Wednesday, August 16, 2017

Supermassive Black Holes Feed on Cosmic Jellyfish

Example of a jellyfish galaxy

Example of a jellyfish galaxy

Visualisation of MUSE view of Jellyfish Galaxy

Example of a jellyfish galaxy


Videos 

ESOcast 122 Light: Supermassive Black Holes Feed on Cosmic Jellyfish (4K UHD)
ESOcast 122 Light: Supermassive Black Holes Feed on Cosmic Jellyfish (4K UHD)

Visualisation of galaxy undergoing ram pressure stripping
Visualisation of galaxy undergoing ram pressure stripping

Artist's impression of ram pressure stripping
Artist's impression of ram pressure stripping

Visualisation of a galaxy undergoing ram pressure stripping
Visualisation of a galaxy undergoing ram pressure stripping


ESO’s MUSE instrument on the VLT discovers new way to fuel black holes


Observations of “Jellyfish galaxies” with ESO’s Very Large Telescope have revealed a previously unknown way to fuel supermassive black holes. It seems the mechanism that produces the tentacles of gas and newborn stars that give these galaxies their nickname also makes it possible for the gas to reach the central regions of the galaxies, feeding the black hole that lurks in each of them and causing it to shine brilliantly. The results appeared today in the journal Nature.

An Italian-led team of astronomers used the MUSE (Multi-Unit Spectroscopic Explorer) instrument on the Very Large Telescope (VLT) at ESO’s Paranal Observatory in Chile to study how gas can be stripped from galaxies. They focused on extreme examples of jellyfish galaxies in nearby galaxy clusters, named after the remarkable long “tentacles” of material that extend for tens of thousands of light-years beyond their galactic discs [1][2].

The tentacles of jellyfish galaxies are produced in galaxy clusters by a process called ram pressure stripping. Their mutual gravitational attraction causes galaxies to fall at high speed into galaxy clusters, where they encounter a hot, dense gas which acts like a powerful wind, forcing tails of gas out of the galaxy’s disc and triggering starbursts within it.

Six out of the seven jellyfish galaxies in the study were found to host a supermassive black hole at the centre, feeding on the surrounding gas [3]. This fraction is unexpectedly high — among galaxies in general the fraction is less than one in ten.

“This strong link between ram pressure stripping and active black holes was not predicted and has never been reported before,” said team leader Bianca Poggianti from the INAF-Astronomical Observatory of Padova in Italy. “It seems that the central black hole is being fed because some of the gas, rather than being removed, reaches the galaxy centre.” [4]

A long-standing question is why only a small fraction of supermassive black holes at the centres of galaxies are active. Supermassive black holes are present in almost all galaxies, so why are only a few accreting matter and shining brightly? These results reveal a previously unknown mechanism by which the black holes can be fed.

Yara Jaffé, an ESO fellow who contributed to the paper explains the significance: “These MUSE observations suggest a novel mechanism for gas to be funnelled towards the black hole’s neighbourhood. This result is important because it provides a new piece in the puzzle of the poorly understood connections between supermassive black holes and their host galaxies.”

The current observations are part of a much more extensive study of many more jellyfish galaxies that is currently in progress.

“This survey, when completed, will reveal how many, and which, gas-rich galaxies entering clusters go through a period of increased activity at their cores,” concludes Poggianti. “A long-standing puzzle in astronomy has been to understand how galaxies form and change in our expanding and evolving Universe. Jellyfish galaxies are a key to understanding galaxy evolution as they are galaxies caught in the middle of a dramatic transformation.”


Notes

 [1] To date, just over 400 candidate jellyfish galaxies have been found.
[2] The results were produced as part of the observational programme known as GASP (GAs Stripping Phenomena in galaxies with MUSE), which is an ESO Large Programme aimed at studying where, how and why gas can be removed from galaxies. GASP is obtaining deep, detailed MUSE data for 114 galaxies in various environments, specifically targeting jellyfish galaxies. Observations are currently in progress.

[3] It is well established that almost every, if not every, galaxy hosts a supermassive black hole at its centre, between a few million and a few billion times as massive as our Sun. When a black hole pulls in matter from its surroundings, it emits electromagnetic energy, giving rise to some of the most energetic of astrophysical phenomena: active galactic nuclei (AGN).

[4] The team also investigated the alternative explanation that the central AGN activity contributes to stripping gas from the galaxies, but considered it less likely. Inside the galaxy cluster, the jellyfish galaxies are located in a zone where the hot, dense gas of the intergalactic medium is particularly likely to create the galaxy’s long tentacles, reducing the possibility that they are created by AGN activity. There is therefore stronger evidence that ram pressure triggers the AGN and not vice versa.


More Information
This research was presented in a paper entitled “Ram Pressure Feeding Supermassive Black Holes” by B. Poggianti et al., to appear in the journal Nature on 17 August 2017.

The team is composed of B. Poggianti (INAF-Astronomical Observatory of Padova, Italy), Y. Jaffé (ESO, Chile), A. Moretti (INAF-Astronomical Observatory of Padova, Italy), M. Gullieuszik (INAF-Astronomical Observatory of Padova, Italy), M. Radovich (INAF-Astronomical Observatory of Padova, Italy), S. Tonnesen (Carnegie Observatory, USA), J. Fritz (Instituto de Radioastronomía y Astrofísica, Mexico), D. Bettoni (INAF-Astronomical Observatory of Padova, Italy), B. Vulcani (University of Melbourne, Australia; INAF-Astronomical Observatory of Padova, Italy), G. Fasano (INAF-Astronomical Observatory of Padova, Italy), C. Bellhouse (University of Birmingham, UK; ESO, Chile), G. Hau (ESO, Chile) and A. Omizzolo (Vatican Observatory, Vatican City State).

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its world-leading Very Large Telescope Interferometer as well as two survey telescopes, VISTA working in the infrared and the visible-light VLT Survey Telescope. ESO is also a major partner in two facilities on Chajnantor, APEX and ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre Extremely Large Telescope, the ELT, which will become “the world’s biggest eye on the sky”.


