Astronomers observe lone distant galaxy that appears to have consumed all of its former companions

Over 13 billion years in the past, the primary galaxies within the universe fashioned. They had been elliptical, with intermediate black holes (IMBHs) at their facilities surrounded by a halo of stars, gasoline, and dust. Over time, these galaxies advanced by flattening out into disks with a big bulge within the center. They had been then drawn collectively by mutual gravitational attraction to type galaxy clusters, huge collections that comprise the large-scale cosmic construction. This drive of attraction additionally led to mergers, the place galaxies and their central black holes got here collectively to create bigger spiral galaxies with central supermassive black holes (SMBHs).

This means of mergers and assimilation (and their position in galactic evolution) remains to be a thriller to astronomers at this time since a lot of it passed off through the early universe, which remains to be very tough to watch with present telescopes. Utilizing information from NASA’s Chandra X-ray Observatory and the Worldwide Gemini Observatory, a global staff of astronomers noticed a lone distant galaxy that seems to have consumed all of its former companions. Their findings, which not too long ago appeared in The Astrophysical Journal, counsel galaxies within the early universe grew sooner than beforehand thought.

The analysis staff was led by Valentina Missaglia, a postdoctoral astrophysicist on the College of Turin. She was joined by colleagues from the Nationwide Nuclear Physics Institute (INFN), the Astrophysical Observatory of Turin, The College of Texas Rio Grande Valley, the Max Planck Institute for Astronomy (MPIA), the Brazil Ministry of Science, Know-how, Innovation, and Communication (MCTIC), the Instituto Nacional de Pesquisas Espaciais (INPE), the Harvard & Smithsonian Heart for Astrophysics, Institute of Theoretical and Experimental Astronomy (IATE), and the Nationwide Institute of Astrophysics (INAF).

The staff reported the surprising discovery of a solo galaxy (3C 297) about 9.2 billion light-years away. In addition they famous that it contained a quasar at its middle and highly effective jets (shiny within the radio spectrum) emanating from its poles. The atmosphere of this galaxy seems to have a number of key options of a galaxy cluster; however, the galaxy seems to be alone. As Missaglia mentioned in a Harvard-Chandra press launch, “Plainly we now have a galaxy cluster that’s lacking nearly all of its galaxies,” she mentioned. “We anticipated to see at the least a dozen galaxies concerning the dimension of the Milky Way, but we see just one.”

Missaglia and her colleagues famous three options related to galaxy clusters based mostly on the Chandra information. First, the X-ray information revealed that 3C 297 is surrounded by massive portions of high-temperature gasoline (tens of tens of millions of levels)—one thing hardly ever seen outdoors of galaxy clusters. Second, the relativistic jet streaming from its SMBH created a shiny X-ray supply about 140,000 light-years away, which implied it had pushed by way of gasoline surrounding the galaxy. Third, one of many radio jets appeared bent, indicating it was interacting with its environment.

This final discovering was beforehand noticed based mostly on information collected by the Karl G. Jansky Very Giant Array (VLA). However when the staff consulted their information from the Gemini Observatory, they seen that not one of the 19 galaxies that appeared near 3C 297 had been truly on the identical distance. Mentioned co-author Juan Madrid, an assistant professor on the College of Texas Rio Grande Valley:

“The query is, what occurred to all of those galaxies? We predict the gravitational pull of the one massive galaxy mixed with interactions between the galaxies was too robust, and so they merged with the big galaxy. For these galaxies, apparently, resistance was futile.”

Whereas the authors can not rule out the potential of dwarf galaxies positioned round 3C 297, their presence would nonetheless not clarify why no bigger galaxies are close by. As well as, they anticipate that 3C 297 will spend a number of billion years by itself earlier than it beneficial properties any massive galactic companions (like M87 and the Virgo Cluster). Whereas it isn’t clear how 3C 297 ended up by itself in a cluster-like atmosphere, the staff theorizes that it could possibly be a “fossil group”—the tip stage of a galaxy merging with a number of others.

Whereas many different fossil teams have been detected earlier than, at 9.2 billion light-years distant, this one is probably the most distant ever seen. The earlier file holders for fossil teams had been 4.9 and seven.9 billion light-years away (respectively). “It could be difficult to clarify how the universe can create this technique solely 4.6 billion years after the Massive Bang,” mentioned co-author Mischa Schirmer of the MPIA. “This does not break our concepts of cosmology, however it begins to push the bounds on how shortly each galaxies and galaxy clusters should have fashioned.”