Starship Asterisk*

Image Credit: ESO/A. Rossi et al.

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Do you see that small red spot? That’s an extremely distant explosion in the early universe imaged by the X-Shooter instrument at ESO’s Very Large Telescope (VLT). This light is from a gamma-ray burst (GRB), one of the most luminous and puzzling phenomena in the universe.

In September 2021, NASA's Neil Gehrels Swift Observatory detected a bright source of gamma rays in this area of the sky. Once the initial bright flash of a GRB has died down, the afterglow shines at longer wavelengths like visible or infrared light. But they fade very quickly, so astronomers must react fast! A team of astronomers led by Andrea Rossi at INAF in Bologna observed the aftermath of the GRB with a number of telescopes around the world, including several ESO instruments on the VLT and the robotic telescopes REM and GROND hosted at ESO’s La Silla Observatory.

Besides taking images with X-Shooter, the team also used this instrument to obtain spectra. This was key to discover that the burst originates from an extremely distant galaxy, when the universe was only 6% of its current age, making this one of the most distant GBRs ever found.

The origins of gamma-ray bursts however remain a bit of a mystery. According to Rossi’s team, this particular GRB put out so much energy that it was probably powered by material falling onto a black hole or (less likely) a magnetar –– a neutron star with a very strong magnetic field. With ESO’s upcoming Extremely Large Telescope (ELT), properties of bursts like these and their progenitors can be studied in greater detail, and their elusive origin can be uncovered.

Image Credit: ESA/Hubble & NASA, Dark Energy Survey/ DOE/FNAL/DECam/CTIO/NOIRLab/NSF/AURA, J. Dalcanton

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The two interacting galaxies making up the pair known as Arp-Madore 608-333 seem to float side by side in this image from the NASA/ESA Hubble Space Telescope. Though they appear serene and unperturbed, the two are subtly warping one another through a mutual gravitational interaction that is disrupting and distorting both galaxies. This drawn-out galactic interaction was captured by Hubble’s Advanced Camera for Surveys (ACS).

The interacting galaxies in Arp-Madore 608-333 were captured as part of an effort to build up an archive of interesting targets for more detailed future study with Hubble, ground-based telescopes, and the NASA/ESA/CSA James Webb Space Telescope (JWST). To build up this archive, astronomers scoured existing astronomical catalogues for a list of targets spread throughout the night sky. By so doing, they hoped to include objects that had already been identified as interesting and that would be easy for Hubble to observe no matter which direction it was pointing.

Deciding how to award Hubble observing time is a drawn-out, competitive and difficult process, and the observations are allocated so as to use every last second of Hubble time available. However, there is a small but persistent fraction of time — around 2–3% — that goes unused as Hubble turns to point at new targets. Snapshot programmes, such as the one which captured Arp-Madore 608-333, exist to fill this gap and take advantage of the moments between longer observations. As well as creating beautiful images such as this, these snapshot programs enable astronomers to gather as much data as possible with Hubble.

cosmicwreckingball wrote: ↑Sun Oct 09, 2022 5:13 pm Lagoon to Eagle by Dennis Sprinkle
Copyright: Dennis Sprinkle

https://www.astrobin.com/kugtmt/

From Dennis' Astrobin Page:

This is a 5 panel mosaic shot from my remote telescope in Marathon, TX.

Software used to capture image:
Sequence Generator Pro
PHD2

Software used to edit:
PixInsight
Photoshop

Total data gathered:
(76) Ha @ 900s – 1x1
(319) Lum @ 45s - 1x1
(79) R @ 130s - 1x1
(80) G @ 150s - 1x1
(79) B @ 205s - 1x1

Camera : QHY600 with 0.72x reducer set to Readout mode 1, Gain set to 0, and Offset to 20
Telescope: Takahashi FSQ-106EDX4
Mount: AP Mach1GTO

Image Credits: ESO/King & Fletcher. Jupiter Background Image: NASA, ESA, A. Simon (GSFC), and M. H. Wong (UC Berkeley) and the OPAL team.

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This Picture of the Week shows two of Jupiter’s moons, the icy Ganymede and Europa, which have been imaged in the infrared using the SPHERE instrument on ESO’s Very Large Telescope (VLT). Whilst Europa is quite similar in size to our own Moon, Ganymede is the largest moon in the whole Solar System – it’s even bigger than the planet Mercury!

Their orbits around Jupiter are slightly elliptical, so they get closer and further away from the planet as they orbit it. This results in the moons being stretched and squeezed by the gravitational pull from Jupiter at periodical intervals. This creates frictional heat, warming the insides of the moons, which has made them geologically active. Europa in particular is likely to have active plumes and geysers erupting from the oceans of liquid water beneath the thick ice cover that makes up the surface.

Estimates on the abundances of chemical species on the marble-like surfaces of these moons could be made thanks to these new images and also spectra, which have been published in two studies by Oliver King and Leigh N. Fletcher at the University of Leicester in the United Kingdom. They found that the bright regions of Ganymede consist mainly of water in the form of ice with hints of various salts, and that they have formed more recently than the older darker patches, whose composition still remains a mystery to astronomers.

Observing these moons with ground-based telescopes is challenging, because they look as small as a 1 Euro coin seen from 3-5 km away. Earth’s atmosphere would completely blur these images, but SPHERE’s adaptive optics system corrects these distortions, delivering very sharp images with details as small as 150 km.

Image Credit: ESA/Hubble & NASA, R. Cohen

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Terzan 1 is a globular cluster that lies about 22,000 light-years from Earth in the constellation Scorpius. It is one of 11 globular clusters that were discovered by the Turkish-Armenian astronomer Agop Terzan between 1966 and 1971 when he was working in France, based mostly at Lyon Observatory.

Somewhat confusingly, the 11 Terzan globular clusters are numbered from Terzan 1 to Terzan 12. This is due to an error made by Terzan in 1971, when he rediscovered Terzan 5 — a cluster he had already discovered and reported back in 1968 — and named it Terzan 11. He published its discovery alongside those of Terzan 9, 10 and 12. He quickly realised his mistake, and attempted to have Terzan 12 renamed as Terzan 11. Unfortunately, he did not make it clear that Terzan 5 and Terzan 11 were one and the same, although another astronomer, Ivan Robert King, did publish a note to try and clear up the confusion. Nowadays, most papers recognise the original Terzan 5 and Terzan 12, and accept the oddity that there is no Terzan 11. There have, however, been instances of confusion in the scientific literature over the past few decades.

Terzan 1 is not a new target for Hubble — an image of the cluster was released back in 2015, taken by Hubble’s Wide Field Planetary Camera 2 (WFPC2). That instrument was replaced by the Wide Field Camera 3 (WFC3) during the 2009 Hubble servicing mission (SM4). WFC3 has both superior resolving power and a wider field of view than WFPC2, and the improvement is obvious in this fantastically detailed image.