Links


Contacts

 Bianca Poggianti
INAF-Astronomical Observatory of Padova
Padova, Italy
Tel: +39 340 7448663
Email: bianca.poggianti@oapd.inaf.it

Richard Hook
ESO Public Information Officer
Garching bei München, Germany
Tel: +49 89 3200 6655
Cell: +49 151 1537 3591

Source: ESO/News

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Tuesday, August 15, 2017

Hint of Relativity Effects in Stars Orbiting Supermassive Black Hole at Centre of Galaxy

Artist's impression of the orbits of stars close to the Galactic Centre 

Artist's impression of the effect of general relativity on the orbit of the S2 star at the Galactic Centre 

Image of the Galactic Centre


Videos

ESOcast 121 Light: Star orbiting supermassive black hole suggests Einstein is right (4K UHD)
ESOcast 121 Light: Star orbiting supermassive black hole suggests Einstein is right (4K UHD)

Orbits of three stars very close to the centre of the Milky Way
Orbits of three stars very close to the centre of the Milky Way


A new analysis of data from ESO’s Very Large Telescope and other telescopes suggests that the orbits of stars around the supermassive black hole at the centre of the Milky Way may show the subtle effects predicted by Einstein’s general theory of relativity. There are hints that the orbit of the star S2 is deviating slightly from the path calculated using classical physics. This tantalising result is a prelude to much more precise measurements and tests of relativity that will be made using the GRAVITY instrument as star S2 passes very close to the black hole in 2018.

At the centre of the Milky Way, 26 000 light-years from Earth, lies the closest supermassive black hole, which has a mass four million times that of the Sun. This monster is surrounded by a small group of stars orbiting at high speed in the black hole’s very strong gravitational field. It is a perfect environment in which to test gravitational physics, and particularly Einstein’s general theory of relativity.

A team of German and Czech astronomers have now applied new analysis techniques to existing observations of the stars orbiting the black hole, accumulated using ESO’s Very Large Telescope (VLT) in Chile and others over the last twenty years [1]. They compare the measured star orbits to predictions made using classical Newtonian gravity as well as predictions from general relativity.

The team found suggestions of a small change in the motion of one of the stars, known as S2, that is consistent with the predictions of general relativity [2]. The change due to relativistic effects amounts to only a few percent in the shape of the orbit, as well as only about one sixth of a degree in the orientation of the orbit [3]. If confirmed, this would be the first time that a measurement of the strength of the general relativistic effects has been achieved for stars orbiting a supermassive black hole.

Marzieh Parsa, PhD student at the University of Cologne, Germany and lead author of the paper, is delighted: "The Galactic Centre really is the best laboratory to study the motion of stars in a relativistic environment. I was amazed how well we could apply the methods we developed with simulated stars to the high-precision data for the innermost high-velocity stars close to the supermassive black hole."

The high accuracy of the positional measurements, made possible by the VLT’s near-infrared adaptive optics instruments, was essential for the study [4]. These were vital not only during the star’s close approach to the black hole, but particularly during the time when S2 was further away from the black hole. The latter data allowed an accurate determination of the shape of the orbit.

"During the course of our analysis we realised that to determine relativistic effects for S2 one definitely needs to know the full orbit to very high precision," comments Andreas Eckart, team leader at the University of Cologne.

As well as more precise information about the orbit of the star S2, the new analysis also gives the mass of the black hole and its distance from Earth to a higher degree of accuracy [5].

Co-author Vladimir Karas from the Academy of Sciences in Prague, the Czech Republic, is excited about the future: "This opens up an avenue for more theory and experiments in this sector of science."

This analysis is a prelude to an exciting period for observations of the Galactic Centre by astronomers around the world. During 2018 the star S2 will make a very close approach to the supermassive black hole. This time the GRAVITY instrument, developed by a large international consortium led by the Max-Planck-Institut für extraterrestrische Physik in Garching, Germany [6], and installed on the VLT Interferometer [7], will be available to help measure the orbit much more precisely than is currently possible. Not only is GRAVITY, which is already making high-precision measurements of the Galactic Centre, expected to reveal the general relativistic effects very clearly, but also it will allow astronomers to look for deviations from general relativity that might reveal new physics.


Notes

[1] Data from the near-infrared NACO camera now at VLT Unit Telescope 1 (Antu) and the near-infrared imaging spectrometer SINFONI at the Unit Telescope 4 (Yepun) were used for this study. Some additional published data obtained at the Keck Observatory were also used.

 [2] S2 is a 15-solar-mass star on an elliptical orbit around the supermassive black hole. It has a period of about 15.6 years and gets as close as 17 light-hours to the black hole — or just 120 times the distance between the Sun and the Earth.
[3] A similar, but much smaller, effect is seen in the changing orbit of the planet Mercury in the Solar System. That measurement was one of the best early pieces of evidence in the late nineteenth century suggesting that Newton’s view of gravity was not the whole story and that a new approach and new insights were needed to understand gravity in the strong-field case. This ultimately led to Einstein publishing his general theory of relativity, based on curved spacetime, in 1915.

When the orbits of stars or planets are calculated using general relativity, rather than Newtonian gravity, they evolve differently. Predictions of the small changes to the shape and orientation of orbits with time are different in the two theories and can be compared to measurements to test the validity of general relativity.

[4] An adaptive optics system compensates for the image distortions produced by the turbulent atmosphere in real time and allows the telescope to be used at much angular resolution (image sharpness), in principle limited only by the mirror diameter and the wavelength of light used for the observations.

[5] The team finds a black hole mass of 4.2 × 106 times the mass of the Sun, and a distance from us of 8.2 kiloparsecs, corresponding to almost 27 000 light-years.

[6] The University of Cologne is part of the GRAVITY team (http://www.mpe.mpg.de/ir/gravity) and contributed the beam combiner spectrometers to the system.

[7] GRAVITY First Light was in early 2016 and it is already observing the Galactic Centre.


More Information

This research was presented in a paper entitled “Investigating the Relativistic Motion of the Stars Near the Black Hole in the Galactic Center”, by M. Parsa et al., to be published in the Astrophysical Journal.

