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To obtain full sky coverage, astronomical adaptive optics systemsrequire Na Sodium Beacons (SBs) (also referred to as Laser Guide Starsor LGSs) located at heights extending from 85 to 100 km. When viewed atthe edge of large telescopes these SBs appear elongated. For the Euro5050 meter aperture telescopes this elongation amounts to 6 to 9arcseconds when the laser is launched from a point on the tel

We consider the conditions necessary for the development of an inverted population among the energy levels of free atoms in a medium exposed to radiation in spectral nonequilibrium. In particular, we focus on monochromatic radiation occurring as a result of an accidental wavelength coincidence between a pumping emission line and a pumped absorption line in two different elements. We examine especi

mass close-in planets, despite the latter being exceedingly common. Two migration channels for hot Jupiters have been proposed: through a protoplanetary gas disk or by tidal circularization of highly eccentric planets. We show that highly eccentric giant planets that will become hot Jupiters clear out any low-mass inner planets in the system, explaining the observed lack of such companions to hot

The spectrum of Eta Carinae and its ejecta shows slow variations over a period of 5.5 years. However, the spectrum changes drastically on a time scale of days once every period called the "spectral event". We report on variations in the narrow emission line spectrum of gas condensations (the Weigelt blobs) close to the central star during a spectral event. The rapid changes in the stellar radiatio

To obtain full sky coverage, astronomical adaptive optics systemsrequire Na Sodium Beacons (SBs) (also referred to as Laser Guide Starsor LGSs) located at heights extending from 85 to 100 km. When viewed atthe edge of large telescopes these SBs appear elongated. For the Euro5050 meter aperture telecopes this elongation amounts to 6 to 9 arcsecondswhen the laser is launched from a point on the tele

MATLAB and its companion product Simulink are commonly used tools insystems modelling and other scientific disciplines. A cross-disciplinaryintegrated MATLAB model is used to study the overall performance of theproposed 50m optical and infrared telescope, Euro50. However thecomputational requirements of this kind of end-to-end simulation of thetelescope's behaviour, exceeds the capability of an in

We simulate the velocities of formed Black Holes to determine the fraction of retained Black Holes in 152 Globular Clusters. The model we used for the escape velocity is from Plummer. The scenarios of the natal kick are Neutronstar like kicks and momentum conserving kicks. We also consider the binary fraction which affect the retention of Black Holes. A typical Globular Cluster retains 0 or 102 BlThe Black Hole are popular objects in astronomy, a lot of scientists want to study their formation and evolution. Most astronomers agree with that there is a super massive black hole in the center of our galaxy. Also, some previous observations show that at least some clusters have black holes. As we all known, a typical black hole is formed by a core-collapse supernova of a massive star. The core

We present the results of the first search for gravitational wave bursts associated with high energy neutrinos. Together, these messengers could reveal new, hidden sources that are not observed by conventional photon astronomy, particularly at high energy. Our search uses neutrinos detected by the underwater neutrino telescope ANTARES in its 5 line configuration during the period January - Septemb

The Earthshine telescope project is a collaborative effort between Lund Observatory (LO) in Sweden and the Danish Meteorological Institute (DMI) with the purpose of constructing one or more robotic telescopes to record the albedo of the Earth over a long time. The objective is to measure long-term development of the global cloud cover and reflectivity for climate modeling. A 1% change in the Earth

Photoinduced Ba L x-rays were measured, in the excitation energy range of 5.6-30 keV, by using high-brilliance undulator radiation. The obtained intensity ratios, the excitation-energy independent L beta(4)/L beta(3), L eta/L beta(1), L iota/L alpha(1,2), L beta(6)/ L alpha(1,2) and L beta(2,15)/L alpha(1,2) as well as the excitation- energy dependent L beta(1)/L alpha(1,2), L beta(3)/L alpha(1,2)

We report on 3D radiation-hydrodynamics modelling of the non-magneticsolar atmosphere with emphasis on the problem of the acoustic heating ofthe chromosphere. Our models include the generation of acoustic waves inthe uppermost layers of the solar convection zone their propagationthrough the photospheric layers and their ultimate transformation intoshock fronts which are dissipated in the chromosph

The ESA space astrometry mission Gaia will measure the positions, parallaxes and proper motions of the 1 billion brightest stars on the sky. Expected accuracies are in the 725 as range down to 15 mag and sub-mas accuracies at the faint limit (20 mag). The astrometric data are complemented by low-resolution spectrophotometric data in the 3301000 nm wavelength range and, for the brighter stars, radi

For many applications, including future giant telescopes, there is increased interest in structural cables. Usually integrated models, i.e. combined models of structures, optics and control systems are used for modeling of telescopes. Performance of structural cables is non-linear, so often a linearization is needed to include cable models in integrated models of telescopes. We present two differe

Several recent studies of solar twins in the solar neighbourhood have shown a tight correlation between various elemental abundances and age, in particular [Y/Mg]. If this relation is real and valid for other types of stars as well as elsewhere in the Galaxy, it would provide a very powerful tool to derive ages of stars without the need to resort to determining their masses (evolutionary stage) ve

In a recent paper we presented a procedure for optimal analyticalcontrol of several deformable mirrors based on only the measured guidestar wavefronts. The expected performance was evaluated for variousguide star configurations using up to three deformable mirrors. Forsimplicity the guide stars were assumed to be infinitely distant. Inthis paper we address the effect of using laser guide stars in

We report on recent progress in hydrodynamical modelling of the surfacelayers of late M- and L-type main- as well as pre-main-sequence objects.Despite the complex chemistry encountered in the cool atmospheres ofsuch objects a reasonably accurate representation of the radiativetransfer is possible - even within time-dependent multi-dimensionalmodels. The detailed treatment of the interplay between

This section contains examples of information that can be good to inform your students about before a digital exam. The information itself is a compilation of several faculties' and departments' information to students and we have divided it  into different time periods. As soon as possible, you need to inform about the date and time, tools and software, if there is monitoring and how personal dat

https://www.education.lu.se/en/teaching-tips/digital-examination/build-and-conduct-assessment/inform-your-students - 2026-05-25

22 to 26 April 2026 Welcome to a new edition of INTONAL Festival at IAC!For the 2026 edition, we have shaped a curatorial framework that brings together our 15-years tradition of acousmonium practice and a focus on South and Central American sound scenes. This perspective unfolds through a dedicated talk and curated concerts, with music spatialized live on our 40+ speaker system.The talk will feat

https://www.iac.lu.se/intonal/intonal-2026-acousmatic-concerts-iac - 2026-05-25

In this work we compute for the first time the so-called Complete-NLO predictions for top-quark pair hadroproduction in association with at least one isolated photon (tt¯ γ). We also compute NLO QCD+EW predictions for the similar case with at least two isolated photons (tt¯ γγ) and for single-top hadroproduction in association with at least one isolated photon. In addition, we complement our resul