lundi 26 juin 2017

Chandra Samples Galactic Goulash

NASA - Chandra X-ray Observatory patch.

June 26, 2017

What would happen if you took two galaxies and mixed them together over millions of years? A new image including data from NASA’s Chandra X-ray Observatory reveals the cosmic culinary outcome.

Arp 299 is a system located about 140 million light years from Earth. It contains two galaxies that are merging, creating a partially blended mix of stars from each galaxy in the process.

However, this stellar mix is not the only ingredient. New data from Chandra reveals 25 bright X-ray sources sprinkled throughout the Arp 299 concoction. Fourteen of these sources are such strong emitters of X-rays that astronomers categorize them as “ultra-luminous X-ray sources,” or ULXs.

These ULXs are found embedded in regions where stars are currently forming at a rapid rate. Most likely, the ULXs are binary systems where a neutron star or black hole is pulling matter away from a companion star that is much more massive than the Sun. These double star systems are called high-mass X-ray binaries.

Such a loaded buffet of high-mass X-ray binaries is rare, but Arp 299 is one of the most powerful star-forming galaxies in the nearby Universe. This is due at least in part to the merger of the two galaxies, which has triggered waves of star formation. The formation of high-mass X-ray binaries is a natural consequence of such blossoming star birth as some of the young massive stars, which often form in pairs, evolve into these systems.

This new composite image of Arp 299 contains X-ray data from Chandra (pink), higher-energy X-ray data from NuSTAR (purple), and optical data from the Hubble Space Telescope (white and faint brown). Arp 299 also emits copious amounts of infrared light that has been detected by observatories such as NASA’s Spitzer Space Telescope, but those data are not included in this composite.

Chandra X-ray Observatory

The infrared and X-ray emission of the galaxy is remarkably similar to that of galaxies found in the very distant Universe, offering an opportunity to study a relatively nearby analog of these distant objects. A higher rate of galaxy collisions occurred when the universe was young, but these objects are difficult to study directly because they are located at colossal distances.

The Chandra data also reveal diffuse X-ray emission from hot gas distributed throughout Arp 299. Scientists think the high rate of supernovas, another common trait of star-forming galaxies, has expelled much of this hot gas out of the center of the system.

A paper describing these results appeared in the Aug. 21 issue of the Monthly Notices of the Royal Astronomical Society and is available online. The lead author of the paper is Konstantina Anastasopoulou from the University of Crete in Greece. 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.

Read More from NASA's Chandra X-ray Observatory:

For more Chandra images, multimedia and related materials, visit:

Images, Text, Credits: X-ray: NASA/CXC/Univ. of Crete/K. Anastasopoulou et al, NASA/NuSTAR/GSFC/A. Ptak et al; Optical: NASA/STScI/Lee Mohon.


Saturnian Dawn

NASA - Cassini International logo.

June 26, 2017

NASA's Cassini spacecraft peers toward a sliver of Saturn's sunlit atmosphere while the icy rings stretch across the foreground as a dark band.

This view looks toward the unilluminated side of the rings from about 7 degrees below the ring plane. The image was taken in green light with the Cassini spacecraft wide-angle camera on March 31, 2017.

The view was obtained at a distance of approximately 620,000 miles (1 million kilometers) from Saturn. Image scale is 38 miles (61 kilometers) per pixel.

The Cassini mission is a cooperative project of NASA, ESA (the European Space Agency) and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colorado.

For more information about the Cassini-Huygens mission visit and The Cassini imaging team homepage is at and

Image, Text, Credits: NASA/Tony Greicius/JPL-Caltech/Space Science Institute.


New catalogues for Herschel legacy archive

ESA - Herschel Mission patch.

26 June 2017

Two new catalogues, based on data from ESA's Herschel Space Observatory, have been released to the scientific community. The point source catalogues are examples of a new type of data product from two of Herschel's instruments, SPIRE and PACS. These catalogues are part of the lasting legacy of the Herschel mission, and will further facilitate data exploitation and drive ongoing research.

Image abovee: Sources in the Herschel SPIRE point source catalogue. Image Credits: ESA/NASA/Herschel/SPIRE.

The SPIRE and PACS point source catalogues are examples of Herschel's highly processed data products, or HPDPs. Data from missions such as Herschel are systematically processed into well calibrated 'standard' products via automatic software pipelines that correct many instrumental signatures and artefacts in the data. Some products can greatly benefit from dedicated processing by instrument experts, to improve both their quality and usefulness. There are also data products that these pipelines cannot produce at all, and these two new point source catalogues are examples of this type, providing astronomers with a valuable resource for research.