The team is composed of Marzieh Parsa, Andreas Eckart (I.Physikalisches Institut of the University of Cologne, Germany; Max Planck Institute for Radio Astronomy, Bonn, Germany), Banafsheh Shahzamanian (I.Physikalisches Institut of the University of Cologne, Germany), Christian Straubmeier (I.Physikalisches Institut of the University of Cologne, Germany), Vladimir Karas (Astronomical Institute, Academy of Science, Prague, Czech Republic), Michal Zajacek (Max Planck Institute for Radio Astronomy, Bonn, Germany; I.Physikalisches Institut of the University of Cologne, Germany) and J. Anton Zensus (Max Planck Institute for Radio Astronomy, Bonn, Germany).

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its world-leading Very Large Telescope Interferometer as well as two survey telescopes, VISTA working in the infrared and the visible-light VLT Survey Telescope. ESO is also a major partner in two facilities on Chajnantor, APEX and ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre Extremely Large Telescope, the ELT, which will become “the world’s biggest eye on the sky”.


Links


Contacts

Marzieh Parsa
I. Physikalisches Institut, Universität zu Köln
Köln, Germany
Tel: +49(0)221/470-3495
Email: parsa@ph1.uni-koeln.de

Andreas Eckart
I. Physikalisches Institut, Universität zu Köln
Köln, Germany
Tel: +49(0)221/470-3546
Email: eckart@ph1.uni-koeln.de

Vladimir Karas
Astronomical Institute, Academy of Science
Prague, Czech Republic
Tel: +420-226 258 420
Email: vladimir.karas@cuni.cz

Richard Hook
ESO Public Information Officer
Garching bei München, Germany
Tel: +49 89 3200 6655
Cell: +49 151 1537 3591
Email: rhook@eso.org

Source: ESO/News

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Saturday, August 12, 2017

Small but significant

NGC 5949
Credit: ESA/Hubble & NASA


The subject of this NASA/ESA Hubble Space Telescope image is a dwarf galaxy named NGC 5949. Thanks to its proximity to Earth — it sits at a distance of around 44 million light-years from us, placing it within the Milky Way’s cosmic neighbourhood — NGC 5949 is a perfect target for astronomers to study dwarf galaxies.

With a mass of about a hundredth that of the Milky Way, NGC 5949 is a relatively bulky example of a dwarf galaxy. Its classification as a dwarf is due to its relatively small number of constituent stars, but the galaxy’s loosely-bound spiral arms also place it in the category of barred spirals. This structure is just visible in this image, which shows the galaxy as a bright yet ill-defined pinwheel. Despite its small proportions, NGC 5949’s proximity has meant that its light can be picked up by fairly small telescopes, something that facilitated its discovery by the astronomer William Herschel in 1801. 

Astronomers have run into several cosmological quandaries when it comes to dwarf galaxies like NGC 5949. For example, the distribution of dark matter within dwarfs is quite puzzling (the “cuspy halo” problem), and our simulations of the Universe predict that there should be many more dwarf galaxies than we see around us (the “missing satellites” problem).



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Friday, August 11, 2017

IC 10: A Starburst Galaxy with the Prospect of Gravitational WavesA Quick Look at IC 10

IC 10
Credit: X-ray: NASA/CXC/UMass Lowell/S.Laycock et al.
Optical: Bill Snyder Astrophotography



animation



In 1887, American astronomer Lewis Swift discovered a glowing cloud, or nebula, that turned out to be a small galaxy about 2.2 billion light years from Earth. Today, it is known as the "starburst" galaxy IC 10, referring to the intense star formation activity occurring there.

More than a hundred years after Swift's discovery, astronomers are studying IC 10 with the most powerful telescopes of the 21st century. New observations with NASA's Chandra X-ray Observatory reveal many pairs of stars that may one day become sources of perhaps the most exciting cosmic phenomenon observed in recent years: gravitational waves.

By analyzing Chandra observations of IC 10 spanning a decade, astronomers found over a dozen black holes and neutron stars feeding off gas from young, massive stellar companions. Such double star systems are known as "X-ray binaries" because they emit large amounts of X-ray light. As a massive star orbits around its compact companion, either a black hole or neutron star, material can be pulled away from the giant star to form a disk of material around the compact object. Frictional forces heat the infalling material to millions of degrees, producing a bright X-ray source.

When the massive companion star runs out of fuel, it will undergo a catastrophic collapse that will produce a supernova explosion, and leave behind a black hole or neutron star. The end result is two compact objects: either a pair of black holes, a pair of neutron stars, or a black hole and neutron star. If the separation between the compact objects becomes small enough as time passes, they will produce gravitational waves. Over time, the size of their orbit will shrink until they merge. LIGO has found three examples of black hole pairs merging in this way in the past two years.

Starburst galaxies like IC 10 are excellent places to search for X-ray binaries because they are churning out stars rapidly. Many of these newly born stars will be pairs of young and massive stars. The most massive of the pair will evolve more quickly and leave behind a black hole or a neutron star partnered with the remaining massive star. If the separation of the stars is small enough, an X-ray binary system will be produced.

This new composite image of IC 10 combines X-ray data from Chandra (blue) with an optical image (red, green, blue) taken by amateur astronomer Bill Snyder from the Heavens Mirror Observatory in Sierra Nevada, California. The X-ray sources detected by Chandra appear as a darker blue than the stars detected in optical light.

The young stars in IC 10 appear to be just the right age to give a maximum amount of interaction between the massive stars and their compact companions, producing the most X-ray sources. If the systems were younger, then the massive stars would not have had time to go supernova and produce a neutron star or black hole, or the orbit of the massive star and the compact object would not have had time to shrink enough for mass transfer to begin. If the star system were much older, then both compact objects would probably have already formed. In this case transfer of matter between the compact objects is unlikely, preventing the formation of an X-ray emitting disk.

Chandra detected 110 X-ray sources in IC 10. Of these, over forty are also seen in optical light and 16 of these contain "blue supergiants", which are the type of young, massive, hot stars described earlier. Most of the other sources are X-ray binaries containing less massive stars. Several of the objects show strong variability in their X-ray output, indicative of violent interactions between the compact stars and their companions.

A pair of papers describing these results were published in the February 10th, 2017 issue of The Astrophysical Journal and is available online here and here. The authors of the study are Silas Laycock from the UMass Lowell's Center for Space Science and Technology (UML); Rigel Capallo, a graduate student at UML; Dimitris Christodoulou from UML; Benjamin Williams from the University of Washington in Seattle; Breanna Binder from the California State Polytechnic University in Pomona; and, Andrea Prestwich from the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.

NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.



Fast Facts for IC 10:
Category: Neutron Stars/X-ray Binaries, Normal Galaxies & Starburst Galaxies
Coordinates (J2000): RA 00h 20m 23.2s | Dec 59° 17´ 34.7"
Constellation: Cassiopeia
Observation Date: 6 pointings between December 2009 and September 2010
Observation Time: 24 hours 19.5 min
Obs. ID: 11081-11086
Instrument: ACIS
References: Laycock S. et al., 2017, ApJ, 836, 50; arXiv:1611.08611. Laycock S. et al., 2017, ApJ [in press]; arXiv:1701.03803
Color Code: X-ray (Blue); Optical (Red, Green, Blue)
Distance Estimate: About 2.2 billion light years


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Thursday, August 10, 2017

Four Earth-Sized Planets Found Orbiting the Nearest Sun-Like Star

This illustration compares the four planets detected around the nearby star Tau Ceti (top) and the inner planets of our solar system (bottom). Credit:  F. FENG, University of Hertfordshire, United Kingdom


Maunakea, Hawaii – A new study by an international team of astronomers reveals that Tau Ceti, the nearest Sun-like star about 12 light years away from the Sun, has four Earth-sized planets orbiting it.

These planets have masses as low as 1.7 Earth mass, making them among the smallest planets ever detected around the nearest Sun-like stars. Two of them are Super-Earths located in the habitable zone of the star and thus could support liquid surface water.

The data were obtained by using the High Accuracy Radial Velocity Planet Searcher (HARPS) spectrograph at the European Southern Observatory in Chile, combined with the High-Resolution Echelle Spectrometer (HIRES) at the W. M. Keck Observatory on Maunakea, Hawaii.

“HIRES is one of only a few spectrometers in the world that have routinely delivered the level of radial velocity precision needed for this kind of work,” said co-author Dr. Steve Vogt, professor of astronomy and astrophysics at University of California, Santa Cruz. “And it is one of only two instruments in the world, the other being HARPS, that has been able to deliver this precision level for over a decade. It is a very unique facility in the exoplanet discovery field.”

The four planets were detected by observing the wobbles in the movement of Tau Ceti. This wobble, known as the Doppler effect, happens when a planet’s gravity slightly tugs at its host star as it orbits.

Measuring Tau Ceti’s wobbles required techniques sensitive enough to detect variations in its movement as small as 30 centimeters per second. The smaller the planet, the weaker its gravitational pull on its host star, and the harder it is to detect the star’s wobble.

"We are getting tantalizingly close to the 10 centimeters per second limit required for detecting Earth analogs,” said Dr. Fabo Feng from the University of Hertfordshire in the United Kingdom and lead author of the study. “Our detection of such weak wobbles is a milestone in the search for Earth analogs and the understanding of the Earth’s habitability through comparison with these analogs."

The outer two planets around Tau Ceti are likely to be candidate habitable worlds, although a massive debris disc around the star probably reduces their habitability due to intensive bombardment by asteroids and comets.

The same team also investigated Tau Ceti four years ago in 2013, when Dr. Mikko Tuomi led an effort in developing data analysis techniques and used the star as a benchmark case.

"We came up with an ingenious way of telling the difference between signals caused by planets and those caused by a star's activity. We realized that we could see how a star's activity differed at different wavelengths, then used that information to separate this activity from signals of planets," said Dr. Tuomi.

"We have painstakingly improved the sensitivity of our techniques and could rule out two of the signals our team identified in 2013 as planets. But no matter how we look at the star, there seems to be at least four rocky planets orbiting it," Dr. Tuomi added. "We are slowly learning to tell the difference between wobbles caused by planets and those caused by stellar active surface. This enabled us to essentially verify the existence of the two outer, potentially habitable, planets in the system."

Sun-like stars are thought to be the best targets for searching for habitable Earth-sized planets due to their similarity to the Sun. Unlike more common smaller stars such as the red dwarf stars Proxima Centauri and Trappist-1, they are not so faint that planets would be tidally locked, showing the same side to the star at all times.

Tau Ceti is very similar to the Sun in its size and brightness, and they both host multi-planet systems. If the outer two planets are found to be habitable, Tau Ceti could be an optimal target for interstellar colonization, as seen in science fiction.

"Such weak signals of planets almost the size of the Earth cannot be seen without using advanced statistical and modeling approaches. We have introduced new methods to remove the noise in the data in order to reveal the weak planetary signals," said Dr. Feng.

  About HIRES

The High-Resolution Echelle Spectrometer (HIRES) produces spectra of single objects at very high spectral resolution, yet covering a wide wavelength range. It does this by separating the light into many "stripes" of spectra stacked across a mosaic of three large CCD detectors. HIRES is famous for finding planets orbiting other stars. Astronomers also use HIRES to study distant galaxies and quasars, finding clues to the Big Bang.


Authors
  • Fabo Feng, Mikko Tuomi, Hugh Jones - University of Hertfordshire, UK 
  • John Barnes - The Open University, UK 
  • Guillem Anglada-Escude - Queen Mary University ofLondon, UK 
  • Steve Vogt - University of California at Santa Cruz, USA 
  • Paul Butler - Carnegie Institute of Washington, USA


About W. M. Keck Observatory
The W. M. Keck Observatory operates the most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Maunakea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometers, and world-leading laser guide star adaptive optics systems. The Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California, and NASA.


Media Contact:

 Mari-Ela Chock, Communications Officer
W. M. Keck Observatory
(808) 554-0567
mchock@keck.hawaii.edu


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Wednesday, August 09, 2017

From the Residencia to the Milky Way

Credit: ESO/B. Tafreshi (twanight.org)


This image captures the route from the Residencia — the guesthouse for visitors to ESO's Paranal Observatory— to the breathtaking heart of the Milky Way, which covers the entire night sky.

The site shown here is Cerro Paranal, home to ESO's Very Large Telescope (VLT), a telescope comprising four 8.2-metre Unit Telescopes. The VLT can also act as an interferometer in the form of the appropriately-named VLT Interferometer, or VLTI, by gathering additional light from four smaller Auxiliary Telescopes, which can be independently moved around and placed in different configurations. One of these Auxiliary Telescopes is shown in this image, gazing at the sky with its dome wide open.

