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February 25, 2015

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Mystery of early black holes deepens with huge new find

Feb. 25, 2015
Courtesy of the University of Arizona
and World Science staff

Sci­en­tists have found what they call the big­gest black hole in the early uni­verse, a dis­cov­ery that they say does­n’t square with stand­ard the­o­ries of cos­mic ev­o­lu­tion.

The way most sci­en­tists un­der­stand it, ob­jects in the early uni­verse co­a­lesced bit by bit through gra­vity. So really mas­sive ob­jects should not have formed very early on.

Artist's im­pres­sion of a close-up qua­sar with a su­per­mas­sive black hole in the dis­tant uni­verse. (Cred­it: Zhaoyu Li/NA­SA/JPL-Caltech/Misti Moun­tain Ob­serv­a­to­ry)


But a big black hole is, by de­fin­ition, a really, really mas­sive ob­ject. This new one breaks some rec­ords and is is 3,000 heav­i­er than the black hole at the cen­ter of our gal­axy, ac­cord­ing to the re­search­ers. 

A black hole is an ob­ject so heavy and com­pact that its gra­vity draws in an­y­thing that gets too close. Most ga­lax­ies are be­lieved to have huge black holes at their cores. A cer­tain type of gal­axy whose black hole is ac­tively gob­bling up ma­te­ri­al is called a qua­sar. Quasars are par­tic­u­larly bright be­cause of heat gen­er­at­ed in the vi­o­lent pro­cess.

What the in­ves­ti­ga­tors in the new study said they found is the bright­est qua­sar in the early uni­verse, pow­ered by the most mas­sive black hole yet known at that time. The in­terna­t­ional team led by as­tro­no­mers from Pe­king Uni­vers­ity in Chi­na and the Uni­vers­ity of Ar­i­zo­na is an­nounc­ing their find­ings in the jour­nal Na­ture on Feb. 26.

The qua­sar lies at an es­ti­mat­ed 12.8 bil­lion light-years from Earth. A light-year is the dis­tance light trav­els in a year, mean­ing that sci­en­tists are see­ing the ob­ject ap­prox­i­mately as it was 12.8 bil­lion years ago. The “Big Bang,” an ex­plo­sive event thought to have orig­i­nat­ed the uni­verse, had oc­curred less than a bil­lion years ear­li­er.

The cen­tral black hole weighs the equiv­a­lent of 12 bil­lion Suns and is as bright as 420 tril­lion of them, ac­cord­ing to the au­thors. It’s al­so a huge puz­zle, ex­plained Xi­ao­hui Fan of the Uni­vers­ity of Ar­i­zo­na’s Stew­ard Ob­serv­a­to­ry, who co-au­thored the stu­dy.

“How can a qua­sar so lu­mi­nous, and a black hole so mas­sive, form so early in the his­to­ry of the uni­verse, at an era soon af­ter the ear­li­est stars and ga­lax­ies have just emerged?” Fan said. “And what is the rela­t­ion­ship be­tween this mon­ster black hole and its sur­round­ing en­vi­ron­ment, in­clud­ing its host gal­ax­y?”

The qua­sar dates from a time close to the end of an im­por­tant cos­mic event that as­tro­no­mers call “reion­iz­a­tion”: a sort of cos­mic dawn when a heavy fog over the whole uni­verse grad­u­ally lifted.

First disco­vered in 1963, qua­sars are the most pow­er­ful ob­jects be­yond our Milky Way gal­axy, beam­ing vast amounts of en­er­gy across space as the supermas­sive black hole in their cen­ter sucks in mat­ter from its sur­round­ings. Thanks to the new genera­t­ion of dig­it­al sky sur­veys, as­tro­no­mers have disco­vered more than 200,000 qua­sars, with ages rang­ing from 0.7 bil­lion years af­ter the Big Bang to to­day.

The new qua­sar is sev­en times brighter than the most dis­tant qua­sar known, 13 bil­lion years away, Fan and col­leagues said, and it’s bright­est qua­sar with the most mas­sive black hole among all known very dis­tant, early qua­sars.

Feige Wang, a doc­tor­al stu­dent from Pe­king Uni­vers­ity who is su­per­vised jointly by Fan and Xue-Bing Wu at Pe­king Uni­vers­ity, the stu­dy’s lead au­thor, in­i­tially spot­ted the qua­sar.

