A spongy web of dark matter with supernovae as points embedded throughout.
Illustration of supernova explosions in the large-scale structure. The colormap indicates the dark matter density at 4 Mpc, constrained with 2M++ galaxy data by the BORG algorithm. Credit: Eleni Tsaprazi

One endeavor that has been challenging cosmologists is how to obtain an accurate picture of the universe on large scales in order to understand the origin of cosmic acceleration and how gravity works in that regime. The standard way to map our Universe is by surveying as many galaxies as possible and measuring their distances from us. Beyond a certain distance galaxies become too dim to detect, whereas supernovae are bright point sources that can be detected even further away. The Vera C. Rubin Observatory’s Legacy Survey of Space and Time will soon begin and it is expected to detect tens of thousands of supernovae per year, a detection rate which should allow us to use supernova explosions to map the cosmic structure at large distances.

However, there is a catch! Until now it was not known whether supernovae sample the same large-scale structure as galaxies do! They could potentially only happen in certain regions and not others. This is the very question that these scientists answered in this study. They found that in our nearby Universe supernovae and galaxies trace the cosmic structure in a similar way. 

The three main results of this research are:

1. Supernovae cluster strongly and need to be modelled that way when simulating supernova surveys.

2. Galaxy and supernova surveys can be used jointly to map the large-scale structure.

3. The combination of galaxy and supernova clustering can provide constraints on modified theories of gravity and yield further understanding of the process of structure formation from the early universe until today.