May 20, 2024

‘Double’ Galaxy Mystifies Hubble Astronomers – “We Were Really Stumped”

Astronomers utilizing the Hubble Space Telescope stumbled upon one such odd shape while evaluating quasars, the blazing cores of active galaxies. They identified two bright, direct items that seemed mirror images of each other. Another oddball things was close by.
The functions so bewildered the astronomers that it took them numerous years to unravel the secret. With the assistance of two gravitational-lensing specialists, the scientists figured out that the three things were the distorted images of a faraway, undiscovered galaxy. The greatest surprise was that the linear objects were specific copies of each other, an unusual incident triggered by the exact alignment of the background galaxy and the foreground lensing cluster.

Looking into the universe is like checking out a funhouse mirror. Thats because gravity deforms the material of area, creating optical impressions.
A lot of these optical impressions appear when a remote galaxys light is magnified, stretched, and lightened up as it passes through a massive galaxy or galaxy cluster in front of it. This phenomenon, called gravitational lensing, produces numerous, extended, and brightened images of the background galaxy.
This phenomenon enables astronomers to study galaxies so distant they can not be seen besides by the results of gravitational lensing. The challenge is in trying to reconstruct the far-off galaxies from the odd shapes produced by lensing.

The galaxy clusters immense gravity magnifies and misshapes the light from the distant galaxy behind it, developing the several images. As light from the distant galaxy passes through the cluster along this ripple, two mirror images are produced, along with a 3rd image that can be seen off to the side. Based on a reconstruction of this image, the scientists determined that the distant galaxy appears to an edge-on, barred spiral with continuous, clumpy star formation.

