Jump to content

Gaia maps largest ever collection of quasars in space and time


Recommended Posts

Gaia_maps_largest_ever_collection_of_qua Image:

Astronomers have created the largest yet cosmic 3D map of quasars: bright and active centres of galaxies powered by supermassive black holes. This map shows the location of about 1.3 million quasars in space and time, with the furthest shining bright when the Universe was only 1.5 billion years old.

The new map has been made with data from ESA’s Gaia space telescope. While Gaia’s main objective is to map the stars in our own galaxy, in the process of scanning the sky it also spots objects outside the Milky Way, such as quasars and other galaxies.

The graphic representation of the map (bottom right on the infographic) shows us the location of quasars from our vantage point, the centre of the sphere. The regions empty of quasars are where the disc of our galaxy blocks our view.

Quasars are powered by supermassive black holes at the centre of galaxies and can be hundreds of times as bright as an entire galaxy. As the black hole’s gravitational pull spins up nearby gas, the process generates an extremely bright disk, and sometimes jets of light, that telescopes can observe.

The galaxies that quasars live in sit inside massive clouds of invisible dark matter. The distribution of dark matter gives insight into how much dark matter there is in the Universe, and how strong it clusters. Astronomers compare these measurements across cosmic time to test our current model of the Universe's composition and evolution.

Because quasars are so bright, astronomers use them to map out the dark matter in the very distant Universe, and fill in the timeline of how the cosmos evolved.

For example, scientists have already compared the new quasar map with the cosmic microwave background, a snapshot of the oldest light in our cosmos. As this light travels to us, it is bent by the intervening web of dark matter – the same web mapped out by the quasars – and by comparing the two, scientists can measure how strongly matter clumps together through time.

This map was made by Kate Storey-Fisher of the Donostia International Physics Center in Spain and the New York University, USA, and colleagues, and published in the Astrophysical Journal. It uses data from Gaia’s third data release, which contained 6.6 million quasar candidates, as well as data from NASA’s Wide-Field Infrared Survey Explorer (WISE) and the Sloan Digital Sky Survey (SDSS). Combining the datasets helped clean Gaia’s original dataset of contaminants such as stars and galaxies, and better pinpoint the distances to the quasars. The team also created a map of where dust, stars and other phenomena are expected to block our view of some quasars, which is critical for interpreting the quasar map.

