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An Epic Collaboration Between Hubble and JWST

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In 2012, as part of the MAssive Cluster Survey (MACS), the Hubble Space Telescope (HST) discovered a pair of colliding galaxy clusters (MACS0416) that will eventually combine to form an even bigger cluster. Located about 4.3 billion light-years from Earth, the MACS0416 cluster contains multiple gravitational lenses that allow astronomers to look back in time and view galaxies as they appeared when the Universe was young. In a new collaboration that symbolizes the passing of the torch, the venerable Hubble and the James Webb Space Telescope (JWST) teamed up to conduct an extremely detailed study of MACS0416.

 

This cluster was the first in a series of super-deep views commissioned in 2014 as part of the unprecedented Frontier Fields program. This collaboration relied on massive clusters of galaxies to conduct gravitational lensing studies, a phenomenon originally predicted by Einstein’s Theory of General Relativity. Based on how the gravitational force of massive objects will alter the curvature of spacetime around them, this program relied on galaxy clusters in the foreground to magnify light from fainter, more distant objects in the background.

The images taken by Hubble of MACS0416 were released in 2014 and used in the Cluster Lensing And Supernova survey with Hubble (CLASH) to help scientists view the early Universe and map the distribution of Dark Matter. Along with the other super-deep field views acquired by the Frontier Fields program, these images provided astronomers with the deepest views of the Universe ever. It also established Hubble as a pioneer mission in the search for fainter, more distant galaxies that existed during the early Universe (ca. 1 billion years after the Big Bang).

This illustration shows a phenomenon known as gravitational lensing, which astronomers use to study distant and faint galaxies. Credit: NASA/ESA

One of the many objectives of the JWST is to use its cutting-edge infrared instruments to build on this foundation and provide an even deeper look into the early Universe. Combining Hubble‘s powerful optics with Webb‘s infrared imaging, the two space telescopes produced a composite image that presents the best of both observatories. The combined visible and infrared light – which ranges from 0.4 to 5 microns in the near-infrared (NIR) spectrum – is one of the most comprehensive views of the Universe ever obtained and reveals a wealth of details.

This includes a multitude of galaxies outside the cluster and distant sources that vary in distance (and time). To illustrate the distances, the shortest wavelengths are color-coded in blue, the longest wavelengths in red, and the intermediate wavelengths in green. The blue galaxies were best detected by Hubble, and many showed intense star formation, while the redder galaxies were best represented by Webb. Some galaxies also appear very red because they contain lots of cosmic dust that absorbs light in the blue end of the spectrum.

Beyond the aesthetics, the image reveals several objects that vary in brightness over time (aka. transient objects), which was the purpose of the campaign. To locate these objects in MACS0416, the team used three epochs of observations obtained as part of the Prime Extragalactic Areas for Reionization and Lensing Science (PEARLS) program – Guaranteed Time Observation (GTO) program 1176. The purpose of this program was to study the epoch of galaxy assembly and active galactic nucleus (AGN) growth in the early Universe and included observations of seven gravitationally lensing clusters, taken weeks apart.

These were combined with additional observations by the CAnadian NIRISS Unbiased Cluster Survey (CANUCS) research team. This yielded 14 transients across the entire field of view, twelve located within three highly-magnified galaxies, likely to be individual stars or multiple-star systems. The remaining two transients are within more moderately magnified background galaxies and are likely to be supernovae. One object stood out above all, a star system located that was magnified by a factor of at least 4000 in a galaxy that existed about 3 billion years after the Big Bang.

The locations of Hubble’s observations of the MACS J0416 galaxy cluster (right) and the adjacent parallel field (left) are plotted over a Digitized Sky Survey (DSS) image. Credit: NASA/ESA/STScI/and the CLASH team

The team nicknamed this star system “Mothra,” partly because of its extremely bright and magnified nature, but also to go with another lensed star the team previously identified and nicknamed “Godzilla.” Mothra was also visible in the Hubble observations obtained in 2014, which is surprising given that such powerful lensing effects are due to chance alignments between a foreground galaxy and a background star. The team theorizes that this is due to an additional lensing object in the foreground (possibly a star cluster), which they estimate to be between 10,000 and 1 million Solar masses.

Nevertheless, the fact that the team could find so many transients from observations taken within a relatively short time suggests that many more could be found in this and other clusters. This will be possible through regular monitoring with Webb as it continues its ten-year planned mission (with possible extensions to twenty). The Hubble mission, meanwhile, has been in continuous operation for thirty years and shows no signs of slowing down!

