Using the MUSE and FORS2 instruments on ESO’s Very Large Telescope (VLT), astronomers have spotted a group of six galaxies around SDSS J1030+0524, a quasar powered by a one billion solar mass black hole. The light from this large web-like structure has traveled to us from a time when the Universe was only 900 million years old.
This artist’s impression shows a supermassive black hole in the center of SDSS J1030+0524 and six galaxies — four Lyman-break galaxies and two Lyman-alpha emitting galaxies — trapped in its gas web. The large web-like structure extends over 300 times the size of the Milky Way. Image credit: L. Calçada / ESO.
The Universe’s very first black holes, thought to have formed from the collapse of the first stars, must have grown very fast to reach masses of a billion suns within the first 0.9 billion years of the Universe’s life.
But astronomers have struggled to explain how sufficiently large amounts of ‘black hole fuel’ could have been available to enable these objects to grow to such enormous sizes in such a short time.
The newfound web-like structure around SDSS J1030+0524 offers a likely explanation: the web and the galaxies within it contain enough gas to provide the fuel that the central black hole needs to quickly become a supermassive giant.
“This research was mainly driven by the desire to understand some of the most challenging astronomical objects — supermassive black holes in the early Universe,” said Dr. Marco Mignoli, an astronomer at the National Institute for Astrophysics (INAF).
“These are extreme systems and to date we have had no good explanation for their existence.”
“The cosmic web filaments are like spider’s web threads. The galaxies stand and grow where the filaments cross, and streams of gas — available to fuel both the galaxies and the central supermassive black hole — can flow along the filaments,” he added.
“Our work has placed an important piece in the largely incomplete puzzle that is the formation and growth of such extreme, yet relatively abundant, objects so quickly after the Big Bang,” said Dr. Roberto Gilli, also from INAF.
But how did such large web-like structures form in the first place? Astronomers think giant halos of mysterious dark matter are key.
These large regions of invisible matter are thought to attract huge amounts of gas in the early Universe.
Together, the gas and the invisible dark matter form the web-like structures where galaxies and black holes can evolve.
“Our finding lends support to the idea that the most distant and massive black holes form and grow within massive dark matter halos in large-scale structures, and that the absence of earlier detections of such structures was likely due to observational limitations,” said Dr. Colin Norman, an astronomer at Johns Hopkins University.
“We believe we have just seen the tip of the iceberg, and that the few galaxies discovered so far around this supermassive black hole are only the brightest ones,” said Dr. Barbara Balmaverde, an astronomer at INAF.
The findings were published in the journal Astronomy & Astrophysics.
_____
Marco Mignoli et al. 2020. Web of the giant: Spectroscopic confirmation of a large-scale structure around the z = 6.31 quasar SDSS J1030+0524. A&A 642, L1; doi: 10.1051/0004-6361/202039045
