January 2018

The Milky Way's halo in the Pan-Starrs1 map (Image courtesy Giuseppina Battaglia (Iac))

An article published in the journal “Astronomy & Astrophysics” describes a research on a group of red giant stars located in the halo surrounding the Milky Way. A team of astronomers led by Giuseppina Battaglia of the Istituto de Astrofísica de Canarias examined the composition of a 28-star sample discovering that the presence of some chemical elements is quite different from the halo’s innermost regions. The conclusion is that they were not born in our galaxy but in ancient dwarf galaxies that were absorbed by the Milky Way.

El Gordo (Image ESA/Hubble & NASA, RELICS)

A photo of the galaxy cluster ACT-CL J0102-4915 captured by the Hubble Space Telescope provides a small idea of ​​the vastness of this set of galaxies that has a total mass estimated at 3 million billion times the Sun’s. For this reason it’s been nicknamed “El Gordo”, which in Spanish means “the fat one”. It intensly emits X-rays and that’s another reason of interest for astronomers that led to observe it, discovering that it’s actually formed by two smaller – or less enormous – galaxy clusters that collided.

The Tarantula Nebula (Image X-ray: NASA/CXC/PSU/L.Townsley et al.; Optical: NASA/STScI; Infrared: NASA/JPL/PSU/L.Townsley et al.)

An article published in the journal “Science” describes the really out-of-the-ordinary amount of massive stars discovered in the Tarantula Nebula, a region of the Great Magellanic Cloud, one of the Milky Way’s satellite dwarfs galaxies. A team of researchers participating in the VLT-FLAMES Tarantula Survey (VFTS) used ESO’s Very Large Telescope to observe nearly 1,000 massive stars in that region concluding that there’s a much higher amount than expected by the models with various important astronomical implications.

The galaxy UGC 6093 (Image ESA/Hubble & NASA)

A photo of the galaxy UGC 6093 taken by the Hubble Space Telescope shows some of its interesting features. It’s a barred spiral galaxy, it has an active galactic nucleus powered by a supermassive black hole at its center and acts like a megamaser, which is an astronomical maser that emits microwaves with an intensity about 100 million times greater than that of the astronomical masers found in galaxies such as the Milky Way.

KIC 8462852 at infrareds and ultraviolets (Image: IPAC/NASA for infrareds, STScI (NASA) for ultraviolets)

An article published in “The Astrophysical Journal Letters” describes the results of new observations of the star KIC 8462852, commonly known as Tabby’s star or sometimes Boyajian’s star. A team of astronomers led by Tabetha S. Boyajian, the astronomer who in 2015 realized that its brightness was changing rapidly, dimming up to 20% within a few days, conducted a research possible thanks to a funding obtained through a campaign on Kickstarter. The conclusions confirm the theory of dust that obscures the star, in particular at certain frequencies.