- 4080 - OLDEST GALAXY - discovered by James Webb. A distant swirling galaxy imaged by the powerful space telescope may look serene but it has a violent past. The serene-looking orange-red galaxy is a cosmic spiral of gas, dust, and stars that hides a violent past representing the wreckage of a massive collision between two earlier galaxies that proceeded around 500 million years ago.
------------ 4080 - OLDEST GALAXY - discovered by James Webb.
- The galaxy lies
around 120 million light-years from Earth and is a member of the
Hydra-Centaurus Supercluster. Hints at the chaotic past of this swirl-like
galaxy are hidden within the James Webb Space Telescope image in the form of
long tendrils of shining dust and stars which extend outwards from the main
body of the galaxy and the brightest portions.
-
- This galactic
growth results in the merging and growth of black holes and studying wreckage
like NGC 3256 could also help solve the mystery of how the supermassive black
holes at the heart of most galaxies can grow to masses equivalent to millions
or even billions of times that of the sun.
-
- The historic
merger that created NGC 3256 is also responsible for an intense burst of star
formation in the galaxy. This happens because when galaxies collide, they
channel gas and dust together into dense clouds to become the raw material
needed for star birth.
-
- The creation of
young stars can be seen in the form of the brightest regions within the orange/red
glow of NGC 3256. These stars are blasting out infrared light, irradiating tiny
grains of dust that cause the galaxy to glow brightly and make it a perfect
target for the JWST, which is designed to see the universe in infrared.
-
- When galaxies collide,
most stellar bodies escape the violent collisions unscathed, unlike the gas and
dust content of those galaxies. That's because of large voids between stars.
But it isn’t the case for all the stars in those galaxies. Visible in the JWST
image of NGC 3256 are threads of stars that were wrenched free of their home
galaxies as a result of gravitational interactions between the colliding
galaxies giving rise to incredible tidal forces.
-
- The stunning image
was created by the JWST using data from its Near Infrared Camera (NIRCam) and
its Mid-InfraRed Instrument (MIRI). Visualizing NGC 3256 in this way, JWST is the most powerful telescope ever
placed into orbit around Earth, in understanding the growth of galaxies and the
evolution of the universe.
-
- Stars can't hide
behind the light from feeding supermassive black holes in the infant universe
anymore. With the aid of the James Webb
Space Telescope (JWST), astronomers have seen starlight from two early galaxies
that host feeding supermassive black holes, or quasars, for the first time.
-
- The findings could
eventually help scientists better understand how supermassive black holes
quickly grow to masses equivalent to millions or billions of suns and how they
and the galaxies that host them evolve hand-in-hand.
-
- 25 years ago, it
was limited to observing host galaxies from 3 billion years back, using large
ground-based telescopes. The Hubble
Space Telescope allowed astronomers to probe the peak epoch of black hole
growth 10 billion years ago. And now we have JWST available to see the galaxies
in which the first supermassive black holes emerged.
-
- They observed two
of these so-called active galaxies, which are seen as they were when the 13.8
billion-year-old universe was less than one billion years old. They were able
to calculate both the mass of the galaxies and the mass of the supermassive
black holes that are powering the quasars.
-
- Light from these
two galaxies has taken 12.9 and 12.8 billion years to reach us, thus appearing
to astronomers as they were 870 and 880 million years after the Big Bang.
-
- The observations
revealed that the mass of the galaxies is 130 billion and 30 billion times that
of the sun, and the masses of the monstrous feeding black holes as 1.4 billion
solar masses and 200 million solar masses. This showed the mass of these early
galaxies and their central black holes are related in the same way seen in
galaxies observed closer to the Milky Way.
-
- Quasars are some
of the most extreme objects in the entire universe. Powered by supermassive
black holes surrounded by gas and dust, some of which is accreted to the black
hole, some of which is blasted out at speeds approaching that of light, quasars
emit so much light they can often outshine every star in the galaxy that hosts
them combined.
-
- Almost every galaxy
is believed to have a supermassive black hole at its heart, but not all of
these are quasars. For example, the supermassive black hole at the center of
the Milky Way, Sagittarius A* (Sgr A*), consumes so little matter it is
equivalent to a human eating a grain of rice every million years. Thus, it is
not feeding enough to power a quasar.
-
- The first quasar
was spotted in 1963, and since then, scientists have unraveled the processes
that power their immense emission of light. In the 2000s, it was discovered
that the masses of galaxies and their supermassive black holes are related,
with the mass of stars in a galaxy around 1,000 times greater than the mass of
its central black hole.
-
- The relationship
between the masses of supermassive black holes and their galaxies holds for
galaxies with supermassive black holes with masses millions of times that of
the sun and for those with central black holes billions of times the mass of
our star.
-
- The connection
between the mass of galaxies and the mass of their supermassive black holes may
be related to the fact that both grow via a chain of mergers between galaxies
that eventually leads to the black holes at the heart of those galaxies
violently colliding with each other and creating an even larger black hole.
-
- Consequently,
after numerous mergers, the mass of a galaxy will be around the average mass of
the initial galaxy times the number of galaxies it merged with, while the
central black hole mass will be around the mass of the initial black hole times
the same number, leading to a roughly linear relationship.
-
Another suggestion is that when a supermassive black hole
feeds on enough material to become a quasar, the radiation it blasts out
regulates the material available for both powering the quasar and for forming
new stars. Thus when the quasar runs out of food and stops growing, star
formation also slows in that galaxy.
-
- Whatever the cause
of this relationship, astronomers have been unable to determine if it exists
for galaxies and their supermassive black holes in the very early universe
until now. This is because, while the brightness of quasars allows them to be
studied at distances of billions of light-years away, it also makes the
observation of dimmer starlight from quasar-hosting galaxies challenging.
-
- Ground-based
telescopes struggle to distinguish the light from quasars and the light from
stars in their galaxies due to the effect of Earth's atmosphere. From its
position above the atmosphere, the Hubble Space Telescope has had some success
in unraveling the light from these galaxies when they are around 10 billion
light-years away. But to do this for more distant and earlier galaxies,
astronomers have had to wait for the most powerful space telescope ever placed
in orbit, the JWST.
-
- These quasars
were observed with the JWST's main instrument, the Near Infrared Camera
(NIRCam), for 2 hours at two different wavelengths. This combined spectrum of
quasar light and starlight for both galaxies and separating out the quasar
light to see the light from early stars in such galaxies for the first time.
-
- These observations
and their galaxies with the JWST have shown that the supermassive black hole
galaxy mass relationship exists even in the early universe. This data alone isn't enough to reveal the
origins of this mass relationship and how supermassive black holes grow to such
tremendous sizes, but it will inform future investigations.
-
-
July 7, 2023 OLDEST GALAXY
- discovered by James Webb. 4080
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