Cosmology

The Magellanic Clouds and an interstellar filament seen by the Planck Surveyor satellite (Image ESA and the Planck Collaboration)

ESA has released an image created using data from the Planck Surveyor satellite offering a very special portrait of an interstellar filament and the Magellanic Clouds. Those are two dwarf galaxies that are part of the Milky Way’s neighborhood and Planck detected the dust between the stars within them during its mission. The main purpose of this satellite was to study the cosmic microwave background radiation (CMB or CMBR), but the data collected are also useful to map the galaxies’ dust and magnetic fields.

The appearance of a typical galaxy at different wavelenghts in the GAMA survey (Image ICRAR/GAMA and ESO)

An international team of astronomers examined the data of more than 200,000 galaxies at different electromagnetic wavelengths. The conclusion is that in a section of the universe the energy output today is about half compared to two billion years ago. In essence, the universe is dying but you need not worry because it’s an extremely slow process. This research was presented at the International Astronomical Union XXIX General Assembly and will be published in the journal “Monthly Notices of the Royal Astronomical Society”.

Gamma-ray burst map showing a ring 5 billion light years across (Image courtesy Lajos Balazs)

An article published in the journal “Monthly Notices of the Royal Astronomical Society” describes the discovery of what appears to the largest structure of the universe. It’s a ring of nine gamma-ray bursts, which means as many galaxies, for a length of 5 billions light years. This ring, though it’s not really a circle, seems to contradict the current models and in particular the cosmological principle, the idea that the distribution of matter in the universe is uniform at a large enough scale.

A map of the cosmic microwave background with inserts showing the Cold Spot as seen by PS1 and Planck Surveyor (Image ESA/Planck collaboration. Graphics by Gergő Kránicz)

When astronomers started studying a map of the cosmic microwave background radiation (CMB or CMBR), the residue of the earliest stages of the universe, they found what was called the Cold Spot. That’s a huge area colder than expected which could be the largest single cosmic structure never identified. According to an international team of scientists consists of a cosmic supervoid which about 1.8 billion light years across.

Supernova in the galaxy M82 captured by the Swift satellite. Mid-ultraviolet light is shown in blue, near-UV light in green and visible light in red (Image NASA/Swift/P. Brown, TAMU)

A research conducted by a team led by astronomer Peter A. Milne of the University of Arizona published in two articles in the “Astrophysical Journal” shows that Type Ia supernovae can be divided into two groups with different characteristics. For years, astronomers had thought that their brightness depended almost exclusively on their distance. This can have consequences on our knowledge of the universe expansion, also calculated based on this type of supernovae.