European Association for Astronomy Education

Source: ESO Organisation Release eso1622

Artist’s impression of the star S2 passing very close to the supermassive black hole at the centre of the Milky Way.
Image credits: ESO/L. Calçada.

A European team of astronomers have used the new GRAVITY instrument at ESO’s Very Large Telescope to obtain exciting observations of the centre of the Milky Way by combining light from all four of the 8.2-metre Unit Telescopes for the first time. These results provide a taste of the groundbreaking science that GRAVITY will produce as it probes the extremely strong gravitational fields close to the central supermassive black hole and tests Einstein’s general relativity. (learn more)

Source: ESA/Hubble Photo Release heic1606

The galactic centre.
Image credits: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)
Acknowledgment: NASA, ESA, T. Do and A. Ghez (UCLA), and V. Bajaj (STScI)

Peering deep into the heart of our home galaxy, the Milky Way, the NASA/ESA Hubble Space Telescope reveals a rich tapestry of more than half a million stars. Apart from a few, blue, foreground stars, almost all of the stars pictured in the image are members of the Milky Way nuclear star cluster, the densest and most massive star cluster in the galaxy. Hidden in the centre of this cluster is the Milky Way’s resident supermassive black hole. (learn more)

Credits: ESO Photo Release eso1606

A spectacular new image of the Milky Way has been released to mark the completion of the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL). The APEX telescope in Chile has mapped the full area of the Galactic Plane visible from the southern hemisphere for the first time at submillimetre wavelengths — between infrared light and radio waves — and in finer detail than recent space-based surveys. The pioneering 12-metre APEX telescope allows astronomers to study the cold Universe: gas and dust only a few tens of degrees above absolute zero. (learn more)

Source: ESO Photo Release eso1603

The dwarf galaxy IC 1613.
Image credits: ESO.

Many galaxies are chock-full of dust, while others have occasional dark streaks of opaque cosmic soot swirling in amongst their gas and stars. However, the subject of this new image, snapped with the OmegaCAM camera on ESO’s VLT Survey Telescope in Chile, is unusual — the small galaxy, named IC 1613, is a veritable clean freak! IC 1613 contains very little cosmic dust, allowing astronomers to explore its contents with great clarity. This is not just a matter of appearances; the galaxy’s cleanliness is vital to our understanding of the Universe around us. (learn more)

Source: Chandra Space Telescope

Image credits:NASA/CXC/MPE/G.Ponti et al; Illustration: NASA/CXC/M.Weiss.

Three orbiting X-ray telescopes have been monitoring the supermassive black hole at the center of the Milky Way galaxy for the last decade and a half to observe its behavior, as explained in our latest press release. This long monitoring campaign has revealed some new changes in the patterns of this 4-million-solar-mass black hole known as Sagittarius A* (Sgr A*).(read more)

Source: ESO Science Release eso1339

Artist's impression of the central bulge of the Milky Way.
Image credits: ESO/NASA/JPL-Caltech/M. Kornmesser/R. Hurt.

Two groups of astronomers have used data from ESO telescopes to make the best three-dimensional map yet of the central parts of the Milky Way. They have found that the inner regions take on a peanut-like, or X-shaped, appearance from some angles. This odd shape was mapped by using public data from ESO’s VISTA survey telescope along with measurements of the motions of hundreds of very faint stars in the central bulge.(read more)

Source: ESA/Hubble Science Release heic1314

Astronomers using the NASA/ESA Hubble Space Telescope have solved the 40-year-old mystery of the origin of the Magellanic Stream, a long ribbon of gas stretching nearly halfway around the Milky Way. New Hubble observations reveal that most of this stream was stripped from the Small Magellanic Cloud some two billion years ago, with a smaller portion originating more recently from its larger neighbour.(read more)

Source: NASA

Dozens of newborn stars sprouting jets from their dusty cocoons.
Image credit: NASA/JPL-Caltech/University of Wisconsin.

New views from NASA's Spitzer Space Telescope show blooming stars in our Milky Way galaxy's more barren territories, far from its crowded core.

The images are part of the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (Glimpse 360) project, which is mapping the celestial topography of our galaxy. The map and a full, 360-degree view of the Milky Way plane will be available later this year. Anyone with a computer may view the Glimpse images and help catalog features.

We live in a spiral collection of stars that is mostly flat, like a vinyl record, but it has a slight warp. Our solar system is located about two-thirds of the way out from the Milky Way's center, in the Orion Spur, an offshoot of the Perseus spiral arm. Spitzer's infrared observations are allowing researchers to map the shape of the galaxy and its warp with the most precision yet.

