Search Publications
Spectral similarities in galaxies through an unsupervised classification of spaxels
Fraix-Burnet, D.; Chambon, H. J.
Aims: We present the first unsupervised classification of spaxels in hyperspectral images of individual galaxies. Classes identify regions by spectral similarity and thus take all the information into account that is contained in the data cubes (spatial and spectral).
Methods: We used Gaussian mixture models in a latent discriminant subs…
Optical polarimetry study of the Lambda-Orionis star-forming region
Neha, S.; Soam, A.; Maheswar, G.
We present an optical polarimetry study of the nearby star-forming region Lambda-Orionis to map the plane-of-the-sky magnetic field geometry to understand the magnetized evolution of the HII region and the associated small molecular clouds. We made multiwavelength polarization observations of 34 bright stars distributed across the region. We also …
Multiwavelength observation of 1A 0535+262=HD 245770 from 2010 to 2021
Liu, Wei; Yan, Jingzhi; Xiao, Guangcheng +3 more
Context. 1A 0535+262 is a high-mass X-ray binary that went into a giant X-ray outburst in 2020. During this event, the X-ray luminosity reached the highest value measured over the last 30 years.
Aims: Our aim is to study the long-term variability of 1A 0535+262 before and after the 2020 major X-ray outburst and to uncover the mechanism that l…
Characterisation of the X-ray point source variability in the eROSITA south ecliptic pole field
Salvato, M.; Buchner, J.; Nandra, K. +11 more
Aims: During the Spectrum Roentgen Gamma (SRG)/eROSITA all-sky surveys, X-ray sources close to the South Ecliptic Pole (SEP) are observed almost every 4 h. We aim to identify the sources exhibiting the most significant long-term X-ray variability within 3° of the SEP in the first three surveys, and investigate their properties.
Methods: …
The true nature of HE 0057-5959, the most metal-poor, Li-rich star
Salaris, M.; Bonifacio, P.; Monaco, L. +2 more
The Li-rich stars are a class of rare objects with a surface lithium abundance, A(Li), that exceeds that of other stars in the same evolutionary stage. The origin of these stars is still debated, and valuable routes to look at include the Cameron-Fowler mechanism, a mass-transfer process in a binary system, or the engulfment of rocky planets or br…
Radial velocity homogeneous analysis of M dwarfs observed with HARPS: I. Exoplanet detection and candidates
Bouchy, F.; Meunier, N.; Unger, N. +12 more
Context. The census of planets around M dwarfs in the solar neighbourhood meets two challenges: detecting the best targets for the future characterisation of planets with ELTs, and studying the statistics of planet occurrence that are crucial to formation scenarios. The radial velocity (RV) method remains the most appropriate for such a census as …
Hints of a close outer companion to the ultra-hot Jupiter TOI-2109 b
Alonso, R.; Deleuil, M.; Erikson, A. +86 more
Context. Hot Jupiters (HJs) with close-by planetary companions are rare, with only a handful of them having been discovered so far. This could be due to their suggested dynamical histories, which lead to the possible ejection of other planets. TOI-2109 b is special in this regard because it is the HJ with the closest relative separation from its h…
Triple trouble with PSR J1618‑3921: Mass measurements and orbital dynamics of an eccentric millisecond pulsar
Guillemot, L.; Possenti, A.; Kramer, M. +11 more
Context. PSR J1618‑3921 is one of five known millisecond pulsars (MSPs) in eccentric orbits (eMPSs) located in the Galactic plane, whose formation is poorly understood. Earlier studies of these objects revealed significant discrepancies between observations and predictions from standard binary evolution scenarios of pulsar-helium white dwarf (HeWD…
Solar flares in the Solar Orbiter era: Short-exposure EUI/FSI observations of STIX flares
Krucker, Säm; Veronig, Astrid M.; Polito, Vanessa +10 more
Aims. This paper aims to demonstrate the importance of short-exposure extreme ultraviolet (EUV) observations of solar flares in the study of particle acceleration, heating, and energy partition in flares. This work highlights the observations now available from the Extreme Ultraviolet Imager (EUI) instrument suite on board Solar Orbiter while oper…
J-PLUS: Bayesian object classification with a strum of BANNJOS
Hernández-Monteagudo, C.; Hernán-Caballero, A.; Vázquez Ramió, H. +22 more
Context. With its 12 optical filters, the Javalambre-Photometric Local Universe Survey (J-PLUS) provides an unprecedented multicolor view of the local Universe. The third data release (DR3) covers 3192 deg2 and contains 47.4 million objects. However, the classification algorithms currently implemented in the J-PLUS pipeline are determin…