View the full article

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Similar Topics

    • By NASA
      Unable to render the provided source NASA invites the public to virtually sail along with the Advanced Composite Solar Sail System‘s space journey using NASA’s “Eyes on the Solar System” visualization tool, a digital model of the solar system. This simulation shows the real-time positions of the planets, moons, and spacecraft – including NASA’s Advanced Composite Solar Sail System.
      Solar sails use the pressure of sunlight for propulsion, angling toward or away from the Sun so that photons bounce off the reflective sail to push a spacecraft. This eliminates the need for heavy propulsion systems and could enable longer duration and lower cost missions. The results from this technology demonstration – including the test of the sail’s composite boom system – will advance future space exploration to expand our understanding of our Sun and solar system. 
      The Advanced Composite Solar Sail System, which launched in April 2024, and deployed its reflective sail in August, is currently orbiting approximately 600 miles (1,000 kilometers) above Earth and is frequently visible in the night sky to observers in the Northern Hemisphere. Fans of the spacecraft can look for the sail in the night sky using a new feature in the NASA mobile app. Visibility may be intermittent, and the spacecraft could appear at variable levels of brightness as it moves in orbit.
      For more mission updates, follow NASA’s Small Satellite Missions blog.
      NASA’s Ames Research Center in California’s Silicon Valley, manages the Advanced Composite Solar Sail System project and designed and built the onboard camera diagnostic system. NASA Langley designed and built the deployable composite booms and solar sail system. NASA’s Small Spacecraft Technology (SST) program office based at NASA Ames and led by the agency’s Space Technology Mission Directorate (STMD), funds and manages the mission. NASA STMD’s Game Changing Development program funded the development of the deployable composite boom technology.    
      View the full article
    • By NASA
      NASA Administrator Bill Nelson and Deputy Administrator Pam Melroy visited the agency’s Michoud Assembly Facility in New Orleans on Dec. 8, 2021 for tours and briefings on Michoud’s role in the Artemis program and other capabilities that enrich many facets of the nation’s space exploration endeavors. Credit: NASA/Michael DeMocker NASA Administrator Bill Nelson and Deputy Administrator Pam Melroy will lead the agency’s delegation at the International Astronautical Congress (IAC) from Monday, Oct. 14, to Thursday, Oct. 17, in Milan.
      During the congress, NASA will discuss its Low Earth Orbit Microgravity Strategy, emphasizing the agency’s efforts to advance microgravity science, technology, and exploration. The agency also will highlight its commitment to space sustainability and several missions, including initiatives that support NASA’s Moon to Mars exploration approach and the Artemis Accords.
      NASA will amplify the following talks happening at the congress through its YouTube Channel:
      Monday, Oct. 147:45 a.m. EDT (1:45 p.m. CEST): One-to-One with Heads of Agencies featuring Nelson. 12:15 p.m. EDT (6:15 p.m. CEST): Host Plenary on Responsible and Sustainable Space Exploration for Moon to Mars featuring Melroy. Wednesday, Oct. 16 9 a.m. EDT (3 p.m. CEST): A New Era in Human Presence featuring Melroy. A full agenda for this year’s IAC is available online.
      Members of the media registered for IAC will have three opportunities to meet with NASA leaders. To register, media must apply through the International Astronautical Federation website. Opportunities include:
      Monday, Oct. 14 5:30 p.m. CEST (11:30 a.m. EDT): NASA Deputy Administrator Pam Melroy, Lisa Campbell, president, CSA (Canadian Space Agency), and Teodoro Valente, president, Italian Space Agency, to discuss the 3rd Annual Heads of Agency meeting of the Artemis Accords Signatories. Tuesday, Oct. 15 5 p.m. CEST (11 a.m. EDT): NASA Administrator Bill Nelson to discuss the agency’s international partnerships in the Artemis era. Wednesday, Oct. 16 5 p.m. CEST (11 a.m. EDT): NASA Deputy Administrator Pam Melroy and Robyn Gatens, director of the International Space Station and acting director of Commercial Spaceflight to discuss NASA’s Low Earth Orbit Microgravity Strategy In addition to the events outlined above, NASA will have an exhibit featuring the first sample of the asteroid Bennu to appear publicly in a non-museum setting, as well as information on the Artemis campaign, NASA’s future in low Earth orbit, and several upcoming science and technology missions. NASA also will host subject matter expert talks throughout the week at its exhibit.
      NASA will provide photos and updates about its participation in the International Astronautical Congress from its @NASAExhibit account on X.
      For more information about NASA participation at IAC, visit:
      https://www.nasa.gov/nasa-at-iac
      -end-
      Amber Jacobson
      Headquarters, Washington
      240-298-1832
      amber.c.jacobson@nasa.gov
      Share
      Details
      Last Updated Oct 10, 2024 LocationNASA Headquarters Related Terms
      artemis accords Bill Nelson Pamela A. Melroy View the full article
    • By NASA
      8 Min Read Kathryn Sullivan: The First American Woman to Walk in Space
