Wednesday, November 06, 2024

NASA's Hubble, Webb Probe Surprisingly Smooth Disk Around Vega

Credits/Image: NASA, ESA, CSA, STScI, S. Wolff (University of Arizona), K. Su (University of Arizona), A. Gáspár (University of Arizona)

Credits/Image: NASA, ESA, STScI, S. Wolff (University of Arizona)

Vega Webb Compass Image
Credits/Image: NASA, ESA, CSA, STScI, K. Su (University of Arizona), A. Gáspár (University of Arizona)



In the 1997 movie "Contact," adapted from Carl Sagan's 1985 novel, the lead character scientist Ellie Arroway (played by actor Jodi Foster) takes a space-alien-built wormhole ride to the star Vega. She emerges inside a snowstorm of debris encircling the star – but no obvious planets are visible.

It looks like the filmmakers got it right.

A team of astronomers at the University of Arizona, Tucson used NASA's Hubble and James Webb space telescopes for an unprecedented in-depth look at the nearly 100-billion-mile-diameter debris disk encircling Vega. "Between the Hubble and Webb telescopes, you get this very clear view of Vega. It's a mysterious system because it's unlike other circumstellar disks we've looked at," said Andras Gáspár of the University of Arizona, a member of the research team. "The Vega disk is smooth, ridiculously smooth."

The big surprise to the research team is that there is no obvious evidence for one or more large planets plowing through the face-on disk like snow tractors. "It's making us rethink the range and variety among exoplanet systems," said Kate Su of the University of Arizona, lead author of the paper presenting the Webb findings.

Webb sees the infrared glow from a disk of particles the size of sand swirling around the sizzling blue-white star that is 40 times brighter than our Sun. Hubble captures an outer halo of this disk, with particles no bigger than the consistency of smoke that are reflecting starlight.

The distribution of dust in the Vega debris disk is layered because the pressure of starlight pushes out the smaller grains faster than larger grains. "Different types of physics will locate different-sized particles at different locations," said Schuyler Wolff of the University of Arizona team, lead author of the paper presenting the Hubble findings. "The fact that we're seeing dust particle sizes sorted out can help us understand the underlying dynamics in circumstellar disks."

The Vega disk does have a subtle gap, around 60 AU (astronomical units) from the star (twice the distance of Neptune from the Sun), but otherwise is very smooth all the way in until it is lost in the glare of the star. This shows that there are no planets down at least to Neptune-mass circulating in large orbits, as in our solar system, say the researchers.

Disk Diversity

Newly forming stars accrete material from a disk of dust and gas that is the flattened remnant of the cloud from which they are forming. In the mid-1990s Hubble found disks around many newly forming stars. The disks are likely sites of planet formation, migration, and sometimes destruction. Fully matured stars like Vega have dusty disks enriched by ongoing "bumper car" collisions among orbiting asteroids and debris from evaporating comets. These are primordial bodies that can survive up to the present 450-million-year age of Vega (our Sun is approximately ten times older than Vega). Dust within our solar system (seen as the Zodiacal light) is also replenished by minor bodies ejecting dust at a rate of about 10 tons per second. This dust is shoved around by planets. This provides a strategy for detecting planets around other stars without seeing them directly – just by witnessing the effects they have on the dust.

"Vega continues to be unusual," said Wolff. "The architecture of the Vega system is markedly different from our own solar system where giant planets like Jupiter and Saturn are keeping the dust from spreading the way it does with Vega."

For comparison, there is a nearby star, Fomalhaut, which is about the same distance, age and temperature as Vega. But Fomalhaut's circumstellar architecture is greatly different from Vega's. Fomalhaut has three nested debris belts.

Planets are suggested as shepherding bodies around Fomalhaut that gravitationally constrict the dust into rings, though no planets have been positively identified yet. "Given the physical similarity between the stars of Vega and Fomalhaut, why does Fomalhaut seem to have been able to form planets and Vega didn't?" said team member George Rieke of the University of Arizona, a member of the research team. "What's the difference? Did the circumstellar environment, or the star itself, create that difference? What's puzzling is that the same physics is at work in both," added Wolff.

First Clue to Possible Planetary Construction Yards

Located in the summer constellation Lyra, Vega is one of the brightest stars in the northern sky. Vega is legendary because it offered the first evidence for material orbiting a star – presumably the stuff for making planets – as potential abodes of life. This was first hypothesized by Immanuel Kant in 1775. But it took over 200 years before the first observational evidence was collected in 1984. A puzzling excess of infrared light from warm dust was detected by NASA's IRAS (Infrared Astronomy Satellite). It was interpreted as a shell or disk of dust extending twice the orbital radius of Pluto from the star.

In 2005 NASA's infrared Spitzer Space Telescope mapped out a ring of dust around Vega . This was further confirmed by observations using submillimeter telescopes including Caltech's Submillimeter Observatory on Mauna Kea, Hawaii, and also the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, and ESA's (European Space Agency's) Herschel Space Telescope, but none of these telescopes could see much detail. "The Hubble and Webb observations together provide so much more detail that they are telling us something completely new about the Vega system that nobody knew before," said Rieke.

Two papers from the Arizona team will be published in The Astrophysical Journal.

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 CSA (Canadian Space Agency).

The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble 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 and mission operations. Lockheed Martin Space, based in Denver, Colorado, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, Maryland, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.




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Space Telescope Science Institute, Baltimore, Maryland

Christine Pulliam
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Tuesday, November 05, 2024

eROSITA unveils asymmetries in temperature and shape of our Local Hot Bubble

3D model of the solar neighbourhood. The colour bar represents the temperature of the LHB as coloured on the LHB surface. The direction of the Galactic Centre (GC) and Galactic North (N) is shown in the bottom right. The link to the interactive version can be found at the bottom of the page. © Michael Yeung / MPE


Our Solar System dwells in a low-density environment called the Local Hot Bubble (LHB), filled by a tenuous, million-degree hot gas emitting dominantly in soft X-rays. A team led by scientists at the Max Planck Institute for Extraterrestrial Physics (MPE) used the eROSITA All-Sky Survey data and found a large-scale temperature gradient in this bubble, possibly linked with past supernova explosions that expanded and reheated the bubble. The wealth of the eROSITA data also allowed the team to create a new 3D model of the hot gas in the solar neighbourhood. The highlight of this work features the discovery of a new interstellar tunnel towards the constellation Centaurus, potentially joining our LHB with a neighbouring superbubble.

The idea of the Local Hot Bubble has been around for about half a century, first developed to explain the ubiquitous X-ray background below 0.2 keV. Photons of such energies cannot travel very far in the interstellar medium before they are absorbed. In conjunction with the observation that there is almost no interstellar dust in our immediate environment, the scenario where a soft X-ray emitting plasma displaces the neutral materials in the solar neighbourhood, forming the ‘Local Hot Bubble’, was put forth.