The road from the observatory to the Residencia appears as a shining thread, weaving amongst the rocky outcrops and hills of the desert environment. The yellow glow is caused by dim security lights — the street lighting is kept to a minimum in order to avoid unnecessary light pollution.

Source: ESO/images

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Monday, August 07, 2017

Hubble Detects Exoplanet with Glowing Water Atmosphere

Artist's View of WASP-121b
Illustration: NASA, ESA, and G. Bacon (STScI)
Credits: Science: NASA, ESA, and T. Evans (University of Exeter)

Comparison of WASP-121b Stratosphere with Brown Dwarf Atmosphere
Credits: Illustration: NASA, ESA, and A. Feild (STScI)



Scientists have discovered the strongest evidence to date for a stratosphere on a planet outside our solar system, or exoplanet. A stratosphere is a layer of atmosphere in which temperature increases with higher altitudes.

"This result is exciting because it shows that a common trait of most of the atmospheres in our solar system — a warm stratosphere — also can be found in exoplanet atmospheres," said Mark Marley, study co-author based at NASA's Ames Research Center in California's Silicon Valley. "We can now compare processes in exoplanet atmospheres with the same processes that happen under different sets of conditions in our own solar system."

Reporting in the journal Nature, scientists used data from NASA's Hubble Space Telescope to study WASP-121b, a type of exoplanet called a "hot Jupiter." Its mass is 1.2 times that of Jupiter, and its radius is about 1.9 times Jupiter's — making it puffier. But while Jupiter revolves around our sun once every 12 years, WASP-121b has an orbital period of just 1.3 days. This exoplanet is so close to its star that if it got any closer, the star's gravity would start ripping it apart. It also means that the top of the planet's atmosphere is heated to a blazing 4,600 degrees Fahrenheit (2,500 degrees Celsius), hot enough to boil some metals. The WASP-121 system is estimated to be about 900 light-years from Earth — a long way, but close by galactic standards.

Previous research found possible signs of a stratosphere on the exoplanet WASP-33b as well as some other hot Jupiters. The new study presents the best evidence yet because of the signature of hot water molecules that researchers observed for the first time.

"Theoretical models have suggested stratospheres may define a distinct class of ultra-hot planets, with important implications for their atmospheric physics and chemistry," said Tom Evans, lead author and research fellow at the University of Exeter, United Kingdom. "Our observations support this picture."

To study the stratosphere of WASP-121b, scientists analyzed how different molecules in the atmosphere react to particular wavelengths of light, using Hubble's capabilities for spectroscopy. Water vapor in the planet's atmosphere, for example, behaves in predictable ways in response to certain wavelengths of light, depending on the temperature of the water.

Starlight is able to penetrate deep into a planet's atmosphere, where it raises the temperature of the gas there. This gas then radiates its heat into space as infrared light. However, if there is cooler water vapor at the top of the atmosphere, the water molecules will prevent certain wavelengths of this light from escaping to space. But if the water molecules at the top of the atmosphere have a higher temperature, they will glow at the same wavelengths.

"The emission of light from water means the temperature is increasing with height," said Tiffany Kataria, study co-author based at NASA's Jet Propulsion Laboratory, Pasadena, California. "We’re excited to explore at what longitudes this behavior persists with upcoming Hubble observations."

The phenomenon is similar to what happens with fireworks, which get their colors from chemicals emitting light. When metallic substances are heated and vaporized, their electrons move into higher energy states. Depending on the material, these electrons will emit light at specific wavelengths as they lose energy: sodium produces orange-yellow and strontium produces red in this process, for example. The water molecules in the atmosphere of WASP-121b similarly give off radiation as they lose energy, but in the form of infrared light, which the human eye is unable to detect.

In Earth's stratosphere, ozone gas traps ultraviolet radiation from the sun, which raises the temperature of this layer of atmosphere. Other solar system bodies have stratospheres, too; methane is responsible for heating in the stratospheres of Jupiter and Saturn's moon Titan, for example.

In solar system planets, the change in temperature within a stratosphere is typically around 100 degrees Fahrenheit (about 56 degrees Celsius). On WASP-121b, the temperature in the stratosphere rises by 1,000 degrees (560 degrees Celsius). Scientists do not yet know what chemicals are causing the temperature increase in WASP-121b's atmosphere. Vanadium oxide and titanium oxide are candidates, as they are commonly seen in brown dwarfs, "failed stars" that have some commonalities with exoplanets. Such compounds are expected to be present only on the hottest of hot Jupiters, as high temperatures are needed to keep them in a gaseous state.

"This super-hot exoplanet is going to be a benchmark for our atmospheric models, and it will be a great observational target moving into the Webb era," said Hannah Wakeford, study co-author who worked on this research while at NASA's Goddard Space Flight Center, Greenbelt, Maryland.

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C. The California Institute of Technology (Caltech) manages the Jet Propulsion Laboratory (JPL) for NASA.


Links

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Contacts
Elizabeth Landau
Jet Propulsion Laboratory, Pasadena, California
818-354-6425
elizabeth.landau@jpl.nasa.gov
 
Ray Villard
Space Telescope Science Institute, Baltimore, Maryland
410-338-4514
villard@stsci.edu


Source: HubbleSite

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Sunday, August 06, 2017

Spot the cluster

Credit: ESO
Acknowledgements: Flickr user hdahle70



This image from the Wide-Field Imager on the MPG/ESO 2.2-metre telescope shows the starry skies around a galaxy cluster named PLCKESZ G286.6-31.3. The cluster itself is difficult to spot initially, but shows up as a subtle clustering of yellowish galaxies near the centre of the frame.

PLCKESZ G286.6-31.3 houses up to 1000 galaxies, in addition to large quantities of hot gas and dark matter. As such, the cluster has a total mass of 530 trillion (530 000 000 000 000) times the mass of the Sun.

When viewed from Earth, PLCKESZ G286.6-31.3 is seen through the outer fringes of the Large Magellanic Cloud (LMC) — one of the Milky Way’s satellite galaxies. The LMC hosts over 700 star clusters, in addition to hundreds of thousands of giant and supergiant stars. The majority of the cosmic objects captured in this image are stars and star clusters located inside the LMC .

