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See detailThe Martian diffuse aurora: Monte Carlo simulations and comparison with IUVS-MAVEN observations
Gérard, Jean-Claude ULg; Soret, Lauriane ULg; Schneider, N. et al

Conference (2016, December)

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 with the IUVS on board the MAVEN spacecraft. We describe the results of Monte Carlo simulations of the production of several ultraviolet and visible auroral emissions for initial electron energies from 0.1 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 intensities of several of these emissions for a unit precipitated energy flux. Our results indicate that electrons in the range 100-200 keV produce maximum CO2+ UVD emission near 75 km. We combine SWEA and SEP electron energy spectra measured during diffuse aurora to calculate the volume emission rates and compare with IUVS observations of the emission limb profiles. The strongest predicted emissions are the CO2+ FDB, UVD and the CO Cameron bands. The metastable a 3Π state which radiates the Cameron bands is deactivated by collisions below ~110 km. As a consequence, we show that the CO2+ UVD to the Cameron bands ratio increases at low altitude in the energetic diffuse aurora. [less ▲]

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See detailMartian thermosphere scale height from SPICAM dayglow measurements
Stiepen, Arnaud ULg; Gérard, Jean-Claude; Bougher, Steve et al

Poster (2014)

We analyze the ultraviolet dayglow in the atmosphere of Mars through CO2+ and CO Cameron emissions. These emissions are accumulated on a large dataset of dayside grazing limb performed by the Spectroscopy ... [more ▼]

We analyze the ultraviolet dayglow in the atmosphere of Mars through CO2+ and CO Cameron emissions. These emissions are accumulated on a large dataset of dayside grazing limb performed by the Spectroscopy for Investigation of Characteristics of the Atmosphere of Mars (SPICAM) instrument on board the Mars Express spacecraft. The temperature of the Martian upper atmosphere can be retrieved from these limb emission profiles. We present discussion on the validity domain for such retrieval. We also show evidence for local (spatial and temporal) variability in the scale height of the atmosphere at the altitude of these emissions. [less ▲]

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See detailMartian thermospheric temperatures retrieved from CO2 + SPICAM dayglow measurements
Stiepen, Arnaud ULg; Gérard, Jean-Claude ULg; Bougher, S. et al

Conference (2012, December)

A large dataset of dayside grazing limb CO2+ observations performed by the SPICAM (Spectroscopy for Investigation of Characteristics of the Atmosphere of Mars) instrument on board Mars Express is analyzed ... [more ▼]

A large dataset of dayside grazing limb CO2+ observations performed by the SPICAM (Spectroscopy for Investigation of Characteristics of the Atmosphere of Mars) instrument on board Mars Express is analyzed to retrieve Martian thermospheric temperature, as well as its variation with solar activity, season and latitude. The method permits to retrieve the temperature from the scale height of the CO2+ emission. We also present puzzling features such as limb profiles exhibiting multiple peaks and their characteristics. We furthermore study the behavior of the main emission peak of the CO2+ vertical emission profiles. The CO2+ emission at 289 nm arises from the relaxation of the CO2+* molecule in the B2Σ+ state to the X2Π state. CO2+* molecules are mainly produced in the Martian dayside through photoionisation and photoelectron impact. The CO2+ emission exhibits features that constrain the temperature and density vertical profiles of CO2. Comparisons of retrieved temperatures are made with corresponding simulations from the coupled MGCM-MTGCM. We also use a Monte-Carlo code to model the observed intensity limb profiles. [less ▲]

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See detailMartian thermospheric temperatures retrieved from SPICAM dayglow measurements
Stiepen, Arnaud ULg; Gérard, Jean-Claude ULg; Montmessin, Franck et al

Poster (2013, October)

Detailed reference viewed: 54 (22 ULg)
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See detailMARTIAN ULTRAVIOLET AURORA: RESULTS OF MODEL SIMULATIONS
Gérard, Jean-Claude ULg; Soret, Lauriane ULg; Shematovich, V.I. et al

Conference (2017, January)

We present recent modeling results based on observations performed with the UV spectrographs on board the Mars Express and MAVEN missions.Two types of aurora are discussed: the localized and transient ... [more ▼]

We present recent modeling results based on observations performed with the UV spectrographs on board the Mars Express and MAVEN missions.Two types of aurora are discussed: the localized and transient discrete aurora and the more stable diffuse aurora observed during periods of active solar periods. [less ▲]

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See detailMartian upper atmosphere response to solar EUV flux and soft X-ray flares
Jain, Sonal; Stewart, Ian; Schneider, Nicholas M. et al

in AAS/Division for Planetary Sciences Meeting Abstracts (2016, October 01)

Planetary upper atmosphere energetics is mainly governed by absorption of solar extreme ultraviolet (EUV) radiation. Understanding the response of planetary upper atmosphere to the daily, long and short ... [more ▼]

Planetary upper atmosphere energetics is mainly governed by absorption of solar extreme ultraviolet (EUV) radiation. Understanding the response of planetary upper atmosphere to the daily, long and short term variation in solar flux is very important to quantify energy budget of upper atmosphere. We report a comprehensive study of Mars dayglow observations made by the IUVS instrument aboard the MAVEN spacecraft, focusing on upper atmospheric response to solar EUV flux. Our analysis shows both short and long term effect of solar EUV flux on Martian thermospheric temperature. We find a significant drop (> 100 K) in thermospheric temperature between Ls = 218° and Ls = 140°, attributed primarily to the decrease in solar activity and increase in heliocentric distance. IUVS has observed response of Martian thermosphere to the 27-day solar flux variation due to solar rotation.We also report effect of two solar flare events (19 Oct. 2014 and 24 March 2015) on Martian dayglow observations. IUVS observed about ~25% increase in observed brightness of major ultraviolet dayglow emissions below 120 km, where most of the high energy photons (< 10 nm) deposit their energy. The results presented in this talk will help us better understand the role of EUV flux in total heat budget of Martian thermosphere. [less ▲]