Image above: SPIRE map of NGC 4559 and surroundings. Image Credits: ESA/NASA/Herschel/SPIRE.

"The SPIRE maps contain many objects that would perhaps never have been looked at, because the original proposer was just interested in something very specific," says Bernhard Schulz, Senior Staff Scientist at Caltech/IPAC and lead of the SPIRE point source catalogue production. "For this SPIRE point source catalogue we used the knowledge of the top instrument experts to produce the best photometry for all sources that were suitable for automatic processing. Scientists who use these data can now save the time it would have taken to extract their own photometry. Additionally, they can validate their photometric procedures with sources from our catalogue, before applying them to more difficult-to-extract objects, that need very careful analysis, such as very extended sources or multiple, close-together sources that are hard to separate."

Image above: Multiple sources in PACS map. Image Credits: ESA/Herschel/PACS.

"One area that highlights a strength of the PACS point source catalogue is how we have treated observations that were made to study Solar System Objects, or SSOs," says Gábor Marton, postdoctoral researcher at the Konkoly Observatory of the Hungarian Academy of Sciences in Budapest, Hungary, who led the PACS point source catalogue production. "These SSO maps are the best examples of PACS maps that were until now investigated only for specific objects, while in practice they are very deep observations of a region of the sky and contain information about many other celestial sources. We looked for the full source content of all these PACS maps and, importantly, the data that we deliver is a result of a homogeneous extraction. In addition, we describe the quality of the sources in a uniform way. All of this makes our products easy for the scientific community to use."

The Herschel Space Observatory launched on 14 May 2009 and spent almost four years observing the skies at far-infrared and sub-millimetre wavelengths. Among the early highlights were the spectacular images of previously obscured early phases of star formation deep in galactic molecular clouds, and observations of some of the coldest objects in the Solar System. Since then, scientists have used Herschel data to resolve the cosmic infrared background, to follow the water trail from early phases of star formation to impact on planetary bodies, and to study galaxy evolution throughout the history of Universe. To date, this scientific output has been reported in more than 2000 peer-reviewed journal articles. Although science operations terminated, as anticipated, in April 2013 when the helium coolant was depleted, science investigations will continue for many years, using the data that were accumulated during the operational phase.

Image above: Sources in the Herschel PACS point source catalogue. Image Credits: ESA/Herschel/PACS.

"The newly released SPIRE and PACS point source catalogues will enable investigators to address a multitude of scientific topics, spanning areas as diverse as star formation and galaxy evolution," notes Göran Pilbratt, Herschel Project Scientist at ESA. "In particular, these catalogues will also help investigators not familiar with Herschel data to incorporate this as ancillary data in multi-wavelength studies, and as targets in observing proposals for follow-up studies with other instruments."

"Ever since scientific operations ended in April 2013, the Herschel team has been busy preparing and processing the final products with the goal to leave a lasting legacy of well-calibrated, high-quality data for the scientific community to use," adds Pedro García-Lario, Herschel Mission Manager at ESA. "The catalogues will help bridge the gap between data releases from missions such as Spitzer, Planck, and AKARI, allowing scientists to continue producing vital research in this area of science."

"The two catalogues represent a significant collaborative effort between scientists and staff in Europe and the US, and we hope that their existence will inspire and encourage astronomers from all shades of the electromagnetic spectrum to dig into, and mine, the rich legacy of the Herschel observatory, and its archive, "comments Phil Appleton, Task Lead and Project Scientist for the NASA Herschel Science Center at Caltech/IPAC in Pasadena USA.

Herschel Space Telescope (actually out of service). Image Credit: ESA

The production of the SPIRE point source catalogue was led by the NASA Herschel Science Centre in Pasadena, USA, with important contributions from Konkoly Observatory, the ESA Herschel Science Centre at the European Space Astronomy Centre (ESAC), Eötvös Loránd University, Cardiff University, and the Rutherford Appleton Laboratory.

The PACS point source catalogue was led by Konkoly Observatory in Budapest, Hungary, with important contributions from the ESA Herschel Science Centre at ESAC and the NASA Herschel Science Center at Caltech/IPAC.

