up into outflowing jets that are collimated by the black hole's powerful magnetic fields. The narrow "searchlight beams" are accompanied by a flood of deadly ionizing radiation.

"The central black hole is dynamically variable and is currently powered down," said Gerald Cecil of the University of North Carolina in Chapel Hill. Cecil pieced together, like a jigsaw puzzle, multiwavelength observations from a variety of telescopes that suggest the black hole burps out mini-jets every time it swallows something hefty, like a gas cloud. His multinational team's research has just been published in the Astrophysical Journal.

In 2013 evidence for a stubby southern jet near the black hole came from X-rays detected by NASA's Chandra X-ray Observatory and radio waves detected by the Jansky Very Large Array telescope in Socorro, New Mexico. This jet too appears to be plowing into gas near the black hole.

Cecil was curious if there was a northern counter-jet as well. He first looked at archival spectra of such molecules as methyl alcohol and carbon monosulfide from the ALMA Observatory in Chile (Atacama Large Millimeter/submillimeter Array), which uses millimeter wavelengths to peer through the veils of dust between us and the galactic core. ALMA reveals an expanding, narrow linear feature in molecular gas that can be traced for 15 light-years back towards the black hole.

By connecting the dots, Cecil next found in Hubble infrared-wavelength images a glowing, inflating bubble of hot gas that aligns to the jet at a distance of at least 35 light-years from the black hole. His team suggests that the black hole jet has plowed into it, inflating the bubble. These two residual effects of the fading jet are the only visual evidence of it impacting molecular gas.

As it blows through the gas the jet hits material and bends along multiple streams. "The streams percolate out of the Milky Way's dense gas disk," said co-author Alex Wagner of Tsukuba University in Japan. "The jet diverges from a pencil beam into tendrils, like that of an octopus." This outflow creates a series of expanding bubbles that extend out to at least 500 light-years. This larger "soap bubble" structure has been mapped at various wavelengths by other telescopes.

Wagner and Cecil next ran supercomputer models of jet outflows in a simulated Milky Way disk, which reproduced the observations. "Like in archeology, you dig and dig to find older and older artifacts until you come upon remnants of a grand civilization," said Cecil. Wagner's conclusion: "Our central black hole clearly surged in luminosity at least 1 millionfold in the last million years. That sufficed for a jet to punch into the Galactic halo."

Previous observations by Hubble and other telescopes found evidence that the Milky Way's black hole had an outburst about 2-4 million years ago. That was energetic enough to create an immense pair of bubbles towering above our galaxy that glow in gamma-rays. They were first discovered by NASA's Fermi Gamma-ray Space Telescope in 2010 and are surrounded by X-ray bubbles that were discovered in 2003 by the ROSAT satellite and mapped fully in 2020 by the eROSITA satellite.

Hubble ultraviolet-light spectra have been used to measure the expansion velocity and composition of the ballooning lobes. Hubble spectra later found that the burst was so powerful that it lit up a gaseous structure, called the Magellanic stream, at about 200,000 light-years from the galactic center. Gas is glowing from that event even today.

To get a better idea of what's going on, Cecil looked at Hubble and radio images of another galaxy with a black hole outflow. Located 47 million light-years away, the active spiral galaxy NGC 1068 has a string of bubble features aligned along an outflow from the very active black hole at its center. Cecil found that the scales of the radio and X-ray structures emerging from both NGC 1068 and our Milky Way are very similar. "A bow shock bubble at the top of the NGC 1068 outflow coincides with the scale of the Fermi bubble start in the Milky Way. NGC 1068 may be showing us what the Milky Way was doing during its major power surge several million years ago."

The residual jet feature is close enough to the Milky Way's black hole that it would become much more prominent only a few decades after the black hole powers up again. Cecil notes that "the black hole need only increase its luminosity by a hundredfold over that time to refill the jet channel with emitting particles. It would be cool to see how far the jet gets in that outburst. To reach into the Fermi gamma-ray bubbles would require that the jet sustain for hundreds of thousands of years because those bubbles are each 50,000 light years across!"

The anticipated images of the black hole's shadow made with the National Science Foundation's Event Horizon Telescope may reveal where and how the jet is launched.

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.

Credits:

Media Contact: 

Ray Villard
Space Telescope Science Institute, Baltimore, Maryland

Science Contact:

Gerald Cecil
University of North Carolina–Chapel Hill, Chapel Hill, North Carolina

Contact us: Direct inquiries to the News Team. 