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Peer Reviewed
See detailMartin Heidegger, Extrait du dernier cours de Marbourg
Pieron, Julien ULg

in Philosophie (in press)

Detailed reference viewed: 66 (14 ULg)
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Peer Reviewed
See detailMartin Hilpert, Construction Grammar and its Application to English
Brems, Lieselotte ULg

in English Text Construction (2015), 8(1), 132-136

Detailed reference viewed: 236 (3 ULg)
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See detailMartin le bien nommé !
Libois, Roland ULg

Learning material (1994)

Detailed reference viewed: 19 (2 ULg)
Peer Reviewed
See detailMartin Leichtman, « The Rorschach Contributions of Ernest Schachtel: Uncommon Sense, Phenomenology, and the Testing Relationship » (Journal of Personality Assessment, 71(2), 1998, 149-159)
Englebert, Jérôme ULg; Touahria-Gouesmel, Dominique

in Englebert, Jérôme (Ed.) Test de Rorschach et perception : Perspectives cognitives et phénoménologiques (2013)

Detailed reference viewed: 43 (6 ULg)
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See detailMartin pêcheur d'Europe, Alcedo atthis
Libois, Roland ULg; Hallet, Catherine

in Yeatman-Berthelot, Dosithée; Jarry, Guy (Eds.) Nouvel atlas des oiseaux nicheurs de France 1985-1989 (1994)

Detailed reference viewed: 22 (3 ULg)
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See detailMartin pêcheur d'Europe, Alcedo atthis
Libois, Roland ULg; Hallet, Catherine

in Yeatman-Berthelot, Dosithée; Jarry, Guy (Eds.) Atlas des oiseaux de France en hiver (1991)

Detailed reference viewed: 20 (2 ULg)
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See detailMartin pêcheur d'Europe, Alcedo atthis
Dehem, Christophe; Hallet, Catherine; Libois, Roland ULg

in Jacob, Jean Paul; Dehem, Christophe; Burnel, André (Eds.) et al Atlas des oiseaux nicheurs de Wallonie 2001/ 2007 (2010)

The kingfisher is widespread in Wallonia but is missing locally in middle Belgium and in higher Ardenne. The field prospection for the atlas took place in a favorable climatic context; the current ... [more ▼]

The kingfisher is widespread in Wallonia but is missing locally in middle Belgium and in higher Ardenne. The field prospection for the atlas took place in a favorable climatic context; the current population, estimated at 450 650 pairs, reflects probably the saturation of the habitat. The highest densities are found along large rivers, with important fishing ressources and numerous nesting sites (Lesse, Ourthe, Semois, Viroin). The limiting fator seems to be the lack of nesting sites. [less ▲]

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See detailMartin pêcheur d'Europe, Alcedo atthis
Libois, Roland ULg; Hallet, Catherine

in Rocamora, Gérard; Yeatman Berthelot, Dosithée (Eds.) Oiseaux menacés et à surveiller en France. Liste rouge (1999)

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See detailMartin pêcheur: oiseau de l'année 2005
Libois, Roland ULg

Learning material (2005)

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See detailLe martin pêcheur: un ambassadeur haut en couleur pour un milieu menacé
Libois, Roland ULg; Hallet, Catherine

Learning material (1991)

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See detailLe martin pêcheur: une cohabitation difficile
Libois, Roland ULg

Learning material (1992)

Detailed reference viewed: 17 (0 ULg)
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See detailLe martin-pêcheur (Alcedo atthis) va-t-il bientôt manquer de sites de nidification ?
Libois, Roland ULg

in Aves (2001), 38(4), 161-178

In south-west Belgium, the breeding of the kingfisher was monitored for more than 10 years. During this period, 158 banks were regularly surveyed. Alterations or potential threats were identified: natural ... [more ▼]

In south-west Belgium, the breeding of the kingfisher was monitored for more than 10 years. During this period, 158 banks were regularly surveyed. Alterations or potential threats were identified: natural erosion, cattle trampling, disturbance from kayak-riders or anglers and, last but not least, consolidation works. Only 56 banks (35.4 %) can de considered as "safe". However, since the recent (2001) legal restrictions about the navigation on small rivers, 12 more banks are now safe too. Cattle trampling appears as the main threat (55 sites). However, the enforcement of the law regulating the fences along the rivers could easily solve the problem. Nineteen banks were completely destroyed for different purposes: navigation, road retaining walls or simply anti-erosive measures. Most of these works were undertaken along the river Meuse, the best nidification habitat of the area. (11 photos) [less ▲]

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See detailLe martin-pêcheur : une flèche bleu azur
Libois, Roland ULg

Learning material (1991)

Detailed reference viewed: 10 (0 ULg)
See detailMartini Felice
Amendola, Cristiano ULg

in Malato, Enrico (Ed.) Censimento dei Commenti danteschi. 2. I commenti di tradizione a stampa (dal 1477 al 2000) e altri di tradizione manoscritta posteriori al 1480 (2014)

Detailed reference viewed: 28 (6 ULg)