The new SPIRE point source catalogue, with about 1.6 million sources, and the PACS point source catalogue, containing about 500 000 sources, are available from the Herschel Science Archive through ESASky and Virtual Observatory (VO) tools, such as TopCat, and from the NASA/IPAC Infrared Science Archive. These tools come with a variety of ways to query the data and they are compliant with VO standards.

Related links:

ESA Herschel:

Herschel Science Archive:


NASA/IPAC Infrared Science Archive:

About the SPIRE Point Source Catalogue:

About the PACS Point Source Catalogue:

Herschel astronomers' website:

Images, Text, Credits: ESA/NASA/Herschel/SPIRE.

Best regards,

Artificial brain helps Gaia catch speeding stars

ESA - Gaia Mission patch.

26 June 2017

With the help of software that mimics a human brain, ESA’s Gaia satellite spotted six stars zipping at high speed from the centre of our Galaxy to its outskirts. This could provide key information about some of the most obscure regions of the Milky Way.

Our galactic home, the Milky Way, houses more than a hundred billion stars, all kept together by gravity. Most are located in a flattened structure – the Galactic disc – with a bulge at its centre, while the remaining stars are distributed in a wider spherical halo extending out to about 650 000 light-years from the centre.

Stars speeding through the Galaxy

Stars are not motionless in the Galaxy but move around its centre with a variety of velocities depending on their location – for example, the Sun orbits at about 220 km/s, while the average in the halo is of about 150 km/s.

Occasionally, a few stars exceed these already quite impressive velocities.

Some are accelerated by a close stellar encounter or the supernova explosion of a stellar companion, resulting in runaway stars with speeds up to a few hundred km/s above the average.

A new class of high-speed stars was discovered just over a decade ago. Swooping through the Galaxy at several hundred of km/s, they are the result of past interactions with the supermassive black hole that sits at the centre of the Milky Way and, with a mass of four million Suns, governs the orbits of stars in its vicinity.

“These hypervelocity stars are extremely important to study the overall structure of our Milky Way,” says Elena Maria Rossi from Leiden University in the Netherlands, who presented Gaia’s discovery of six new such stars today at the European Week of Astronomy and Space Science in Prague, Czech Republic.

Catching speeding stars with Gaia

“These are stars that have travelled great distances through the Galaxy but can be traced back to its core – an area so dense and obscured by interstellar gas and dust that it is normally very difficult to observe – so they yield crucial information about the gravitational field of the Milky Way from the centre to its outskirts.”

Unfortunately, fast-moving stars are extremely difficult to find in the stellar haystack of the Milky Way, as current surveys list the speed of at most a few hundred thousand stars.

To find them, scientists have been looking for young, massive stars that would stand out as interlopers in the old stellar population of the Galactic halo. Given away by their out-of-place age, these stars are likely to have received an extra kick to reach the halo. Further measurements of their speeds and estimates of their past paths can confirm if they are indeed hypervelocity stars that were shoved away from the centre of the Milky Way.

So far, only 20 such stars have been spotted. Owing to the specific selection of this method, these are all young stars with a mass 2.5 to 4 times that of the Sun. However, scientists believe that many more stars of other ages or masses are speeding through the Galaxy but remain unrevealed by this type of search.

Gaia mapping the stars of the Milky Way

The billion-star census being performed by Gaia offers a unique opportunity, so Elena and her collaborators started wondering how to use such a vast dataset to optimise the search for fast-moving stars.

After testing various methods, they turned to software through which the computer learns from previous experience.

“In the end, we chose to use an artificial neural network, which is software designed to mimic how our brain works,” explains Tommaso Marchetti, PhD student at Leiden University and lead author of the paper describing the results published in Monthly Notices of the Royal Astronomical Society.

“After proper ‘training’, it can learn how to recognise certain objects or patterns in a huge dataset. In our case, we taught it to spot hypervelocity stars in a stellar catalogue like the one compiled with Gaia.”

As part of Elena's research project to study these stars, the team started developing and training this program in the first half of 2016, in order to be ready for the first release of Gaia data a few months later, on 14 September.

Besides a map of over a billion stellar positions, this first release included a smaller catalogue with distances and motions for two million stars, combining observations from Gaia’s first year with those from ESA’s Hipparcos mission, which charted the sky more than two decades ago. Referred to as the Tycho–Gaia Astrometric Solution, or TGAS, this resource is a taster for future catalogues that will be based solely on Gaia data.

