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takyon writes:

The European Southern Observatory's Very Large Telescope Interferometer (VLTI) has captured the best ever image of another star. The VLTI was used to image the surface of Antares, a red supergiant star about 550 light years away in the heart of the constellation Scorpius (The Scorpion):

The VLTI is a unique facility that can combine the light from up to four telescopes, either the 8.2-metre Unit Telescopes, or the smaller Auxiliary Telescopes, to create a virtual telescope equivalent to a single mirror up to 200 metres across. This allows it to resolve fine details far beyond what can be seen with a single telescope alone.

[...] Using the new results the team has created the first two-dimensional velocity map of the atmosphere of a star other than the Sun. They did this using the VLTI with three of the Auxiliary Telescopes and an instrument called AMBER to make separate images of the surface of Antares over a small range of infrared wavelengths. The team then used these data to calculate the difference between the speed of the atmospheric gas at different positions on the star and the average speed over the entire star. This resulted in a map of the relative speed of the atmospheric gas across the entire disc of Antares — the first ever created for a star other than the Sun..

The astronomers found turbulent, low-density gas much further from the star than predicted, and concluded that the movement could not result from convection, that is, from large-scale movement of matter which transfers energy from the core to the outer atmosphere of many stars. They reason that a new, currently unknown, process may be needed to explain these movements in the extended atmospheres of red supergiants like Antares.

Vigorous atmospheric motion in the red supergiant star Antares (DOI: 10.1038/nature23445) (DX)

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takyon writes:

The Very Large Telescope's (VLT) Multi-unit spectroscopic explorer (MUSE) has been used to study the galaxies in the Hubble Ultra-Deep Field. It has also revealed previously unseen galaxies:

Sometimes, astronomy is about surveying widely to get the big picture. And sometimes it's about looking more and more deeply. First released in 2004, the Hubble Ultra Deep Field is clearly about going deep. It's a composite image of a tiny region of space, located in the direction of the southern constellation Fornax, made from Hubble Space Telescope data gathered over several months. There are an estimated 10,000 galaxies in the Hubble Ultra Deep Field, which exist as far back in time as 13 billion years ago (between 400 and 800 million years after the Big Bang). Being able to see galaxies so near the beginning of our universe has been a fantastic tool for understanding how the universe has evolved. And now – thanks to an instrument called MUSE (Multi Unit Spectroscopic Explorer), astronomers have been able to eke out yet more information – a veritable bonanza of information – from the Hubble Ultra Deep Field. Their work is being published today (November 29, 2017) in a series of 10 papers in a special issue of the peer-reviewed journal Astronomy & Astrophysics.

Also at ESO.

The MUSE Hubble Ultra Deep Field Survey - I. Survey description, data reduction, and source detection (open, DOI: 10.1051/0004-6361/201730833) (DX)

The rest of the papers are paywalled:

*SPOILER* (click to show) *SPOILER* (click to hide)

The MUSE Hubble Ultra Deep Field Survey - II. Spectroscopic redshifts and comparisons to color selections of high-redshift galaxies (DOI: 10.1051/0004-6361/201731195) (DX)

The MUSE Hubble Ultra Deep Field Survey - III. Testing photometric redshifts to 30th magnitude (DOI: 10.1051/0004-6361/201731351) (DX)

The MUSE Hubble Ultra Deep Field Survey - IV. Global properties of C III] emitters (DOI: 10.1051/0004-6361/201730985) (DX)

The MUSE Hubble Ultra Deep Field Survey - V. Spatially resolved stellar kinematics of galaxies at redshift 0.2 ≲ z ≲ 0.8 (DOI: 10.1051/0004-6361/201730905) (DX)

The MUSE Hubble Ultra Deep Field Survey - VI. The faint-end of the Lyα luminosity function at 2.91 (DOI: 10.1051/0004-6361/201731431) (DX)

