European Association for Astronomy Education

Source: ESO

Astronomers often turn their telescopes to the Large Magellanic Cloud (LMC), one of the closest galaxies to our own Milky Way, in their quest to understand the Universe. In this spectacular new image from the Wide Field Imager (WFI) at ESO’s La Silla Observatory in Chile, a celestial menagerie of different objects and phenomena in part of the LMC is on display, ranging from vast globular clusters to the remains left by brilliant supernovae explosions. This fascinating observation provides data for a wide variety of research projects unravelling the life and death of stars and the evolution of galaxies. (read more)

Source: DLR

The German-American Stratospheric Observatory for Infrared Astronomy, SOFIA, completed an important milestone by achieving ‘first light’ when it performed its first observations during the night between 25 and 26 May 2010. SOFIA is the only airborne observatory in the world, operated jointly by NASA and the German Aerospace Center (Deutsches Zentrum fur Luft- und Raumfahrt; DLR). The observatory carried out observations of astronomical objects at infrared wavelengths in flight. (read more)

Source: Chandra

A detailed study of Chandra observations over ten years shows that M31* was in a very dim, or quiet, state from 1999 to the beginning of 2006. However, on January 6, 2006, the black hole became more than a hundred times brighter, suggesting an outburst of X-rays. This was the first time such an event had been seen from a supermassive black hole in the nearby, local universe. After the outburst, M31* entered another relatively dim state, but was almost ten times brighter on average than before 2006. The outburst suggests a relatively high rate of matter falling onto M31* followed by a smaller, but still significant rate. (read more)

Source: ESA – oshi

Thousands of galaxies crowd into this Herschel image of the distant Universe. Each dot is an entire galaxy containing billions of stars.

For more than a decade, astronomers have puzzled over strangely bright galaxies in the distant Universe. These ‘luminous infrared galaxies’ appear to be creating stars at such phenomenal rates that they defy conventional theories of galaxy formation.

Now ESA’s Herschel infrared space observatory, with its ability for very sensitive mapping over wide areas, has seen thousands of these galaxies and pinpointed their locations, showing for the first time that they are packing themselves closely together, forming large clusters of galaxies by the force of their mutual gravity. (read more)

Source: ESO Photo Release eso1020

Messier 83 by HAWK-I/VLT.
Credit: ESO/M. Gieles

ESO is releasing a beautiful image of the nearby galaxy Messier 83 taken by the HAWK-I instrument on ESO’s Very Large Telescope (VLT) at the Paranal Observatory in Chile. The picture shows the galaxy in infrared light and demonstrates the impressive power of the camera to create one of the sharpest and most detailed pictures of Messier 83 ever taken from the ground. (read more)

Source: Max-Planck Institut für extraterrestrische Physik

An international team of astronomers from Germany and Japan has discovered the most distant cluster of galaxies known so far – 9.6 billion light years away. The X-ray and infrared observations showed that the cluster hosts predominantly old, massive galaxies, demonstrating that the galaxies formed when the universe was still very young. These and similar observations therefore provide new information not only about early galaxy evolution but also about history of the universe as a whole.(read more)

Source: ESA Science and Technology

The discovery of a previously unresolved population of galaxies in the GOODS fields and the first measurements of properties of galaxies in the almost unexplored far-infrared domain are among the first exciting scientific results achieved by Herschel’s PACS and SPIRE instruments. These findings confirm the extraordinary capabilities of ESA’s new infrared space observatory to investigate the formation and evolution of galaxies. (read more)

Source: SLAC – National Accelerator Laboratory

Jets of particles streaming from black holes in far-away galaxies operate differently than previously thought, according to a study published today in Nature. The new study reveals that most of the jet’s light—gamma rays, the universe’s most energetic form of light—is created much farther from the black hole than expected and suggests a more complex shape for the jet. (read more)

Source: ESO-eso1008 – Photo Release

NGC 346, the brightest star-forming region in the
neighbouring Small Magellanic Cloud galaxy,
some 210 000 light-years away from Earth.
Credit: ESO