 

Related links and Documents:

Science Paper: The science paper by G. Cecil et al., PDF (5.37 MB)
NASA's Hubble Portal
NASA Goddard's Video (on YouTube)

Source: HubbleSite/News

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How to Shape a Spiral Galaxy

Magnetic fields in NGC 1086, or M77, are shown as streamlines over a visible light and X-ray composite image of the galaxy from the Hubble Space Telescope, the Nuclear Spectroscopic Array, and the Sloan Digital Sky Survey. The magnetic fields align along the entire length of the massive spiral arms — 24,000 light years across (0.8 kiloparsecs) — implying that the gravitational forces that created the galaxy’s shape are also compressing the its magnetic field. This supports the leading theory of how the spiral arms are forced into their iconic shape known as “density wave theory.” SOFIA studied the galaxy using far-infrared light (89 microns) to reveal facets of its magnetic fields that previous observations using visible and radio telescopes could not detect. Credits: NASA/SOFIA; NASA/JPL-Caltech/Roma Tre Univ. Hi-res image

Our Milky Way galaxy has an elegant spiral shape with long arms filled with stars, but exactly how it took this form has long puzzled scientists. New observations of another galaxy are shedding light on how spiral-shaped galaxies like our own get their iconic shape.

Magnetic fields play a strong role in shaping these galaxies, according to research from the Stratospheric Observatory for Infrared Astronomy, or SOFIA. Scientists measured magnetic fields along the spiral arms of the galaxy called NGC 1068, or M77. The fields are shown as streamlines that closely follow the circling arms.

“Magnetic fields are invisible, but they may influence the evolution of a galaxy,” said Enrique Lopez-Rodriguez, a Universities Space Research Association scientist at the SOFIA Science Center at NASA’s Ames Research Center in California’s Silicon Valley. “We have a pretty good understanding of how gravity affects galactic structures, but we’re just starting to learn the role magnetic fields play.”

The M77 galaxy is located 47 million light years away in the constellation Cetus. It has a supermassive active black hole at its center that is twice as massive as the black hole at the heart of our Milky Way galaxy. The swirling arms are filled with dust, gas and areas of intense star formation called starbursts.

SOFIA’s infrared observations reveal what human eyes cannot: magnetic fields that closely follow the newborn-star-filled spiral arms. This supports the leading theory of how these arms are forced into their iconic shape known as “density wave theory.” It states that dust, gas and stars in the arms are not fixed in place like blades on a fan. Instead, the material moves along the arms as gravity compresses it, like items on a conveyor belt.

The magnetic field alignment stretches across the entire length of the massive, arms — approximately 24,000 light years across. This implies that the gravitational forces that created the galaxy’s spiral shape are also compressing its magnetic field, supporting the density wave theory. The results are published in the Astrophysical Journal. 

“This is the first time we’ve seen magnetic fields aligned at such large scales with current star birth in the spiral arms,” said Lopez-Rodriquez. “It’s always exciting to have observational evidence that supports theories.”

Celestial magnetic fields are notoriously difficult to observe. SOFIA’s newest instrument, the High-resolution Airborne Wideband Camera-Plus, or HAWC+, uses far-infrared light to observe celestial dust grains, which align perpendicular to magnetic field lines. From these results, astronomers can infer the shape and direction of the otherwise invisible magnetic field. Far-infrared light provides key information about magnetic fields because the signal is not contaminated by emission from other mechanisms, such as scattered visible light and radiation from high-energy particles. SOFIA’s ability to study the galaxy with far infrared light, specifically at the wavelength of 89 microns, revealed previously unknown facets of its magnetic fields.

Further observations are necessary to understand how magnetic fields influence the formation and evolution of other types of galaxies, such as those with irregular shapes.

SOFIA, the Stratospheric Observatory for Infrared Astronomy, is a Boeing 747SP jetliner modified to carry a 106-inch diameter telescope. It is a joint project of NASA and the German Aerospace Center, DLR. NASA’s Ames Research Center in California’s Silicon Valley manages the SOFIA program, science and mission operations in cooperation with the Universities Space Research Association headquartered in Columbia, Maryland, and the German SOFIA Institute (DSI) at the University of Stuttgart. The aircraft is maintained and operated from NASA’s Armstrong Flight Research Center Building 703, in Palmdale, California. The HAWC+ instrument was developed and delivered to NASA by a multi-institution team led by the Jet Propulsion Laboratory in Pasadena, California.

