Search Publications
A magnetar giant flare in the nearby starburst galaxy M82
Thuillot, William; Mereghetti, Sandro; Esposito, Paolo +32 more
Magnetar giant flares are rare explosive events releasing up to 1047 erg in gamma rays in less than 1 second from young neutron stars with magnetic fields up to 1015−16 G (refs. 1,2). Only three such flares have been seen from magnetars in our Galaxy3,4 and in the Large Magellanic Cloud5 in ro…
Thermonuclear explosions on neutron stars reveal the speed of their jets
Kuulkers, Erik; Degenaar, Nathalie; Sánchez-Fernández, Celia +6 more
Relativistic jets are observed from accreting and cataclysmic transients throughout the Universe, and have a profound impact on their surroundings1,2. Despite their importance, their launch mechanism is not known. For accreting neutron stars, the speed of their compact jets can reveal whether the jets are powered by magnetic fields anch…
A bright γ-ray flare interpreted as a giant magnetar flare in NGC 253
Mitrofanov, I.; Hurley, K.; von Kienlin, A. +33 more
Soft γ-ray repeaters exhibit bursting emission in hard X-rays and soft γ-rays. During the active phase, they emit random short (milliseconds to several seconds long), hard-X-ray bursts, with peak luminosities1 of 1036 to 1043 erg per second. Occasionally, a giant flare with an energy of around 1044 to 10…
A magnetar-powered X-ray transient as the aftermath of a binary neutron-star merger
Lehmer, B. D.; Bauer, F. E.; Brandt, W. N. +14 more
Mergers of neutron stars are known to be associated with short γ-ray bursts1-4. If the neutron-star equation of state is sufficiently stiff (that is, the pressure increases sharply as the density increases), at least some such mergers will leave behind a supramassive or even a stable neutron star that spins rapidly with a strong magneti…
A rapidly changing jet orientation in the stellar-mass black-hole system V404 Cygni
Soria, Roberto; Sarazin, Craig L.; Jonker, Peter G. +18 more
Powerful relativistic jets are one of the main ways in which accreting black holes provide kinetic feedback to their surroundings. Jets launched from or redirected by the accretion flow that powers them are expected to be affected by the dynamics of the flow, which for accreting stellar-mass black holes has shown evidence for precession1
Regulation of black-hole accretion by a disk wind during a violent outburst of V404 Cygni
Ponti, G.; Charles, P. A.; Rodriguez, J. +7 more
Accretion of matter onto black holes is universally associated with strong radiative feedback and powerful outflows. In particular, black-hole transients have outflows whose properties are strongly coupled to those of the accretion flow. This includes X-ray winds of ionized material, expelled from the accretion disk encircling the black hole, and …
Positron annihilation signatures associated with the outburst of the microquasar V404 Cygni
Beloborodov, Andrei M.; Diehl, Roland; Greiner, Jochen +7 more
Microquasars are stellar-mass black holes accreting matter from a companion star and ejecting plasma jets at almost the speed of light. They are analogues of quasars that contain supermassive black holes of 106 to 1010 solar masses. Accretion in microquasars varies on much shorter timescales than in quasars and occasionally p…
Repetitive patterns in rapid optical variations in the nearby black-hole binary V404 Cygni
Ruiz, Javier; Enoto, Teruaki; Nogami, Daisaku +65 more
How black holes accrete surrounding matter is a fundamental yet unsolved question in astrophysics. It is generally believed that matter is absorbed into black holes via accretion disks, the state of which depends primarily on the mass-accretion rate. When this rate approaches the critical rate (the Eddington limit), thermal instability is supposed…
Cobalt-56 γ-ray emission lines from the type Ia supernova 2014J
Sunyaev, R.; Sazonov, S.; Churazov, E. +8 more
A type Ia supernova is thought to be a thermonuclear explosion of either a single carbon-oxygen white dwarf or a pair of merging white dwarfs. The explosion fuses a large amount of radioactive 56Ni (refs 1-3). After the explosion, the decay chain from 56Ni to 56Co to 56Fe generates γ-ray photons, which a…
Swings between rotation and accretion power in a binary millisecond pulsar
Wieringa, M. H.; Campana, S.; Stella, L. +20 more
It is thought that neutron stars in low-mass binary systems can accrete matter and angular momentum from the companion star and be spun-up to millisecond rotational periods. During the accretion stage, the system is called a low-mass X-ray binary, and bright X-ray emission is observed. When the rate of mass transfer decreases in the later evolutio…