MAGIC detects the nuclear explosion of a ‘vampire’ star
The results of the observations, made with the MAGIC Cherenkov telescopes, and the new discoveries about these stellar explosions are published today in the journal Nature Astronomy.
IEEC participates in this project through researchers from the Institute of Cosmos Sciences (ICCUB) and the Centre for Space Studies and Research (CERES) of the Universitat Autònoma de Barcelona (UAB).
On 8 August 2021, an alert of the very high-energy gamma-ray burst of one of the most studied novae in the Milky Way, RS Ophiuchi, in the constellation Ophiuchus (‘the serpent bearer’) was received. The incredible explosion of the RS Oph nova reached Earth and was immediately detected by optical telescopes and the Large Area Telescope (LAT) on board the gamma-ray satellite Fermi. An extensive tracking mechanism was immediately activated and a whole series of observations followed, making this the first nova to be detected in such a wide energy range, both from Earth and from space. The following day, on 9 August 2021, the MAGIC collaboration used its twin Cherenkov telescope system, located at the Roque de los Muchachos Observatory (at La Palma island), to observe in the direction of RS Oph, also detecting the source.
The result of the work, published today in the journal Nature Astronomy, identifies novae as a new type of very high-energy gamma-ray source. This event is the first to be detected at these energies and provides a better understanding of this kind of outburst and its potential role in the production of the mysterious cosmic rays in the Milky Way.
“The eruption of RS Oph is a very rare event in the gamma-ray sky: it is the most luminous and highest flux nova detected in gamma rays to date, and we observed it just in time,” says Rubén López-Coto, researcher at the Istituto Nazionale di Fisica Nucleare – Sezione di Padova (INFN Padova) and visitor at the Instituto de Astrofísica de Andalucía (IAA, CSIC), and one of the lead authors of the paper. The Institute of Space Studies of Catalonia (IEEC — Institut d’Estudis Espacials de Catalunya) participates in this project through researchers from the Institute of Cosmos Sciences of the Universitat de Barcelona (ICCUB) and the Centre for Space Studies and Research (CERES) of the Universitat Autònoma de Barcelona (UAB).
Thanks to the excellent observing conditions on La Palma, the rapid reaction of the collaboration and the high sensitivity of the MAGIC telescopes, the nova could be detected at energies one hundred billion times higher than visible light. Optical observations were also conducted the following nights with the Joan Oró Telescope (TJO) at the Montsec Observatory (managed by IEEC), among other facilities.
“This work has identified novae as a new type of very high-energy gamma-ray source. It has therefore opened a new line of research in very high-energy gamma-ray astronomy,” adds Alicia López-Oramas, researcher at the Instituto de Astrofísica de Canarias (IAC), and also co-lead author of the paper.
The MAGIC telescope system observing the eruption of the RS Ophiuchi nova on the
night of the very high-energy gamma-ray detection (11 August 2021). Credit: Urs
Leutenegger.
What is a nova?
The end of a star after its death depends on its mass. In about five billion years, when the Sun burns out, it will expand into a red giant star and then collapse into a stellar corpse known as a white dwarf. These stellar remnants are very dense and, under certain circumstances, can produce large explosions.
In binary systems where the white dwarf has a red giant star as a companion, hydrogen from the outermost layers of the red giant can succumb to the gravitational pull of the white dwarf and accumulate on its surface. “This ‘vampirism’ of a white dwarf onto an active-phase star results in a nuclear explosion on its surface, which causes it to expel most of the hydrogen and fusion products into interstellar space,” says Marc Ribó, MAGIC Deputy Physics Coordinator, Director of the Montsec Observatory and IEEC researcher at ICCUB.
Such explosions are very luminous, up to 100,000 times brighter than our Sun, and are known as novae. If the cycle of material transfer between the two stars starts again, it can restart the process that in the future will lead to another explosion in what are known as recurrent systems.