This dramatic new image of the Small Magellanic Cloud (NGC 346) that will make you want to keep your eyes on the night sky. Today ESO has released a dramatic new image of NGC 346, the brightest star-forming region in our neighbouring galaxy, the Small Magellanic Cloud, 210 000 light-years away towards the constellation of Tucana (the Toucan). The light, wind and heat given off by massive stars have dispersed the glowing gas within and around this star cluster, forming a surrounding wispy nebular structure that looks like a cobweb. NGC 346, like other beautiful astronomical scenes, is a work in progress, and changes as the aeons pass. As yet more stars form from loose matter in the area, they will ignite, scattering leftover dust and gas, carving out great ripples and altering the face of this lustrous object. (read more)

Credit:NASA/ESA/HST

Using data from the NASA/ESA Hubble Space Telescope, astronomers have, for the first time, created a demographic census of galaxy types and shapes from a time before the Earth and the Sun existed, to the present day. The results show that, contrary to contemporary thought, more than half of the present-day spiral galaxies had so-called peculiar shapes only 6 billion years ago, which, if confirmed, highlights the importance of collisions and mergers in the recent past of many galaxies. It also provides clues for the unique status of our own galaxy, the Milky Way.(read more)

Source: arXiv

Artist’s impression of the heart of a quasar, where a black hole is hidden in a disk of gas and dust.
Credit: NASA Education and Public Outreach at Sonoma State University – Aurore Simonnet.

The thermal state of the intergalactic medium (IGM) provides an indirect probe of both the HI and He II reionisation epochs. Current constraints on the IGM temperature from the Lyα  forest are restricted to the redshift range 2 z 4.5, limiting the ability to probe the thermal memory of HI reionisation toward higher redshift. In this work, the authors using  a high resolution Keck/HIRES spectrum in combination with detailed numerical modelling present the first direct measurement of the IGM temperature around a z = 6 quasar by analysing the Doppler widths of Ly_ absorption lines in the proximity zone of SDSS J0818+1722.(read more)

Source: arXiv:0911.4480v2 [astro-ph.CO]

In 1936 Edwin Hubble invented a morphological classification scheme for galaxies that is now known as Hubble sequence. It is often known colloquially as the “Hubble tuning-fork” because of the shape in which it is traditionally represented.

Hubble sequence. Source: Wikimedia Commons. Credit:Ville Koistinen

Hubble’s scheme divides galaxies into 3 broad classes based on their visual appearance: Elliptical (E), lenticular(S0) and spiral (S). Spiral galaxies can also present a central bar and be classified as spiral barred (SB). All galaxies that don’t fit on these classes are called irregular like the Magellanic Clouds.

Two astronomers, Andrew J. Benson and Nick Devereux, have now used the  alform semi-analytic model of galaxy formation is used to explore the mechanisms primarily responsible for the three types of galaxies seen in the local universe: bulge, bulge+disk and disk, identified with the visual morphological types E, S0/a-Sbc, and Sc-Scd, respectively.(read more)

Links:
arXiv: Benson,A.J., Devereux,N. (2010) The Origin of the Hubble Sequence in ΛCDM Cosmology, MNRAS, in press
Space Daily

Source: Universe Today

The current view of galactic formation is that galaxies form from a “bottom-up” method. In this picture, small dwarf galaxies, full of metal poor stars, were attracted by dark matter halos in the early universe which merged into larger galaxies. Many of those metal poor stars can still be seen today in the halo of the galaxy, but it was thought that the building blocks from which the galaxies were constructed were long gone or had evolved on their own and would no longer resemble the primordial building blocks.

However, earlier this year, an extremely metal poor star with only 0.00025% of the iron in the Sun was discovered in the Sculptor dwarf galaxy. If confirmed, this would show a strong link to further support the notion that metal poor dwarf galaxies were related to the metal poor stars that still populate our halo. Confirming this was the subject of a recent paper. (read more)