The MUSE Hubble Ultra Deep Field Survey - VII. Fe ii* emission in star-forming galaxies (DOI: 10.1051/0004-6361/201731499) (DX)

The MUSE Hubble Ultra Deep Field Survey - VIII. Extended Lyman-α haloes around high-z star-forming galaxies (DOI: 10.1051/0004-6361/201731480) (DX)

The MUSE Hubble Ultra Deep Field Survey - IX. Evolution of galaxy merger fraction since z ≈ 6 (DOI: 10.1051/0004-6361/201731586) (DX)

The MUSE Hubble Ultra Deep Field Survey - X. Lyα equivalent widths at 2.9 (DOI: 10.1051/0004-6361/201731579) (DX)

Original Submission

takyon writes:

ESO's Very Large Telescope has combined the light from all four of its Unit Telescopes into its ESPRESSO instrument for the first time, effectively creating a 16 meter aperture optical telescope:

The ESPRESSO instrument on ESO's Very Large Telescope in Chile has for the first time been used to combine light from all four of the 8.2-metre Unit Telescopes. Combining light from the Unit Telescopes in this way makes the VLT the largest optical telescope in existence in terms of collecting area.

One of the original design goals of ESO's Very Large Telescope (VLT) was for its four Unit Telescopes (UTs) to work together to create a single giant telescope. With the first light of the ESPRESSO spectrograph using the four-Unit-Telescope mode of the VLT, this milestone has now been reached.

After extensive preparations by the ESPRESSO consortium (led by the Astronomical Observatory of the University of Geneva, with the participation of research centres from Italy, Portugal, Spain and Switzerland) and ESO staff, ESO's Director General Xavier Barcons initiated this historic astronomical observation with the push of a button in the control room.

[...] Light from the four Unit Telescopes is routinely brought together in the VLT Interferometer for the study of extremely fine detail in comparatively bright objects. But interferometry, which combines the beams "coherently", cannot exploit the huge light-gathering potential of the combined telescopes to study faint objects.

Previously: First Light for VLT's ESPRESSO Exoplanet Hunter

Original Submission

Arthur T Knackerbracket has found the following story:

After 12 years of development, the MATISSE interferometry instrument has been installed during the last 3 months at ESO’s Very Large Telescope (VLT). The instrument combines four of the VLT telescopes to obtain an interferometer with an extremely high spatial resolution. This instrument allows astronomers to study the environment of young stars, the surfaces of stars and Active Galactic Nuclei in the mid-infrared wavelength range. In February 2018, MATISSE successfully achieved ‘First Light’. This achievement consummates the decade-long efforts of a large number of engineers and astronomers in europe, including the infrared interferometry research group at the MPIfR in Bonn, Germany.

MATISSE is a second-generation Very Large Telescope Interferometer (VLTI) instrument providing extremely high spatial resolution. It is a combined imager and spectrograph for interferometry in the mid-infrared 3–5 μm spectral region (L- and M-bands) and the 8–13 μm region (N-band). MATISSE builds on the experience gained with the VLTI’s first-generation instruments, but vastly extends their capability to produce detailed images.

The instrument exploits multiple telescopes and the wave nature of the light to produce more detailed images of celestial objects than can be obtained with any existing or planned single telescope. High- resolution imaging in the infrared is technically demanding but has yielded spectacular results in detecting planet-forming discs around stars, images of the surfaces of stars, and dusty discs around Active Galactic Nuclei.

takyon writes:

It's Official: Astronomers Caught The First-Ever Direct Picture of a Planet Being Born

For the very first time, astronomers have captured an image of a baby planet as it carves a path through the disc of dust that surrounds its star, an orange dwarf 113.4 parsecs (370 light-years) away from Earth.

[...] PDS 70 has a few features that made it a good candidate for this sort of search. Its protoplanetary disc is large, spanning a radius of around 130 astronomical units (the distance between Earth and the Sun; the Kuiper belt only goes up to about 50 au).

