Tag Archives: esa

The elliptical galaxy NGC 1600, 200 million light-years away — shown in the centre of the image and highlighted in the box —, hosts in its centre one of the biggest supermassive black holes known . Until the discovery of this example, astronomers assumed that such huge black holes could only be found in the centres of massive galaxies at the centre of galaxy clusters. NGC 1600, however, is a rather isolated galaxy.

The image is a composition of a ground based view and observations made with the NASA/ESA Hubble Space Telescope.

Credit:
NASA, ESA, Digital Sky Survey 2

NGC 1600′s super massive blackhole discovery puzzles astronomers

Astronomers have uncovered one of the biggest supermassive black holes, with the mass of 17 billion Suns, in an unlikely place: the centre of a galaxy that lies in a quiet backwater of the Universe. The observations, made with the NASA/ESA Hubble Space Telescope and the Gemini Telescope in Hawaii, indicate that these monster objects may be more common than once thought. The results of this study are released in the journal Nature.

The elliptical galaxy NGC 1600, 200 million light-years away — shown in the centre of the image and highlighted in the box —, hosts in its centre one of the biggest supermassive black holes known . Until the discovery of this example, astronomers assumed that such huge black holes could only be found in the centres of massive galaxies at the centre of galaxy clusters. NGC 1600, however, is a rather isolated galaxy. The image is a composition of a ground based view and observations made with the NASA/ESA Hubble Space Telescope. Credit: NASA, ESA, Digital Sky Survey 2
The elliptical galaxy NGC 1600, 200 million light-years away — shown in the centre of the image and highlighted in the box —, hosts in its centre one of the biggest supermassive black holes known . Until the discovery of this example, astronomers assumed that such huge black holes could only be found in the centres of massive galaxies at the centre of galaxy clusters. NGC 1600, however, is a rather isolated galaxy.
The image is a composition of a ground based view and observations made with the NASA/ESA Hubble Space Telescope.
Credit:
NASA, ESA, Digital Sky Survey 2

Until now, the biggest supermassive black holes — those having more than 10 billion times the mass of our Sun — have only been found at the cores of very large galaxies in the centres of massive galaxy clusters. Now, an international team of astronomers using the NASA/ESA Hubble Space Telescope has discovered a supersized black hole with a mass of 17 billion Suns in the centre of the rather isolated galaxy NGC 1600.

NGC 1600 is an elliptical galaxy which is located not in a cluster of galaxies, but in a small group of about twenty. The group is located 200 million light-years away in the constellation Eridanus. While finding a gigantic supermassive black hole in a massive galaxy within a cluster of galaxies is to be expected, finding one in an average-sized galaxy group like the one surrounding NGC 1600 is much more surprising.

“Even though we already had hints that the galaxy might host an extreme object in the centre, we were surprised that the black hole in NGC 1600 is ten times more massive than predicted by the mass of the galaxy,” explains lead author of the study Jens Thomas from the Max Planck-Institute for Extraterrestrial Physics, Germany.

Based on previous Hubble surveys of supermassive black holes, astronomers had discovered a correlation between a black hole’s mass and the mass of its host galaxy’s central bulge of stars: the larger the galaxy bulge, the more massive the black hole is expected to be. “It appears from our finding that this relation does not work so well with extremely massive black holes,” says Thomas. “These monster black holes account for a much larger fraction of the host galaxy’s mass than the previous correlations would suggest.”

Finding this extremely massive black hole in NGC 1600 leads astronomers to ask whether these objects are more common than previously thought. “There are quite a few galaxies the size of NGC 1600 that reside in average-size galaxy groups,” explains co-author Chung-Pei Ma, an astronomer from the University of California, Berkeley, USA, and head of the MASSIVE Survey [1]. “We estimate that these smaller groups are about fifty times more abundant than large, dense galaxy clusters. So the question now is: is this the tip of an iceberg? Maybe there are a lot more monster black holes out there.”

It is assumed that this black hole grew by merging with another supermassive black hole from another galaxy. It may then have continued to grow by gobbling up gas funneled to the core of the galaxy by further galaxy collisions. Thus may also explain why NGC 1600 resides in a sparsely populated region of the Universe and why it is at least three times brighter than its neighbours.