The MPG/ESO 2.2-metre telescope has been in operation at ESO’s La Silla Observatory since 1984. The telescope has been utilised for a variety of cutting-edge scientific studies, including ground-breaking research into gamma-ray bursts, the most powerful explosions in the Universe. The 67-million-pixel Wide Field Imager (WFI) — mounted on the telescope’s Cassegrain focus — has been obtaining detailed views of faint, distant objects since 1999.

The data to create this image was selected from the ESO archive as part of the Hidden Treasures competition.




Source: ESO/Images

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Saturday, August 05, 2017

The Hockey Stick Galaxy

 Credit: ESA/Hubble & NASA


The star of this Hubble Picture of the Week is a galaxy known as NGC 4656, located in the constellation of Canes Venatici (The Hunting Dogs). However, it also has a somewhat more interesting and intriguing name: the Hockey Stick Galaxy! The reason for this is a little unclear from this partial view, which shows the bright central region, but the galaxy is actually shaped like an elongated, warped stick, stretching out through space until it curls around at one end to form a striking imitation of a celestial hockey stick.

This unusual shape is thought to be due to an interaction between NGC 4656 and a couple of near neighbours, NGC 4631 (otherwise known as The Whale Galaxy) and NGC 4627 (a small elliptical). Galactic interactions can completely reshape a celestial object, shifting and warping its constituent gas, stars, and dust into bizarre and beautiful configurations. The NASA/ESA Hubble Space Telescope has spied a large number of interacting galaxies over the years, from the cosmic rose of Arp 273 to the egg-penguin duo of Arp 142 and the pinwheel swirls of Arp 240. More Hubble images of interacting galaxies can be seen here.



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Friday, August 04, 2017

Two Weeks in the Life of a Sunspot

A blended view of the sunspot in visible and extreme ultraviolet light reveals bright coils arcing over the active region — particles spiraling along magnetic field lines. Credit: NASA’s Goddard Space Flight Center/SDO

On July 5, 2017, NASA’s Solar Dynamics Observatory watched an active region — an area of intense and complex magnetic fields — rotate into view on the Sun. The satellite continued to track the region as it grew and eventually rotated across the Sun and out of view on July 17.  

With their complex magnetic fields, sunspots are often the source of interesting solar activity: During its 13-day trip across the face of the Sun, the active region — dubbed AR12665 — put on a show for NASA’s Sun-watching satellites, producing several solar flares, a coronal mass ejection and a solar energetic particle event. Watch the video below to learn how NASA’s satellites tracked the sunspot over the course of these two weeks.


On July 5, 2017, the Solar Dynamics Observatory watched an active region — an area of intense and complex magnetic fields — rotate into view. During its 13-day trip across the face of the Sun, the active region put on a show for several NASA Sun-watching satellites, producing several solar flares, a coronal mass ejection and a solar energetic particle event. Credits: NASA’s Goddard Space Flight Center/SDO/SOHO/CCMC/SWRC/Genna Duberstein, producer. Download this video in HD formats from NASA Goddard's Scientific Visualization Studio


Such sunspots are a common occurrence on the Sun, but less frequent at the moment, as the Sun is moving steadily toward a period of lower solar activity called solar minimum — a regular occurrence during its approximately 11-year cycle. Scientists track such spots because they can help provide information about the Sun’s inner workings. Space weather centers, such as NOAA’s Space Weather Prediction Center, also monitor these spots to provide advance warning, if needed, of the radiation bursts being sent toward Earth, which can impact our satellites and radio communications.

On July 9, a medium-sized flare burst from the sunspot, peaking at 11:18 a.m. EDT. Solar flares are explosions on the Sun that send energy, light and high-speed particles out into space — much like how earthquakes have a Richter scale to describe their strength, solar flares are also categorized according to their intensity. This flare was categorized as an M1. M-class flares are a tenth the size of the most intense flares, the X-class flares. The number provides more information about its strength: An M2 is twice as intense as an M1, an M3 is three times as intense and so on.

Days later, on July 14, a second medium-sized, M2 flare erupted from the Sun. The second flare was long-lived, peaking at 10:09 a.m. EDT and lasting over two hours.

This was accompanied by another kind of solar explosion called a coronal mass ejection, or CME. Solar flares are often associated with CMEs — giant clouds of solar material and energy. NASA’s Solar and Heliospheric Observatory, or SOHO, saw the CME at 9:36 a.m. EDT leaving the Sun at speeds of 620 miles per second and eventually slowing to 466 miles per second.

Following the CME, the turbulent active region also emitted a flurry of high-speed protons, known as a solar energetic particle event, at 12:45 p.m. EDT.

Research scientists at the Community Coordinated Modeling Center — located at NASA’s Goddard Space Flight Center in Greenbelt, Maryland — used these spacecraft observations as input for their simulations of space weather throughout the solar system. Using a model called ENLIL, they are able to map out and predict whether the solar storm will impact our instruments and spacecraft, and send alerts to NASA mission operators if necessary.

By the time the CME made contact with Earth’s magnetic field on July 16, the sunspot’s journey across the Sun was almost complete. As for the solar storm, it took this massive cloud of solar material two days to travel 93 million miles to Earth, where it caused charged particles to stream down Earth’s magnetic poles, sparking enhanced aurora.

After a large sunspot rotated out of Earth’s view on July 17, 2017, NASA instruments could still track its effects on the far side of the star. This imagery from NASA’s Solar Terrestrial Relations Observatory on July 23, 2017, captures an eruption of solar material — a coronal mass ejection — from that same active region. Credits: NASA’s Goddard Space Flight Center/STEREO/Bill Thompson


Related

Editor: Rob Garner


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New Storm Makes Surprise Appearance on Neptune


Images of Neptune taken during twilight observing revealed an extremely large bright storm system near Neptune’s equator (labeled ‘cloud complex’ in the upper figure), a region where astronomers have never seen a bright cloud. The center of the storm complex is ~9,000 km across, about 3/4 the size of Earth, or 1/3 of Neptune’s radius. The storm brightened considerably between June 26 and July 2, as noted in the logarithmic scale of the images taken on July 2. Credit: N.Molter/I. de Pater, UC Berkeley/C. Alvarez, W.M. Keck Observatory

Extremely large, bright storm system caught on camera at W. M. Keck Observatory


Maunakea, Hawaii – Striking images of a storm system nearly the size of Earth have astronomers doing a double-take after pinpointing its location near Neptune’s equator, a region where no bright cloud has ever been seen before. 

