vendredi 4 mai 2012

Forty years of the PS Booster

CERN - European Organization for Nuclear Research logo.

May 4, 2012

Image above: The Proton Synchrotron Booster in October 1972, just four months after being switched on for the first time (Image: CERN).

The Proton Synchrotron (PS) Booster – a key accelerator in the CERN complex – is 40 years old this month.

The accelerator is made up of four superimposed synchrotron rings that receive beams of protons from the linear accelerator (Linac) at 50 MeV and accelerate them to 800 MeV for injection into the Proton Synchrotron (PS).

CERN Accelerator Complex

Before the Booster received its first beams on 26 May 1972, protons were injected directly from the Linac into the PS, where they were accelerated to 26 GeV. The low injection energy of 50 MeV limited the number of protons the PS could accept. The Booster allows the PS to accept an order of magnitude more protons, which greatly enhances the beam's utility for experiments.


1. CERN, the European Organization for Nuclear Research, is the world's leading laboratory for particle physics. It has its headquarters in Geneva. At present, its Member States are Austria, Belgium, Bulgaria, the Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Italy, the Netherlands, Norway, Poland, Portugal, Slovakia, Spain, Sweden, Switzerland and the United Kingdom. Romania is a candidate for accession. Israel is an Associate Member in the pre-stage to Membership. India, Japan, the Russian Federation, the United States of America, Turkey, the European Commission and UNESCO have Observer status.

Find out more - CERN Bulletin:

Images, Text, Credit: CERN.


The height of the ISS orbit raised

ISS - International Space Station patch / ESA - ATV-3 Edoardo Amaldi Mission patch.


May 4, in accordance with the flight program of the International Space Station to provide optimum conditions for its rendezvous and docking with the manned spacecraft Soyuz TMA-04M (launch is scheduled for May 15, 2012), the correction of the ISS orbit.

ATV reboost ISS

The correction is made using the engines of European cargo spacecraft ATV-3 Edoardo Amaldi, resulting in an average height of the orbit of the ISS has increased by 5.1 kilometers and is 399 kilometers.

The operation carried out in normal mode, in accordance with the calculations of ballistic Service Mission Control Center Engineering Research Institute.

ATV reboost

The crew of the station as part of the commander - Oleg Kononenko (Roscosmos), flight engineers Andre Cowper (ESA) and Donald Pettit (NASA) during the maneuver worked on the planned program. The atmosphere in low Earth orbit was controlled by Mission Control Center, located in suburban Houston and American Queen.

Original texr in Russian:

Image, Video, Text, Credits: Press-service of Federal Space Agency (Roscosmos PAO) and the PCO / ESA / EADS / Translation:


Signs of ancient flowing water on Mars

ESA - Mars Express Mission patch.

4 May 2012

 Acidalia Planitia and Tempe Terra transition

ESA’s Mars Express has returned images of a region on the Red Planet that appears to have been sculpted in part by flowing liquid. This again adds to the growing evidence that Mars had large volumes of water on its surface in the distant past.

On 21 June last year, Mars Express pointed its high-resolution stereo camera at the western part of Acidalia Planitia, a gigantic basin in the planet’s northern lowlands, at the interface with Tempe Terra, an older, higher terrain.

Acidalia Planitia is a region so vast that it can be seen from Earth by amateur astronomers.

The famous observer Giovanni Schiaparelli named this large dark feature on his map of Mars after the mythical Acidalian (or Venusian) fountain in Boeotia, where the three graces of ancient Greek myth bathed. 

Perspective view

The images taken cover part of the western edge of the region, where some of the numerous valleys descending from Tempe Terra show subtle evidence for ‘dendritic’ drainage patterns emanating from them.

The word dendritic comes from the Greek for tree and the channels in the images are believed to have been formed by the surface run-off of flowing water from rain or melting snow during some distant martian epoch.

The presence of deep valleys, with very few tributaries in the form of smaller valleys further downstream, shows that the region itself probably formed by a process called ‘sapping’ or ‘undermining’, which occurs when erosion along the base of a cliff wears away softer layers of material.

3D view

Sapping removes support for the upper harder rock which breaks off into large blocks, and falls from the cliff face.

This way, deep valleys can erode progressively upwards, as can be seen in the Colorado Plateau on Earth.

The lower-left part of the image appears to be in shadow, but this darkening is in fact is due to differences in surface material: the left-hand side is covered with dark sand, probably of volcanic origin, while the right side is covered with brighter dust.

The images also show faults in the martian crust, extending towards the Idaeus Fossae region. They are believed to have played a vital role in releasing water by exposing subsurface reservoirs, possibly forming lakes in nearby craters.