As the supermassive black hole is currently dormant, astronomers were only able to find it and estimate its mass by measuring the velocities of stars close to it, using the Gemini North 8-metre telescope on Mauna Kea, Hawaii. Using these data the team discovered that stars lying about 3000 light-years from the core are moving as if there had been many more stars in the core in the distant past. This indicates that most of the stars in this region have been kicked out from the centre of the galaxy.

Archival Hubble images, taken with the Near Infrared Camera and Multi-Object Spectrometer (NICMOS), support the idea that the two merging supermassive black holes in the distant past gave stars the boot. The NICMOS images revealed that the galaxy’s core is unusually faint, indicating a lack of stars close to the galactic centre. “We estimate that the mass of stars tossed out of the central region of NGC 1600 is equal to 40 billion Suns,” concludes Thomas. “This is comparable to ejecting the entire disc of our Milky Way galaxy.”

Notes
[1] The MASSIVE Survey, which began in 2014, measures the mass of stars, dark matter, and the central black hole of the 100 most massive, nearby galaxies, those larger than 300 billion solar masses and within 350 million light-years of Earth. Among its goals are to find the descendants of luminous quasars that may be sleeping unsuspected in large nearby galaxies and to understand how galaxies form and grow supermassive black holes.

More information
The Hubble Space Telescope is a project of international cooperation between ESA and NASA.

The study “A 17-billion-solar-mass black hole in a group galaxy with a diffuse core” appeared in the journal Nature.

The international team of astronomers in this study consists of J. Thomas (Max Planck Institute for Extraterrestrial Physics, Germany), C.-P. Ma (University of California, Berkeley, USA), N. McConnell (Dominion Astrophysical Observatory, Canada), J. Greene (Princeton University, USA), J. Blakeslee (Dominion Astrophysical Observatory, Canada), and R. Janish (University of California, Berkeley, USA)

Source: Space Telescope

Using images from ESO’s Very Large Telescope and the NASA/ESA Hubble Space Telescope, astronomers have discovered fast-moving wave-like features in the dusty disc around the nearby star AU Microscopii. These odd structures are unlike anything ever observed, or even predicted, before now.

The top row shows a Hubble image of the AU Mic disc from 2010, the middle row Hubble from 2011 and the bottom row VLT/SPHERE data from 2014. The black central circles show where the brilliant light of the central star has been blocked off to reveal the much fainter disc, and the position of the star is indicated schematically.

The scale bar at the top of the picture indicates the diameter of the orbit of the planet Neptune in the Solar System (60 AU).

Note that the brightness of the outer parts of the disc has been artificially brightened to reveal the faint structure.

Credit:
ESO, NASA & ESA

Mysterious Ripples Found Racing Through Planet-forming Disc: ESO

Unique structures spotted around nearby star


 

Using images from ESO’s Very Large Telescope and the NASA/ESA Hubble Space Telescope, astronomers have discovered fast-moving wave-like features in the dusty disc around the nearby star AU Microscopii. These odd structures are unlike anything ever observed, or even predicted, before now. The top row shows a Hubble image of the AU Mic disc from 2010, the middle row Hubble from 2011 and the bottom row VLT/SPHERE data from 2014. The black central circles show where the brilliant light of the central star has been blocked off to reveal the much fainter disc, and the position of the star is indicated schematically. The scale bar at the top of the picture indicates the diameter of the orbit of the planet Neptune in the Solar System (60 AU). Note that the brightness of the outer parts of the disc has been artificially brightened to reveal the faint structure. Credit: ESO, NASA & ESA
Using images from ESO’s Very Large Telescope and the NASA/ESA Hubble Space Telescope, astronomers have discovered fast-moving wave-like features in the dusty disc around the nearby star AU Microscopii. These odd structures are unlike anything ever observed, or even predicted, before now.
The top row shows a Hubble image of the AU Mic disc from 2010, the middle row Hubble from 2011 and the bottom row VLT/SPHERE data from 2014. The black central circles show where the brilliant light of the central star has been blocked off to reveal the much fainter disc, and the position of the star is indicated schematically.
The scale bar at the top of the picture indicates the diameter of the orbit of the planet Neptune in the Solar System (60 AU).
Note that the brightness of the outer parts of the disc has been artificially brightened to reveal the faint structure.
Credit:
ESO, NASA & ESA

Using images from ESO’s Very Large Telescope and the NASA/ESA Hubble Space Telescope, astronomers have discovered never-before-seen structures within a dusty disc surrounding a nearby star. The fast-moving wave-like features in the disc of the star AU Microscopii are unlike anything ever observed, or even predicted, before now. The origin and nature of these features present a new mystery for astronomers to explore. The results are published in the journal Nature on 8 October 2015.