“Seeing a storm this bright at such a low latitude is extremely surprising,” said Ned Molter, a graduate student at University of California, Berkeley, who spotted the storm complex during a test run of twilight observing at W. M. Keck Observatory on Maunakea, Hawaii. “Normally, this area is really quiet and we only see bright clouds in the mid-latitude bands, so to have such an enormous cloud sitting right at the equator is spectacular.”

This massive storm system is about 9,000 kilometers in length, or 1/3 the size of Neptune’s radius, spanning at least 30 degrees in both latitude and longitude. Molter observed it getting much brighter between June 26 and July 2.

“Historically, very bright clouds have occasionally been seen on Neptune, but usually at latitudes closer to the poles, around 15 to 60 degrees north or south,” said Molter’s advisor, Professor Imke de Pater of UC Berkeley’s Astronomy Department. “Never before has a cloud been seen at, or so close to the equator, nor has one ever been this bright.”

At first, de Pater (pictured above) thought it was the same Northern Cloud Complex seen by the Hubble Space Telescope in 1994, after the iconic Great Dark Spot, imaged by Voyager 2 in 1989, had disappeared. But de Pater says measurements of its locale do not match, signaling that this cloud complex is different from the one Hubble first saw more than two decades ago.

A huge, high-pressure, dark vortex system anchored deep in Neptune’s atmosphere may be what’s causing the colossal cloud cover. As gases rise up in a vortex, they cool down. When its temperature drops below the condensation temperature of a condensable gas, that gas condenses out and forms clouds, just like water on Earth. On Neptune we expect methane clouds to form.

As with every planet, winds in Neptune’s atmosphere vary drastically with latitude, so if there is a big bright cloud system that spans many latitudes, something must hold it together, such as a dark vortex. Otherwise, the clouds would shear apart. 

“This big vortex is sitting in a region where the air, overall, is subsiding rather than rising,” said de Pater. “Moreover, a long-lasting vortex right at the equator would be hard to explain physically.”

If it is not tied to a vortex, the system may be a huge convective cloud, similar to those seen occasionally on other planets like the huge storm on Saturn that was detected in 2010. Although
one would also then expect the storm to have smeared out considerably over a week’s time.

“This shows that there are extremely drastic changes in the dynamics of Neptune’s atmosphere, and perhaps this is a seasonal weather event that may happen every few decades or so,” said de Pater.

Neptune is the windiest planet in our solar system, with the fastest observed wind speeds at the equator reaching up to a violent 1000 miles per hour. To put this into perspective, a Category 5 hurricane has wind speeds of 156 miles per hour. Neptune orbits the Sun every 160 years, and one season is about 40 years.

 Keck visiting scholars program

The discovery of Neptune’s mysterious equatorial cloud complex was made possible by the Keck Visiting Scholars Program, a new program launched this summer that gives graduate students and post-doctoral researchers experience working at the telescope, while contributing to Keck Observatory and its scientific community.

“This result by Imke and her first year graduate student, Ned, is a perfect example of what we’re trying to accomplish with the Keck Visiting Scholars Program,” said Anne Kinney, chief scientist at Keck Observatory. “Ned is our first visiting scholar, and his incredible work is a testament to the value of this program. It’s just been an outrageous success.”

Molter (pictured to the left with Kinney) is one of eight scholars accepted into the program this year. His assignment during his six-week stay at the Observatory was to develop a more efficient method for twilight observing, making use of time that otherwise might not be used. Most observers in the Keck Observatory community peer deep into the night sky and cannot observe their targets during the ‘Twilight Zone.’

“Ned had never observed before, and he’s very bright, so when Anne told me about the program, I knew he would be the perfect student for it,” said de Pater. “Now that we’ve discovered this interesting cloud complex in Neptune, Ned has a running start on a nice paper for his PhD thesis.”

“I loved being at Keck. Everyone was extremely friendly and I had a ton of personal interaction with the support astronomers and observing assistants,” said Molter. Being able to go behind the scenes to see how they run the telescopes and instruments every day, getting 10 nights of observing and engineering time on the telescopes, and going up to the summit twice to see the incredible engineering behind this gigantic machine has turned me from a student to an actual observer. It was an incredible opportunity.”

The Keck Visiting Scholars Program is generously sponsored by Roy and Frances Simperman, with major contributions from the M. R. and Evelyn Hudson Foundation, William M. Keck, Jr. Foundation, Edge of Space, Inc., Thomas McIntyre, and Jeff and Rebecca Steele.


Next Steps

Molter and De Pater will continue to analyze their data and propose for more twilight observing time at Keck Observatory this fall so they can learn more about the nature of this storm and get an idea of what it will be doing over time. 

Having a better understanding of Neptune’s atmosphere will help give astronomers a clearer picture of this icy giant’s global circulation. This has become increasingly more important in the exoplanet realm, as a majority of exoplanets found so far are nearly the size of Neptune. While scientists can calculate their size and mass, not much is currently known about exoplanets’ atmosphere.



About W. M. Keck Observatory
The W. M. Keck Observatory operates the most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Maunakea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometers, and world-leading laser guide star adaptive optics systems. The Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California, and NASA.




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Thursday, August 03, 2017

Cutting-edge Adaptive Optics Facility Sees First Light

PR Image eso1724a
The planetary nebula IC 4406 seen with MUSE and the AOF 

NGC 6369 before and after the AOF 

The planetary nebula NGC 6563 observed with the AOF

The AOF + MUSE at work

The AOF + MUSE at work

UT4 and the AOF at work

The powerful lasers of the AOF

NGC 6369 

ESO 338-4 

The planetary nebula NGC 6563 observed with MUSE and the AOF 


Videos
 
ESOcast 119: AOF First Light
ESOcast 119: AOF First Light

NGC 6369 AO on/off crossfade
NGC 6369 AO on/off crossfade


Image Comparisons

NGC 6369 with and without the AOF
NGC 6369 with and without the AOF

NGC 6563 with and without the AOF
NGC 6563 with and without the AOF 


Spectacular improvement in the sharpness of MUSE images

The Unit Telescope 4 (Yepun) of ESO’s Very Large Telescope (VLT) has now been transformed into a fully adaptive telescope. After more than a decade of planning, construction and testing, the new Adaptive Optics Facility (AOF) has seen first light with the instrument MUSE, capturing amazingly sharp views of planetary nebulae and galaxies. The coupling of the AOF and MUSE forms one of the most advanced and powerful technological systems ever built for ground-based astronomy.