      Astronaut Kathryn D. Sullivan checks the latch of the SIR-B antenna in the space shuttle Challenger's open cargo bay during her historic extravehicular activity (EVA) on Oct. 11, 1984. Earlier, America's first woman to perform an EVA and astronaut David C. Leestma, participated in an in-space simulation of refueling a spacecraft in orbit. Credits: NASA Forty years ago, in October 1984, Kathryn D. Sullivan became the first American woman to walk in space. But being the first presented several challenges that started well before she took those historic steps. Things got complicated just after she learned of her assignment.
      Questions of Physiology
      Biomedical researchers at NASA’s Johnson Space Center (JSC) raised what they believed was a serious issue with women walking in space and alerted George W.S. Abbey, the head of the Flight Crew Operations Directorate. Females, he learned, were more likely than their male counterparts to develop the bends in the low-pressure environment of the extravehicular mobility unit (EMU), the spacesuit she would wear. To alleviate the possibility of developing decompression syndrome, all spacewalkers had to breathe pure oxygen before a spacewalk to eliminate nitrogen from their bloodstream. Researchers insisted Sullivan (and any future women spacewalkers) spend more time than their male counterparts breathing pure oxygen before going outside of the space shuttle. Sullivan quickly learned that there were flaws in the research, which she countered, and Abbey ended up approving the same requirements for men and women doing an extravehicular activity (EVA). 
      Setting the Record
      After the STS-41G crew had been named in the fall of 1983, a colleague—flush with excitement over the recent flight announcement — congratulated Sally K. Ride and Sullivan on their new titles: Ride being the first woman to fly in space twice and Sullivan the first woman to walk in space. Both shook their heads and explained that it would be many months before launch and that a Soviet woman would fly and do a spacewalk well before the space shuttle Challenger and her crew made it to orbit. As expected, the Soviets assigned cosmonaut Svetlana Y. Savitskaya to a second mission in 1983, less than a month after NASA’s crew announcement. In July 1984, Savitskaya, not Ride, went on to become the first woman to enter space twice and earned the distinction of being the first female to walk in space.
      Astronauts Sally K. Ride (right) and Kathryn D. Sullivan, two of three mission specialists, synchronize their watches prior to ingressing the Space Shuttle Challenger on the launch pad at Kennedy Space Center on October 5, 1984.NASA Sullivan was not disappointed at losing the title. As she recalled in an oral history interview, being selected for an EVA was an “extraordinary opportunity,” and it did not matter where she was in the queue. She could not understand how people arrived at the idea that the “seventh, tenth, or thirteenth … is [any] less meaningful … than some historical first.”
      Others at the Johnson Space Center still thought there was a way they could best the Soviets. Sullivan’s trainers took note of how short Savitskaya’s EVA was. It was only about three and a half hours. “A little bit more than that,” they explained, and “you’ll get the duration record!” But the idea of breaking her record by a few minutes seemed ludicrous. “I’m certainly not going to go tromping around on dinner speeches … saying, ‘Well yes, but I have the duration record.’” 
      “Hello, I’m right here!”
      While the issue of breaking and setting records remained of interest at NASA more than twenty years after the Soviets sent cosmonaut Yuri Gagarin into space, Sullivan found herself grappling with other matters she found equally frustrating. First, there was the sexist media. No journalist asked how she was feeling about her role in the mission. Flying women in space was still new to the American news media in 1983—Ride had only flown her first mission in June, and while Judith A. Resnik had been named to a mission, she had not yet been in orbit. But Ride had not completed an EVA; only men had walked in space, and some found the activity challenging. Astronaut Eugene A. Cernan described his first EVA as the “spacewalk from hell.” Spacewalks can be physically demanding, and it was assumed that women might not have the strength to do so. Reporters asked commander Robert L. Crippen and Ride, “Do you think Kathy can do this?” Sitting at the preflight press conference she reminded reporters that she could speak for herself. “Hello, I’m right here! Hello. Hello.”
      The crew assigned to the STS-41G mission included (seated left to right) Jon A. McBride, pilot; mission specialists Sally K. Ride, Kathryn D. Sullivan, and David C. Leestma. Standing in the rear, left to right, are payload specialist Paul D. Scully-Power, mission commander Robert Crippen, and payload specialist Marc Garneau. Launched aboard the Space Shuttle Challenger on October 5, 1984, the STS-41G mission marked the first flight to include two women.NASA There was also the matter of why her spacewalking partner, David C. Leestma, led the EVA. She had two years seniority in the Astronaut Office, arriving in 1978; NASA named Leestma to the corps in 1980. She also worked on spacesuit issues and the mission’s payload longer than he had, but both were rookies on this mission. Sullivan did not think Crippen and Abbey thought she was incapable, but for traditional norms to have been breached in this instance she could not explain why she—the senior ranking astronaut—was playing a support role instead of leading. If anyone asked why, Sullivan told Crippen he—not she—would have to answer the tough questions.
      Space Suit Fit