This understanding of our immediate environment was not without its challenges, especially after the discovery of the solar wind charge exchange process in 1996 — an interaction between the solar wind ions and neutral atoms within the Earth’s geocorona and the heliosphere that emits X-rays at similar energies as the LHB. After years of analysis, the consensus now is that both contribute to the soft X-ray background, and the LHB must exist to explain the observations.

The eROSITA telescope is the first X-ray observatory to observe the sky from an orbit completely external to the Earth’s geocorona, avoiding the latter’s contamination. Also, the timing of the first eROSITA All-Sky Survey (eRASS1) coincided with the solar minimum, significantly reducing the heliospheric solar wind charge exchange contamination. ‘In other words, the eRASS1 data released to the public this year provides the cleanest view of the X-ray sky to date, making it the perfect instrument for studying the LHB, ‘says Michael Yeung from MPE, the lead author of this work.

3D structure of the LHB with colours indicating its temperature. The two surfaces indicate the measurement uncertainty of the LHB extent: the most probable extent most likely lies between the two. The location of the Sun and a sphere of 100 parsec radius are marked for comparison. © Michael Yeung / MPE

eROSITA’s Unparalleled X-ray Observations

The team divided the western Galactic hemisphere into about 2000 regions, and extracted and analysed the spectra from each one. They also leveraged data from ROSAT, the predecessor of eROSITA built also by MPE, which complements the eROSITA spectra at energies lower than 0.2 keV. They found a clear temperature dichotomy in the LHB, with the Galactic South (0.12 keV; 1.4 MK) slightly hotter than the Galactic North (0.10 keV; 1.2 MK). This feature could be explained by the latest numerical simulations of the LHB caused by supernova explosions in the last few million years.

Diffuse X-ray background spectra inform scientists not just of the temperature but also of the 3D structure of the hot gas. Previous work by the same team has established that the density of the LHB is relatively uniform, calibrating the density of the hot gas with sight lines to giant molecular clouds located on the surface of the LHB. Relying on this assumption, they generated a new 3D model of the LHB from the measured intensity of the LHB emission in each sight line. They found the LHB has a larger extent towards the Galactic poles as expected, as the hot gas prefers to expand towards directions of the least resistance, away from the Galactic disc.

‘This is not surprising, as was already found by the ROSAT survey’, pointed out by Michael Freyberg, a core author of this work and was a part of the pioneering work in the ROSAT era three decades ago. ‘What we didn’t know was the existence of an interstellar tunnel towards Centaurus, which carves a gap in the cooler interstellar medium (ISM). This region stands out in stark relief thanks to the much-improved sensitivity of eROSITA and a vastly different surveying strategy compared to ROSAT,’ added Freyberg. The authors of this work suggest the Centaurus tunnel may just be a local example of a wider hot ISM network sustained by stellar feedback across the Galaxy — a popular idea proposed in the 70s that remains difficult to prove.

Temperature map of the LHB in the western Galactic hemisphere in zenithal equal-area projection. The high-latitude region in the northern and southern hemispheres exhibits a clear temperature dichotomy. © Michael Yeung / MPE

A 3D Model of the Solar Neighbourhood

In addition to the 3D LHB model, the team compiled a list of known supernova remnants, superbubbles, and 3D dust information from the literature and created an interactive 3D model of the solar neighbourhood. Some features of the LHB could be easily appreciated from such representation, for instance, the well-known Canis Majoris tunnel on the Galactic disc, possibly connecting the LHB to the Gum nebula or another superbubble (called GSH238+00+09), as well as dense molecular clouds (in orange) lying close to the surface of the LHB in the direction of the Galactic Centre (GC). Recent works found that these clouds possess velocities in the radial direction (away from us). The location and the velocity of the clouds could be explained if they were formed from the condensation of swept-up materials during the early stage of the LHB formation. ‘Another interesting fact is that the Sun must have entered the LHB a few million years ago, a short time compared to the age of the Sun, remarked Gabriele Ponti, a co-author of this work. ‘It is purely coincidental that the Sun seems to occupy a relatively central position in the LHB as we continuously move through the Milky Way.’

3D interactive view of the LHB and the solar neighbourhood




Contacts:

Michael Yeung
PhD Student Highenergy-Group
tel:+49 89 30000-3899

mjf@mpe.mpg.de
Max Planck Institute for Extraterrestrial Physics

Dr. Michael Freyberg
Scientist Highenergy Group
tel:+49 89 30000-3849

myeung@mpe.mpg.de
Max Planck Institute for Extraterrestrial Physics

Dr. Gabriele Ponti
Visiting Scientist Highenergy Group
tel:+49 89 30000-3572

ponti@mpe.mpg.de
Max Planck Institute for Extraterrestrial Physics

Dr. Andrea Merloni
Senior Scientist Highenergy Group; PI eROSITA
tel:+49 89 30000-3893

am@mpe.mpg.de
Max Planck Institute for Extraterrestrial Physics



Original Publication

M. C. H. Yeung, G. Ponti, M. J. Freyberg et al.
The SRG/eROSITA diffuse soft X-ray background. I. The local hot bubble in the western Galactic hemisphere
A&A, 690, A399


Source



Further Information

eROSITA website of the MPE

eROSITA finds hot gas all around the Milky Way – closer than expected

December 14, 2023
A new all-sky map by the eROSITA telescope reveals X-rays emitted by million-degree hot plasma in and around the Milky Way. This discovery sheds light on the shape and size of a large portion of the Milky Way circumgalactic medium, providing a large reservoir of gas to fuel future star formation.

Massive black holes in low-mass galaxies: what happened to the X-ray Corona?

June 11, 2024
Identifying massive black holes in low-mass galaxies is crucial for understanding black hole formation and growth over cosmic time but challenging due to their low accretion luminosities. Astronomers at MPE, led by Riccardo Arcodia, used the eROSITA X-ray telescope's all-sky survey to study massive black hole candidates selected based on variability in other wavelength ranges.

The X-ray sky opens to the world

January 31, 2024
First eROSITA sky-survey data release makes public the largest ever catalogue of high-energy cosmic sources



Monday, November 04, 2024

Planets Beware: NASA Unburies Danger Zones of Star Cluster

Cygnus OB2

Credit X-ray: NASA/CXC/SAO/J. Drake et al, IR: NASA/JPL-Caltech/Spitzer; Image Processing: NASA/CXC/SAO/N. Wolk

JPEG (697.3 kb) - Large JPEG (14.3 MB) - Tiff (24 MB - More Images

A Tour of 3C 58 - More Videos



Most stars form in collections, called clusters or associations, that include very massive stars. These giant stars send out large amounts of high-energy radiation, which can disrupt relatively fragile disks of dust and gas that are in the process of coalescing to form new planets.

