Search Publications
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…
Accretion history of AGN: Estimating the host galaxy properties in X-ray luminous AGN from z = 0-3
Kirkpatrick, Allison; Marchesi, Stefano; LaMassa, Stephanie +10 more
We aim to determine the intrinsic far-Infrared (far-IR) emission of X-ray-luminous quasars over cosmic time. Using a 16 deg2 region of the Stripe 82 field surveyed by XMM-Newton and Herschel Space Observatory, we identify 2905 X-ray luminous (LX > 1042 erg/s) active galactic nuclei (AGN) in the range z ≈ 0-3. Th…
Multiple components in the molecular outflow of the red supergiant NML Cyg
De Beck, E.; Andrews, H.; Hirvonen, P.
Despite their large impact on stellar and galactic evolution, the properties of outflows from red supergiants are not well characterized. We used the Onsala 20m telescope to perform a spectral survey at 3 and 4 mm (68-116 GHz) of the red supergiant NML Cyg, alongside the yellow hypergiant IRC + 10420. Our observations of NML Cyg were combined with…
Distance and age of the massive stellar cluster Westerlund 1 - II. The eclipsing binary W36
Damineli, Augusto; Mace, Gregory N.; Navarete, Felipe +3 more
Westerlund 1 (Wd 1) is one of the most relevant star clusters in the Milky Way to study massive star formation, although it is still poorly known. Here, we used photometric and spectroscopic data to model the eclipsing binary W36, showing that its spectral type is O6.5 III + O9.5 IV, hotter and more luminous than thought before. Its distance d