Apparent sediments covering the floors of some of the older, more eroded craters are of particular interest for scientists, as they again point to the existence of surface water at some stage.

 Acidalia Planitia in context

In some cases, valleys start at the rim of the craters, suggesting that water was released from them into the surrounding terrain.

Some newer craters are seen in the central areas of the image. Their relatively young age is demonstrated by the lack of erosion and the fact that they lie on top of older features.

  Topographical view

These Mars Express images give scientists yet more evidence of a watery past for the Red Planet, and will help them to decode how the water ebbed, flowed and eroded the surface at different times.

Related links:

Mars Express in depth:

High Resolution Stereo Camera:

Behind the lens:

Frequently asked questions:

For specialists:
ESA Planetary Science archive (PSA):

NASA Planetary Data System:

HRSC data viewer:

Images, Text, Credits: ESA / DLR / FU Berlin (G. Neukum) / NASA / MGS & MOLA Science Team.

Best regards,

Spotlight on Sentinel-2

ESA - SENTINEL 2 Mission logo.

4 May 2012

The vast potential of ESA’s upcoming Sentinel-2 satellites came into focus last week at a symposium in Italy on how they will benefit current and future projects that exploit Earth observation data.

The humid and moist tropical climate of Gabon yields immense forests that cover over 85% of the land, making them the number-two driver of the national economy – and deforestation a subject of concern.

Gabon forest cover

The GMES project on Forest Monitoring Reducing Emissions from Deforestation and Degradation mapped deforestation in Gabon from 1990 to 2010 using NASA’s Landsat satellite.

But the Equatorial African country’s heavy cloud cover means that imagery is often difficult to acquire over some areas.

While it takes Landsat 1.5–3.5 years to obtain imagery of the entire country, the future Sentinel-2 mission would require less than a year because of its more frequent coverage.

The future monitoring of land cover by Sentinel-2 was just one of the many topics covered at the Sentinel-2 Preparatory Symposium, hosted this week at ESA’s ESRIN centre for Earth observation in Frascati, Italy. 

Other applications discussed include forestry, agriculture, cartography and the mapping of glaciers and wetlands.

Sentinel-2 image mockup

“Sentinel-2 will fill the gap from both a research and operations perspective,” said Chris Steenmans, Head of Programme at the European Environment Agency’s Shared Environmental Information System.

“We are currently struggling with fragmented satellite data, so the timely information that Sentinel-2 will provide is important. The mission will also complement other Earth observation investments on a global level.”

Sentinel-2, planned for launch next year, is one of five Sentinel missions that ESA is developing for Europe’s Global Monitoring for Environment and Security (GMES) programme.

Through GMES, decision-makers will have access to reliable, timely and accurate information services to manage the environment, understand and mitigate the effects of climate change and ensure civil security.

At the recent symposium, Medhavy Thankappan, Director of Science and Strategy at Geoscience Australia’s National Earth Observation Group, presented a national land cover dataset based on analysis of satellite data acquired over an eight-year period.

The dataset will provide the basis for monitoring Australia’s water resources, agricultural practices, soil erosion and forests.


“The next step is to update the land cover information with new data from a consistent source – to move from mapping to monitoring,” said Mr Thankappan.

“We would also like to move to a higher spatial resolution – that’s where Sentinel-2 comes in.”

Owing to its high resolution of 10 m per pixel, and wide swath of 290 km, global products from Sentinel-2 will be able to be applied locally.

The mission will adhere to the Sentinel Data Policy, which establishes full and open access to data acquired by all five of the upcoming Sentinels.

Participants at the symposium, however, expressed concern over the data delivery arrangement.

“Sentinel-2 is like a dream come true for the forest remote sensing community,” said Tuomas Häme, Research Professor at the VTT Technical Research Centre of Finland.

“It is of utmost importance that the mission can be fully utilised by organising data delivery to the users as smoothly as it is organised for the similar missions with a free and open data policy.”

Related links:

Sentinel-2 Preparatory Symposium:

GSE Forest Monitoring REDD:

European Environment Agency:

Australia’s National Earth Observation Group:

VTT Technical Research Centre of Finland:

Global Monitoring for Environment and Security (GMES):

Images, Text, Credits: ESA / SIRS / RapidEye / Astrium GmbH.


mercredi 2 mai 2012

Black Hole Caught Red-Handed in a Stellar Homicide

NASA - GALEX Mission patch.

May 2, 2012

Astronomers have gathered the most direct evidence yet of a supermassive black hole shredding a star that wandered too close. NASA's Galaxy Evolution Explorer, a space-based observatory, and the Pan-STARRS1 telescope on the summit of Haleakala in Hawaii, were among the first to help identify the stellar remains.