A team of astronomers used NASA’s Chandra X-ray Observatory, in combination with ultraviolet, optical, and infrared data, to show where some of the most treacherous places in a star cluster may be, where planets’ chances to form are diminished.

The target of the observations was Cygnus OB2, which is the nearest large cluster of stars to our Sun — at a distance of about 4,600 light-years. The cluster contains hundreds of massive stars as well as thousands of lower-mass stars. The team used long Chandra observations pointing at different regions of Cygnus OB2, and the resulting set of images were then stitched together into one large image.

The deep Chandra observations mapped out the diffuse X-ray glow in between the stars, and they also provided an inventory of the young stars in the cluster. This inventory was combined with others using optical and infrared data to create the best census of young stars in the cluster.

In this new composite image, the Chandra data (purple) shows the diffuse X-ray emission and young stars in Cygnus OB2, and infrared data from NASA’s now-retired Spitzer Space Telescope (red, green, blue, and cyan) reveals young stars and the cooler dust and gas throughout the region.
In these crowded stellar environments, copious amounts of high-energy radiation produced by stars and planets are present. Together, X-rays and intense ultraviolet light can have a devastating impact on planetary disks and systems in the process of forming.

Planet-forming disks around stars naturally fade away over time. Some of the disk falls onto the star and some is heated up by X-ray and ultraviolet radiation from the star and evaporates in a wind. The latter process, known as “photoevaporation,” usually takes between 5 and 10 million years with average-sized stars before the disk disappears. If massive stars, which produce the most X-ray and ultraviolet radiation, are nearby, this process can be accelerated.

The researchers using this data found clear evidence that planet-forming disks around stars indeed disappear much faster when they are close to massive stars producing a lot of high-energy radiation. The disks also disappear more quickly in regions where the stars are more closely packed together.

For regions of Cygnus OB2 with less high-energy radiation and lower numbers of stars, the fraction of young stars with disks is about 40%. For regions with more high-energy radiation and higher numbers of stars, the fraction is about 18%. The strongest effect — meaning the worst place to be for a would-be planetary system — is within about 1.6 light-years of the most massive stars in the cluster.

A separate study by the same team examined the properties of the diffuse X-ray emission in the cluster. They found that the higher-energy diffuse emission comes from areas where winds of gas blowing away from massive stars have collided with each other. This causes the gas to become hotter and produce X-rays. The less energetic emission probably comes from gas in the cluster colliding with gas surrounding the cluster.

Two separate papers describing the Chandra data of Cygnus OB2 are available. The paper about the planetary danger zones, led by Mario Giuseppe Guarcello (National Institute for Astrophysics in Palermo, Italy), appeared in the November 2023 issue of the Astrophysical Journal Supplement Series, and is available here. The paper about the diffuse emission, led by Juan Facundo Albacete-Colombo (University of Rio Negro in Argentina) was published in the same issue of Astrophysical Journal Supplement, and is available here.

NASA's Marshall Space Flight Center in Huntsville, Alabama, 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.

JPL managed the Spitzer Space Telescope mission for NASA’s Science Mission Directorate in Washington until the mission was retired in January 2020. Science operations were conducted at the Spitzer Science Center at Caltech. Spacecraft operations were based at Lockheed Martin Space in Littleton, Colorado. Data are archived at the Infrared Science Archive operated by IPAC at Caltech. Caltech manages JPL for NASA.






Visual Description:

This release features a composite image of the Cygnus OB2 star cluster, which resembles a night sky blanketed in orange, purple, and grey clouds.

The center of the square image is dominated by purple haze. This haze represents diffuse X-ray emissions, and young stars, detected by the Chandra X-ray observatory. Surrounding the purple haze is a mottled, streaky, brick orange cloud. Another cloud resembling a tendril of grey smoke stretches from our lower left to the center of the image. These clouds represent relatively cool dust and gas observed by the Spitzer Space Telescope.

Although the interwoven clouds cover most of the image, the thousands of stars within the cluster shine through. The lower-mass stars present as tiny specks of light. The massive stars gleam, some with long refraction spikes.



Fast Facts for Cygnus OB2:

Scale: Image is about 1.5 arcmin (120 light-years) across.
Category: Normal Stars & Star Clusters
Coordinates (J2000): RA 20h 33m 12s | Dec +41° 19´ 00"
Constellation: Cygnus
Observation Dates: 40 pointings between January 2004 and March 2010
Observation Time: 331 hours 30 minutes (13 days 19 hours 30 minutes)
Obs. ID: 4501, 4511, 7426, 10939-10974, 12099
Instrument: ACIS
References: Guarcell, M.G. et al, 2023, ApJS, 269, 13; Albacete-Colombo, J.F. et al, 2023, ApJS, 269, 14.
Color Code: X-ray: purple; Infrared (IRAC): red, green, blue; Infrared (MIPS): cyan;
Distance Estimate: About 4,600 light-years


Sunday, November 03, 2024

Catching the edge of the Phantom Galaxy (NIRCam and MIRI image)

A large spiral galaxy takes up the entirety of the image. The core is mostly bright white, but there are also swirling, detailed structures that resemble water circling a drain. There is small white and pale blue light that emanates from stars and dust at the core’s centre, but it is tightly limited to the core. The rings feature colours of deep red and orange and highlight filaments of dust around cavernous black bubbles.

In August 2022, to mark the launch of the Picture of the Month series, ESA/Webb published a stunning image of the Phantom Galaxy (also known as M74 and NGC 628). Now, this series is revisiting the target to feature new data on this iconic spiral galaxy.

M74 resides around 32 million light-years away from Earth in the constellation Pisces, and lies almost face-on to Earth. This, coupled with its well-defined spiral arms, makes it a favourite target for astronomers studying the origin and structure of galactic spirals.

This image features data from two of Webb’s instruments: MIRI (Mid-InfraRed Instrument) and NIRCam (Near-InfraRed Camera). Observations in the infrared reveal the galaxy’s creeping tendrils of gas, dust and stars. In this image the dark red regions trace the filamentary warm dust permeating the galaxy. The red regions show the reprocessed light from complex molecules forming on dust grains, while orange and yellow colours reveal the regions of gas ionised by the recently formed star clusters. Stellar feedback has a dramatic effect on the medium within the galaxy and creates a complex network of bright knots as well as cavernous black bubbles. The lack of gas in the nuclear region of this galaxy also provides an unobscured view of the nuclear star cluster at the galaxy's centre. M74 is a particular class of spiral galaxy known as a ‘grand design spiral’, meaning that its spiral arms are prominent and well-defined, unlike the patchy and ragged structure seen in some spiral galaxies.

