An international group of researchers, with the participation of Astronomical Observatory of Universitat de València, has discovered the first lightning from a black hole from the eruption that had the most powerful bright variations in an extragalactic object ever observed until today. In an astronomical sense, they are flashes of a duration of only five minutes. The research results of this extremely strong phenomenon of gamma rays in the galaxy IC 310 were published in the magazine “Science” yesterday.
The radio galaxy IC 310 in the Perseo constelation is at 260 millions of light years away of the Earth. Astronomers believe its centre harbours a supermassive black hole. At the centre of this galaxy it has been produced a strong eruption of gamma rays detected by the MAGIC telescope in the island of La Palma, with complementary images of the European Very-long-baseline Interferometry Network (EVN).
The researchers observed, with surprise, variations in the radiation from the heart of the galaxy IC 310 in time scales of 5 minutes. «The horizon of events of the black hole -the time-space surface from which nothing can scape the black hole, not even the light- is three times the amount of the distance between the Earth and the sun, that is, 450 millions of kilometres. The light needs 25 minutes to go over this distance», explains Eduardo Ros, researcher of the Max Planck Institute for Radio Astronomy and Universitat de València, co-author of the work.
The surface of an object cannot change completely its bright in a shorter period of time that light requires to cross it. Therefore, the region from which derive these gamma rays has to be smaller than even the horizon of events of the black hole, according to the researchers. This implies that the astronomers have accomplished to observe the galaxy IC 310 even in a more detailed way than the central black hole. Besides, the question about what is happening in the gravitational trap which the object has had in the space is still open.
DETAILED IMAGE OF THE JETS
The black holes in the centre of the galaxies have a mass of about one million and several billion times the mass of our sun. The fallen matter towards these objects is able to produce huge flashes of light in all the ranges of the electromagnetic spectrum. This active galaxy nuclei produced what is called jets, in which matter is expeled at velocities nearing the speed of light, that is thrown towards the outer space to the same galaxy. Through radioastronomy methods it is possible to obtain images of these jets with unique detail in astrophysics, an investigation area in which stand out the Astronomy and Astrophysics Department and the Astronomycal Observatory of Universitat de València.
IC 310, in the Perseo cluster of galaxies, belongs to this type of active galaxies. In 2009, both the Fermi space observatory and MAGIC telescope detected the gamma radiation of this object. And, asked how it is possible bright variations this fast are produced, the astronomers suggest that the black hole in the nucleus of IC 310 is a fast rotation and rounded by a powerful magnetic field and «we believe that in the polar regions of the black hole there are some enormous magnetic fields able to accelerate fundamental particles to relativistics speeds, so when interacting them with others of lower power, they are capable of producing gamma rays of very high energy», agues Ros. And adds: «we can imagine this process as a strong electrical storm with lightning».
In fact, every few minutes it is produced an electric shock that affects regions of the size of our solar system. Like this it is possible this particles are thrown at velocities nearing the speed of light, where they will be accelerated, slowed down, re-accelerated and, finally, centrifuged beyond the limits of the galaxy itself.
Ros comments that if the black holes are seen at high energies (gamma rays) and with Interferometry Networks VLBI, «we are capable of obtaining an unique information of the closer regions to the black hole. This observations of MAGIC and EVN indicate the mechanisms by which jets are formed in the immediate environment of black holes, and they have been possible thanks to the quality of both instruments».
By its part, the director of Astronomical Observatory of Universitat de València, José Carlos Guirado, emphasises the importance of this discovery, «result of an efficient synergy between instruments that works at different wavelenghts, gamma rays (MAGIC) and radio waves (the European Network of VLBI)». At the same time, highlights «the presence of astronomers of Universitat de València in this publication, that reflects a sustained effort of a good number of experts of Astronomical Observatory in the environment of black holes research, both from the theoric and observational fields, and that are regulars of radioastronomical instrumentation of first line. Just this way can be reached results as the ones published this week in “Science”».
The European Interferometry Network EVN is a collaboration of several radio telescopes in Europe, China, South Africa, Puerto Rico and other countries, within them the radio telescopes of Yebes in Guadalajara or the one of Effeslberg close to Bonn. MAGIC telescope is located in Roque de los Muchachos in La Palma and consists in two telescopes of 17 metres in diameter and is able of receiving cosmic gamma rays at energies from 25 gigaelectron-volts to 50 teraelectron-volts. These gamma rays produce avalanches of particles when entering the atmosphere and generate a bluish light called Cherenkov radiation, from which MAGIC can study objects in our galaxy and in other distant galaxies, IC 310 in this case.
Eduardo Ros is a tenured lecturer in Universitat de València, currently at the Max Planck Institute for Radio Astronomy in Bonn, Germany, by virtue of an agreement between both institutions. He has been manager of the Astronomical Observatory of La Universitat and scientific coordinator of the mentioned institute. His scope of search is focused on the study of active galaxy nuclei and other compact objects by means of radio interferometric and astronomic methods of high energies.
Link to the original article:
http://www.sciencemag.org/content/early/2014/11/05/science.1256183.full
For more information:
http://www.evlbi.org
https://wwwmagic.mpp.mpg.de/
Publicity video:
https://www.youtube.com/watch?v=UbXU5l_btUQ
Last update: 11 de november de 2014 14:30.
News release