While Spitzer and other telescopes have created mosaics of the galaxy's plane looking in the direction of its center before, the region behind us, with its sparse stars and dark skies, is less charted. (read more)

Credit: ESA/Herschel

ESA’s Herschel space observatory has made detailed observations of surprisingly hot molecular gas that may be orbiting or falling towards the supermassive black hole lurking at the centre of our Milky Way galaxy.(read more)

Source: ESO Photo Release eso1242

VISTA gigapixel mosaic of the central parts of the Milky Way.
Image credits:ESO/VVV Consortium
Acknowledgement: Ignacio Toledo, Martin Kornmesser

 Using a whopping nine-gigapixel image from the VISTA infrared survey telescope at ESO’s Paranal Observatory, an international team of astronomers has created a catalogue of more than 84 million stars in the central parts of the Milky Way. This gigantic dataset contains more than ten times more stars than previous studies and is a major step forward for the understanding of our home galaxy. The image gives viewers an incredible, zoomable view of the central part of our galaxy. It is so large that, if printed with the resolution of a typical book, it would be 9 metres long and 7 metres tall. (read more)

Source: NASA

Milky Way and Andromeda are moving toward each other.
Image credit: NASA; ESA; A. Feild and R. van der Marel, STScI.

NASA astronomers announced today they can now predict with certainty the next major cosmic event to affect our galaxy, sun, and solar system: the titanic collision of our Milky Way galaxy with neighboring Andromeda.(read more)

Source: NASA Science Casts

Source: NASA Chandra

Supermassive black hole Sagittarius A* at the center of the Milky Way.
Credits: X-ray: NASA/CXC/MIT/F. Baganoff et al.; Illustrations: NASA/CXC/M.Weiss

The giant black hole at the center of the Milky Way may be vaporizing and devouring asteroids, which could explain the frequent flares observed, according to astronomers using data from NASA's Chandra X-ray Observatory.

For several years Chandra has detected X-ray flares about once a day from the supermassive black hole known as Sagittarius A*, or "Sgr A*" for short. The flares last a few hours with brightness ranging from a few times to nearly one hundred times that of the black hole's regular output. The flares also have been seen in infrared data from ESO's Very Large Telescope in Chile. (read more)

Source: Science Magazine AAAS

Detailed view of the Milky Way's core.
Image credits: NASA/ESA/SSC/ CXC/ STScI

The Milky Way's center houses a supermassive black hole so sleepy that it probably hasn't swallowed a decent meal for years. Yet a growing body of evidence indicates that the now-dormant beast, about as massive as 4 million suns, fueled a firestorm of activity just a few million years ago, including the sustained emission of some of the highest energy radiation in the universe. A new study offers a dramatic explanation for these past fireworks: The sleeping giant woke when a smaller black hole from another galaxy smashed into it.(read more)

Source: Smithsonian Astrophysical Observatory (SAO)

Milky Way's new arm. Credit: T. Dame.

Our Milky Way galaxy, like other spiral galaxies, has a disk with sweeping arms of stars, gas, and dust that curve around the galaxy like the arms of a huge pinwheel. The Sun, Earth, and solar system are located in a spur of material that lies between two of the spiral arms, collectively orbiting around the galaxy about 25,000 light-years from its center.

Using a small 1.2-meter radio telescope on the roof of their science building in Cambridge, CfA astronomers Tom Dame and Pat Thaddeus used carbon monoxide emission to search for evidence of spiral arms in the most distant parts of the galaxy, and discovered a large new spiral arm peppered with dense concentrations of molecular gas. (read source)

Source: Space Daily

Supercomputer simulationof the density of dark matter in the Milky Way galaxy.
Image cedit: Stelios Kazantzidis, Ohio State University.

How unique is the Milky Way? To find out, a group of researchers led by Stanford University astrophysicist Risa Wechsler compared the Milky Way to similar galaxies and found that just four percent are like the galaxy Earth calls home.(read more)

Source: ESA PR 15-2010

ESA's Planck mission has delivered its first all-sky image. It not only provides new insight into the way stars and galaxies form but also tells us how the  Universe itself came to life after the Big Bang.
"This is the moment that Planck was conceived for," says ESA Director of Science and Robotic Exploration, David Southwood. "We're not giving the answer. We are opening the door to an Eldorado where scientists can seek the nuggets that will lead to deeper understanding of how our Universe came to be and how it works now. The image itself and its remarkable quality is a tribute to the engineers who built and have operated Planck. Now the scientific harvest must
begin."
From the closest portions of the Milky Way to the furthest reaches of space and time, the new all-sky Planck image is an extraordinary treasure chest of new data for astronomers.
The main disc of our Galaxy runs across the centre of the image. Immediately striking are the streamers of cold dust reaching above and below the Milky Way.
This galactic web is where new stars are being formed, and Planck has found many locations where individual stars are edging toward birth or just beginning their cycle of development.
Less spectacular but perhaps more intriguing is the mottled backdrop at the top and bottom. This is the 'cosmic microwave background radiation' (CMBR). It is the oldest light in the Universe, the remains of the fireball out of which our Universe sprang into existence 13.7 billion years ago.

