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See detailThe Mars discrete aurora: morphology, altitude and role of crustal magnetic field
Gérard, Jean-Claude ULg

Scientific conference (2015, December 01)

We present results obtained during 2015 in the framework of BELSPO's SCOOP/BRAIN project. They concern the morphology, frequency, structure of the Mars discrete aurora and the influence of the residual ... [more ▼]

We present results obtained during 2015 in the framework of BELSPO's SCOOP/BRAIN project. They concern the morphology, frequency, structure of the Mars discrete aurora and the influence of the residual crustal magnetic field. [less ▲]

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See detailMars nightglow review
Stiepen, Arnaud ULg

Conference (2014, July)

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See detailMars nighttime aurora
European Space Agency, ESA/ATG medialab; Gérard, Jean-Claude ULg; Soret, Lauriane ULg

E-print/Working paper (2015)

Press release by the European Space Agency (ESA) on the occasion of the publication in two journals of the peer-reviewed literature

Detailed reference viewed: 26 (1 ULg)
See detailMars Ozone mapping with MAVEN IUVS
Lefèvre; Stiepen, Arnaud ULg; IUVS team

Conference (2017, January 20)

Detailed reference viewed: 13 (1 ULg)
See detailMars Ozone Mapping with MAVEN IUVS
Lefèvre; IUVS team; Stiepen, Arnaud ULg

Poster (2015, December)

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See detailMars thermospheric temperatures retrieved from SPICAM dayglow measurements
Stiepen, Arnaud ULg; Gérard, Jean-Claude ULg; Bougher, S et al

Conference (2013, September 10)

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See detailMars Topography Investigated Through the Wavelet Leaders Method: a Multidimensional Study of its Fractal Structure
Deliège, Adrien ULg; Kleyntssens, Thomas ULg; Nicolay, Samuel ULg

in Planetary and Space Science (2017), 136C

This work examines the scaling properties of Mars topography through a wavelet-based formalism. We conduct exhaustive one-dimensional (both longitudinal and latitudinal) and two-dimensional studies based ... [more ▼]

This work examines the scaling properties of Mars topography through a wavelet-based formalism. We conduct exhaustive one-dimensional (both longitudinal and latitudinal) and two-dimensional studies based on Mars Orbiter Laser Altimeter (MOLA) data using the multifractal formalism called Wavelet Leaders Method (WLM). This approach shows that a scale break occurs at approximately 15 km, giving two scaling regimes in both 1D and 2D cases. At small scales, these topographic profiles mostly display a monofractal behavior while a switch to multifractality is observed in several areas at larger scales. The scaling exponents extracted from this framework tend to be greater at small scales. In the 1D context, these observations are in agreement with previous works and thus suggest that the WLM is well-suited for examining scaling properties of topographic fields. Moreover, the 2D analysis is the first such complete study to our knowledge. It gives both a local and global insight on the scaling regimes of the surface of Mars and allows to exhibit the link between the scaling exponents and several famous features of the Martian topography. These results may be used as a solid basis for further investigations of the scaling laws of the Red planet and show that the WLM could be used to perform systematic analyses of the surface roughness of other celestial bodies. [less ▲]

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See detailMars ultraviolet dayglow variability: SPICAM observations and comparison with airglow model
Cox, Cédric ULg; Gérard, Jean-Claude ULg; Hubert, Benoît ULg et al

in Journal of Geophysical Research. Planets (2010), 115

Dayglow ultraviolet emissions of the CO Cameron bands and the CO[SUB]2[/SUB][SUP]+[/SUP] doublet in the Martian atmosphere have been observed with the Spectroscopy for Investigation of Characteristics of ... [more ▼]

Dayglow ultraviolet emissions of the CO Cameron bands and the CO[SUB]2[/SUB][SUP]+[/SUP] doublet in the Martian atmosphere have been observed with the Spectroscopy for Investigation of Characteristics of the Atmosphere of Mars on board the Mars Express spacecraft. A large amount of limb profiles has been obtained which makes it possible to analyze variability of the brightness as well as of the altitude of the emission peak. Focusing on one specific season (Ls = [90,180] °), we find that the average CO peak brightness is equal to 118 ± 33 kR, with an average peak altitude of 121.1 ± 6.5 km. Similarly, the CO[SUB]2[/SUB][SUP]+[/SUP] emission shows a mean brightness of 21.6 ± 7.2 kR with a peak located at 119.1 ± 7.0 km. We show that the brightness intensity of the airglows is mainly controlled by the solar zenith angle and by solar activity. Moreover, during Martian summer of year 2005, an increase of the airglow peak altitude has been observed between Ls = 120° and 180°. We demonstrate that this variation is due to a change in the thermospheric local CO[SUB]2[/SUB] density, in agreement with observations performed by stellar occultation. Using a Monte Carlo one-dimensional model, we also show that the main features of the emission profiles can be reproduced for the considered set of data. However, we find it necessary to scale the calculated intensities by a fixed factor. [less ▲]