      As she prepared for the flight, she began training in the shuttle EMU, which never quite fit her body. The suit’s elbow did not align with hers so when she bent her arm, she had to use extra force. The lower portion of the suit was misaligned, making it difficult to bend her knee. Being the first American woman to do a spacewalk, she decided what was most important was to perform the EVA and demonstrate the EMU worked for women. “I reckoned the wrong thing to do was to turn the first evolution of a woman doing a spacewalk into a controversy. … I just sucked it up and dealt with it.” The suit techs knew the EMU was not quite her size, but she made it work. Later, when assigned to STS-45, one of the techs noticed how poorly the suit fit. “We ought to do something about it. It ought to fit you,” he said. Sullivan responded, “We can start that conversation now, but if you think I was going to make that the conversation on the first EVA you’re crazy.”
      Astronaut Kathryn D. Sullivan, STS-41G mission specialist, gets some help with her extravehicular mobility unit (EMU) prior to participating in an underwater simulation of an extravehicular activity (EVA) scheduled for her flight aboard the Columbia in October 1984. Dr. Sullivan and David C. Leestma (out of frame) participated in the rehearsal in NASA’s weightless environment training facility (WET-F) at the Johnson Space Center.NASA A Walk to Remember
      Two days after Sullivan’s thirty-third birthday, STS-41G launched on October 5, 1984. Once in orbit, the flight plan changed quickly. A problem with a malfunctioning Ku-band antenna meant that the EVA had to be pushed back to the day before reentry. Sullivan worried that the walk might be scrapped, but when they finally began the pre-breathing protocol, she relaxed. “Challenger, Houston: You are GO for EVA,” Sullivan recalled, “were the sweetest words I had ever heard.” Sullivan and Leestma’s EVA was short—only three hours and twenty-nine minutes—but busy. Leestma demonstrated it was possible to refuel satellites in orbit, while Sullivan monitored his work. When he wrapped up his task, Sullivan finally had the opportunity to “do something, not just watch things.” She stowed the malfunctioning antenna and before they went back inside the shuttle, they filmed a scene for an IMAX film, The Dream is Alive—where the two spacewalkers rose from the bottom of the space shuttle’s windows and waved at the crew inside, mimicking the “Kilroy Was Here” meme. When filming concluded, Sullivan and Leestma returned to Challenger. “My first spacewalking adventure,” Sullivan wrote in her memoir, “was over all too soon.” The next day, President Ronald Reagan called to ask Sullivan about her experience. “Kathy, when we met at the White House, I know you were excited about walking in space. Was it what you expected?” he asked. Sullivan responded affirmatively and added, “I think it was the most fantastic experience of my life.”
      I think it was the most fantastic experience of my life.
      Kathryn Sullivan
      NASA Astronaut
      When she returned to JSC she learned that the EVA flight team had tried to figure out how to send her a diplomatic message to stay outside longer to beat Savitskaya’s record. There ended up being a “five-or six-minute difference” between Sullivan and Savitskaya, “and in the wrong direction as far as they were concerned.”
      Despite all the challenges she faced as the first American woman to walk in space, Sullivan called the EVA “a fabulously cool experience.” She hoped to do another, but she never received another assignment to walk in space. She recognized what a unique opportunity she had—very few people have flown in space, and even fewer “get to sneak outside. I’m not going to diminish one dose of sneaking outside just because I didn’t get two, three, or four.”
      Watch Suit Up – 50 Years of Spacewalks About the Author
      Jennifer Ross-Nazzal
      NASA Human Spaceflight HistorianJennifer Ross-Nazzal is the NASA Human Spaceflight Historian. She is the author of Winning the West for Women: The Life of Suffragist Emma Smith DeVoe and Making Space for Women: Stories from Trailblazing Women of NASA's Johnson Space Center.
      Share
      Details
      Last Updated Oct 07, 2024 Related Terms
      NASA History Astronauts Former Astronauts Humans in Space Kathryn D. Sullivan STS-41G Women at NASA Explore More
      4 min read The Iconic Photos from STS-41B: Documenting the First Untethered Spacewalk
      Article 8 months ago 5 min read Eileen Collins Broke Barriers as America’s First Female Space Shuttle Commander
      Article 3 months ago 10 min read 35 Years Ago: STS-41G – A Flight of Many Firsts
      Article 5 years ago Keep Exploring Discover More Topics From NASA
      Explore NASA’s History
      Women at NASA
      Space Shuttle
      International Space Station Spacewalks
      View the full article
    • By European Space Agency
      ESA engineers have focused microscopes, hardness testers and an X-ray computer aided tomography machine onto a special aluminium weld just a single centimetre across – the historic result of the very first autonomous welding to be performed in space, and the first ESA has been involved with.
      View the full article
    • By Space Force
      The X-37B Orbital Test Vehicle will begin executing a series of novel maneuvers, called aerobraking, to change its orbit around Earth and safely dispose of its service module components in accordance with recognized standards for space debris mitigation.

      View the full article
  • Check out these Videos

×
×
  • Create New...