AU Microscopii, or AU Mic for short, is a young, nearby star surrounded by a large disc of dust [1]. Studies of such debris discs can provide valuable clues about how planets, which form from these discs, are created.

Astronomers have been searching AU Mic’s disc for any signs of clumpy or warped features, as such signs might give away the location of possible planets. And in 2014 they used the more powerful high-contrast imaging capabilities of ESO’s newly installed SPHERE instrument, mounted on the Very Large Telescope for their search — and discovered something very unusual.

Our observations have shown something unexpected,” explains Anthony Boccaletti, LESIA (Observatoire de Paris/CNRS/UPMC/Paris-Diderot), France, and lead author on the paper. “The images from SPHERE show a set of unexplained features in the disc which have an arch-like, or wave-like, structure, unlike anything that has ever been observed before.

Five wave-like arches at different distances from the star show up in the new images, reminiscent of ripples in water. After spotting the features in the SPHERE data the team turned to earlier images of the disc taken by the NASA/ESA Hubble Space Telescope in 2010 and 2011 to see whether the features were also visible in these [2]. They were not only able to identify the features on the earlier Hubble images — but they also discovered that they had changed over time. It turns out that these ripples are moving — and very fast!

We reprocessed images from the Hubble data and ended up with enough information to track the movement of these strange features over a four-year period,” explains team member Christian Thalmann (ETH Zürich, Switzerland). “By doing this, we found that the arches are racing away from the star at speeds of up to about 40 000 kilometres/hour!

The features further away from the star seem to be moving faster than those closer to it. At least three of the features are moving so fast that they could well be escaping from the gravitational attraction of the star. Such high speeds rule out the possibility that these are conventional disc features caused by objects — like planets — disturbing material in the disc while orbiting the star. There must have been something else involved to speed up the ripples and make them move so quickly, meaning that they are a sign of something truly unusual [3].

Everything about this find was pretty surprising!” comments co-author Carol Grady of Eureka Scientific, USA. “And because nothing like this has been observed or predicted in theory we can only hypothesise when it comes to what we are seeing and how it came about.

The team cannot say for sure what caused these mysterious ripples around the star. But they have considered and ruled out a series of phenomena as explanations, including the collision of two massive and rare asteroid-like objects releasing large quantities of dust, and spiral waves triggered by instabilities in the system’s gravity.

But other ideas that they have considered look more promising.

One explanation for the strange structure links them to the star’s flares. AU Mic is a star with high flaring activity — it often lets off huge and sudden bursts of energy from on or near its surface,” explains co-author Glenn Schneider of Steward Observatory, USA. “One of these flares could perhaps have triggered something on one of the planets — if there are planets — like a violent stripping of material which could now be propagating through the disc, propelled by the flare’s force.

It is very satisfying that SPHERE has proved to be very capable at studying discs like this in its first year of operation,” adds Jean-Luc Beuzit, who is both a co-author of the new study and also led the development of SPHERE itself.

The team plans to continue to observe the AU Mic system with SPHERE and other facilities, including ALMA, to try to understand what is happening. But, for now, these curious features remain an unsolved mystery.

Notes

[1] AU Microscopii lies just 32 light-years away from Earth. The disc essentially comprises asteroids that have collided with such vigour that they have been ground to dust.

[2] The data were gathered by Hubble’s Space Telescope Imaging Spectrograph (STIS).

[3] The edge-on view of the disc complicates the interpretation of its three-dimensional structure.

More information

This research was presented in a paper entitled “Fast-Moving Structures in the Debris Disk Around AU Microscopii”, to appear in the journal Nature on 8 October 2015.

