Starship Asterisk*

Image Credit: ESA/Hubble & NASA, P. Erwin et al

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This image from the NASA/ESA Hubble Space Telescope shows IC 2051, a galaxy in the southern constellation of Mensa (The Table Mountain), lying about 85 million light-years away. It is a spiral galaxy, as evidenced by its characteristic whirling, pinwheeling arms, and it has a bar of stars slicing through its centre.

This galaxy was observed for a Hubble study on galactic bulges, the bright round central region of spiral galaxies. Spiral galaxies like IC 2051 are shaped a bit like flying saucers when seen from the side; they comprise a thin, flat disc, with a bulky bulge of stars in the centre that extends above and below the disc. These bulges are thought to play a key role in how galaxies evolve, and to influence the growth of the supermassive black holes lurking at the centres of most spirals. While more observations are needed in this area, studies suggest that some, or even most, galactic bulges may be complex composite structures rather than simple ones, with a mix of spherical, disc-like, or boxy components, potentially leading to a wide array of bulge morphologies in the Universe.

This image comprises data from Hubble’s Wide Field Camera 3 at visible and infrared wavelengths.

bystander wrote: ↑Mon Dec 16, 2019 5:27 pm Discs and Bulges
ESA Hubble Picture of the Week | 2019 Dec 16

Image Credit: ESA/Hubble & NASA, P. Erwin et al

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This image from the NASA/ESA Hubble Space Telescope shows IC 2051, a galaxy in the southern constellation of Mensa (The Table Mountain), lying about 85 million light-years away. It is a spiral galaxy, as evidenced by its characteristic whirling, pinwheeling arms, and it has a bar of stars slicing through its centre.

This galaxy was observed for a Hubble study on galactic bulges, the bright round central region of spiral galaxies. Spiral galaxies like IC 2051 are shaped a bit like flying saucers when seen from the side; they comprise a thin, flat disc, with a bulky bulge of stars in the centre that extends above and below the disc. These bulges are thought to play a key role in how galaxies evolve, and to influence the growth of the supermassive black holes lurking at the centres of most spirals. While more observations are needed in this area, studies suggest that some, or even most, galactic bulges may be complex composite structures rather than simple ones, with a mix of spherical, disc-like, or boxy components, potentially leading to a wide array of bulge morphologies in the Universe.

This image comprises data from Hubble’s Wide Field Camera 3 at visible and infrared wavelengths.

Image Credit: ESA/Hubble & NASA, D. Rosario et al

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This swirling mass of celestial gas, dust, and stars is a moderately luminous spiral galaxy named ESO 021-G004, located just under 130 million light-years away.

This galaxy has something known as an active galactic nucleus. While this phrase sounds complex, this simply means that astronomers measure a lot of radiation at all wavelengths coming from the centre of the galaxy. This radiation is generated by material falling inwards into the very central region of ESO 021-G004, and meeting the behemoth lurking there — a supermassive black hole. As material falls towards this black hole it is dragged into orbit as part of an accretion disc; it becomes superheated as it swirls around and around, emitting characteristic high-energy radiation until it is eventually devoured.

The data comprising this image were gathered by the Wide Field Camera 3 aboard the NASA/ESA Hubble Space Telescope.

Image Credit: ESO/Yuri Beletsky (TWAN)

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This Picture of the Week captures the skies above ESO’s Paranal Observatory ablaze with colour — blues, purples, oranges, greens, yellows and reds all mingle together to create this striking view of the Chilean site. One of the Auxiliary Telescopes (ATs) comprising ESO’s Very Large Telescope (VLT) is visible in the foreground, bathed in an eerie yellow-green glow.

This AT is just one of the VLT’s four 1.8-metre auxiliaries, which also includes four giant 8.2-metre cousins (Unit Telescopes).The ATs are unique; they are self-contained and, depending on the needs of the observing project, can be repositioned in up to 30 different observing locations along a system of tracks. Acting together as the VLT Interferometer (VLTI), they capture light from celestial objects and send it to the same focal point through a system of mirrors housed within underground tunnels, allowing researchers to observe the cosmos in incredible detail.

Comprising eight telescopes in total, the VLT is the world’s most advanced visible-light astronomical observatory. Its magnificent resolution makes it possible to see fine detail on the surface of a star, and even to study the surroundings of a black hole.

Credit: ESA/Hubble & NASA, I. Karachentsev et al

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This smattering of celestial sequins is a spiral galaxy named NGC 4455, located in the northern constellation of Coma Berenices (Berenice’s Hair). This might sound like an odd name for a constellation — and in fact it is somewhat unusual; it’s the only modern constellation to be named in honour of a real person from history: Queen Berenice II of Egypt.

The story of Queen Berenice II is an interesting one. A ruling queen of the ancient Greek city of Cyrene in modern-day Libya, and later a queen of Ptolemaic Egypt through her marriage to her cousin Ptolemy III Euergetes, Berenice became known for sacrificing locks of her hair as an offering to ensure her husband’s safe return from battle. Her husband did indeed return safely and her hair, which she had left in a Zephyrium temple, had disappeared — it had apparently been stolen and placed among the stars.

Should it be located in NGC 4455, it travelled a long way. The galaxy is about 45 million light-years away. This image was taken by the NASA/ESA Hubble Space Telescope’s Advanced Camera for Surveys.

bystander wrote: ↑Mon Dec 30, 2019 4:07 pm Placed among the Stars
ESA Hubble Picture of the Week | 2019 Dec 30

Credit: ESA/Hubble & NASA, I. Karachentsev et al

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This smattering of celestial sequins is a spiral galaxy named NGC 4455, located in the northern constellation of Coma Berenices (Berenice’s Hair). This might sound like an odd name for a constellation — and in fact it is somewhat unusual; it’s the only modern constellation to be named in honour of a real person from history: Queen Berenice II of Egypt.

The story of Queen Berenice II is an interesting one. A ruling queen of the ancient Greek city of Cyrene in modern-day Libya, and later a queen of Ptolemaic Egypt through her marriage to her cousin Ptolemy III Euergetes, Berenice became known for sacrificing locks of her hair as an offering to ensure her husband’s safe return from battle. Her husband did indeed return safely and her hair, which she had left in a Zephyrium temple, had disappeared — it had apparently been stolen and placed among the stars.

Should it be located in NGC 4455, it travelled a long way. The galaxy is about 45 million light-years away. This image was taken by the NASA/ESA Hubble Space Telescope’s Advanced Camera for Surveys.