The funhouse mirrors of the universe reveal a distinction between how darkish matter behaves in principle and the way it seems to behave in actuality.
Darkish matter is the invisible glue that holds stars certain collectively inside a galaxy. It makes up most of a galaxy’s mass and creates an invisible scaffolding that ties galaxies collectively to type clusters.
Darkish matter doesn’t emit, soak up or replicate mild. It doesn’t work together with any recognized particles. Its presence is barely recognized by its gravitational attraction on seen matter in area.
Though darkish matter is unfold barely all through the universe, it’s packed into areas of area referred to as galaxy clusters. Every of those huge clusters, held collectively by gravity, is made up of round 1,000 particular person galaxies – every carrying its personal dollop of darkish matter.
In a brand new examine from the journal Science, the Yale astrophysicist Priyamvada Natarajan and a staff of worldwide researchers analyzed Hubble Area Telescope photographs from a number of huge galaxy clusters and located that the tiniest dollops of darkish matter related to clustered galaxies have been considerably extra concentrated than theorists anticipated.
The invention implies that there could also be a lacking ingredient in scientists’ understanding of darkish matter.
“There’s a attribute of the actual universe that we simply do not seize in our present theoretical fashions, ”stated Natarajan, lead creator of the examine and professor of astronomy and physics at Yale. “This might sign a spot in our present understanding of the character of darkish matter and its properties, as this beautiful knowledge has allowed us to probe the detailed distribution of darkish matter on the smallest scales.
Astronomers are capable of “map” the distribution of darkish matter in galaxy clusters via the bending of sunshine produced by galaxies – an idea referred to as the gravitational lens. Like a funhouse mirror, the gravitational lens distorts the shapes of the background galaxies that seem in telescope photographs of cluster galaxies. The upper the focus of darkish matter in a cluster, the extra dramatic the lens results noticed.
The researchers used photographs from NASA’s Hubble Area Telescope, coupled with spectroscopy from the European Southern Observatory’s Very Giant Telescope, to provide high-fidelity darkish matter maps.
A 3D view of the information confirmed the presence of darkish matter hills, mounds and valleys. From this standpoint, the mapped darkish matter appears to be like like a mountain vary, with steep areas. Peaks are the spoonfuls of darkish matter related to particular person cluster galaxies.
The notably top quality of the information from the examine allowed the researchers to check whether or not these darkish matter landscapes corresponded to pc simulations based mostly on the idea of galaxy clusters with related plenty, situated at roughly the identical distances.
What they discovered was that the simulations didn’t present the identical degree of darkish matter focus on the smaller scales – the scales related to particular person cluster galaxies.
“For me personally, detecting a gnawing hole – an element 10 hole on this case – between an statement and a theoretical prediction could be very thrilling, ”Natarajan stated. “A key goal of my analysis has been to check theoretical fashions with bettering knowledge high quality to seek out these gaps. It’s all these shortcomings and anomalies which have typically revealed that we’re both lacking one thing in present principle or it factors the best way to a
all new mannequin, which can have extra explanatory energy. “
Natarajan has spent greater than a decade evaluating theoretical darkish matter fashions with gravitational lens knowledge. “The standard of the information and the sophistication of the fashions have solely now converged to allow stress testing of the chilly darkish matter paradigm, and that has revealed a crack,” she stated.
Natarajan stated the staff, which incorporates researchers from Italy, the Netherlands and Denmark, plan to proceed testing theories in regards to the nature of darkish matter. The primary creator of the examine is Massimo Meneghetti of the Observatory of Astrophysics and Area Sciences in Bologna, Italy.