M74 was observed by Webb as part of a series of observations collectively entitled Feedback in Emerging extrAgalactic Star clusTers, or FEAST (PI: A. Adamo). Many other targets of the FEAST programme, including NGC 4449, M51, and M83, were the subjects of previous ESA/Webb Picture of the Month images in 2023 and 2024. The FEAST observations were designed to shed light on the interplay between stellar feedback and star formation in environments outside the Milky Way galaxy. Stellar feedback is the term used to describe the outpouring of energy from stars into the environments which form them, and is a process that contributes significantly to determining the rates at which stars form. Understanding stellar feedback is vital for building accurate universal models of star formation.

The new Webb data obtained by the FEAST team has allowed scientists to look at the stellar nurseries in galaxies that are many light years away. Astronomers are learning how other galaxies are forming stars and how stars actively participate to model the galaxy interstellar medium. They have found that newly born stars slowly carve they gas and dust nurseries modifying the morphological appearance and essentially destructing them, as Webb has shown that this evolution is connected with star clusters. Furthermore, the team has concluded from their studies that the spiral arms captured by the extended coverage of the FEAST programme are the places where stars are forming more actively in the galaxy. The brighter and larger complexes of stellar nurseries are in the spiral arms fully captured by the new Webb data. The telescope is now revealing the map of hydrogen emission lines in the near-infrared. These lines are less affected than the dusts and reveals the places where new massive stars have just formed.

Links

Polar Ring Galaxy NGC 660


NGC 660 is a polar ring galaxy located in the constellation Pisces. It features a large, extended ring structure surrounding the central spiral galaxy at a near-perpendicular angle. The ring emits blue light from active star-forming regions within it. The dark lanes in the ring and the galactic disk intersect, highlighting its complicated structure. This ring structure is thought to have been formed through the gravitational interaction of the central galaxy with another galaxy.

Distance from Earth: About 44 million light-years
Instrument: Hyper Suprime-Cam (HSC)



Saturday, November 02, 2024

A galactic rejuvenation

Astronomers observing the galaxy NGC 1386, located 53 million light-years away, have discovered a unique pattern of star formation. Using data from the VLT Survey Telescope, ALMA, and other instruments, they found a central blue ring filled with young stars that all formed nearly simultaneously 4 million years ago—a rare synchronized event for a galaxy with mostly older stars. Also, ALMA data revealed gas clouds forming a golden ring, suggesting a new wave of star formation may begin in about 5 million years. Credit: ESO/ALMA (ESO/NAOJ/NRAO)/A. Prieto et al./Fornax Deep Survey. Crdit: ESO/ALMA (ESO/NAOJ/NRAO)/A. Prieto et al./Fornax Deep Survey

Something odd is happening in NGC 1386, a spiral galaxy located 53 million light-years away in Eridanus's constellation. This Picture combines data from the Atacama Large Millimetre/Submillimetre Array (ALMA) and the VLT Survey Telescope (VST), hosted at ESO’s Paranal Observatory in Chile. When astronomers observed the central regions of this galaxy, they found new stars forming… albeit in a peculiar way.

Stars often form within stellar clusters – groups of thousands of stars that originate from massive clouds of molecular gas. The blue ring at the center of this galaxy is ripe with stellar clusters full of young stars, as seen by VST. A new study led by Almudena Prieto, an astronomer at the Instituto de Astrofísica de Canarias in Spain, used data from ESO’s Very Large Telescope (VLT) and the NASA/ESA Hubble Space Telescope to look at this ring in more detail. The data shows that all these star clusters formed almost simultaneously 4 million years ago. It is the first time synchronized star formation has been observed in a galaxy mainly containing old stars.

The same study used ALMA to reveal even more secrets in this galaxy. Shown in this picture as a golden ring is a multitude of gas clouds, ready to form a second batch of young stars. However, we will still have to wait 5 million years for these to be born. Even if old, NGC 1386 keeps rejuvenating itself.

Scienfic Paper



Additional Information

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 US 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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Education and Public Outreach Coordinator
Joint ALMA Observatory, Santiago - Chile
Phone:
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Email: nicolas.lira@alma.cl

Juan Carlos Muñoz Mateos
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Garching bei München, Germany
Phone: +49 89 3200 6176
Email:
press@eso.org


Friday, November 01, 2024

'Blood-Soaked' Eyes: NASA's Webb, Hubble Examine Galaxy Pair

Galaxies IC 2163 and NGC 2207 (Webb and Hubble Image)
Credits/Image: NASA, ESA, CSA, STScI

Galaxies IC 2163 and NGC 2207 (Webb MIRI Image)
Credits/Image: NASA, ESA, CSA, STScI




Stare deeply at these galaxies. They appear as if blood is pumping through the top of a flesh-free face. The long, ghastly “stare” of their searing eye-like cores shines out into the supreme cosmic darkness.

It’s good fortune that looks can be deceiving.

These galaxies have only grazed one another to date, with the smaller spiral on the left, cataloged as IC 2163, ever so slowly “creeping” behind NGC 2207, the spiral galaxy at right, millions of years ago.

The pair’s macabre colors represent a combination of mid-infrared light from NASA’s James Webb Space Telescope with visible and ultraviolet light from NASA’s Hubble Space Telescope.

Look for potential evidence of their “light scrape” in the shock fronts, where material from the galaxies may have slammed together. These lines represented in brighter red, including the “eyelids,” may cause the appearance of the galaxies’ bulging, vein-like arms.

The galaxies’ first pass may have also distorted their delicately curved arms, pulling out tidal extensions in several places. The diffuse, tiny spiral arms between IC 2163’s core and its far left arm may be an example of this activity. Even more tendrils look like they’re hanging between the galaxies’ cores. Another extension “drifts” off the top of the larger galaxy, forming a thin, semi-transparent arm that practically runs off screen.

Both galaxies have high star formation rates, like innumerable individual hearts fluttering all across their arms. Each year, the galaxies produce the equivalent of two dozen new stars that are the size of the Sun. Our Milky Way galaxy only forms the equivalent of two or three new Sun-like stars per year. Both galaxies have also hosted seven known supernovae in recent decades, a high number compared to an average of one every 50 years in the Milky Way. Each supernova may have cleared space in their arms, rearranging gas and dust that later cooled, and allowed many new stars to form.

To spot the star-forming “action sequences,” look for the bright blue areas captured by Hubble in ultraviolet light, and pink and white regions detailed mainly by Webb’s mid-infrared data. Larger areas of stars are known as super star clusters. Look for examples of these in the top-most spiral arm that wraps above the larger galaxy and points left. Other bright regions in the galaxies are mini starbursts — locations where many stars form in quick succession. Additionally, the top and bottom “eyelid” of IC 2163, the smaller galaxy on the left, is filled with newer star formation and burns brightly.

