Search Publications
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…
A rapidly spinning supermassive black hole at the centre of NGC 1365
Harrison, F. A.; Zhang, W. W.; Nardini, E. +9 more
Broad X-ray emission lines from neutral and partially ionized iron observed in active galaxies have been interpreted as fluorescence produced by the reflection of hard X-rays off the inner edge of an accretion disk. In this model, line broadening and distortion result from rapid rotation and relativistic effects near the black hole, the line shape…
A variable absorption feature in the X-ray spectrum of a magnetar
Mereghetti, Sandro; Esposito, Paolo; Turolla, Roberto +9 more
Soft-γ-ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are slowly rotating, isolated neutron stars that sporadically undergo episodes of long-term flux enhancement (outbursts) generally accompanied by the emission of short bursts of hard X-rays. This behaviour can be understood in the magnetar model, according to which these sources are ma…
The rapid assembly of an elliptical galaxy of 400 billion solar masses at a redshift of 2.3
Altieri, B.; Aussel, H.; Pérez-Fournon, I. +41 more
Stellar archaeology shows that massive elliptical galaxies formed rapidly about ten billion years ago with star-formation rates of above several hundred solar masses per year. Their progenitors are probably the submillimetre bright galaxies at redshifts z greater than 2. Although the mean molecular gas mass (5 × 1010 solar masses) of th…
Bright radio emission from an ultraluminous stellar-mass microquasar in M 31
Done, Chris; Macquart, Jean-Pierre; Della Valle, Massimo +34 more
A subset of ultraluminous X-ray sources (those with luminosities of less than 1040 erg s-1 ref. 1) are thought to be powered by the accretion of gas onto black holes with masses of ~5-20, probably by means of an accretion disk. The X-ray and radio emission are coupled in such Galactic sources; the radio emission originates in…
Baryons in the relativistic jets of the stellar-mass black-hole candidate 4U1630-47
Miller-Jones, James C. A.; Tzioumis, Tasso; Migliari, Simone +2 more
Accreting black holes are known to power relativistic jets, both in stellar-mass binary systems and at the centres of galaxies. The power carried away by the jets, and, hence, the feedback they provide to their surroundings, depends strongly on their composition. Jets containing a baryonic component should carry significantly more energy than elec…