Search Publications
Discovery of a pulse-phase-transient cyclotron line in the X-ray pulsar Swift J1808.4-1754 and identification of an optical companion
Tsygankov, Sergey S.; Lutovinov, Alexander A.; Molkov, Sergey V. +3 more
In this work, the temporal and spectral properties of the poorly studied X-ray pulsar Swift J1808.4-1754 were investigated in the 0.8-79 keV energy range based on the data from the NuSTAR and Swift observatories collected during the 2014 outburst. Strong pulsations with a period of 909.73 ± 0.03 s were detected in the source light curve, with the …
Probabilistic orbits and dynamical masses of emission-line binaries
Grant, David; Blundell, Katherine
The observed orbits of emission-line stars may be affected by systematics owing to their broad emission lines being formed in complex and extended environments. This is problematic when orbital parameter probability distributions are estimated assuming radial-velocity data are solely comprised of Keplerian motion plus Gaussian white noise, leading…
Tracing a decade of activity towards a yellow hypergiant. The spectral and spatial morphology of IRC+10420 at au scales
de Wit, W. -J.; Black, J. H.; Mérand, A. +3 more
The fate of a massive star during the latest stages of its evolution is highly dependent on its mass-loss history and geometry, with the yellow hypergiants (YHGs) being key objects. We present near-IR interferometric observations of the famous YHG IRC+10420 and blue spectra taken between 1994 and 2019. Our 2.2-µm GRAVITY/VLTI observations at…
The probabilistic random forest applied to the QUBRICS survey: improving the selection of high-redshift quasars with synthetic data
Grazian, Andrea; Murphy, Michael T.; Boutsia, Konstantina +10 more
Several recent works have focused on the search for bright, high-z quasars (QSOs) in the South. Among them, the QUasars as BRIght beacons for Cosmology in the Southern hemisphere (QUBRICS) survey has now delivered hundreds of new spectroscopically confirmed QSOs selected by means of machine learning algorithms. Building upon the results obtained b…
Helium-like X-ray line complexes show that the hottest plasma on the O supergiant ζ Puppis is in its wind
Leutenegger, Maurice A.; Cohen, David H.; Gagné, Marc +3 more
We present an analysis of Chandra grating spectra of key helium-like line complexes to put constraints on the location with respect to the photosphere of the hottest (T ≳ 6 × 106 K) plasma in the wind of the O supergiant ζ Pup and to explore changes in the 18 yr between two sets of observations of this star. We fit two models - one empi…
Signature of a chemical spread in the open cluster M37
Salaris, M.; Bedin, L. R.; Pietrinferni, A. +2 more
Recent Gaia photometry of the open cluster M37 has disclosed the existence of an extended main sequence turn-off - like in Magellanic clusters younger than about 2 Gyr - and a main sequence that is broadened in colour beyond what is expected from the photometric errors, at magnitudes well below the region of the extended turn-off, where neither ag…
Collisional evolution of the trans-Neptunian region in an early dynamical instability scenario
Vincent, Jean-Baptiste; Campo Bagatin, Adriano; Benavidez, Paula G. +2 more
Any early or late dynamical instability in the outer Solar system should have left their footprint on the trans-Neptunian object (TNO) populations. Here, we study the collisional and dynamical evolution of such populations numerically by an updated version of ALICANDEP, which suitably takes into account the onset of an early dynamical instability.…
Populations of highly variable X-ray sources in the XMM-Newton slew survey
Saxton, R. D.; Yuan, Weimin; Starling, R. L. C. +2 more
We present the identifications of a flux-limited sample of highly variable X-ray sources on long time-scales from the second catalogue of the XMM-Newton SLew survey (XMMSL2). The carefully constructed sample, comprising 265 sources (2.5 per cent) selected from the XMMSL2 clean catalogue, displayed X-ray variability of a factor of more than 10 in 0…
The XXL survey. XLIX. Linking the members star formation histories to the cluster mass assembly in the z = 1.98 galaxy cluster XLSSC 122
Pierre, M.; Poggianti, B.; Carnall, A. C. +5 more
The most massive protoclusters virialize to become clusters at z ~ 2, which is also a critical epoch for the evolution of their member galaxies. XLSSC 122 is a z = 1.98 galaxy cluster with 37 spectroscopically confirmed members. We aim to characterize their star formation histories in the context of the cluster accretion history. We measure their …
An asymmetrical model for high-energy radiation of Cassiopeia A
Wang, Wei; Li, Zhuo; Mou, Guobin +1 more
The supernova remnant Cassiopeia A (Cas A) shows strong radiation from radio to gamma-ray bands. The mechanism of gamma-ray radiation in Cas A and its possible contribution to PeV cosmic rays are still under debate. The X-ray imaging reveals an asymmetric profile of Cas A, suggesting the existence of a jet-like structure. In this paper, we propose…