What’s next for these spirals? Over many millions of years, the galaxies may swing by one another repeatedly. It’s possible that their cores and arms will meld, leaving behind completely reshaped arms, and an even brighter, cyclops-like “eye” at the core. Star formation will also slow down once their stores of gas and dust deplete, and the scene will calm.

Want to “pull apart” these images? Examine the galaxies’ skeleton-like appearance in Webb’s mid-infrared image, and compare the Hubble and Webb images side by side.

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 CSA (Canadian Space Agency).

The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble 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 and mission operations. Lockheed Martin Space, based in Denver, Colorado, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, Maryland, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.




About This Release

Credits:

Media Contact:

Claire Blome
Space Telescope Science Institute, Baltimore, Maryland

Christine Pulliam
Space Telescope Science Institute, Baltimore, Maryland


Permissions: Content Use Policy

Contact Us: Direct inquiries to the News Team.

Related Links and Documents



Revisiting an old beauty

A large spiral galaxy is seen tilted diagonally. The arms of the galaxy’s disc are speckled with glowing patches; some are blue in colour, others are pink, showing gas illuminated by new stars. A faint glow surrounds the galaxy, which lies on a dark, nearly empty background. The galaxy's centre glows in white.

This image from the NASA/ESA Hubble Space Telescope unbarred spiral galaxy roughly 51 million light-years away from Earth in the constellation Coma Berenices.

You can see an old image of NGC 4414 that features Hubble data from 1995 and 1999 here, which was captured as one of the telescope’s primary missions to determine the distance to galaxies. This was achieved as part of an ongoing research effort to study Cepheid variable stars. Cepheids are a special type of variable star with very stable and predictable brightness variations. The period of these variations depends on physical properties of the stars such as their mass and true brightness. This means that astronomers, just by looking at the variability of their light, can find out about the Cepheids' physical nature, which then can be used very effectively to determine their distance. For this reason cosmologists call Cepheids 'standard candles'.

Astronomers have used Hubble to observe Cepheids, like those that reside in NGC 4414, with extraordinary results. The Cepheids have then been used as stepping-stones to make distance measurements for supernovae, which have, in turn, given a measure for the scale of the Universe. Today we know the age of the Universe to a much higher precision than before Hubble: around 13.7 billion years.

Links

Thursday, October 31, 2024

New ESO image captures a dark wolf in the sky

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The Dark Wolf Nebula

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Highlights of the Dark Wolf Nebula

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The Dark Wolf Nebula in the constellation Scorpius



Videos

Panning across the Dark Wolf Nebula
PR Video eso2416a
Panning across the Dark Wolf Nebula



For Halloween, the European Southern Observatory (ESO) reveals this spooktacular image of a dark nebula that creates the illusion of a wolf-like silhouette against a colourful cosmic backdrop. Fittingly nicknamed the Dark Wolf Nebula, it was captured in a 283-million-pixel image by the VLT Survey Telescope (VST) at ESO’s Paranal Observatory in Chile.

Found in the constellation Scorpius, near the centre of the Milky Way on the sky, the Dark Wolf Nebula is located around 5300 light-years from Earth. This image takes up an area in the sky equivalent to four full Moons, but is actually part of an even larger nebula called Gum 55. If you look closely, the wolf could even be a werewolf, its hands ready to grab unsuspecting bystanders…

If you thought that darkness equals emptiness, think again. Dark nebulae are cold clouds of cosmic dust, so dense that they obscure the light of stars and other objects behind them. As their name suggests, they do not emit visible light, unlike other nebulae. Dust grains within them absorb visible light and only let through radiation at longer wavelengths, like infrared light. Astronomers study these clouds of frozen dust because they often contain new stars in the making.

Of course, tracing the wolf’s ghost-like presence in the sky is only possible because it contrasts with a bright background. This image shows in spectacular detail how the dark wolf stands out against the glowing star-forming clouds behind it. The colourful clouds are built up mostly of hydrogen gas and glow in reddish tones excited by the intense UV radiation from the newborn stars within them.

Some dark nebulae, like the Coalsack Nebula, can be seen with the naked eye –– and play a key role in how First Nations interpret the sky [1] –– but not the Dark Wolf. This image was created using data from the VLT Survey Telescope, which is owned by the National Institute for Astrophysics in Italy (INAF) and is hosted at ESO’s Paranal Observatory, in Chile’s Atacama Desert. The telescope is equipped with a specially designed camera to map the southern sky in visible light.

The picture was compiled from images taken at different times, each one with a filter letting in a different colour of light. They were all captured during the VST Photometric Hα Survey of the Southern Galactic Plane and Bulge (VPHAS+), which has studied some 500 million objects in our Milky Way. Surveys like this help scientists to better understand the life cycle of stars within our home galaxy, and the obtained data are made publicly available through the ESO science portal. Explore this treasure trove of data yourself: who knows what other eerie shapes you will uncover in the dark?

Source: ESO/News



Notes

[1] The Mapuche people of south-central Chile refer to the Coalsack Nebula as ‘pozoko’ (water well), and the Incas called it ‘yutu’ (a partridge-like bird).



More information

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 for astronomy. Established as an intergovernmental organisation in 1962, today ESO is supported by 16 Member States (Austria, Belgium, Czechia, 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 survey telescopes such as VISTA. 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 ALMA on Chajnantor, a facility that observes 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.



Links



Contacts:

Juan Carlos Muñoz Mateos
ESO Media Officer
Garching bei München, Germany
Tel: +49 89 3200 6176
Email:
jmunoz@eso.org

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


Re-analysis of Data from Milky Way Central Supermassive Black Hole Observations

Radio image of Sagittarius A* in the center of the Milky Way Galaxy, obtained from this re-analysis. The structure is elongated from east to west. The east side is bright and the west side is dark, which the research team interprets to mean that the east side is moving towards us. Credit: Miyoshi et al.

A research team led by Assistant Professor Makoto Miyoshi of the National Astronomical Observatory of Japan (NAOJ) has independently re-analyzed observation data of the supermassive black hole at the center of the Milky Way Galaxy obtained and published by the international joint observation project Event Horizon Telescope (EHT). They found that the structure is slightly elongated in the east-west direction. This research takes a new look at the publicly available EHT data and demonstrates the scientific process in which the certainty of the answer increases as different researchers continue to examine and discuss a theory.