Supermassive black holes, weighing millions to billions times more than the sun, lurk in the centers of most galaxies. These hefty monsters lay quietly until an unsuspecting victim, such as a star, wanders close enough to get ripped apart by their powerful gravitational clutches.

Simulation of Black Hole Flare

Astronomers have spotted these stellar homicides before, but this is the first time they identified the victim. Using several ground- and space-based telescopes, a team of astronomers led by Suvi Gezari of the Johns Hopkins University in Baltimore identified the victim as a star rich in helium gas. The star resides in a galaxy 2.7 billion light-years away. The team's results will appear in today's online edition of the journal Nature.

"When the star is ripped apart by the gravitational forces of the black hole, some part of the star's remains falls into the black hole while the rest is ejected at high speeds," Gezari said. "We are seeing the glow from the stellar gas falling into the black hole over time. We're also witnessing the spectral signature of the ejected gas, which we find to be mostly helium. It is like we are gathering evidence from a crime scene. Because there is very little hydrogen and mostly helium in the gas, we detect from the carnage that the slaughtered star had to have been the helium-rich core of a stripped star."

This observation yields insights about the harsh environment around black holes and the types of stars swirling around them. It is not the first time the unlucky star had a brush with the behemoth black hole.

The team believes the star's hydrogen-filled envelope surrounding the core was lifted off a long time ago by the same black hole. The star may have been near the end of its life. After consuming most of its hydrogen fuel, it had probably ballooned in size, becoming a red giant. Astronomers think the bloated star was looping around the black hole in a highly elliptical orbit, similar to a comet's elongated orbit around the sun. On one of its close approaches, the star was stripped of its puffed-up atmosphere by the black hole's powerful gravity. The stellar remains continued its journey around the center, until it ventured even closer to the black hole to face its ultimate demise.

These images, taken with NASA's Galaxy Evolution Explorer and the Pan-STARRS1 telescope in Hawaii, show a brightening inside a galaxy caused by a flare from its nucleus. Image credit: NASA/JPL-Caltech/JHU/STScI/Harvard-Smithsonian CfA.

Astronomers predict stripped stars circle the central black hole of our Milky Way galaxy. These close encounters are rare, occurring roughly every 100,000 years. To find this event, Gezari's team monitored hundreds of thousands of galaxies in ultraviolet light with the Galaxy Evolution Explorer, and in visible light with Pan-STARRS1. Pan-STARRS, short for Panoramic Survey Telescope and Rapid Response System, scans the entire night sky for all kinds of transient phenomena, including supernovae.

The team was looking for a bright flare in ultraviolet light from the nucleus of a galaxy with a previously dormant black hole. Both telescopes spotted one in June 2010. Astronomers continued to monitor the flare as it reached peak brightness a month later and slowly faded during the next 12 months. The brightening event was similar to the explosive energy unleashed by a supernova, but the rise to the peak was much slower, taking nearly one and a half months.

"The longer the event lasted, the more excited we got, because we realized this is either a very unusual supernova or an entirely different type of event, such as a star being ripped apart by a black hole," said team member Armin Rest of the Space Telescope Science Institute in Baltimore.


Video above: This computer simulation shows a star being shredded by the gravity of a massive black hole. Some of the stellar debris falls into the black hole and some of it is ejected into space at high speeds. The areas in white are regions of highest density, with progressively redder colors corresponding to lower-density regions. The blue dot pinpoints the black hole's location. The inset is a close-up of the region around the black hole. The elapsed time corresponds to the amount of time it takes for a Sun-like star to be ripped apart by a black hole a million times more massive than the Sun. Credit: NASA, S. Gezari (The Johns Hopkins University), and J. Guillochon (University of California, Santa Cruz).

By measuring the increase in brightness, the astronomers calculated the black hole's mass to be several million suns, which is comparable to the size of our Milky Way's black hole.

Spectroscopic observations with the Multiple Meter Telescope Observatory located on Mount Hopkins in Arizona showed the black hole was swallowing lots of helium. Spectroscopy divides light into its rainbow colors, which yields an object's characteristics, such as its temperature and gaseous makeup.

To completely rule out the possibility of an active nucleus flaring up in the galaxy, the team used NASA's Chandra X-ray Observatory to study the hot gas. Chandra showed that the characteristics of the gas didn't match those from an active galactic nucleus.