The Adaptive Optics Facility (AOF) is a long-term project on ESO’s Very Large Telescope (VLT) to provide an adaptive optics system for the instruments on Unit Telescope 4 (UT4), the first of which is MUSE (the Multi Unit Spectroscopic Explorer) [1]. Adaptive optics works to compensate for the blurring effect of the Earth’s atmosphere, enabling MUSE to obtain much sharper images and resulting in twice the contrast previously achievable. MUSE can now study even fainter objects in the Universe.

“Now, even when the weather conditions are not perfect, astronomers can still get superb image quality thanks to the AOF,” explains Harald Kuntschner, AOF Project Scientist at ESO.

Following a battery of tests on the new system, the team of astronomers and engineers were rewarded with a series of spectacular images. Astronomers were able to observe the planetary nebulae IC 4406, located in the constellation Lupus (The Wolf), and NGC 6369, located in the constellation Ophiuchus (The Serpent Bearer). The MUSE observations using the AOF showed dramatic improvements in the sharpness of the images, revealing never before seen shell structures in IC 4406 [2].

The AOF, which made these observations possible, is composed of many parts working together. They include the Four Laser Guide Star Facility (4LGSF) and the very thin deformable secondary mirror of UT4 [3] [4]. The 4LGSF shines four 22-watt laser beams into the sky to make sodium atoms in the upper atmosphere glow, producing spots of light on the sky that mimic stars. Sensors in the adaptive optics module GALACSI (Ground Atmospheric Layer Adaptive Corrector for Spectroscopic Imaging) use these artificial guide stars to determine the atmospheric conditions.

One thousand times per second, the AOF system calculates the correction that must be applied to change the shape of the telescope’s deformable secondary mirror to compensate for atmospheric disturbances. In particular, GALACSI corrects for the turbulence in the layer of atmosphere up to one kilometre above the telescope. Depending on the conditions, atmospheric turbulence can vary with altitude, but studies have shown that the majority of atmospheric disturbance occurs in this “ground layer” of the atmosphere.

“The AOF system is essentially equivalent to raising the VLT about 900 metres higher in the air, above the most turbulent layer of atmosphere,” explains Robin Arsenault, AOF Project Manager. “In the past, if we wanted sharper images, we would have had to find a better site or use a space telescope — but now with the AOF, we can create much better conditions right where we are, for a fraction of the cost!”

The corrections applied by the AOF rapidly and continuously improve the image quality by concentrating the light to form sharper images, allowing MUSE to resolve finer details and detect fainter stars than previously possible. GALACSI currently provides a correction over a wide field of view, but this is only the first step in bringing adaptive optics to MUSE. A second mode of GALACSI is in preparation and is expected to see first light early 2018. This narrow-field mode will correct for turbulence at any altitude, allowing observations of smaller fields of view to be made with even higher resolution.

“Sixteen years ago, when we proposed building the revolutionary MUSE instrument, our vision was to couple it with another very advanced system, the AOF,” says Roland Bacon, project lead for MUSE. “The discovery potential of MUSE, already large, is now enhanced still further. Our dream is becoming true.”

One of the main science goals of the system is to observe faint objects in the distant Universe with the best possible image quality, which will require exposures of many hours. Joël Vernet, ESO MUSE and GALACSI Project Scientist, comments: “In particular, we are interested in observing the smallest, faintest galaxies at the largest distances. These are galaxies in the making — still in their infancy — and are key to understanding how galaxies form.”

Furthermore, MUSE is not the only instrument that will benefit from the AOF. In the near future, another adaptive optics system called GRAAL will come online with the existing infrared instrument HAWK-I, sharpening its view of the Universe. That will be followed later by the powerful new instrument ERIS.

“ESO is driving the development of these adaptive optics systems, and the AOF is also a pathfinder for ESO’s Extremely Large Telescope,” adds Arsenault. “Working on the AOF has equipped us — scientists, engineers and industry alike — with invaluable experience and expertise that we will now use to overcome the challenges of building the ELT.”


Notes

 [1] MUSE is an integral-field spectrograph, a powerful instrument that produces a 3D data set of a target object, where each pixel of the image corresponds to a spectrum of the light from the object. This essentially means that the instrument creates thousands of images of the object at the same time, each at a different wavelength of light, capturing a wealth of information.
[2] IC 4406 has previously been observed with the VLT (eso9827a).

[3] At just over one metre in diameter, this is the largest adaptive optics mirror ever produced and demanded cutting-edge technology. It was mounted on UT4 in 2016 (ann16078) to replace the telescope’s original conventional secondary mirror.

 [4] Other tools to optimise the operation of the AOF have been developed and are now operational. These include an extension of the Astronomical Site Monitor software that monitors the atmosphere to determine the altitude at which the turbulence is occurring, and the Laser Traffic Control System (LTCS) that prevents other telescopes looking into the laser beams or at the artificial stars themselves and potentially affecting their observations.


More Information

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its world-leading Very Large Telescope Interferometer as well as two survey telescopes, VISTA working in the infrared and the visible-light VLT Survey Telescope. ESO is also a major partner in two facilities on Chajnantor, APEX and ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre Extremely Large Telescope, the ELT, which will become “the world’s biggest eye on the sky”.


Links


 Contacts

Harald Kuntschner
ESO, AOF Project Scientist
Garching bei München, Germany
Tel: +49 89 3200 6465
Email: hkuntsch@eso.org

Richard Hook
ESO Public Information Officer
Garching bei München, Germany
Tel: +49 89 3200 6655
Cell: +49 151 1537 3591
Email: rhook@eso.org

Joël Vernet
ESO MUSE and GALACSI Project Scientist
Garching bei München, Germany
Tel: +49 89 3200 6579
Email: jvernet@eso.org

Source: ESO/News

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