[...] Using its coronagraph and polarisation filters, the [Very Large Telescope] team discovered a very large planet orbiting in the gap in PDS 70's protoplanetary disc - which means it's probably still in the process of accumulating material. Further analysis of the planet, described in a second paper, was conducted based on its spectrum. Its mass is several times that of Jupiter, and its orbit is around 22 AU, just a little bit farther than Uranus's orbit around the Sun. It takes about 120 Earth years to complete one orbit around its star, and its surface temperature is around 1,200 Kelvin.

PDS 70. Also at ESO and Syfy Wire.

Discovery of a planetary-mass companion within the gap of the transition disk around PDS 70

Orbital and atmospheric characterization of the planet within the gap of the PDS 70 transition disk

Original Submission

takyon writes:

Telescope array will spy on spy satellites, star surfaces and black holes

At a time when astronomers are building billion-dollar telescopes with mirrors 30 meters across, the 1.4-meter instrument being installed this month atop South Baldy Mountain in New Mexico may seem like a bit player. But over the next few years, nine more identical telescopes will join it on the grassy, 3200-meter summit, forming a Y-shaped array that will surpass any other optical telescope in its eye for detail. When it's complete around 2025, the $200 million Magdalena Ridge Observatory Interferometer (MROI) will have the equivalent resolution of a gigantic telescope 347 meters across.

MROI's small telescopes can't match the light-gathering power of its giant cousins, so it will be limited to bright targets. But by combining light from the spread-out telescopes, it is expected to make out small structures on stellar surfaces, image dust around newborn stars, and peer at supermassive black holes at the center of some galaxies. It will even be able to make out details as small as a centimeter across on satellites in geosynchronous orbit, 36,000 kilometers above Earth, enabling it to spy on spy satellites.

That's one reason why the U.S. Air Force, which wants to monitor its own orbital assets and presumably those of others, is funding MROI. "They want to know: Did the boom break or did some part of the photovoltaic panels collapse?" says Michelle Creech-Eakman, an astronomer at the New Mexico Institute of Mining and Technology in Socorro and project scientist on MROI. But if the facility succeeds, its biggest impact could be on the field of astronomy, by drawing new attention to the promise of optical interferometry, a powerful but challenging strategy for extracting exquisitely sharp images from relatively small, cheap telescopes.

Wikipedia article on Astronomical Optical Interferometry.

Related: Very Large Telescope's MUSE Instrument Studies the Hubble Ultra-Deep Field
Very Large Telescope's ESPRESSO Combines Light From All Four Unit Telescopes for the First Time
Very Large Telescope Captures First Direct Image of a Planet Being Formed

Original Submission

takyon writes:

Instead of Building Single Monster Scopes like James Webb, What About Swarms of Space Telescopes Working Together?

... Jayce Dowell and Gregory B. Taylor, a research assistant professor and professor (respectively) with the Department of Physics and Astronomy at the University of New Mexico [...] outlined their idea in a study titled "The Swarm Telescope Concept [pdf]", which recently appeared online and was accepted for publication by the Journal of Astronomical Instrumentation.

[...] Instead of a single instrument, the telescope would consist of a distributed array where many autonomous elements come together through a data transport system to function as a single facility. This approach, they claim, would be especially useful when it comes to the Next Generation Very Large Array (NGVLA) – a future interferometer that will build on the legacy of the Karl G. [J]ansky Very Large Array and Atacama Large Millimeter/submillimeter Array (ALMA). As they state in their study:

At the core of the swarm telescope is a shift away from thinking about an observatory as a monolithic entity. Rather, an observatory is viewed as many independent parts that work together to accomplish scientific observations. This shift requires moving part of the decision making about the facility away from the human schedulers and operators and transitioning it to "software defined operators" that run on each part of the facility. These software agents then communicate with each other and build dynamic arrays to accomplish the goals of multiple observers, while also adjusting for varying observing conditions and array element states across the facility.

Original Submission