For images, video and more information about this study, visit: and

For graphics and information about the Galaxy Evolution Explorer, visit: and

Images, Animation, Text, Credits: NASA, S. Gezari (The Johns Hopkins University), and J. Guillochon (University of California, Santa Cruz)/A. Rest (STScI), and R. Chornock (Harvard-Smithsonian Center for Astrophysics).


Sifting through Dust near Orion's Belt

ESO - European Southern Observatory logo.

2 May 2012

 Cosmic dust clouds in Messier 78

A new image of the region surrounding the reflection nebula Messier 78, just to the north of Orion’s Belt, shows clouds of cosmic dust threaded through the nebula like a string of pearls. The observations, made with the Atacama Pathfinder Experiment (APEX) telescope[1], use the heat glow of interstellar dust grains to show astronomers where new stars are being formed.

Dust may sound boring and uninteresting — the surface grime that hides the beauty of an object. But this new image of Messier 78 and surroundings, which reveals the submillimetre-wavelength radiation from dust grains in space, shows that dust can be dazzling. Dust is important to astronomers as dense clouds of gas and dust are the birthplaces of new stars.

Messier 78: a reflection nebula in Orion

In the centre of the image is Messier 78, also known as NGC 2068. When seen in visible light, this region is a reflection nebula, meaning that we see the pale blue glow of starlight reflected from clouds of dust. The APEX observations are overlaid on the visible-light image in orange. Sensitive to longer wavelengths, they reveal the gentle glow of dense cold clumps of dust, some of which are even colder than -250ºC. In visible light, this dust is dark and obscuring, which is why telescopes such as APEX are so important for studying the dusty clouds in which stars are born.

Sifting through Dust near Orion’s Belt (data coverage)

One filament seen by APEX appears in visible light as a dark lane of dust cutting across Messier 78. This tells us that the dense dust lies in front of the reflection nebula, blocking its bluish light. Another prominent region of glowing dust seen by APEX overlaps with the visible light from Messier 78 at its lower edge. The lack of a corresponding dark dust lane in the visible light image tells us that this dense region of dust must lie behind the reflection nebula.

At the top of the image is another reflection nebula, NGC 2071. While the lower regions in this image contain only low-mass young stars, NGC 2071 contains a more massive young star with an estimated mass five times that of the Sun, located in the brightest peak seen in the APEX observations.

Image above: Visible light image of the region around Messier 78. In visible light, this dust is dark and obscuring. One filament seen by APEX appears in visible light as a dark lane of dust cutting across Messier 78. This tells us that the dense dust lies in front of the reflection nebula, blocking its bluish light. Another prominent region of glowing dust seen by APEX overlaps with the visible light from Messier 78 at its lower edge. The lack of a corresponding dark dust lane in visible light tells us that this dense dust must lie behind the reflection nebula.

Sifting through Dust near Orion’s Belt (mouseover comparison):

Observations of the gas in these clouds reveal gas flowing at high velocity out of some of the dense clumps. These outflows are ejected from young stars while the star is still forming from the surrounding cloud. Their presence is therefore evidence that these clumps are actively forming stars.

Sifting through Dust near Orion’s Belt (zoom)

Sifting through Dust near Orion’s Belt (pan)

The APEX observations used in this image were led by Thomas Stanke (ESO), Tom Megeath (University of Toledo, USA), and Amy Stutz (Max Planck Institute for Astronomy, Heidelberg, Germany). For more information about this region as seen in visible light, including the recently discovered — and highly variable — McNeil’s Nebula, see eso1105.


[1] APEX is a collaboration between the Max Planck Institute for Radio Astronomy (MPIfR), the Onsala Space Observatory (OSO) and ESO. Operation of APEX at Chajnantor is entrusted to ESO. APEX is a pathfinder for the next-generation submillimetre telescope, the Atacama Large Millimeter/submillimeter Array (ALMA), which is being built and operated on the same plateau.

More information:

The year 2012 marks the 50th anniversary of the founding of the European Southern Observatory (ESO). ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive astronomical observatory. It is supported by 15 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. 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, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 40-metre-class European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.


    Information about APEX:

    Images related to APEX:

Images Text, Credit: ESO/APEX (MPIfR/ESO/OSO)/T. Stanke et al./Igor Chekalin/Digitized Sky Survey 2/IAU and Sky & Telescope/Videos: ESO/APEX (MPIfR/ESO/OSO)/T. Stanke et al./S. Brunier/Chris Johnson ( Sky Survey 2, and Igor Chekalin. Music: Disasterpeace (

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lundi 30 avril 2012

NASA's Chandra Sees Remarkable Outburst From Old Black Hole

NASA - Chandra X-ray Observatory patch.


