Spiral galaxy NGC 5033

This is not a painting!

An incredible Hubble photo of spiral galaxy NGC 5033

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NGC 5866

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Why is this galaxy so thin? Many disk galaxies are actually just as thin as NGC 5866, pictured above, but are not seen edge-on from our vantage point. One galaxy that is situated edge-on is our own Milky Way Galaxy. Classified as a lenticular galaxy, NGC 5866 has numerous and complex dust lanes appearing dark and red, while many of the bright stars in the disk give it a more blue underlying hue. The blue disk of young stars can be seen extending past the dust in the extremely thin galactic plane, while the bulge in the disk center appears tinged more orange from the older and redder stars that likely exist there. Although similar in mass to our Milky Way Galaxy, light takes about 60,000 years to cross NGC 5866, about 30 percent less than light takes to cross our own Galaxy. In general, many disk galaxies are very thin because the gas that formed them collided with itself as it rotated about the gravitational center. Galaxy NGC 5866 lies about 50 million light years distant toward the constellation of the Dragon (Draco).

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Massive stars lie within NGC 6357

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Massive stars lie within NGC 6357, an expansive emission nebula complex some 6,500 light-years away toward the tail of the constellation Scorpius. In fact, positioned near center in this ground-based close-up of NGC 6357, star cluster Pismis 24 includes some of the most massive stars known in the galaxy, stars with nearly 100 times the mass of the Sun. The nebula’s bright central region also contains dusty pillars of molecular gas, likely hiding massive protostars from the prying eyes of optical instruments. Intricate shapes in the nebula are carved as interstellar winds and energetic radiation from the young and newly forming massive stars clear out the natal gas and dust and power the nebular glow. Enhancing the nebula’s cavernous appearance, narrowband image data was included in this composite color image in a Hubble palette scheme. Emission from sulfur, hydrogen, and oxygen atoms is shown in red green and blue hues. The alluring telescopic view spans about 50 light-years at the estimated distance of NGC 6357.

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NGC 2623 ( Galaxy )

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NGC 2623 is really two galaxies that are
becoming one. Seen to be in the final stages
of a titanic galaxy merger, the pair lies some
300 million light-years distant toward the
constellation Cancer. The violent encounter
between two galaxies that may have been
similar to the Milky Way has produced
widespread star formation near a luminous
core and along eye-catching tidal tails. Filled
with dust, gas, and young blue star clusters,
the opposing tidal tails extend well over
50,000 light-years from the merged nucleus.
Likely triggered by the merger, accretion by a
supermassive black hole drives activity within
the nuclear region. The star formation and its
active galactic nucleus make NGC 2623 bright
across the spectrum. This sharp cosmic
snapshot of NGC 2623 (aka Arp 243) is based
on Hubble Legacy Archive image data that
also reveals even more distant background
galaxies scattered through the field of view.
(APOD)

Plasma Lenses

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This finding could help solve the longstanding
mystery of where a major part of the galaxy’s
matter is hiding, the scientists added.
Astronomers first detected clues of these
mysterious structures 30 years ago as they
monitored quasarsquasars, the brightest
objects in the universe. Quasars are the most
energetic form of active galactic nuclei, which
are supermassive black holes in the centers of
distant galaxies that release extraordinarily
large amounts of light as they rip apart stars
and gobble matter.Previous research found
that radio waves from quasars could vary
wildly in strength, a phenomenon technically
known as an extreme scattering event.
Astronomers suggested these events were due
to clouds of plasma — that is, electrically
charged particles. These clouds are essentially
lumps in the thin gas that fills the space
between the stars in the Milky Way.
“Lumps in this gas work like lenses, focusing
and defocusing the radio waves, making them
appear to strengthen and weaken over a
period of days, weeks or months,” study lead
author Keith Bannister, an astronomer at the
Commonwealth Scientific and Industrial
Research Organization (CSIRO) in Australia,
said in a statement.
Previous research suggested these “plasma
lenses” are huge — about 620 million miles (1
billion kilometers) wide, a distance nearly
seven times the distance between Earth and
the sun. Ones detected so far lie about 3,200
light-years away, nearly 800 times farther than
the nearest star to Earth, Proxima
Centauri.Plasma lenses have been difficult to
find, so much about them is a mystery. For
instance, estimates suggested the pressures
within these plasma lenses are about 1,000
times greater than the surrounding interstellar
gas. It was uncertain how these structures
could form and survive long enough for
astronomers to detect as often as they have.
In addition, until now, scientists knew nothing
about the shape of these plasma lenses. This
made it difficult to figure out what these
structures were or what their origins were.
Now astronomers have for the first time
successfully detected a lensing event while it
was happening. This helped them conduct
follow-up analyses that permitted the first
estimates of plasma lens shapes.
Researchers used the Australia Telescope
Compact Array to scan about 1,000 active
galactic nuclei for sudden changes in their
radio waves. They detected a lensing event in
2014 that went on for a year in connection
with the quasar PKS 1939-315, located in the
constellation Sagittarius. Whereas old
analyses of lensing events only monitored two
radio frequencies, “our new method gave us
9,000 frequencies at once,” Bannister told
Space.com. “It was like going from black-and-
white TV to color.”
Based on their findings, the researchers
suggest this plasma lens could neither be a
spherical cloud nor a corrugated or bent
sheet.

NGC 5408

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NGC 5408 is a galaxy located about 16
million light-years from Earth in the
constellation of Centaurus (The Centaur). This
galaxy, with an indefinable shape lacking a
spiral or elliptical structure, is called an
irregular galaxy, and about one fourth of
galaxies share that title. NGC 5408’s shape
led astronomers to believe that it was a
planetary nebula, before determining that it
was a galaxy. Also within this galaxy lies a
rare object, an ultraluminous X-ray source
known as NGC 5408 X-1, one of the best
studied of its class. This object blasts out
vast amounts of energetic X-rays