- 3978 - X-RAY GALAXIES - new revelations. Astronomer's will depend on getting more data from “simulated galactic clusters”. SLAC cosmologists are currently attempting to expand the size of computer simulations of the cosmos while improving accuracy.
--------------------- 3978 - X-RAY GALAXIES - new revelations.
- A new
investigation of the structure of galaxy clusters has found it agrees with
predictions made by the standard model of cosmology, the best explanation
scientists have of the evolution of the universe over its 13.8 billion-year
existence.
-
- The SLAC
National Accelerator Laboratory at Stanford University, measured X-ray
emissions from clusters of galaxies to reveal the structure of these clusters and
the distribution of matter throughout them.
-
- The data
they collected conform to a model of universal evolution and structure called
the “lambda cold dark matter” (ΛCDM) model, which suggests that the infant
universe was an extremely hot, dense sea of photons and matter tightly coupled
as plasma.
-
- As the
infant universe underwent a period of rapid expansion called “inflation:, small
perturbations spread through the plasma as a sound wave, producing under- and
over-densities of both matter and radiation, but not affecting dark matter.
-
- According
to the ΛCDM model, the plasma expanded and cooled, and electrons and protons
soon combined to form the first atoms, with free electrons no longer infinitely
scattering photons.
-
- This allowed
the universe to become transparent to light. Overdense regions collapsed to
birth the first stars, and the universe eventually reached its current state,
with clusters of galaxies as the largest bound objects linked by a vast cosmic
web of dark matter.
-
- Confirming
this ΛCDM model by inferring the mass distributions of galactic clusters from
X-ray emissions was no easy task. It is
easier to use X-ray emissions as a measurement of mass distribution when the
energy of the gas in clusters is balanced by the pull of gravity as it binds
the entire system.
-
- This
balance is achieved when galaxy clusters have settled down into a
"relaxed" state. When
researchers compare real observations with the theoretical predictions of the
ΛCDM model, they must take into account that there has been a bias toward
selecting these "relaxed" galaxies.
-
- Redshift
is the stretching of the wavelength of light that occurs as a result of the
expansion of the universe. The farther light has traveled, the more it is
shifted toward the red end of the electromagnetic spectrum. That means the
earlier and more distant the galaxy, the more extreme the redshift, thus making
this a great measure of both distance and age.
-
- This
research has found that over the universe's 13.8 billion-year existence,
clusters have become more centrally concentrated. At the same time, at any
given epoch of the universe, less massive clusters are more centrally
concentrated than more massive ones.
-
- When the
Vera C. Rubin Observatory opens its eye on the universe, it will begin the
“Legacy Survey of Space and Time”, which should spot far more galaxy clusters.
Joining this quest will be the fourth-generation cosmic microwave background
experiment, while the European Space Agency's Athena satellite mission will
follow up with more X-ray measurements.
-
April 29, 2023 X-RAY
GALAXIES - new revelations. 3978
----------------------------------------------------------------------------------------
----- Comments
appreciated and Pass it on to whomever is interested. ---
--- Some
reviews are at: -------------- http://jdetrick.blogspot.com -----
-- email
feedback, corrections, request for copies or Index of all reviews
--- to: ------
jamesdetrick@comcast.net
------ “Jim Detrick” -----------
--------------------- --- Sunday, April 30, 2023
---------------------------
-
No comments:
Post a Comment