AHEAD 
Το παρατηρητήριο ακτίνων-Χ, ATHENA της Ευρωπαϊκής Υπηρεσίας Διαστήματος και η ελληνική συμμετοχή Το διαστημικό τηλεσκόπιο ακτίνων-Χ, ATHENA, μια συνεργασία της ευρωπαϊκής υπηρεσίας διαστήματος, ESA, της NASA και της Iαπωνικής Jaxa θα παρατηρήσει την ακτινοβολία που εκλύει το Σύμπαν στις Read More …
Astronomers from the National Observatory of Athens and the Niels Bohr Institute, used the largest X-ray sample up to date to investigate how active supermassive black holes (SMBH) at the centre of galaxies affect their star formation. They found that, in a similar manner as an oscillator tries to keep the system around the equilibrium point, the SMBH (oscillator) tries to keep the galaxy in the main sequence (equilibrium point)!!
Is there a feeding mechanism that activates supermassive black holes at the centre of galaxies or active black holes occur naturally during the lifetime of a galaxy?
Neutrinos are particle in the size of electrons, but without charge. We know that they have mass, but we haven’t measured it yet. Although they are everywhere (our bodies are hit by about 100 trillion neutrinos every second), neutrinos cannot be detected since they rarely interact with matter. Scientists now managed to spot one of them and trace its origin, a blazar located 3 billion light years away from us!
Red nuggets is a population of small, but massive galaxies. Most of these systems have gone through mergers over the billions of years of their existence. However, some of them have remained isolated and this makes them extremely interesting since they allow us to study how galaxies and the supermassive black holes (SMBHs) at their centres evolve over billions of years of isolation!!
The total amount of ordinary matter, called baryonic matter, makes up for about 5% of the total matter of our Universe. The other 95% consists of the exotic dark matter and dark energy. However, even this 5% of baryonic matter is hard to detect! Only 60% of the baryonic matter has been observed! Now scientists, used ESA’s XMM-Newton X-ray space observatory and found evidence of where these missing baryons are!!
Scientists used ESA’s XMM-Newton and NASA’s Chandra X-ray Observatories as well as the Swift X-ray Telescope to find evidence for the existence of a rare type of black hole, an intermediate-mass black hole!!
Wolf-Rayet (WR) stars are massive, energetic stars at the end of their lives. They generate strong winds that sweep their surrounding material and create strong shockwaves as they collide with the interstellar medium (ISM). This process heats up the ISM to high enough temperatures to produce X-rays. This rare phenomenon was observed using XMM-Newton, ESA’s space telescope.
The neutron star merger named GW170817/GRB 170817A that took place last August, was the first cosmic event that astronomers were able to observe both light and gravitational waves! Now scientists discovered that probably this merging process also created the lowest mass black hole ever detected!!
In a recent study, astronomers used ESA’s XMM-Newton X-ray telescope to observe six spiral galaxies, in an attempt to uncover the missing matter in the universe.