3D animation showing the Hubble Space Telescope over the Earth. Credit: ESA/Hubble (M. Kornmesser & & L. L. Christensen).
Astronomers have seen some pretty weird things spread throughout our vast universe, from exploding stars to colliding galaxies. You d think that when they see an unusual celestial item, they would be able to identify it.
But NASAs Hubble Space Telescope discovered what appears to be a pair of similar things that look so strange it took astronomers several years to identify what they are.
” We were really stumped,” said astronomer Timothy Hamilton of Shawnee State University in Portsmouth, Ohio.
The oddball items consist of a set of galaxy bulges (the main star-filled center of a galaxy) and at least three nearly parallel split streaks. Hamilton spotted them by mishap while utilizing Hubble to survey a collection of quasars, the blazing cores of active galaxies.
After going after dead-end theories, obtaining help from colleagues, and doing lots of head-scratching, Hamilton and the growing group, led by Richard Griffiths of the University of Hawaii in Hilo, finally created all of the clues to solve the secret.
The direct things were the extended images of a gravitationally lensed far-off galaxy, situated more than 11 billion light-years away. And, they appeared to be mirror images of each other.
The group discovered that the tremendous gravity of a stepping in, and uncatalogued, foreground cluster of galaxies was contorting area, amplifying, lightening up, and extending the image of a remote galaxy behind it, a phenomenon called gravitational lensing. Though Hubble surveys reveal a lot of these funhouse-mirror distortions triggered by gravitational lensing, this things was distinctively perplexing.
In this case, a precise positioning between a background galaxy and a foreground galaxy cluster produces twin magnified copies of the very same image of the remote galaxy. Since the background galaxy straddles a ripple in the fabric of area, this uncommon phenomenon happens. This “ripple” is a location of biggest magnification, caused by the gravity of dense amounts of dark matter, the hidden glue that makes up the majority of the universes mass. As light from the faraway galaxy passes through the cluster along this ripple, 2 mirror images are produced, along with a third image that can be seen off to the side.
Griffiths compares this effect to the intense wavy patterns seen on the bottom of a swimming pool. “Think of the rippled surface area of a swimming pool on a warm day, revealing patterns of brilliant light on the bottom of the swimming pool,” he explained. “These brilliant patterns on the bottom are brought on by a similar sort of effect as gravitational lensing. The ripples on the surface area act as partial lenses and focus sunshine into intense squiggly patterns on the bottom.”.
In the gravitationally lensed far-off galaxy, the ripple is greatly amplifying and misshaping the light from the background galaxy that is travelling through the cluster. The ripple acts like an imperfect curvy mirror that creates the dual copies.
Fixing the Mystery.
This unusual phenomenon wasnt widely known when Hamilton found the weird direct features in 2013.
As he browsed the quasar images, the photo of the mirrored images and parallel streaks stood out. Hamilton had never ever seen anything like it previously, and neither had other staff member.
” My first idea was that possibly they were communicating galaxies with tidally stretched-out arms,” Hamilton stated. “It didnt actually fit well, however I didnt understand what else to believe.”.
So Hamilton and the group began their mission to fix the secret of these tantalizing straight lines, later on called Hamiltons Object for its innovator. They showed the strange image to associates at astronomy conferences, which generated a range of responses, from cosmic strings to planetary nebulae.
But then Griffiths, who was not a member of the initial team, offered the most possible description when Hamilton showed him the image at a NASA conference in 2015. It was a magnified and distorted image brought on by a lensing phenomenon similar to those seen in Hubble pictures of other enormous galaxy clusters that are amplifying images of really far-off galaxies. Griffiths verified this concept when he discovered of a similar linear things in among Hubbles deep-cluster studies.
The researchers, however, still had an issue. They couldnt determine the lensing cluster. Usually, astronomers who study galaxy clusters first see the foreground cluster thats causing the lensing, and then discover the magnified images of distant galaxies within the cluster. A search of the Sloan Digital Sky Survey images exposed that a galaxy cluster lived in the same location as the magnified images, however it did disappoint up in any catalogued study. The reality that the weird images were at the center of a cluster made it clear to Griffiths that the cluster was producing the lensed images.
The researchers next action was in figuring out whether the 3 lensed images were at the same distance, and for that reason were all the distorted portraits of the same far galaxy. Spectroscopic measurements with the Gemini and W. M. Keck observatories in Hawaii assisted the scientists make that confirmation, revealing that the lensed images were from a galaxy situated more than 11 billion light-years away.
The remote galaxy, based upon a reconstruction of the 3rd lensed image, appears to be an edge-on, barred spiral with ongoing, clumpy star formation.
Around the very same time as the spectroscopic observations by Griffiths and undergrads in Hilo, a separate group of scientists in Chicago recognized the cluster and measured its distance using Sloan data. The cluster resides more than 7 billion light-years away.
With extremely little details about the cluster, Griffiths group was still having a hard time with how to interpret these unusual lensing shapes. “This gravitational lens is extremely various from most of the lenses that were studied before by Hubble, especially in the Hubble Frontier Fields study of clusters,” Griffiths discussed.
Mapping the Invisible.
Their software application assisted the team figure out how all three lensed images came to be. They concluded that the dark matter around the stretched images had to be “efficiently” distributed in area at little scales.
” Its excellent that we just need two mirror images in order to get the scale of how clumpy or not dark matter can be at these positions,” Wagner stated. We just take the observables of the numerous images and the reality they can be changed into one another.
This outcome is crucial, Griffiths stated, due to the fact that astronomers still do not know what dark matter is, nearly a century after its discovery. “We know its some form of matter, but we have no idea what the constituent particle is. The smaller sized the dark matter clumps, the more enormous the particles need to be.”.
The groups paper appears in the September issue of The Monthly Notices of the Royal Astronomical Society.
Recommendation: “Hamiltons Object– a clumpy galaxy straddling the gravitational caustic of a galaxy cluster: restrictions on dark matter clumping” by Richard E Griffiths, Mitchell Rudisel, Jenny Wagner, Timothy Hamilton, Po-Chieh Huang and Carolin Villforth, 17 May 2021, The Monthly Notices of the Royal Astronomical Society.DOI: 10.1093/ mnras/stab1375.
The Hubble Space Telescope is a project of international cooperation in between NASA and ESA (European Space Agency). NASAs Goddard Space Flight Center in Greenbelt, Maryland, handles the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, carries out Hubble science operations. STScI is run for NASA by the Association of Universities for Research in Astronomy in Washington, D.C.

The galaxy clusters immense gravity amplifies and distorts the light from the distant galaxy behind it, developing the numerous images. In this case, a precise positioning in between a background galaxy and a foreground galaxy cluster produces twin magnified copies of the very same image of the remote galaxy. As light from the far galaxy passes through the cluster along this ripple, two mirror images are produced, along with a third image that can be seen off to the side.
It was an amplified and misshaped image triggered by a lensing phenomenon comparable to those seen in Hubble images of other huge galaxy clusters that are magnifying images of very far-off galaxies. Usually, astronomers who study galaxy clusters very first see the foreground cluster thats causing the lensing, and then find the magnified images of remote galaxies within the cluster.