“This qua­sar was first disco­vered by our 2.4-meter Li­jiang Tel­e­scope in Yun­nan, Chi­na, mak­ing it the only qua­sar ev­er disco­vered by a 2-meter tel­e­scope at such dis­tance, and we’re very proud of it,” Wang said. The “size” of a tel­e­scope refers to the width of its light-collecting ar­ea. Af­ter the in­i­tial find­ing, two tel­e­scopes in south­ern Ar­i­zo­na did the heavy lift­ing in meas­ur­ing char­ac­ter­is­tics of the black hole: the 8.4-meter Large Bin­oc­u­lar Tel­e­scope on Mount Gra­ham and the 6.5-meter Mul­ti­ple Mir­ror Tel­e­scope on Mount Hop­kins.

The re­search team plans to fur­ther in­ves­t­i­gate the ob­ject with more in­terna­t­ional tel­e­scopes, in­clud­ing NASA’s Hub­ble Space Tel­e­scope and the Chan­dra X-ray Tel­e­scope.


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Scientists have found what they call the biggest black hole in the early universe, a discovery that they say doesn’t square with standard theories of cosmic evolution. The way most scientists understand it, objects in the early universe coalesced bit by bit, so really massive objects should not have formed very early on. But a black hole is just that—a really, really massive object. This new one is 3,000 heavier than the black hole at the center of our galaxy, according to the researchers. A black hole is an object so heavy and compact that its gravity draws in anything that gets too close. Most galaxies are believed to have huge black holes at their cores. A certain type of galaxy whose black hole is actively gobbling up material is called a quasar. Quasars are particularly bright because of heat generated in the violent process. What the investigators in the new study said they found is the brightest quasar in the early universe, powered by the most massive black hole yet known at that time. The international team led by astronomers from Peking University in China and from the University of Arizona is announcing their findings in the journal Nature on Feb. 26. The quasar lies at an estimated 12.8 billion light-years from Earth. A light-year is the distance light travels in a year, meaning that scientists are seeing the object approximately as it was 12.8 billion years ago. The “Big Bang,” an explosive event thought to have originated the universe, had occurred less than a billion years earlier. The central black hole weighs the equivalent of 12 billion Suns and is as bright as 420 trillion of them, according to the authors. It’s also a huge puzzle, explained Xiaohui Fan of the University of Arizona’s Steward Observatory, who co-authored the study. “How can a quasar so luminous, and a black hole so massive, form so early in the history of the universe, at an era soon after the earliest stars and galaxies have just emerged?” Fan said. “And what is the relationship between this monster black hole and its surrounding environment, including its host galaxy? The quasar dates from a time close to the end of an important cosmic event that astronomers referred to as the “epoch of reionization”: a sort of cosmic dawn when a heavy fog over the whole universe gradually lifted. First discovered in 1963, quasars are the most powerful objects beyond our Milky Way galaxy, beaming vast amounts of energy across space as the supermassive black hole in their center sucks in matter from its surroundings. Thanks to the new generation of digital sky surveys, astronomers have discovered more than 200,000 quasars, with ages ranging from 0.7 billion years after the Big Bang to today. The new quasar is seven times brighter than the most distant quasar known, 13 billion years away, Fan and colleagues said, and it’s brightest quasar with the most massive black hole among all known very distant quasars. Feige Wang, a doctoral student from Peking University who is supervised jointly by Fan and Prof. Xue-Bing Wu at Peking University, the study’s lead author, initially spotted the quasar. “This quasar was first discovered by our 2.4-meter Lijiang Telescope in Yunnan, China, making it the only quasar ever discovered by a 2-meter telescope at such distance, and we’re very proud of it,” Wang said. The “size” of a telescope refers to the width of its light-collecting area. After the initial finding, two telescopes in southern Arizona did the heavy lifting in measuring characteristics of the black hole: the 8.4-meter Large Binocular Telescope, or LBT, on Mount Graham and the 6.5-meter Multiple Mirror Telescope, or MMT, on Mount Hopkins. The research team plans to further investigate the object with more international telescopes, including NASA’s Hubble Space Telescope and the Chandra X-ray Telescope.