Search Publications
Generation of interplanetary type II radio emission
Jebaraj, I. C.; Mann, G.; Poedts, S. +4 more
Context. Coronal mass ejections (CMEs) are eruptive phenomena that can accelerate energetic particles and drive shock waves. The CME-driven shocks propagate from the low corona to interplanetary space. The radio emission that results from fast electrons energised by shock waves are called type II bursts. This radio emission can provide information…
Long-term pulse period evolution of the ultra-luminous X-ray pulsar NGC 7793 P13
Ptak, A.; Stern, D.; Fabian, A. C. +14 more
Ultra-luminous X-ray pulsars (ULXPs) provide a unique opportunity to study persistent super-Eddington accretion. Here we present the results of a long-term monitoring campaign of ULXP NGC 7793 P13, focusing on the pulse period evolution and the determination of the orbital ephemeris. Over our four year monitoring campaign with Swift, XMM-Newton, a…
Radio halos in a mass-selected sample of 75 galaxy clusters. I. Sample selection and data analysis
Brunetti, G.; Pratt, G. W.; Kale, R. +9 more
Context. Radio halos are synchrotron diffuse sources at the centre of a fraction of galaxy clusters. The study of large samples of clusters with adequate radio and X-ray data is necessary to investigate the origin of radio halos and their connection with the cluster dynamics and formation history.
Aims: The aim of this paper is to compile a w…
Relation between AGN type and host galaxy properties
Georgantopoulos, I.; Masoura, V. A.; Mountrichas, G. +1 more
We use 3213 active galactic nuclei (AGNs) from the XMM-XXL northern field to investigate the relation of AGN type with host galaxy properties. Applying a Bayesian method, we derive the hardness ratios, and through these the hydrogen column density (NH) for each source. We consider those with NH > 1021.5 cm-…
H II regions and high-mass starless clump candidates. II. Fragmentation and induced star formation at 0.025 pc scale: an ALMA continuum study
Liu, H.; Zavagno, A.; Zhang, S. +7 more
Context. The ionization feedback from H II regions modifies the properties of high-mass starless clumps (HMSCs, of several hundred to a few thousand solar masses with a typical size of 0.1-1 pc), such as dust temperature and turbulence, on the clump scale. The question of whether the presence of H II regions modifies the core-scale (~0.025 pc) fra…
The nature of VX Sagitarii. Is it a TŻO, a RSG, or a high-mass AGB star?
Negueruela, I.; Tabernero, H. M.; Dorda, R. +1 more
Aims: We present a spectroscopic analysis of the extremely luminous red star VX Sgr based on high-resolution observations combined with AAVSO light curve data. Given the puzzling characteristics of VX Sgr, we explore three scenarios for its nature: a massive red supergiant (RSG) or red hypergiant (RHG), a Thorne Żytkow object, and an extreme …
Stellar clustering and orbital architecture of planetary systems
Adibekyan, V.; Sousa, S. G.; Barros, S. C. C. +9 more
Context. Revealing the mechanisms shaping the architecture of planetary systems is crucial for our understanding of their formation and evolution. In this context, it has been recently proposed that stellar clustering might be the key in shaping the orbital architecture of exoplanets.
Aims: The main goal of this work is to explore the factors…
Photometric selection and redshifts for quasars in the Kilo-Degree Survey Data Release 4
Heymans, C.; Hildebrandt, H.; Erben, T. +10 more
We present a catalog of quasars with their corresponding redshifts derived from the photometric Kilo-Degree Survey (KiDS) Data Release 4. We achieved it by training machine learning (ML) models, using optical ugri and near-infrared ZYJHKs bands, on objects known from Sloan Digital Sky Survey (SDSS) spectroscopy. We define inference subs…
MPS-ATLAS: A fast all-in-one code for synthesising stellar spectra
Solanki, S. K.; Shapiro, A. I.; Tagirov, R. V. +6 more
Context. Stellar spectral synthesis is essential for various applications, ranging from determining stellar parameters to comprehensive stellar variability calculations. New observational resources as well as advanced stellar atmosphere modelling, taking three dimensional effects from radiative magnetohydrodynamics calculations into account, requi…
Seasonal reappearance of HCl in the atmosphere of Mars during the Mars year 35 dusty season
Forget, F.; Montmessin, F.; Irwin, P. G. J. +15 more
Hydrogen chloride was discovered in the atmosphere of Mars for the first time during the global dust storm in Mars year (MY) 34 (July 2018) using the Atmospheric Chemistry Suite mid-infrared channel (ACS MIR) on the ExoMars Trace Gas Orbiter. The simultaneity of variations in dust and HCl, and a correlation between water vapour and HCl, led to the…