Academia Sinica researchers said they have calculated that a supermassive black hole in a galaxy 4 billion light-years away might contain more than 300 million times the Sun’s mass by analyzing images taken by radio telescopes, adding that the findings are key to understanding the formation and evolution of black holes and their host galaxies.
A team led by research fellows Kenneth Wong (黃活生), Sherry Suyu (蘇游瑄) and Satoki Matsushita on Monday said that it analyzed the high-resolution images of SDP.81, a galaxy located 4 billion light-years from Earth, taken by the Atacama Large Millimeter Array (ALMA) in Chile — the biggest radio telescope array in the world for observing radiation from the early universe, molecular gas and interstellar dust.
The images were taken during a chance alignment of the Earth, SDP.81 and another galaxy — all located in a straight line spanning 12 billion light-years, Wong said.
The images display what is known as the Einstein ring: the deformation of light from a source — in this case, the background galaxy 12 billion light-years away — into a ring due to gravitational lensing by an object with an extremely large mass — SDP.81, Wong said.
The gravity of the massive foreground galaxy deflects the light from the background galaxy and creates the ring structure, allowing the team to calculate the mass of a supermassive black hole, located near the center of SDP.81, by analyzing the brightness of the ring and of the central image within the ring, Wong said, adding that the Hubble Space Telescope is unable to capture such images as it only detects visible and infrared light.
“This is the highest resolution image of a gravitational lens that has ever been taken, and the amount of detail in this image is much greater than even space-based telescope observations,” he said.
Almost all massive galaxies seem to have supermassive black holes at their centers. Previously, scientists could only directly calculate the mass for galaxies immediately adjacent, Wong said.
“ALMA now gives us the sensitivity to look at the central image of the lens, which can allow us to determine the mass of much more distant black holes,” Wong said.
Measuring the masses of more distant black holes is critical to understanding their relationship with their host galaxies and how they grow over time, he added.
The research was published last month in the peer-reviewed Astrophysical Journal periodical.
Next year the team plans to observe a gravitational lens located 6 billion light-years away.
TOO CLOSE FOR COMFORT: A US Air Force KC-135 tanker came less than 1,000 feet of an EVA plane and was warned off by a Taipei air traffic controller, a report said A US aerial refueling aircraft came very close to an EVA Airways jet in the airspace over southern Taiwan, a military aviation news Web site said. A report published by Alert 5 on Tuesday said that automatic dependent surveillance–broadcast (ADS-B) data captured by planfinder.net on Wednesday last week showed a US Air Force KC-135 tanker “coming less than 1,000 feet [305m] vertically with EVA Air flight BR225 as both aircraft crossed path south of Taiwan” that morning. The report included an audio recording of a female controller from the Taipei air traffic control center telling the unidentified aircraft that it was
A US aircraft carrier group led by the USS Theodore Roosevelt has entered the South China Sea to promote “freedom of the seas,” the US military said yesterday, as tensions between China and Taiwan raise concerns in Washington. US Indo-Pacific Command said in a statement that the strike group entered the South China Sea on Saturday, the same day Taiwan reported a large incursion of Chinese bombers and fighter jets into its air defense identification zone near the Pratas Islands (Dongsha Islands, 東沙群島). The US military said the carrier strike group was in the South China Sea, a large part of which
STRATEGIC MISTAKE: Beijing’s deployment of aircraft near Taiwan proves the ‘China threat theory’ that sees it attempting to destabilize the region, an analyst said China on Saturday and yesterday sent a record number of military aircraft into the nation’s air defense identification zone (ADIZ), in what analysts said was an attempt to flex its military might for US President Joe Biden. Thirteen Chinese warplanes flew into Taiwan’s southwestern ADIZ on Saturday and 15 entered yesterday, the highest number observed in a single day this year, the Ministry of National Defense said. On Saturday, eight Xian H-6K bombers, four Shenyang J-16 fighters and a Y-8 anti-submarine aircraft, entered the ADIZ, while yesterday there were two Y-8s, two Su-30s, four J-16s, six J-10 fighters and a Y-8 reconnaissance
DISPOSING MYTHS: A new constitution would better reflect reality, as the current one was drafted ‘in and for China,’ without the consent of Taiwanese, advocates said Independence advocates yesterday launched the Taiwan New Constitution Alliance to promote drafting a new, localized constitution. “This is a historic moment for Taiwan. Drafting a new constitution is the most important task Taiwanese face,” veteran independence advocate Koo Kwang-ming (辜寬敏) said at the inaugural event in Taipei. “Although the Democratic Progressive Party is in power, its authority is based on the Republic of China [ROC] Constitution, which has no connection to Taiwan,” said the 95-year-old Koo, a former presidential adviser. “The historic task of drafting a new constitution depends on efforts by all Taiwanese,” Koo said. “A constitution for a sovereign, independent Taiwan