Further Reading: ESA

 

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The body of a Ugandan Olympic athlete who was set on fire by her partner is received by family

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NAIROBI, Kenya (AP) — The body of Ugandan Olympic athlete Rebecca Cheptegei — who died after being set on fire by her partner in Kenya — was received Friday by family and anti-femicide crusaders, ahead of her burial a day later.

Cheptegei’s family met with dozens of activists Friday who had marched to the Moi Teaching and Referral Hospital’s morgue in the western city of Eldoret while chanting anti-femicide slogans.

She is the fourth female athlete to have been killed by her partner in Kenya in yet another case of gender-based violence in recent years.

Viola Cheptoo, the founder of Tirop Angels – an organization that was formed in honor of athlete Agnes Tirop, who was stabbed to death in 2021, said stakeholders need to ensure this is the last death of an athlete due to gender-based violence.

“We are here to say that enough is enough, we are tired of burying our sisters due to GBV,” she said.

It was a somber mood at the morgue as athletes and family members viewed Cheptegei’s body which sustained 80% of burns after she was doused with gasoline by her partner Dickson Ndiema. Ndiema sustained 30% burns on his body and later succumbed.

Ndiema and Cheptegei were said to have quarreled over a piece of land that the athlete bought in Kenya, according to a report filed by the local chief.

Cheptegei competed in the women’s marathon at the Paris Olympics less than a month before the attack. She finished in 44th place.

Cheptegei’s father, Joseph, said that the body will make a brief stop at their home in the Endebess area before proceeding to Bukwo in eastern Uganda for a night vigil and burial on Saturday.

“We are in the final part of giving my daughter the last respect,” a visibly distraught Joseph said.

He told reporters last week that Ndiema was stalking and threatening Cheptegei and the family had informed police.

Kenya’s high rates of violence against women have prompted marches by ordinary citizens in towns and cities this year.

Four in 10 women or an estimated 41% of dating or married Kenyan women have experienced physical or sexual violence perpetrated by their current or most recent partner, according to the Kenya Demographic and Health Survey 2022.

The Canadian Press. All rights reserved.

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The ancient jar smashed by a 4-year-old is back on display at an Israeli museum after repair

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TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.

Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.

Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.

The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.

The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.

It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.

Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.

Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.

Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.

Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.

Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.

The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”

The Canadian Press. All rights reserved.

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B.C. sets up a panel on bear deaths, will review conservation officer training

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VICTORIA – The British Columbia government is partnering with a bear welfare group to reduce the number of bears being euthanized in the province.

Nicholas Scapillati, executive director of Grizzly Bear Foundation, said Monday that it comes after months-long discussions with the province on how to protect bears, with the goal to give the animals a “better and second chance at life in the wild.”

Scapillati said what’s exciting about the project is that the government is open to working with outside experts and the public.

“So, they’ll be working through Indigenous knowledge and scientific understanding, bringing in the latest techniques and training expertise from leading experts,” he said in an interview.

B.C. government data show conservation officers destroyed 603 black bears and 23 grizzly bears in 2023, while 154 black bears were killed by officers in the first six months of this year.

Scapillati said the group will publish a report with recommendations by next spring, while an independent oversight committee will be set up to review all bear encounters with conservation officers to provide advice to the government.

Environment Minister George Heyman said in a statement that they are looking for new ways to ensure conservation officers “have the trust of the communities they serve,” and the panel will make recommendations to enhance officer training and improve policies.

Lesley Fox, with the wildlife protection group The Fur-Bearers, said they’ve been calling for such a committee for decades.

“This move demonstrates the government is listening,” said Fox. “I suspect, because of the impending election, their listening skills are potentially a little sharper than they normally are.”

Fox said the partnership came from “a place of long frustration” as provincial conservation officers kill more than 500 black bears every year on average, and the public is “no longer tolerating this kind of approach.”

“I think that the conservation officer service and the B.C. government are aware they need to change, and certainly the public has been asking for it,” said Fox.

Fox said there’s a lot of optimism about the new partnership, but, as with any government, there will likely be a lot of red tape to get through.

“I think speed is going to be important, whether or not the committee has the ability to make change and make change relatively quickly without having to study an issue to death, ” said Fox.

This report by The Canadian Press was first published Sept. 9, 2024.

The Canadian Press. All rights reserved.

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