Source: ESO

Image credit : ESA

Philae landed successfully on comet : Rosetta update

Image credit : ESA
Image credit : ESA

A remarkable feat in human history has been achieved by European Space Agency (ESA) when Rosetta mission’s Philae lander landed on a comet successfully.

This achievement is not only a great achievement for ESA but it can be useful for space science and technology in general as now humanity knows that it is doable!

Congratulations ESA and all the scientists, engineers and everyone involved with the mission.

 

Following is a tweet from @Philae2014

 

ambitious

ESA enters into the sci-fi realm with ‘Ambitious’

European Space Agency has entered the area of science fiction in an unusual and innovative way of doing public outreach. This new experimental work was done in the form of a short film ‘Ambitious’, premiered on Friday in London.

ambitious

Ambition is a collaboration between Platige Image and ESA. Directed by Tomek Bagiński and starring Aiden Gillen and Aisling Franciosi, Ambition was shot on location in Iceland, and screened on 24 October 2014 during the British Film Institute’s celebration of Sci-Fi: Days of Fear and Wonder, at the Southbank, London. 

Source: ESA

Rover landing site candidates. Credit : ESA

Four possible landing sites are being considered for the ExoMars mission in 2018 :ESA

Four possible landing sites are being considered for the ExoMars mission in 2018. Its rover will search for evidence of martian life, past or present.

ExoMars is a joint two-mission endeavour between ESA and Russia’s Roscosmos space agency. The Trace Gas Orbiter and an entry, descent and landing demonstrator module, Schiaparelli, will be launched in January 2016, arriving at Mars nine months later. The Rover and Surface Platform will depart in May 2018, with touchdown on Mars in January 2019.

Rover landing site candidates. Credit : ESA
Rover landing site candidates. Credit : ESA

The search for a suitable landing site for the second mission began in December 2013, when the science community was asked to propose candidates.

The eight proposals were considered during a workshop held by the Landing Site Selection Working Group in April. By the end of the workshop, there were four clear front-runners.

Following additional review by an ESA-appointed panel, the four sites have now been formally recommended for further detailed analysis.

 

The sites – Mawrth Vallis, Oxia Planum, Hypanis Vallis and Aram Dorsum – are all located relatively close to the equator.

“The present-day surface of Mars is a hostile place for living organisms, but primitive life may have gained a foothold when the climate was warmer and wetter, between 3.5 billion and 4 billion years ago,” says Jorge Vago, ESA’s ExoMars project scientist.

“Therefore, our landing site should be in an area with ancient rocks where liquid water was once abundant. Our initial assessment clearly identified four landing sites that are best suited to the mission’s scientific goals.”

The area around Mawrth Vallis and nearby Oxia Planum contains one of the largest exposures of rocks on Mars that are older than 3.8 billion years and clay-rich, indicating that water once played a role here. Mawrth Vallis lies on the boundary between the highlands and lowlands and is one of the oldest outflow channels on Mars.

The exposed rocks at both Mawrth Vallis and Oxia Planum have varied compositions, indicating a variety of deposition and wetting environments. In addition, the material of interest has been exposed by erosion only within the last few hundred million years, meaning the rocks are still well preserved against damage from the planet’s harsh radiation and oxidation environment.

By contrast, Hypanis Vallis lies on an exhumed fluvial fan, thought to be the remnant of an ancient river delta at the end of a major valley network. Distinct layers of fine-grained sedimentary rocks provide access to material deposited about 3.45 billion years ago.

Finally, the Aram Dorsum site receives its name from the eponymous channel, curving from northeast to west across the location. The sedimentary rocks around the channel are thought to be alluvial sediments deposited much like those around Earth’s River Nile.

This region experienced both sustained water activity followed by burial, providing protection from radiation and oxidation for most of Mars’ geological history, also making this a site with strong potential for finding preserved biosignatures.

“While all four sites are clearly interesting scientifically, they must also allow for the operational and engineering requirements for safe landing and roving on the surface,” adds Jorge.

“Technical constraints are satisfied to different degrees in each of these locations and, although our preliminary evaluation indicates that Oxia Planum has fewer problems compared to the other sites, verification is still on going.”