While the Milky Way shows us what the local Universe looks like now, those the microwave pattern is the cosmic blueprint from which today's clusters and superclusters of galaxies were built. The different colours represent minute
differences in the temperature and density of matter across the sky. Somehow these small irregularities evolved into denser regions that became the galaxies of today.
The CMBR covers the entire sky but most of it is hidden in this image by the Milky Way's emission, which must be digitally removed from the final data in order to see the microwave background in its entirety.
When this work is completed, Planck will show us the most precise picture of the microwave background ever obtained. The big question will be whether the data will reveal the cosmic signature of the primordial period called inflation.
This era is postulated to have taken place just after the Big Bang and resulted in the Universe expanding enormously in size over an extremely short period.
Planck continues to map the Universe. By the end of its mission in 2012, it will have completed four all-sky scans. The first full data release of the CMBR is planned for 2012. Before then, the catalogue containing individual objects in our
Galaxy and whole distant galaxies will be released in January 2011.
"This image is just a glimpse of what Planck will ultimately see," says Jan Tauber, ESA's Planck Project Scientist.(read more)

Source: Royal Astronomical Society

Many of the Milky Way’s ancient stars are remnants of other smaller galaxies torn apart by violent galactic collisions around five billion years ago, according to researchers at Durham University, who publish their results in a new paper in the journal Monthly Notices of the Royal Astronomical Society. (read more)

Source: ESA

Giant filaments of cold dust stretching through our Galaxy are revealed in a new image from ESA's Planck satellite. Analyzing these structures could help to determine the forces that shape our Galaxy and trigger star formation.(read more)

Source: arXiv:1001.2521v1

The formation and evolution of the Galactic bulge and its relationship with the other Galactic populations is still poorly understood.

To establish the chemical differences and similarities between the bulge and other stellar populations, the astronomers have performed elemental abundance analysis of oxygen, magnesium, silicon, calcium, titanium, sodium and aluminium of red giant stars in the bulge as well as of local thin disk, thick disk and halo giants (see figure).

The authors used high-resolution optical spectra of 25 bulge giants in Baade’s window and made a comparison with 55 giants (4 halo, 29 thin disk and 22 thick disk giants) in the solar neighbourhood.

Baade's Window is named after the German astronomer Walter Baade and lies towards the constellation of Sagittarius. This region has relatively low amounts of interstellar "dust" along our line of sight and is a "window" because in this direction we are able to see all the way to the Milky Way Galactic Center and beyond. Therefore it is used to inspect distant stars and to determine the internal geometry of the Milky Way. Using bulge giants and giants in our neighbourhood the authors could compare the inner structure of the Galaxy with our vicinity.

The authors have found that all stars have similar stellar parameters but cover a broad range in metallicity. In astronomy, the metallicity of an object is the proportion of its matter made up of chemical elements other than hydrogen and helium. Since stars, which comprise most of the visible matter in the universe, are composed mostly of hydrogen and helium, astronomers, for convenience's sake, use the blanket term "metal" to describe all other elements collectively.

The team of astronomers was able to confirm the well-established differences for [α /Fe] at a given metallicity between the local thin and thick disks. For all the elements investigated, they found no chemical distinction between the bulge and the local thick disk.

Their findings lead to the conclusion that the bulge and local thick disk stars experienced similar formation timescales, star formation rates and initial mass functions. The scientific team thinks that the identical types of stars that can be found on the thick disk and bulge stars may reflect a rapid chemical evolution taking place before the bulge and thick disk structures we see today were formed, or it may reflect Galactic orbital migration of inner disk/bulge stars resulting in stars in the solar neighbourhood with thick-disk kinematics.

This reasearch was accepted for publication byAstronomy & Astrophysics.(read more)

Links:
Original paper:Alves-Brito,A., Melendez,J., Asplund,M., Ramirez,I., Yong,D. (2010) Chemical similarities between Galactic bulge and local thick disk red giants: O, Na, Mg, Al, Si, Ca and Ti, Astronomy & Astrophysics, in press.