Galaxies

The galaxies NGC 4302 and NGC 4298 (Photo NASA, ESA, and M. Mutchler (STScI))

On April 25, 1990, the Hubble Space Telescope was put into orbit after being launched the day before on the Space Shuttle Discovery. To celebrate that event’s 27th anniversary representing a milestone in the history of astronomy, one of the many breathtaking photographs that accompanied Hubble’s activity was published, which in this case portrays two galaxies together, NGC 4302 and NGC 4298.

Example of galaxy pair connected by dark matter filaments (Image courtesy S. Epps & M. Hudson / University of Waterloo)

An article published in the journal “Monthly Notices of the Royal Astronomical Society” describes a research on dark matter filaments that connect two galaxies. A team of astronomers led by Mike Hudson of the University of Waterloo in Canada exploited a weak gravitational lensing effect to create an image that shows even if indirectly a kind of dark matter bridge between two galaxies.

The galaxy Was 49 (Image DCT/NRL)

A galaxy merger observed with NASA’s NuSTAR space telescope gave surprising results. The galaxy called Was 49 is being formed from the fusion of a large disk galaxy called Was 49a and a dwarf galaxy called Was 49b. The researchers were surprised when they realized that the supermassive black hole at the center of the dwarf galaxy was much bigger and more powerful than expected, going against current models regarding galactic mergers.

The quasar 3C 186 and its galaxy (Image NASA, ESA, and M. Chiaberge (STScI and JHU))

An article published in the journal “Astronomy & Astrophysics” describes the discovery of a supermassive black hole pushed out from its galaxy’s core. A team of astronomers led by Marco Chiaberge of the Space Telescope Science Institute in the USA used the Hubble Space Telescope to observe the quasar 3C 186 in which this phenomenon occurred. Another interesting element is that the black hole’s movement may have been accelerated by gravitational waves.

Artist's concept of primordial spiral galaxy with quasar in the background (Image A. Angelich (NRAO/AUI/NSF))

An article published in the journal “Science” describes a research about two very young galaxies that probably look very wimilar to the Milky Way 12 billion years ago. Called ALMA J081740.86+135138.2 and ALMA J120110.26+211756.2, they were observed by a team of astronomers using the ALMA radio telescope as a follow-up of previous research conducted using the light from a quasar behind the two galaxies. The new research showed that the two galaxies are surrounded by a halo of gas and that their star formation rate is rather high.