The Milky Way Galaxy, in which we live, contains more than 100 billion sun-like stars. There are countless such large galaxies in the Universe, most of which are thought to have supermassive black holes at their centers with masses millions to billions of times that of the Sun. The Milky Way Galaxy also has a supermassive black hole at its center, called Sagittarius A* (A star). The black hole swallows everything, including light, making it impossible to see the supermassive black hole itself, but analysis of stars circling the black hole at high speed indicates that Sagittarius A* has a mass approximately 4 million times that of the Sun. By closely observing its surroundings, we can obtain clues to the nature of the invisible black hole.

The EHT observed Sagittarius A* in 2017 with a network of eight ground-based radio telescopes using a technique known as radio interferometry to combine the results from the various telescopes. The results of these observations were published in 2022, including an image of a bright ring structure surrounding a central dark region, indicating the presence of a black hole.

In contrast to typical photography, data from observations linking several widely-separated radio telescopes contain many gaps in the completeness, so special algorithms are used to construct an image from the data. In this research, the team applied widely-used traditional methods to EHT data, as opposed to the EHT’s own original analysis method. Miyoshi explains, “Our image is slightly elongated in the east-west direction, and the eastern half is brighter than the western half. We think this appearance means the accretion disk surrounding the black hole is rotating.”

The EHT’s observational data and analysis methods are freely available, and many researchers have validated the results of EHT analysis. This research is also part of these regular verification activities. Radio interferometry connecting telescopes across the globe is a developing technology, and research on data analysis and image processing is ongoing, incorporating knowledge from statistics and other related disciplines. The structures presented in this research differ from the results of the EHT team, but both are plausible structures derived from the data using the respective methods. The EHT plays an important role in black hole research by soliciting independent verification and providing open data for verification. It is hoped that a more reliable picture of Sagittarius A* will emerge from active discussion by researchers based on improved analysis methods and data from follow-up observations carried out since 2018.



Detailed Article(s)


JASMINE Project



Release Information

Researcher(s) Involved in this Release
Makoto Miyoshi (National Astronomical Observatory of Japan)
Yoshiaki Kato (Japan Meteorological Agency)
Junichiro Makino (Kobe University)

Coordinated Release Organization(s)
National Astronomical Observatory of Japan
Royal Astronomical Society

Paper(s)
Makoto Miyoshi et al. “An Independent Hybrid Imaging of Sgr A* from the Data in EHT 2017 Observations”, in Monthly Notices of the Royal Astronomical Society, DOI: 10.1093/mnras/stae1158




Related Link(s)


Wednesday, October 30, 2024

Astronomers Discover New Building Blocks of Complex Organic Matter

Credit: NSF/NSF NRAO/AUI/S. Dagnello

CfA scientists help detect a new molecule in interstellar space as list of identified complex molecules grows

The element carbon is a building block for life, both on Earth and potentially elsewhere in the vast reaches of space. There should be a lot of carbon in space, but surprisingly, it's not always easy to find.

While it can be observed in many places, it doesn’t add up to the volume astronomers would expect to see. The discovery of a new, complex molecule (1-cyanopyrene), challenges expectations about where the building blocks for carbon are found and how they evolve.

Astronomers have long understood that certain carbon-rich stars are soot factories that release copious quantities of small molecular sheets of carbon into the interstellar medium. Scientists thought, however, that these types of carbon-rich molecules could neither survive the harsh conditions of interstellar space nor be re-formed there by combustion-like chemistry because the temperature is far too low.

Researchers from the Center for Astrophysics | Harvard & Smithsonian (CfA) helped lead this research. A paper describing these results was published today in the journal Science.

“Our detection of 1-cyanopyrene gives us important new information about the chemical origin and fate of carbon -- the single most important element to complex chemistry both on Earth and in space,” said Bryan Changala of the CfA, a co-author of the Science paper.

The 1-cyanopyrene molecule is made up of multiple fused benzene rings. It belongs to a class of compounds known as Polycyclic Aromatic Hydrocarbons (PAHs), which were previously believed to form only at high temperatures in regions with lots of energy, like the environments surrounding aging stars. On Earth, PAHs are found in burning fossil fuels, and as char marks on grilled food.

Astronomers study PAHs not just to learn about their particular lifecycle, but to learn more about how they interact with and reveal more about the interstellar medium (ISM) and celestial bodies around them. PAHs are believed to be responsible for the unidentified infrared bands observed in many astronomical objects. These bands arise from the infrared fluorescence of PAHs after they absorb ultraviolet (UV) photons from stars. The intensity of these bands reveal PAHs could account for a significant fraction of carbon in the ISM.

However, the newly observed 1-cyanopyrene molecules were found in Taurus Molecular Cloud-1 (TMC-1), a cold interstellar cloud. Located in the Taurus constellation, TMC-1 has not yet begun forming stars, and the temperature is only about 10 degrees above absolute zero.

“TMC-1 is a natural laboratory for studying these molecules that go on to form the building blocks of stars and planets,” said Gabi Wenzel, a postdoctoral fellow at the Massachusetts Institute of Technology who led the lab work and is the first author on the Science paper.

“These are the largest molecules we’ve found in TMC-1 to date. This discovery pushes the boundaries of our understanding of the complexity of molecules that can exist in interstellar space,” said co-author Brett McGuire, an Assistant Professor of Chemistry at MIT and an adjunct astronomer at the National Science Foundation (NSF) National Radio Astronomy Observatory (NRAO).

Astronomers used the NSF Green Bank Telescope, the largest fully steerable radio telescope in the world, to discover 1-cyanopyrene. Every molecule has a unique rotational spectrum, like a fingerprint, which allows for its identification. However, their large size and lack of a permanent dipole moment, can make some PAHs difficult – or even impossible – to detect. The observations of cyanopyrene can provide indirect evidence for the presence of even larger and more complex molecules in future observations.

“Identifying the unique rotational spectrum of 1-cyanopyrene required the work of an interdisciplinary scientific team,” explains co-author Harshal Gupta, NSF Program Director for the Green Bank Observatory and Research Associate at the CfA. “This discovery is a great illustration of synthetic chemists, spectroscopists, astronomers, and modelers working closely and harmoniously.”

This research combined the expertise of astronomy and chemistry with measurements and analysis conducted in the molecular spectroscopy laboratory of Dr. Michael McCarthy at the CfA.

“The microwave spectrometers developed at the CfA are unique, world-class instruments specifically designed to measure the precise radio fingerprints of complex molecules like 1-cyanopyrene,” said McCarthy. “Predictions from even the most advanced quantum chemical theories are still thousands of times less accurate than what is needed to identify these molecules in space with radio telescopes, so experiments in laboratories like ours are indispensable to these ground-breaking astronomical discoveries."