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See detailThe Mars ultraviolet dayglow variability: SPICAM observations and model comparison
Gérard, Jean-Claude ULg; Cox, Cédric ULg; Bougher, S. W. et al

Conference (2009, September 16)

Limb profiles of the CO Cameron and CO2+ doublet airglow have been observed over different conditions (latitude, season, SZA, F10.7). They have been individually modelled using currently accepted cross ... [more ▼]

Limb profiles of the CO Cameron and CO2+ doublet airglow have been observed over different conditions (latitude, season, SZA, F10.7). They have been individually modelled using currently accepted cross sections, and outputs from the MTGCM. They have been shown to co-vary, with a ICO/ICO2+ ratio of about 4.7, less than the modelled ratio.The peak brightness varies linearly with the F10.7 solar flux proxy, in a way compatible with the Mariner 6 and 7 observations. The intensity of both emissions is overestimated by the model (but large uncertainties exist in excitation cross sections). An increase of the altitude of both emissions has been observed during the 2005 summer season. It is a consequence of the dust load, followed by an increased thermospheric CO2 density observed with SPICAV during the same period. This density enhancement is partly predicted by GCM models. [less ▲]

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See detailLa Marseillaise, ou le devenir d'un chant révolutionnaire en Wallonie.
Raxhon, Philippe ULg

Book published by Institut Jules Destrée (1998)

Detailed reference viewed: 39 (1 ULg)
See detailMarsick (Familie)
Pirenne, Christophe ULg

in Finscher, Ludwig (Ed.) Die Musik in Geschichte und Gegenwart (2004)

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Peer Reviewed
See detailMarsilio Ficino and Political Syncretism in Ian McEwan's Black Dogs
Delville, Michel ULg

in Notes on Contemporary Literature (1996), XXIV(3), 11-12

Detailed reference viewed: 160 (17 ULg)
See detailMarthe Moisset (1871-1945)
De Marco, Rosa ULg

in Allgemeines Künstlerlexikon (AKL) (2015)

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See detailMartí "Taxista"
Dejasse, Erwin ULg

in 9e Art : Les Cahiers du Musée de la Bande Dessinée (2009), 15

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See detailMartial : Livre 7. Édition - traduction - commentaire
Polis, Stéphane ULg

Master's dissertation (2002)

Detailed reference viewed: 146 (11 ULg)
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See detailThe Martian diffuse aurora: a model of ultraviolet and visible emissions
Gérard, Jean-Claude ULg; Soret, Lauriane ULg; Shematovich, V.I. et al

in Icarus (2017), 288

A new type of Martian aurora, characterized by an extended spatial distribution, an altitude lower than the discrete aurora and electron precipitation up to 200 keV has been observed following solar ... [more ▼]

A new type of Martian aurora, characterized by an extended spatial distribution, an altitude lower than the discrete aurora and electron precipitation up to 200 keV has been observed following solar activity on several occasions from the MAVEN spacecraft. We describe the results of Monte Carlo simulations of the production of several ultraviolet and violet auroral emissions for initial electron energies extending from 0.25 to 200 keV. These include the CO2+ ultraviolet doublet (UVD) at 288.3 and 289.6 nm and the Fox–Duffendack–Barker (FDB) bands, CO Cameron and Fourth Positive bands, OI 130.4 and 297.2 nm and CI 156.1 nm and 165.7 nm multiplets. We calculate the nadir and limb production rates of several of these emissions for a unit precipitated energy flux. Our results indicate that electrons in the range 50-200 keV produce maximum CO2+ UVD emission below 75 km, in agreement with the MAVEN observations. We calculate the efficiency of photon production per unit precipitated electron power. The strongest emissions are the CO2+ FDB, UVD and CO Cameron bands and the oxygen mission at 297.2 nm. The metastable a 3Π state which radiates the Cameron bands is deactivated by collisions below about 110 km. As a consequence, we show that the Cameron band emission is expected to peak at a higher altitude than the CO2+ UVD and FDB bands. Collisional quenching also causes the intensity ratio of the CO2+ UVD to CO Cameron bands to increase below ∼100 km in the energetic diffuse aurora. [less ▲]

Detailed reference viewed: 22 (2 ULg)