Starship Asterisk*

Susanna Kohler wrote:

DB Bowen et al, ApJ, 2019 July

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What happens to accreting gas when two supermassive black holes merge? The dramatic scene above shows the behavior of disk gas in a still from a simulation of such a merger; the two smaller black disks represent the black holes, and the larger disk in the center is a cutout at the center of mass. In this new study, a team of scientists led by Dennis Bowen (Los Alamos National Laboratory and Rochester Institute of Technology) have conducted the first exploration of how magnetized mini-disks around supermassive black holes can couple to the accreting gas surrounding the binary in the moments shortly before the black holes merge. The team’s simulations show that asymmetries in this coupling can drive strong oscillations in the system — and these could introduce distinctive, increasingly rapid fluctuations in the electromagnetic emission that we might be able to detect from supermassive black hole mergers that are surrounded by gas. To learn more about the authors’ discoveries, check out the article below.

• Astrophysical Journal 879(2):76 (2019 Jul 10) DOI: 10.3847/1538-4357/ab2453
• arXiv.org > astro-ph > arXiv:1904.12048 > 26 Apr 2019

Credit: ESA/Hubble & NASA, A. Filippenko, R. Jansen

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Believe it or not, this long, luminous streak, speckled with bright blisters and pockets of material, is a spiral galaxy like our Milky Way. But how could that be?

It turns out that we see this galaxy, named NGC 3432, orientated directly edge-on to us from our vantage point here on Earth. The galaxy’s spiral arms and bright core are hidden, and we instead see the thin strip of its very outer reaches. Dark bands of cosmic dust, patches of varying brightness, and pink regions of star formation help with making out the true shape of NGC 3432 — but it’s still somewhat of a challenge! Because observatories such as the NASA/ESA Hubble Space Telescope have seen spiral galaxies at every kind of orientation, astronomers can tell when we happen to have caught one from the side.

The galaxy is located in the constellation of Leo Minor (The Lesser Lion). Other telescopes that have had NGC 3432 in their sights include those of the Sloan Digital Sky Survey (SDSS), the Galaxy Evolution Explorer (GALEX), and the Infrared Astronomical Satellite (IRAS).

Credit: ESO/SPECULOOS Team/E. Jehin

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This spectacular portrait of the Centaurus A galaxy was captured under clear skies by the newest operational ESO observatory, SPECULOOS (Search for habitable Planets EClipsing ULtra-cOOl Stars), located at the Paranal Observatory in Chile. The state of the art observatory is fitted an array of four one-metre telescopes, each named after one of the four Galilean moons. The SPECULOOS telescopes are neighbours of two of ESO’s most powerful telescopes, the Very Large Telescope (VLT) and VISTA. SPECULOOS is set to survey up to ten times more red dwarf stars than the TRAPPIST telescope (located at ESO La Silla Observatory) currently does. It is predicted statistically that it will then find at least twelve solar systems of a similar size to the now famous TRAPPIST-1 system.

The Centaurus A galaxy (NGC 5128) is one of the brightest objects in the southern hemisphere night sky, located in the constellation of Centaurus. It was discovered in 1826 by Scottish astronomer James Dunlop at the former Parramata Observatory. At a distance of 11 million light-years, it is the closest active galactic nucleus (AGN) to us. Astronomers theorise that what was originally an elliptical galaxy collided with a relatively smaller spiral shaped galaxy, giving it the peculiar shape we see now. NGC 5128 has an impressive collection of stars. From this image, you can observe red/pink star-forming regions on the bottom left of the image and young blue star clusters on the top right of the image; with dust lanes captured in stunning detail.

Towards the centre of the galaxy, leftover cosmic dust is slowly being eaten by the supermassive black hole, which has a mass of roughly 100 million solar masses. This accretion of matter results in powerful radio waves being emitted from the AGN.

This image was taken as one of the first light images from the SPECULOOS telescopes. First light images are the very first images that are taken by a telescope when it is being commissioned for science operation to guarantee that it is in good working order and that the images are clear.

Ann wrote: ↑Sat Jul 27, 2019 7:45 pm

starsurfer wrote: ↑Sat Jul 27, 2019 1:05 pm Jacoby 1
http://www.capella-observatory.com/Imag ... acoby1.htm
Copyright: Frank Sackenheim, Josef Pöpsel and Stefan Binnewies
Jacoby1.jpg

That's a very interesting picture. The nebula is all blue, meaning it contains no hydrogen. The central star is very blue indeed, and it is quite obviously the bluest object in the picture. According to Simbad, the light output of this star peaks in the ultraviolet, and then it gets fainter and fainter at longer and longer wavelengths. It is really faint in infrared light.

This star seems to be at the threshold where it loses its planetary nebula "fluff" and becomes a white dwarf pure and simple.

Ann

starsurfer wrote: ↑Sat Jul 27, 2019 1:05 pm Jacoby 1
http://www.capella-observatory.com/Imag ... acoby1.htm
Copyright: Frank Sackenheim, Josef Pöpsel and Stefan Binnewies
Jacoby1.jpg

Image Credit: ESA/Hubble & NASA, L. Ho

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Every now and then, the NASA/ESA Hubble Space Telescope glimpses a common object — say, a spiral galaxy — in an interesting or unusual way. A sharply angled perspective, such as the one shown in this Picture of the Week, can make it seem as if we, the viewers, are craning our necks to see over a barrier into the galaxy's bright centre.

In the case of NGC 3169, this barrier is the thick dust embedded within the galaxy's spiral arms. Cosmic dust comprises a potpourri of particles, including water ice, hydrocarbons, silicates, and other solid material. It has many origins and sources, from the leftovers of star and planet formation to molecules modified over millions of years by interactions with starlight.

NGC 3169 is located about 70 million light-years away in the constellation of Sextans (The Sextant). It is part of the Leo I Group of galaxies, which, like the Local Group that houses our home galaxy, the Milky Way, is part of a larger galactic congregation known as the Virgo Supercluster.

Image Credit: ESO/Yuri Beletsky (LCO)

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The modern building in this image is the Residencia at ESO's Paranal Observatory in Chile, a home from home for the many professionals and technicians working at the observatory. Above the astronomers’ home in the Atacama Desert, the image shows the Milky Way galaxy — our home in the Universe.

The Residencia was designed by the German architects Auer+Weber, and integrates perfectly into the arid landscape of the Atacama Desert in order to disturb astronomical observations as little as possible. The sandy colour and modern design of the building suit the Mars-like terrain around the observatory. The Residencia was chosen as the perfect hide-out for the Bond villain in the movie Quantum of Solace, and was blown up — only virtually — in one of the key scenes.

Paranal Observatory hosts ESO's Very Large Telescope (VLT), as well as four Auxiliary Telescopes (AT) that can work together to form the Very Large Telescope Interferometer (VLTI).