A new dark matter map has provided scientists insight into the existence of cold dark matter particles.
International scientists led by a Yale University astrophysicist successfully rendered the distribution of dark matter in the galaxy in high-resolution images, producing the most detailed map of it to date.
The new map is based on data captured by the Hubble Space Telescope Frontier Fields from three galaxy clusters, which astronomers liken to "cosmic magnifying glasses" that peer into more distant parts of the universe. This process is called gravitational lensing.
Elusive Dark Matter
Priyamvada Natarajan, a theoretical astrophysicist at Yale, said that thanks to data from these lensing cluster, the research team mapped dark matter granularity in exquisite detail.
"We have mapped all of the clumps of dark matter that the data permit us to detect," said Natarajan.
Dark matter, which makes up about 80 percent of the universe, is thought to hold many secrets about galaxy formation and structures. Its particles do not absorb or reflect light, and theoretical evidence for its existence have all been indirect.
Natarajan said although they have a precise cosmic inventory for dark matter in the galaxy, its particles remain elusive.
Dark Matter Distribution
It is believed that the gravitational pull of dark matter can influence gravitational lensing, a phenomenon that bends distant light around galactic clusters and intermediary galaxies.
In the new study, Natarajan and her colleagues took advantage of this gravitational lensing, which magnified distant galaxies and multiplied the images.
After poring over the images taken by Hubble, scientists identified several dozens of background galaxies and then deduced dark matter distribution based on this dataset.
For instance, for galaxy MACSJ0416, which is pictured above, the distribution of dark matter is made up of two broad, overlapping spots covered with hundreds of denser knots that enshroud individual galaxies.
Existence Of Cold Dark Matter Particles
Significantly, the new dark matter map fits well with predictions of standard models of cold dark matter particles, which are thought to be sluggish particles that make up a huge bulk of the universe.
In fact, cold dark matter particles are slower than the speed of light and does not interact with each other, while hot dark matter particles are faster.
All this makes the new dark matter map notable for its distribution because it agrees with previous distribution maps generated by predictive computer models.
In late February, NASA's Fermi telescope detected gamma-rays that may point to the presence of dark matter at the center of the Andromeda galaxy about 2.5 million light-years away from Earth. Scientists have yet to verify whether the gamma-ray signals were generated by dark matter particles or pulsars.
Details of the study are published in Monthly Notices of the Royal Astronomical Society.