Gaia’s first sky map

“On the day of the data release, we ran our brand new algorithm on the two million stars of TGAS,” says Elena.

“In just one hour, the artificial brain had already reduced the dataset to some 20 000 potential high-speed stars, reducing its size to about 1%.

“A further selection including only measurements above a certain precision in distance and motion brought this down to 80 candidate stars.”

The team looked at these 80 stars in further detail. Since only information on the star's motion across the sky are included in the TGAS data, they had to find additional clues to infer their velocity, looking at previous stellar catalogues or performing new observations.

“Combining all these data, we found that six stars can be traced back to the Galactic Centre, all with velocities above 360 km/s,” says Tommaso.

Most importantly, the scientists succeeded at probing a different population from the 20 stars that were already known: the newly identified stars all have lower masses, similar to the mass of our Sun.

One of the six stars seems to be speeding so fast, at over 500 km/s, that it is no longer bound by the gravity of the Galaxy and will eventually leave. But the other, slightly slower stars, are perhaps even more fascinating, as scientists are eager to learn what slowed them down – the invisible dark matter that is thought to pervade the Milky Way might also have played a role.

While the new program was optimised to search for stars that were accelerated at the centre of the Galaxy, it also identified five of the more traditional runaway stars, which owe their high speeds to stellar encounters elsewhere in the Milky Way.

“This result showcases the great potential of Gaia opening up new avenues to investigate the structure and dynamics of our Galaxy,” says Anthony Brown from Leiden University, a co-author on the study and chair of the Gaia Data Processing and Analysis Consortium.

The scientists are looking forward to using data from the next Gaia release, which is planned for April 2018 and will include distances and motions on the sky for over a billion stars, as well as velocities for a subset.

Dealing with a billion stars, rather than the two million explored so far, is an enormous challenge, so the team is busy upgrading their program to handle such a huge catalogue and to uncover the many speeding stars that will be lurking in the data.

“The sheer number of stars probed by Gaia is an exciting but also challenging opportunity for astronomers, and we are glad to see that they are happily embracing the challenge,” says Timo Prusti, Gaia project scientist at ESA.

Notes for Editors:

“An artificial neural network to discover Hypervelocity stars: Candidates in Gaia DR1/TGAS,” by T. Marchetti et al, is published in Monthly Notices of the Royal Astronomical Society:

These results were presented today at the European Week of Astronomy and Space Science in Prague, Czech Republic:

For more information about Gaia mission, visit:

Gaia overview:

Gaia factsheet:

Gaia Data Release 1 Media Kit:

Frequently asked questions:

Related articles:

How many stars are there in the Universe?:

The billion-pixel camera:

Images, Video, Text, Credits: ESA/CC BY-SA 3.0 IGO/ATG medialab; background: ESO/S. Brunier/Gaia/DPAC.

Best regards,

dimanche 25 juin 2017

SpaceX - Iridium-2 Mission success

SpaceX - Falcon 9 / Iridium-2 Mission patch.

June 25, 2017

Falcon 9 rocket launches Iridium-2

On Sunday, June 25 at 1:25 p.m. PDT, SpaceX’s Falcon 9 rocket successfully launched 10 satellites to low-Earth orbit for Iridium, a global leader in mobile voice and data satellite communications.

Iridium-2 Launch Webcast

This is the second set of 10 satellites in a series of 75 total satellites that SpaceX will launch for Iridium’s next generation global satellite constellation, Iridium® NEXT.

Iridium’s next generation global satellite

Following stage separation, the first stage of Falcon 9 successfully landed on the “Just Read the Instructions” droneship stationed in the Pacific Ocean, despite challenging weather conditions.

For more information about SpaceX, visit:

Images, Video, Text, Credits: SpaceX/Thales Alenia.


MUSES Facility Enables Investigation Opportunities For Future Users

ISS - International Space Station logo.

June 25, 2017

Artist's view of MUSES Facility on ISS. Image Credit: NASA

The Multiple User System for Earth Sensing Facility (MUSES) will inspire and enable numerous branches of research and science through its ability to support many different kinds of investigations and hardware aboard the International Space Station. Providing a platform for payloads such as high-resolution digital cameras and hyperspectral imagers, MUSES provides precision pointing and other accommodations for various kinds of research and science.