An extraordinary outburst produced by a black hole in a nearby galaxy has provided direct evidence for a population of old, volatile stellar black holes. The discovery, made by astronomers using NASA's Chandra X-ray Observatory, provides new insight into the nature of a mysterious class of black holes that can produce as much energy in X-rays as a million suns radiate at all wavelengths.

Researchers used Chandra to discover a new ultraluminous X-ray source, or ULX. These objects give off more X-rays than most binary systems, in which a companion star orbits the remains of a collapsed star. These collapsed stars form either a dense core called a neutron star or a black hole. The extra X-ray emission suggests ULXs contain black holes that might be much more massive than the ones found elsewhere in our galaxy.

Image above: Composite image of spiral galaxy M83. (X-ray: NASA/CXC/Curtin University/R. Soria et al., Optical: NASA/STScI/ Middlebury College/F. Winkler et al.).

The companion stars to ULXs, when identified, are usually young, massive stars, implying their black holes are also young. The latest research, however, provides direct evidence that ULXs can contain much older black holes and some sources may have been misidentified as young ones.

The intriguing new ULX is located in M83, a spiral galaxy about 15 million light years from Earth, discovered in 2010 with Chandra. Astronomers compared this data with Chandra images from 2000 and 2001, which showed the source had increased in X-ray brightness by at least 3,000 times and has since become the brightest X-ray source in M83.

The sudden brightening of the M83 ULX is one of the largest changes in X-rays ever seen for this type of object, which do not usually show dormant periods. No sign of the ULX was found in historical X-ray images made with Einstein Observatory in 1980, ROSAT in 1994, the European Space Agency's XMM-Newton in 2003 and 2008, or NASA's Swift observatory in 2005.

"The flaring up of this ULX took us by surprise and was a sure sign we had discovered something new about the way black holes grow," said Roberto Soria of Curtin University in Australia, who led the new study. The dramatic jump in X-ray brightness, according to the researchers, likely occurred because of a sudden increase in the amount of material falling into the black hole.

Image above: An extraordinary outburst produced by a black hole in a nearby galaxy has provided direct evidence for a population of old, volatile stellar black holes. The discovery, made by astronomers using data from NASA's Chandra X-ray Observatory, provides new insight into the nature of a mysterious class of black holes that can produce as much energy in X-rays as a million suns radiate at all wavelengths. Image Credits: X-ray: NASA/CXC/Curtin University/R. Soria et al., Optical: NASA/STScI/ Middlebury College/F. Winkler et al.

In 2011, Soria and his colleagues used optical images from the Gemini Observatory and NASA's Hubble Space Telescope to discover a bright blue source at the position of the X-ray source. The object had not been previously observed in a Magellan Telescope image taken in April 2009 or a Hubble image obtained in August 2009. The lack of a blue source in the earlier images indicates the black hole's companion star is fainter, redder and has a much lower mass than most of the companions that previously have been directly linked to ULXs. The bright, blue optical emission seen in 2011 must have been caused by a dramatic accumulation of more material from the companion star.

"If the ULX only had been observed during its peak of X-ray emission in 2010, the system easily could have been mistaken for a black hole with a massive, much younger stellar companion, about 10 to 20 million years old," said co-author William Blair of Johns Hopkins University in Baltimore.

The companion to the black hole in M83 is likely a red giant star at least 500 million years old, with a mass less than four times the sun's. Theoretical models for the evolution of stars suggest the black hole should be almost as old as its companion.

Another ULX containing a volatile, old black hole recently was discovered in the Andromeda galaxy by Amanpreet Kaur, from Clemson University, and colleagues and published in the February 2012 issue of Astronomy and Astrophysics. Matthew Middleton and colleagues from the University of Durham reported more information in the March 2012 issue of the Monthly Notices of the Royal Astronomical Society. They used data from Chandra, XMM-Newton and HST to show the ULX is highly variable and its companion is an old, red star.

Chandra X-ray Observatory

"With these two objects, it's becoming clear there are two classes of ULX, one containing young, persistently growing black holes and the other containing old black holes that grow erratically," said Kip Kuntz, a co-author of the new M83 paper, also of Johns Hopkins University. "We were very fortunate to observe the M83 object at just the right time to make the before and after comparison."

A paper describing these results will appear in the May 10th issue of The Astrophysical Journal.

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

For Chandra images, multimedia and related materials, visit:

For an additional interactive image, podcast, and video on the finding, visit:

Images, Text, Credits: Left image - Optical: ESO/VLT; Close-up - X-ray: NASA/CXC/Curtin University/R. Soria et al., Optical: NASA/STScI/Middlebury College/F. Winkler et al.