NASA's James Webb telescopes will reveal hidden galaxies

Date:
October 15, 2020
Source:
University of Melbourne
Summary:
Simulations show it's possible to distinguish host galaxy from
quasars, although still challenging due to the galaxy's small size
on the sky.



FULL STORY ==========================================================================
Two new studies from the University of Melbourne will help the largest,
most powerful and complex space telescope ever built to uncover galaxies
never before seen by humanity.


==========================================================================
The papers are published in The Astrophysical Journal and the Monthly
Notices of the Royal Astronomical Society and show that NASA's James
Webb Space Telescope, scheduled for launch late next year, will reveal
hidden galaxies.

Powerful lights called 'quasars' are the brightest objects in the
universe.

Powered by supermassive black holes up to a trillion times the mass of
our Sun, they outshine entire galaxies of billions of stars.

Simulations led by Science PhD candidate, Madeline Marshall, show that
while even NASA's Hubble Space Telescope can't see galaxies currently
hidden by these quasars, the James Webb Telescope will be able to get
past the glare.

"Webb will open up the opportunity to observe these very distant host
galaxies for the first time," said Ms Marshall, who conducted her research
at the ARC Centre of Excellence in All Sky Astrophysics in 3 Dimensions
(ASTRO 3D).

"That can help us answer questions like: How can black holes grow so
big so fast? Is there a relationship between the mass of the galaxy
and the mass of the black hole, like we see in the nearby universe?"
Although quasars are known to reside at the centers of galaxies, it has
been difficult to tell what those galaxies are like and how they compare
to galaxies without quasars.



========================================================================== "Ultimately, Webb's observations should provide new insights into these
extreme systems," said ASTRO 3D co-author Stuart Wyithe of the University
of Melbourne.

"The data it gathers will help us understand how a black hole could
grow to weigh a billion times as much as our Sun in just a billion
years. These big black holes shouldn't exist so early because there
hasn't been enough time for them to grow so massive." The University
of Melbourne team collaborated with researchers from the US, China,
Germany, and The Netherlands to use the Hubble Space Telescope to try
to observe these galaxies.

They then used a state-of-the-art computer simulation called BlueTides,
which was developed by a team led by ASTRO 3D distinguished visitor,
Tiziana Di Matteo, from Carnegie Mellon University in Pittsburgh,
Pennsylvania, US.

"BlueTides is designed to study the formation and evolution of galaxies
and quasars in the first billion years of the universe's history,"
said Yueying Ni of Carnegie Mellon University, who ran the BlueTides simulation.



==========================================================================
"Its large cosmic volume and high spatial resolution enables us to study
those rare quasar hosts on a statistical basis." The team used these simulations to determine what Webb's cameras would see if the observatory studied these distant systems. They found that distinguishing the host
galaxy from the quasar would be possible, although still challenging
due to the galaxy's small size on the sky.

They also found that the galaxies hosting quasars tended to be smaller
than average, spanning only about 1/30 the diameter of the Milky Way
despite containing almost as much mass as our galaxy.

"The host galaxies are surprisingly tiny compared to the average galaxy
at that point in time," said Ms Marshall.


========================================================================== Story Source: Materials provided by University_of_Melbourne. Note:
Content may be edited for style and length.


========================================================================== Journal References:
1. M. A. Marshall, M. Mechtley, R. A. Windhorst, S. H. Cohen,
R. A. Jansen,
L. Jiang, V. R. Jones, J. S. B. Wyithe, X. Fan, N. P. Hathi,
K. Jahnke, W. C. Keel, A. M. Koekemoer, V. Marian, K. Ren,
J. Robinson, H. J. A.

Ro"ttgering, R. E. Ryan, E. Scannapieco, D. P. Schneider,
G. Schneider, B. M. Smith, H. Yan. Limits to Rest-frame
Ultraviolet Emission from Far- infrared-luminous z ≃ 6
Quasar Hosts. The Astrophysical Journal, 2020; 900 (1): 21 DOI:
10.3847/1538-4357/abaa4c
2. Madeline A Marshall, Yueying Ni, Tiziana Di Matteo, J Stuart
B Wyithe,
Stephen Wilkins, Rupert A C Croft, Jussi K Kuusisto. The host
galaxies of z = 7 quasars: predictions from the BlueTides
simulation. Monthly Notices of the Royal Astronomical Society,
2020; DOI: 10.1093/mnras/staa2982 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/10/201015003439.htm

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