Orbiting approximately 250 miles above the Earth, the MUSES platform offers researchers a unique vantage point from the outside of the station for tasks like Earth observation, disaster response, maritime domain awareness, agricultural/land use applications, food security, air quality, oil and gas exploration, mining, atmospheric investigations, and fire detection.

Image above: The first investigation to be hosted aboard the MUSES platform will be the DLR Earth Sensing Imaging Spectrometer (DESIS) (shown above attached to the MUSES platform in a digital mock-up), on Expeditions 51/52 and 53/54. Image Credit: Teledyne Brown Engineering.

“The space station’s path is ideal for Earth science,” said Paul Galloway, the project’s manager and lead systems engineer. “The repeated exposure to the Earth’s land masses gives you a good revisit time for target areas. MUSES’ ability to point and track ground targets also enhances the revisit opportunities and viewing angles.”

The space station’s orbit cover’s 90% of the Earth’s inhabited surfaces and allows for both day and nighttime passes, allowing a variety of observation and data collection times.

MUSES will provide Earth imagery data to NASA’s SERVIR team to provide disaster response information to aid in the team’s humanitarian missions, improving environmental decision-making among developing nations. The MUSES payload data can be used in response to disasters world-wide.

Image above: The MUSES platform accommodates up to four instruments simultaneously. Each instrument can be installed and removed robotically by the ISS robotic arm operators on the ground. Image Credit: Teledyne Brown Engineering.

Instruments flying aboard the platform will be able to detect phenomenon like flooding, coastal erosion, water pollution, red tide, and landslides. Space-based imagery is one of many tools used in the disaster response decision-making process.

The MUSES platform is a U.S. National Laboratory sponsored pointing system and can accommodate up to four instruments at a time. Each instrument can be installed and removed robotically. These payloads can be operated simultaneously, triggering a system that can communicate with all the systems aboard the space station and store and transmit large amounts of data back to the ground.  The system will be operated from the Teledyne Operations Center in Huntsville, Alabama.

Developed in a cooperative agreement between Teledyne Brown Engineering and NASA, MUSES will provide many commercial companies the opportunity to conduct their science and research in space.

Image above: The MUSES platform includes a Star Tracker and Miniature Inertial Measurement Unit which are used to generate precise pointing knowledge information to be used by the hosted payloads. MUSES also uses the ISS External Wireless Communications system for image data transfer via custom built electronics and a NASA-provided antenna. Image Credit: Teledyne Brown Engineering.

MUSES provides low-cost access to space for instrument developers.  MUSES and the ability to return payloads from the space station to Earth provides an excellent platform for technology demonstration and the space qualification of hardware.

 “Unlike the Earth views from ISS’s internal viewing windows which are somewhat limited by surrounding structure, the view to the Earth from the ISS truss is essentially unobstructed,” said Galloway

The first investigation to be hosted aboard the MUSES platform will be the DLR Earth Sensing Imaging Spectrometer (DESIS), on Expeditions 51/52 and 53/54, and is planned for launch later this year. DESIS is a hyperspectral imager operating in the 400-1000 nanometer spectral range. “The German Space Agency, DLR, will use the DESIS imagery for scientific purposes.  Teledyne Brown Engineering will use the imagery for commercial purposes,” according to Galloway.

“MUSES was designed to interface with every possible data network on ISS and take maximum utilization of the downlink capability from ISS to ground to achieve our goal of getting large amounts of image and scientific data down from these instruments,” said Galloway.  

For more information about the science happening aboard the orbiting laboratory, follow

Related links:

Multiple User System for Earth Sensing Facility (MUSES):


U.S. National Laboratory:

Space Station Research and Technology:

International Space Station (ISS):

Images (mentioned), Text, Credits: NASA/Kristine Rainey/JSC/Jenny Howard.


samedi 24 juin 2017

Soyuz 2-1v conducts secret military launch


June 24, 2017

On June 23, 2017 Russia undertook a low-key launch of a Soyuz-2-1v rocket with a military payload. The launch, out of the Plesetsk Cosmodrome in northwest Russia, took place at 21:04 local time (18:04 UTC).

Image (above) archive of Soyuz 2-1v rocket during second successful flight. Image Credit:  Russian Ministry of Defense.

A Russian Soyuz 2-1v rocket launches a payload designated 14F150. Details on the payload’s mission are unavailable.

For reading very informative article from my friend Anatoly Zak, visit:

Soyuz-2-1v launches a secret satellite

Image (mentioned), Text, Credits: Aerospace/Roland Berga.