Researchers mapped the mass within a distant galaxy more precisely than ever before using the NASA/ESA Hubble Space Telescope.
The team measured the mass inside of the galaxy cluster MCS J0416.1-2403 using data from the telescope and a phenomenon know as gravitational lensing. This occurs when clumps of mass in the universe warp the space time around them; they acts a "lens" and appear to bend light.
"The depth of the data lets us see very faint objects and has allowed us to identify more strongly lensed galaxies than ever before," said Mathilde Jauzac of Durham University, UK, and Astrophysics & Cosmology Research Unit, South Africa, lead author of the new Frontier Fields paper. "Even though strong lensing magnifies the background galaxies they are still very far away and very faint. The depth of these data means that we can identify incredibly distant background galaxies. We now know of more than four times as many strongly lensed galaxies in the cluster than we did before."
The researchers identified 51 new multiply imaged galaxies around the cluster, which quadruples what has been seen in previous surveys, bringing the number of lensed galaxies to 68.
"Although we've known how to map the mass of a cluster using strong lensing for more than twenty years, it's taken a long time to get telescopes that can make sufficiently deep and sharp observations, and for our models to become sophisticated enough for us to map, in such unprecedented detail, a system as complicated as MCS J0416.1-2403," team member Jean-Paul Kneib said.
The new map is considered to be twice as good as any previously made of this galaxy cluster. The total mass within MCS J0416.1-2403 was found to be 160 trillion times that of the Sun.
"Frontier Fields' observations and gravitational lensing techniques have opened up a way to very precisely characterise distant objects -- in this case a cluster so far away that its light has taken four and a half billion years to reach us," Kneib said. "But, we will not stop here. To get a full picture of the mass we need to include weak lensing measurements too. Whilst it can only give a rough estimate of the inner core mass of a cluster, weak lensing provides valuable information about the mass surrounding the cluster core."
