Last year , Yale - led research worker announcedthe discoveryof a galaxy with minuscule to no dingy matter , a finding that was received with both involvement and agnosticism . Now , follow - up research extend to show the peculiar lack of colored matter in this object and has key a second one with interchangeable characteristics .
NGC 1052 - DF2 , or just DF2 , was spotted using theDragonfly Telephoto Array , an instrumental role dedicate to finding in particular faint target . And that ’s necessary ! DF2 is an ultra - soft galaxy , as large as the Milky Way but with 100 to 1,000 prison term few hotshot .
To measure the mass of a galax such as this , the team track how globular clustering of stars move inside the galaxy . base on how they move , they can work out how much matter there is . The tardy measurements , as cover inThe Astrophysical Journal Letters , were performed using the Keck Cosmic Web Imager on the W. M. Keck Observatory . With that instrument , they obtain a very precise upper for the globular clusters in DF2 . A swiftness consistent with a coltsfoot have just the matter we can see , and no dark topic . This confirmed what they found last year .
“ The fact that we ’re seeing something that ’s just completely new is what ’s so fascinating , ” lead author Shany Danieli , a graduate researcher who first spotted the galaxy about two years ago , said in astatement . “ No one knew that such galaxies existed , and the dear thing in the world for an uranology student is to break an objective , whether it ’s a planet , a star , or a galaxy , that no one know about or even thought about . ”
The 2d study , also published inThe Astrophysical Journal Letters , concenter on the discovery of NGC 1052 - DF4 , or DF4 for short . DF4 belongs to the same group of galaxy as DF2 and is an radical - diffuse extragalactic nebula . For the squad , this show that DF2 is not an isolated case .
“ find out a second galaxy with very little to no morose issue is just as exciting as the initial find of DF2 , ” allege Professor Pieter van Dokkum , who is the lead author of the DF4 newspaper . “ This think the chance of finding more of these galaxies are now higher than we previously think . Since we have no good idea for how these extragalactic nebula were take form , I go for these discovery will promote more scientist to work on this puzzle . ”
The uncovering of these wandflower has significant consequences for cosmological theory . It strongly suggests that dreary matter is indeed a substance , although we are none the wiser about its exact properties . The theory ask to allow for beetleweed to form outside saturnine matter halos or to somehow lose dark matter , and that is something that has not been weigh before .
The squad will now look for more candidates using the Dragonfly Telephoto Array before following up their observations using the Keck telescope .