The next stage of analysis will include simulations to predict the probability of landing success based on the entry profile, atmospheric and terrain properties at each of the candidate sites.

The aim is to complete the certification of at least one site by the second half of 2016, with a final decision on the landing site for the ExoMars 2018 rover to be taken sometime in 2017.


Download the full report: Recommendation for the narrowing of ExoMars 2018 landing sites

More ExoMars images, including digital terrain models of the candidate landing sites, are availablehere.

Source: ESA

ROSETTA TO DEPLOY LANDER ON 12 NOVEMBER:ESA

The European Space Agency’s Rosetta mission will deploy its lander, Philae, to the surface of Comet 67P/Churyumov–Gerasimenko on 12 November.

Philae’s landing site, currently known as Site J, is located on the smaller of the comet’s two ‘lobes’, with a backup site on the larger lobe. The sites were selected just six weeks after Rosetta arrived at the comet on 6 August, following its 10-year journey through the Solar System.

In that time, the Rosetta mission has been conducting an unprecedented scientific analysis of the comet, a remnant of the Solar System’s 4.6 billion-year history. The latest results from Rosetta will be presented on the occasion of the landing, during dedicated press briefings.

The main focus to date has been to survey 67P/Churyumov–Gerasimenko in order to prepare for the first ever attempt to soft-land on a comet.

Site J was chosen unanimously over four other candidate sites as the primary landing site because the majority of terrain within a square kilometre area has slopes of less than 30º relative to the local vertical and because there are relatively few large boulders. The area also receives sufficient daily illumination to recharge Philae and continue surface science operations beyond the initial 64-hour battery-powered phase.

Over the last two weeks, the flight dynamics and operations teams at ESA have been making a detailed analysis of flight trajectories and timings for Rosetta to deliver the lander at the earliest possible opportunity.

Two robust landing scenarios have been identified, one for the primary site and one for the backup. Both anticipate separation and landing on 12 November.

For the primary landing scenario, targeting Site J, Rosetta will release Philae at 08:35 GMT/09:35 CET at a distance of 22.5 km from the centre of the comet, landing about seven hours later. The one-way signal travel time between Rosetta and Earth on 12 November is 28 minutes 20 seconds, meaning that confirmation of the landing will arrive at Earth ground stations at around 16:00 GMT/17:00 CET.

If a decision is made to use the backup Site C, separation will occur at 13:04 GMT/14:04 CET, 12.5 km from the centre of the comet. Landing will occur about four hours later, with confirmation on Earth at around 17:30 GMT/18:30 CET. The timings are subject to uncertainties of several minutes.

Final confirmation of the primary landing site and its landing scenario will be made on 14 October after a formal Lander Operations Readiness Review, which will include the results of additional high-resolution analysis of the landing sites conducted in the meantime. Should the backup site be chosen at this stage, landing can still occur on 12 November.

A competition for the public to name the primary landing site will also be announced during the week of 14 October.

The Rosetta orbiter will continue to study the comet and its environment using its 11 science instruments as they orbit the Sun together. The comet is on an elliptical 6.5-year orbit that takes it from beyond Jupiter at its furthest point, to between the orbits of Mars and Earth at its closest to the Sun. Rosetta will accompany the comet for more than a year as they swing around the Sun and back to the outer Solar System again.

The analyses made by the Rosetta orbiter will be complemented by the in situ measurements performedby Philae’s 10 instruments.

An invitation to media with an outline of the programme for the 12 November event will be issued soon.

More about Rosetta

Rosetta is an ESA mission with contributions from its Member States and NASA. Rosetta’s Philae lander is provided by a consortium led by DLR, MPS, CNES, and ASI. Rosetta is the first mission in history to rendezvous with a comet. It is escorting the comet as they orbit the Sun, and will deploy a lander.

Comets are time capsules containing primitive material left over from the epoch when the Sun and its planets formed. By studying the gas, dust and structure of the nucleus and organic materials associated with the comet, via both remote and in situ observations, the Rosetta mission should become the key to unlocking the history and evolution of our Solar System, as well as answering questions regarding the origin of Earth’s water and perhaps even life.

Learn more about Rosetta at: http:// www.esa.int/rosetta

Source: ESA