Media Contact


Felicia Chou
NASA Headquarters, Washington
202-358-0257
felicia.chou@nasa.gov

Editor: Kassandra Bell

Source: NASA/SOFIA

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Going Against the Flow Around a Supermassive Black Hole

Artist impression of the heart of galaxy NGC 1068, which harbors an actively feeding supermassive black hole, hidden within a thick doughnut-shaped cloud of dust and gas. ALMA discovered two counter-rotating flows of gas around the black hole. The colors in this image represent the motion of the gas: blue is material moving toward us, red is moving away. Credit: NRAO/AUI/NSF, S. Dagnello. Hi-Res File/Screensize File

ALMA image showing two disks of gas moving in opposite directions around the black hole in galaxy NGC 1068. The colors in this image represent the motion of the gas: blue is material moving toward us, red is moving away. The white triangles are added to show the accelerated gas that is expelled from the inner disk - forming a thick, obscuring cloud around the black hole. Credit: ALMA (ESO/NAOJ/NRAO), V. Impellizzeri; NRAO/AUI/NSF, S. Dagnello. Hi-Res File/Screensize File

Star chart showing the location of NGC 1068 (also known as Messier 77), a spiral galaxy approximately 47 million light-years from Earth in the direction of the constellation Cetus. Credit: IAU; Sky & Telescope magazine; NRAO/AUI/NSF, S. Dagnello. Hi-Res File/Screensize File

At the center of a galaxy called NGC 1068, a supermassive black hole hides within a thick doughnut-shaped cloud of dust and gas. When astronomers used the Atacama Large Millimeter/submillimeter Array (ALMA)

to study this cloud in more detail, they made an unexpected discovery that could explain why supermassive black holes grew so rapidly in the early Universe.

“Thanks to the spectacular resolution of ALMA, we measured the movement of gas in the inner orbits around the black hole,” explains Violette Impellizzeri of the National Radio Astronomy Observatory (NRAO), working at ALMA in Chile and lead author on a paper published in the Astrophysical Journal. “Surprisingly, we found two disks of gas rotating in opposite directions.”

Supermassive black holes already existed when the Universe was young – just a billion years after the Big Bang. But how these extreme objects, whose masses are up to billions of times the mass of the Sun, had time to grow in such a relatively short timespan, is an outstanding question among astronomers. This new ALMA discovery could provide a clue. “Counter-rotating gas streams are unstable, which means that clouds fall into the black hole faster than they do in a disk with a single rotation direction,” said Impellizzeri. “This could be a way in which a black hole can grow rapidly.”

NGC 1068 (also known as Messier 77) is a spiral galaxy approximately 47 million light-years from Earth in the direction of the constellation Cetus. At its center is an active galactic nucleus, a supermassive black hole that is actively feeding itself from a thin, rotating disk of gas and dust, also known as an accretion disk.

Previous ALMA observations revealed that the black hole is not only gulping down material, but also spewing out gas at incredibly high speeds – up to 500 kilometers per second (more than one million miles per hour). This gas that gets expelled from the accretion disk likely contributes to hiding the region around the black hole from optical telescopes.

Impellizzeri and her team used ALMA’s superior zoom lens ability to observe the molecular gas around the black hole. Unexpectedly, they found two counter-rotating disks of gas. The inner disk spans 2-4 light-years and follows the rotation of the galaxy, whereas the outer disk (also known as the torus) spans 4-22 light-years and is rotating the opposite way.

“We did not expect to see this, because gas falling into a black hole would normally spin around it in only one direction,” said Impellizzeri. “Something must have disturbed the flow, because it is impossible for a part of the disk to start rotating backward all on its own.”

Counter-rotation is not an unusual phenomenon in space. “We see it in galaxies, usually thousands of light-years away from their galactic centers,” explained co-author Jack Gallimore from Bucknell University in Lewisburg, Pennsylvania. “The counter-rotation always results from the collision or interaction between two galaxies. What makes this result remarkable is that we see it on a much smaller scale, tens of light-years instead of thousands from the central black hole.”

The astronomers think that the backward flow in NGC 1068 might be caused by gas clouds that fell out of the host galaxy, or by a small passing galaxy on a counter-rotating orbit captured in the disk.

At the moment, the outer disk appears to be in a stable orbit around the inner disk. “That will change when the outer disk begins to fall onto the inner disk, which may happen after a few orbits or a few hundred thousand years. The rotating streams of gas will collide and become unstable, and the disks will likely collapse in a luminous event as the molecular gas falls into the black hole. Unfortunately, we will not be there to witness the fireworks,” said Gallimore.

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

Source: National Radio Astronomy Observatory (NRAO)/News

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Contact:

Iris Nijman
Interim Public Information Officer for ALMA
alma-pr@nrao.edu

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Reference:

“Counter-Rotation and High Velocity Outflow in the Parsec-Scale Molecular Torus of NGC 1068,” C. M. Violette Impellizzeri et. al., the Astrophysical Journal. DOI: 10.3847/2041-8213/ab3c64

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 Ministry of Science and Technology (MOST) 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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