Search Publications
Dramatic spectral transition of X-ray pulsar GX 304-1 in low luminous state
Doroshenko, Victor; Tsygankov, Sergey S.; Mushtukov, Alexander A. +5 more
We report on the discovery of a dramatic change in the energy spectrum of the X-ray pulsar GX 304-1 appearing at low luminosity. Particularly, we found that the cut-off power-law spectrum typical for accreting pulsars, including GX 304-1 at higher luminosities of LX ∼ 1036-1037 erg s-1, transformed at lo…
60Fe in core-collapse supernovae and prospects for X-ray and gamma-ray detection in supernova remnants
Safi-Harb, Samar; Fryer, Chris L.; Mumpower, Matthew R. +6 more
We investigate 60Fe in massive stars and core-collapse supernovae focussing on uncertainties that influence its production in 15, 20, and 25 M⊙ stars at solar metallicity. We find that the 60Fe yield is a monotonic increasing function of the uncertain 59Fe(n, γ)60Fe cross-section and that a fa…
Tracking the variable jets of V404 Cygni during its 2015 outburst
Altamirano, D.; Bremer, M.; Russell, D. M. +14 more
We present multifrequency monitoring observations of the black hole X-ray binary V404 Cygni throughout its 2015 June outburst. Our data set includes radio and mm/sub-mm photometry, taken with the Karl G. Jansky Very Large Array, Arc-Minute MicroKelvin Imager Large Array, Sub-millimeter Array, James Clerk Maxwell Telescope, and the Northern Extende…
Long-term evolutions of the cyclotron line energies in Her X-1, Vela X-1, and Cen X-3 as observed with Swift/BAT
Santangelo, A.; Ducci, L.; Zhang, S. +3 more
We study the long-term evolution of the centroid energy of cyclotron lines - often referered to as cyclotron resonance scattering features (CRSFs) - in Her X-1, Vela X-1, and Cen X-3, using survey observations of the Burst Alert Telescope onboard Swift. We find a significant decrease of the fundamental CRSF energy in Her X-1 and the first harmonic…
A multiwavelength analysis of a collection of short-duration GRBs observed between 2012 and 2015
Cepa, J.; Troja, E.; Lee, W. H. +71 more
We investigate the prompt emission and the afterglow properties of short-duration gamma-ray burst (sGRB) 130603B and another eight sGRB events during 2012-2015, observed by several multiwavelength facilities including the Gran Canarias Telescope 10.4 m telescope. Prompt emission high energy data of the events were obtained by INTEGRAL-SPI-ACS, Swi…
The long outburst of the black hole transient GRS 1716-249 observed in the X-ray and radio band
Motta, S. E.; Segreto, A.; Malzac, J. +9 more
We present the spectral and timing analysis of X-ray observations performed on the Galactic black hole transient GRS 1716-249 during the 2016-2017 outburst. The source was almost continuously observed with the Neil Gehrels Swift Observatory from 2016 December until 2017 October. The X-ray hardness ratio and timing evolution indicate that the sourc…
New insights on the puzzling LMXB 1RXS J180408.9-342058: the intermediate state, the clocked type-I X-ray bursts, and much more
Segreto, A.; Ferrigno, C.; Malzac, J. +7 more
1RXS J180408.9-342058 is a low-mass X-ray binary hosting a neutron star, which shows X-ray activity at very different mass-accretion regimes, from very faint to almost the Eddington luminosity. In this work, we present a comprehensive X-ray study of this source using data from the Neil Gehrels Swift Observatory, NuSTAR, and INTEGRAL/JEM-X. In orde…
New constraints on Lorentz invariance violation with polarized gamma-ray bursts
Wei, Jun-Jie
Lorentz invariance violations (LIV) can yield vacuum birefringence, which results in an energy-dependent rotation of the polarization vector of linearly polarized emission from astrophysical sources. It is believed that if the relative rotation angle (ΔΘ) of the polarization vector of high-energy photons with respect to that of low-energy photons …
Synthetic 26Al emission from galactic-scale superbubble simulations
Diehl, R.; Rodgers-Lee, D.; Krause, M. G. H. +1 more
Emission from the radioactive trace element 26Al has been observed throughout the Milky Way with the COMPTEL and INTEGRAL satellites. In particular, the Doppler shifts measured with INTEGRAL connect 26Al with superbubbles, which may guide 26Al flows off spiral arms in the direction of Galactic rotation. In order to…
Optical and X-ray correlations during the 2015 outburst of the black hole V404 Cyg
Dhillon, V. S.; Gandhi, P.; Marsh, T. R. +6 more
We present a serendipitous multiwavelength campaign of optical photometry simultaneous with Integral X-ray monitoring of the 2015 outburst of the black hole V404 Cyg. Large-amplitude optical variability is generally correlated with X-rays, with lags of order a minute or less compatible with binary light travel time-scales or jet ejections. Rapid o…