This telescope’s data still has astronomers in a tizzy
From:
International Centre for Radio Astronomy Research
December 1, 2021 -- Data collected by
the Arecibo Radio Telescope before it collapsed late last year will help
astronomers better understand how our local neighborhood of galaxies formed.
Arecibo was the world's largest single-dish radio telescope until it was
surpassed in 2016 by China's Five-hundred-meter Aperture Spherical Telescope
(FAST). At the end of 2020, Arecibo's 900-ton receiver platform suddenly and
spectacularly fell onto the dish below, destroying the telescope.
A team of astronomers from the
University of Western Australia and the International Centre for Radio
Astronomy Research (ICRAR) in Perth have used Arecibo's observations of nearby
galaxies to test the 'Fall relation'.
First presented by S. Michael Fall in
1983, the Fall relation suggests the mass of stars belonging to a galaxy and
its rotation directly correlate to each other and dictate how a galaxy will
grow and evolve.
Funded by the Australian Research
Council and published in the journal Monthly Notices of the Royal Astronomical
Society (MNRAS), the new study tests this relationship using data collected
from 564 galaxies of varying shapes and ages, making it the largest
representative sample of its kind.
Lead author and PhD candidate Jennifer
Hardwick said the study would help researchers better understand how a wide
range of galaxies evolved and formed, including our galaxy, the Milky Way.
"Although the Fall relation was
first suggested almost 40 years ago, previous research to refine its properties
had small samples and was limited in the types of galaxies used," Hardwick
said.
"This work challenges astronomers'
current understanding of how galaxies change over their lifetime and provides a
constraint for future researchers to develop these theories further."
Prior research into this relationship
has been restricted by the type and number of known galaxies with resolved
accurate data, which researchers use to measure galaxy rotation through the
Doppler effect.
The study shows that the relationship
between the mass of stars and a galaxy's rotation is not what we first thought,
with different galaxy types displaying a different relationship between the two
properties.
"Because galaxies evolve over
billions of years, we have to work with snapshots of their evolution -- taken
from different stages of their life -- and try to piece together their
journey."
This process has left astronomers with
lots of unanswered questions about a galaxy's lifecycle.
"By developing a better
understanding of galaxies properties now, we can incorporate these into our
simulations to work backwards," she said.
Associate Professor Luca Cortese, Ms
Hardwick's supervisor and co-author, said the study shows the importance of
revisiting research as our technology advances.
"This creates a cycle of
technological development, resulting in new discoveries which push for further
advances," he said. "However, before getting to the new discoveries,
it is critical to revisit previous knowledge to make sure that our foundations
are correct.
"Since the dawn of extragalactic
astronomy, it was clear that angular momentum is a key property for
understanding how galaxies form and evolve. However, due to the difficulty of
measuring angular momentum, direct observational constraints to our theory have
been lacking.
"This work provides an important
reference for future studies, offering one of the best measurements of the
connection between angular momentum and other galaxy properties in the local
Universe."
The research also reinforces the
importance of the Arecibo Radio Telescope to astronomy over the past 58 years,
even after its forced retirement in 2020.
"Despite the fact that the Arecibo
Radio Telescope suddenly collapsed last year, observations of atomic hydrogen
content in galaxies carried out with this facility still provide the deepest
census of gas content in galaxies," Associate Professor Cortese said.
"We will have to wait for the
second half of this decade before these kinds of observations are superseded by
data obtained with the precursors of the Square Kilometre Array, such as
Australia's SKA Pathfinder Telescope (ASKAP), South Africa's Karoo Array
Telescope (MeerKAT) and China's Five-hundred-meter Aperture Spherical radio
Telescope (FAST)."
https://www.sciencedaily.com/releases/2021/12/211201112000.htm
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