Two separate teams of astronomers find evidence of missing Baryonic matter


Credit: CC0 Public Domain

(—Two teams working independently have found
evidence of the existence of missing Baryonic
matter—particles that link galaxies together. One team was
made of members from the Institute of Space Astrophysics, the
other was based out of the University of Edinburgh. Both
teams have uploaded a paper describing their work to the
arXiv preprint server and both are claiming their
findings solve the mystery of where so much of the normal
matter—protons, neutrons and electrons—in the universe has
been hiding.

Once scientists came up with the Big Bang Theory, a problem
immediately arose—after calculating how much normal matter
should exist in the universe at this point in time, they found
approximately 50 percent of it is missing. Since then,
scientists have worked on theories to explain where all that
matter was hiding—the prevailing theory suggests that it exists
as strands of Baryonic matter floating in the space between
galaxies and cannot be seen with conventional instruments—this
was the theory both teams in this new effort tested.

To get around the problem of not being able to see the Baryonic
matter directly, the researchers considered a phenomenon called
the Sunyaev-Zel’dovich effect in which light left over from the
Big Bang scatters as it passes through hot gas—it should be
measurable in the . Both teams
used data from the Planck Collaboration presented two years ago
to create a map of where Baryonic matter strands might exist.
Each selected a pair of galaxies to study, focusing on the
space between them. Then, they stacked data from between the
two galaxies to magnify data believed to be from Baryonic

Both teams repeated this process for multiple pairs of galaxies
to show that their readings were consistent across multiple
test sites—one team tested a million pairs, the other 260,000.
Both report finding evidence of the theorized filaments between
the galaxies. One group found them to be three times as dense
as the mean of observable matter, the other group six times—a
difference that was expected, the groups explain, due to
differences in distances from the that were studied.

Both groups claim their findings prove the existence of missing
Baryonic matter and thus solve the mystery of where all the
unmeasurable has been hiding.

Explore further:
Shines Cosmic Light on Missing Ordinary Matter

More information: A Search for Warm/Hot Gas Filaments
Between Pairs of SDSS Luminous Red Galaxies, arXiv:1709.05024

Missing baryons in the cosmic web revealed by the
Sunyaev-Zel’dovich effect, arXiv:1709.10378 [astro-ph.CO]

© 2017