- 4302 - SUPERMASSIVE BLACKHOLES - in the galactic centers. Astronomers want James Webb Space Telescope to study the Milky Way core for hundreds of hours. To understand the Universe, we need to understand the extreme processes that shape it and drive its evolution.
------ 4302 - SUPERMASSIVE BLACKHOLES - in the galactic centers?
- Things like
“supermassive black holes” (SMBHs,) supernovae, massive reservoirs of dense
gas, and crowds of stars both on and off the main sequence. Fortunately there’s
a place where these objects dwell in close proximity to one another in the
Milky Way’s Galactic Center.
-
- There are many
unanswered questions in astronomy and astrophysics, and some of the answers are
hidden in our densely-packed galactic center. But while its densely-packed
nature make it an area practically begging to be studied, it also makes it
difficult to study. Only the most powerful telescopes have the angular
resolution to make sense of the Milky Way’s central region and its crowded
constituents.
-
- The Galactic
Center as a laboratory for extreme astrophysics and can help us understand how
galactic nuclei shape the galaxy population.
What are the unknowns in this turbulent region? Sgr. A*. The Blackhole at the heart of it all, draws matter towards
itself, shredding stars that get too close and creating an enormous swirling
mass of gas and dust.
-
- Vast gas clouds
are caught up in it all, and out of these clouds, stars in their multitudes are
born and then extinguished, many as ultra-powerful supernovae. The Milky Way’s
nuclear star cluster is there, too, and is many times more massive than Sgr.
A*, an anomaly in galaxies. And then there’s the nuclear bulge, where old,
comparatively metal-rich stars congregate.
-
- What is the
formation history of the Galactic Center and its relation to the overall
formation history of the Milky Way?
-
- How much stellar
mass formed in the past 30 Myr and what does this imply for the overall
energetics of the Galactic Center?
-
- What is the origin
of, and environmental variation in, the stellar initial mass function?
-
- Why is the star
formation rate one to two orders of magnitude lower than predicted by standard
star-formation-dense-gas relations?
-
- What is the 3D structure
of the interstellar medium orbiting and fueling accretion and star formation at
the Galactic Center?
-
- Perhaps the only
things not mentioned are dark matter and dark energy, and those two phenomena
are outside of the JWST’s primary focus.
-
- By being able to
resolve physical processes down to size scales separating individual stars,
this survey will provide a foundation for addressing key open questions in
other fields.
-
- As a multi-epoch
survey, it would examine the Galactic Center in three separate epochs separated
by 1, 5, and 10 years. It would observe the nuclear stellar disk and associated
giant molecular clouds in the central molecular zone a region containing about
60 million solar masses of star-forming gas. To see inside the region
accurately, the survey would utilize the JWST’s NIRCam and its system of
filters.
-
- One telescope
can’t reveal everything, and the JWST won’t be alone in this survey. Success
will rely on synergy with other telescopes. ALMA and the Hubble Space Telescope
will be part of this observational coalition, as will future telescopes like
the Roman Space Telescope, the ESO’s Extremely Large Telescope, and Japan’s
JASMINE infrared astrometry mission.
-
- One of the
questions the survey hopes to address is particularly fundamental in
astrophysics: the Initial Mass Function (IMF.) The IMF describes how mass is
distributed during star formation in a giant cloud of gas. The IMF is like an
agglomeration of smaller sub-functions in star formation, and it also links
individual star formation to larger issues of galaxy formation and evolution.
-
- The Milky Way’s
galactic center contains hundreds of mysterious magnetized radio filaments that
are so far unexplained. Then there are the questions around stellar feedback
and how it interacts with the Interstellar Medium and how black hole feedback
plays into it all.
-
- This survey can
discern the proper motion for more than 10 million stars in the Galactic
Center.
-
-
January 3, 2023 SUPERMASSIVE BLACKHOLES
- galactic centers 4302
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Wednesday, January 3, 2024 ---------------------------------
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