Media Contact:

Megan Watzke
Interim CfA Public Affairs Officer
Center for Astrophysics | Harvard & Smithsonian
617-496-7998

mwatzke@cfa.harvard.edu



About the Center for Astrophysics | Harvard & Smithsonian

The Center for Astrophysics | Harvard & Smithsonian is a collaboration between Harvard and the Smithsonian designed to ask—and ultimately answer—humanity's greatest unresolved questions about the nature of the universe. The Center for Astrophysics is headquartered in Cambridge, MA, with research facilities across the U.S. and around the world.


Tuesday, October 29, 2024

Dandelion Supernova Revealed in 3-D

An artist’s concept of a supernova remnant called Pa 30—the leftover remains of a supernova explosion that was witnessed from Earth in the year 1181. Unusual filaments of sulfur protrude beyond a dusty shell of ejected material. The remains of the original star that exploded, now a hot inflated star which may cool to become a white dwarf, are seen at the center of the remnant. The Keck Cosmic Web Imager (KCWI) at the W. M. Keck Observatory in Hawai‘i has mapped the strange filaments in 3-D and shown that they are flying outward at approximately 1,000 kilometers per second. Credit: W. M. Keck Observatory/Adam Makarenko



New observations probe a sphere of filaments around a dead star

Maunakea, Hawaiʻi – For nearly six months during the year 1181, people looked up to the skies to find a new star glittering in the constellation Cassiopeia. Chinese and Japanese astronomers recorded the rare event, an explosion of a star, or supernova. In the centuries since, astronomers have searched for the remains of the blast, but it was not until 2013 that they were finally found. As part of a citizen scientist project, amateur astronomer Dana Patchick—who had sifted through images taken by the now-retired Wide-field Infrared Survey Explorer, or WISE—found a nebula at the site where the supernova had occurred.

Further observations convinced astronomers that this nebula, called Pa 30, was in fact the leftover ejected material from the 1181 supernova. Later, in 2023, astronomers discovered strange filaments within the supernova remnant, which resemble the wispy tendrils of a dandelion flower.

Now, with the help of the Caltech-built Keck Cosmic Web Imager (KCWI) at the W. M. Keck Observatory on Maunakea, Hawai‘i Island, astronomers have, for the first time, mapped the location of those unusual filaments in three dimensions in addition to the speed at which they are streaming outward from the site of the blast.

“A standard image of the supernova remnant would be like a static photo of a fireworks display,” says Caltech professor of physics Christopher Martin, who led the team that built KCWI. “KCWI gives us something more like a ‘movie’ since we can measure the motion of the explosion’s embers as they streak outward from the central explosion.”

Martin is a co-author of a new paper reporting the findings published today in The Astrophysical Journal Letters. The study is led by Tim Cunningham, a NASA Hubble Fellow at the Center for Astrophysics |Harvard & Smithsonian (CfA), and the co-lead author is Ilaria Caiazzo, a former Caltech postdoctoral scholar who recently became an assistant professor at the Institute of Science and Technology Austria.

In 1181, astronomers in China and Japan recorded a new star in the sky, a rare supernova explosion. The remains of that supernova, called SN 1181, are depicted here in this artist’s animation, which flies around the remnant as it appears today in one moment in time. The corpse of the star that detonated, a hot and inflated “zombie” star, is seen within a dusty shell of ejected material. Beyond the dusty shell, bright radial filaments of sulfur extend three light-years out from their point of origin. The Keck Cosmic Web Imager (KCWI) at the W. M. Keck Observatory has mapped these filaments in 3-D and shown that they are flying outward at approximately 1,000 kilometers per second. Credit: W. M. Keck Observatory/Adam Makarenko

The 1181 supernova is thought to have occurred when a thermonuclear explosion was triggered on a dense dead star called a white dwarf. Typically, the white dwarf would be completely destroyed in this type of explosion, but in this case some of the star survived, leaving behind a sort of “zombie star.” This type of partial explosion is called a Type Iax supernova. “Because this was a failed explosion, it was fainter than normal supernovae, which has been shown to be consistent with the historical records,” Caiazzo says.

Material ejected in the 1181 explosion makes up the Pa 30 nebula that astronomers observe today. While the scientists know that the peculiar filaments, which glow with light from sulfur, were also generated by the supernova, they do not know how and when they formed.

To probe the three-dimensional structure of the supernova remnant, the astronomers turned to KCWI, an instrument that can capture multiwavelength, or spectral, information for every pixel in an image. This is like breaking apart the light captured in every pixel into a rainbow of colors. The spectral information enabled the team to measure the motions of the filaments poking out from the center of the explosion and ultimately create a 3D map of the structure. The filament material that is flying toward us shifted toward the blue higher-energy portion end of the visible spectrum (blue-shifted), while light from material moving away from us shifted toward the red end of the spectrum (red-shifted).

This is analogous to the Doppler shift one can hear as a blaring firetruck races by. As the vehicle moves toward us, the sound waves from its horn become squeezed into higher frequencies; as the truck moves away from us, the sound waves become elongated to lower frequencies.

Specifically, this study used the “red arm” of the KCWI instrument, which was installed at Keck Observatory last summer. KCWI consists of two halves: One captures light wavelengths at the blue end of the visible spectrum, and the other half covers the red end in addition to infrared light. “The addition of the red arm more than doubled the spectral coverage of KCWI and made these observations possible,” says Caltech graduate student and co-author Nikolaus Prusinski. “This 3D map comprises the most sensitive spatial and spectral measurements of Pa 30 to date and holds the current record for the largest contiguous region surveyed with the red channel.”

The results showed that the filament material in the supernova is flying outward from the site of the explosion at approximately 1,000 kilometers per second.

“We find the material in the filaments is expanding ballistically,” says Cunningham. “This means that the material has not been slowed down nor sped up since the explosion. From the measured velocities, looking back in time, you can pinpoint the explosion to almost exactly the year 1181.”

The 3D information also revealed a large cavity inside the spindly, spherical structure in addition to some evidence that the supernova explosion of 1181 occurred asymmetrically.

As to how the filaments formed after the blast, the scientists are still puzzled. “A reverse shock wave may be condensing surrounding dust into filaments, but we don’t know yet,” says Cunningham. “The morphology of this object is very strange and fascinating.”




About KCWI

The Keck Cosmic Web Imager (KCWI) is designed to provide visible band, integral field spectroscopy with moderate to high spectral resolution formats and excellent sky-subtraction. The astronomical seeing and large aperture of the telescope enables studies of the connection between galaxies and the gas in their dark matter halos, stellar relics, star clusters, and lensed galaxies. KCWI covers the blue side of the visible spectrum; the instrument also features the Keck Cosmic Reionization Mapper (KCRM), extending KCWI’s coverage to the red side of the visible spectrum. The combination of KCWI-blue and KCRM provides simultaneous high-efficiency spectral coverage across the entire visible spectrum. Support for KCWI was provided by the National Science Foundation, Heising-Simons Foundation, and Mt. Cuba Astronomical Foundation. Support for KCRM was provided by the National Science Foundation and Mt. Cuba Astronomical Foundation.