“MAGIC has been unsuccessfully following nova explosions for some time now. It is gratifying when you see that the effort pays off and we manage to open new windows that bring a deeper understanding of our Universe,” says Óscar Blanch, spokesperson for the MAGIC collaboration and researcher at the Institut de Física d'Altes Energies (IFAE). “It is the fruit of the work of many people,” he concludes.
To fully understand the complex relationship between violent events in the interstellar medium of our Galaxy will require more observations like the ones presented in the paper published today. The MAGIC collaboration will continue the celestial surveillance of stellar remnants, both in the Milky Way and in other galaxies.
About MAGIC
The Spanish community has been involved in MAGIC since its inception. The following are currently members of the collaboration: the Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), the Instituto de Astrofísica de Canarias (IAC), the Institut de Física d'Altes Energies (IFAE), the Universitat Autònoma de Barcelona (UAB), the Institute of Cosmos Sciences of the Universitat de Barcelona (ICCUB), the Universidad Complutense de Madrid (UCM) and the Instituto de Astrofísica de Andalucía (IAA). The Institute of Space Studies of Catalonia (IEEC — Institut d’Estudis Espacials de Catalunya) participates in this project through researchers from ICCUB and the Centre for Space Studies and Research (CERES, UAB). In addition, the MAGIC data centre is the Port d'Informació Científica (PIC), a collaboration between IFAE and CIEMAT.
Press release prepared in collaboration with the Communication Offices of the Instituto de Astrofísica de Canarias (IAC) and the Instituto de Astrofísica de Andalucía (IAA), together with the MAGIC collaboration.
Main Image
White dwarf "sucking" material from a red giant star
Caption: Recreation of a white dwarf accreting material from its red giant companion star, which would result in a very high-energy gamma-ray burst like the one observed in this study.
Credit: Superbossa / Max Planck Institute.
Links
– IEEC
– CERES
– ICCUB
– MAGIC
More information
This research is presented in a paper entitled “Proton acceleration in thermonuclear nova explosions revealed by gamma rays”, of D. Green, R. López-Coto, A. López-Oramas, J. Sitarek et al., that appears in the journal Nature Astronomy on 14 April 2022.
The Institute of Space Studies of Catalonia (IEEC — Institut d’Estudis Espacials de Catalunya) promotes and coordinates space research and technology development in Catalonia for the benefit of society. IEEC fosters collaborations both locally and worldwide and is an efficient agent of knowledge, innovation and technology transfer. As a result of 25 years of high-quality research, done in collaboration with major international organisations, IEEC ranks among the best international research centers, focusing on areas such as: astrophysics, cosmology, planetary science, and Earth Observation. IEEC’s engineering division develops instrumentation for ground- and space-based projects, and has extensive experience in working with private or public organisations from the aerospace and other innovation sectors.
IEEC is a private non-profit foundation, governed by a Board of Trustees composed of Generalitat de Catalunya and four other institutions that each have a research unit, which together constitute the core of IEEC R&D activity: the Universitat de Barcelona (UB) with the research unit ICCUB — Institute of Cosmos Sciences; the Universitat Autònoma de Barcelona (UAB) with the research unit CERES — Center of Space Studies and Research; the Universitat Politècnica de Catalunya · BarcelonaTech (UPC) with the research unit CTE — Research Group in Space Sciences and Technologies; the Spanish Research Council (CSIC) with the research unit ICE — Institute of Space Sciences. IEEC is a CERCA (Centres de Recerca de Catalunya) center.
Contacts
IEEC Communication Office
Barcelona, Spain
Ana Montaner and Rosa Rodríguez
E-mail: comunicacio@ieec.cat
Lead Researcher at IEEC
Barcelona, Spain
Josep Maria Paredes
Institute of Cosmos Sciences of the Universitat de Barcelona (ICCUB)
Institute of Space Studies of Catalonia (IEEC)
E-mail: jmparedes@ieec.cat, jmparedes@ub.edu
Lluís Font
Centre for Space Studies and Research (CERES, UAB)
Institute of Space Studies of Catalonia (IEEC)
E-mail: font@ieec.cat, lluis.font@uab.cat