About W. M. KECK OBSERVATORY

The W. M. Keck Observatory telescopes are among the most scientifically productive on Earth. The two 10-meter optical/infrared telescopes atop Maunakea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometers, and world-leading laser guide star adaptive optics systems. Some of the data presented herein were obtained at Keck Observatory, which is a private 501(c) 3 non-profit organization operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the Native Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.


Monday, October 28, 2024

Gemini North Captures Galactic Archipelago Entangled In a Web Of Dark Matter

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NGC 1270: A Galactic Archipelago



Videos

Cosmoview Episode 88: Gemini North Captures Galactic Archipelago Entangled In a Web Of Dark Matter
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Cosmoview Episode 88: Gemini North Captures Galactic Archipelago Entangled In a Web Of Dark Matter

Pan on NGC 1270
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Pan on NGC 1270

Zooming into NGC 1270
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Zooming into NGC 1270

Cosmoview Episodio 88: Un archipiélago galáctico en un mar de materia oscura
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Cosmoview Episodio 88: Un archipiélago galáctico en un mar de materia oscura



One century after astronomers proved the existence of galaxies beyond the Milky Way, enormous galaxy clusters are offering clues to today’s cosmic questions

10 years ago Edwin Hubble discovered decisive evidence that other galaxies existed far beyond the Milky Way. This image, captured by the Gemini North telescope, one half of the International Gemini Observatory, features a portion of the enormous Perseus Cluster, showcasing its ‘island Universes’ in awe-inspiring detail. Observations of these objects continue to shed light not only on their individual characteristics, but also on cosmic mysteries such as dark matter.

Among the many views of the Universe that modern telescopes offer, some of the most breathtaking are images like this. Dotted with countless galaxies — each one of incomprehensible size — they make apparent the tremendous scale and richness of the cosmos. Taking center stage here, beguiling in its seeming simplicity, the elliptical galaxy NGC 1270 radiates an ethereal glow into the surrounding darkness. And although it may seem like an island adrift in the deep ocean of space, this object is part of something much larger than itself.

NGC 1270 is just one member of the Perseus Cluster, a group of thousands of galaxies that lies around 240 million light-years from Earth in the constellation Perseus. This image, taken with the Gemini Multi-Object Spectrograph (GMOS) on the Gemini North telescope, one half of the International Gemini Observatory — supported in part by the U.S. National Science Foundation and operated by NSF NOIRLab — captures a dazzling collection of galaxies in the central region of this enormous cluster.

Looking at such a diverse array, shown here in spectacular clarity, it’s astonishing to think that when NGC 1270 was first discovered in 1863 it was not widely accepted that other galaxies even existed. Many of the objects that are now known to be galaxies were initially described as nebulae, owing to their cloudy, amorphous appearance. The idea that they are entities of a similar size to our own Milky Way, or ‘island Universes’ as Immanuel Kant called them, was speculated on by several astronomers throughout history, but was not proven. Instead, many thought they were smaller objects on the outskirts of the Milky Way, which many believed to comprise most or all of the Universe.

The nature of these mysterious objects and the size of the Universe were the subjects of astronomy’s famous Great Debate, held in 1920 between astronomers Heber Curtis and Harlow Shapley. The debate remained unsettled until 1924 when Edwin Hubble, using the Hooker Telescope at Mount Wilson Observatory, observed stars within some of the nebulae to calculate how far they were from Earth. The results were decisive; they were far beyond the Milky Way. Astronomers’ notion of the cosmos underwent a dramatic shift, now populated with innumerable strange, far-off galaxies as large and complex as our own.

As imaging techniques have improved, piercing ever more deeply into space, astronomers have been able to look closer and closer at these ‘island Universes’ to deduce what they might be like. For instance, researchers have observed powerful electromagnetic energy emanating from the heart of NGC 1270, suggesting that it harbors a frantically feeding supermassive black hole. This characteristic is seen in around 10% of galaxies and is detectable via the presence of an accretion disk — an intense vortex of matter swirling around and gradually being devoured by the central black hole.

It’s not only the individual galaxies that astronomers are interested in; hints at many ongoing mysteries lie in their relationship to and interactions with one another. For example, the fact that huge groups like the Perseus Cluster exist at all points to the presence of the enigmatic substance we call dark matter [1]. If there were no such invisible, gravitationally interactive material, then astronomers believe galaxies would be spread more or less evenly across space rather than collecting into densely populated clusters. Current theories suggest that an invisible web of dark matter draws galaxies together at the intersections between its colossal tendrils, where its gravitational pull is strongest.

Although dark matter is invoked to explain observed cosmic structures, the nature of the substance itself remains elusive. As we look at images like this one, and consider the strides made in our understanding over the past century, we can sense a tantalizing hint of just how much more might be discovered in the decades to come. Perhaps hidden in images like this are clues to the next big breakthrough. How much more will we know about our Universe in another century?




Notes

[1] The discovery of dark matter in galaxies is in-part attributed to American astronomer Vera C. Rubin, who used the rotation of galaxies to infer the presence of an invisible, yet gravitationally interactive, material holding them together. She is also the name inspiration for NSF–DOE Vera C. Rubin Observatory, currently under construction in Chile, which will begin operations in 2025.



More information

NSF NOIRLab (U.S. National Science Foundation National Optical-Infrared Astronomy Research Laboratory), the U.S. center for ground-based optical-infrared astronomy, operates the International Gemini Observatory (a facility of NSF, NRC–Canada, ANID–Chile, MCTIC–Brazil, MINCyT–Argentina, and KASI–Republic of Korea), Kitt Peak National Observatory (KPNO), Cerro Tololo Inter-American Observatory (CTIO), the Community Science and Data Center (CSDC), and Vera C. Rubin Observatory (operated in cooperation with the Department of Energy’s SLAC National Accelerator Laboratory). It is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with NSF and is headquartered in Tucson, Arizona. The astronomical community is honored to have the opportunity to conduct astronomical research on I’oligam Du’ag (Kitt Peak) in Arizona, on Maunakea in Hawai‘i, and on Cerro Tololo and Cerro Pachón in Chile. We recognize and acknowledge the very significant cultural role and reverence that these sites have to the Tohono O’odham Nation, to the Native Hawaiian community, and to the local communities in Chile, respectively.



Links



Contacts:

Josie Fenske
Jr. Public Information Officer
NSF NOIRLab
Email:
josie.fenske@noirlab.edu