Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
Full Text
Peer Reviewed
See detailQ 1208 + 1011 - The most distant imaged quasar, or a binary?
Magain, Pierre ULg; Surdej, Jean ULg; Vanderriest, C. et al

in Astronomy and Astrophysics (1992), 253(Letters), 13-16

The paper reports the discovery of a new gravitational lens candidate: the high redshift (z = 3.803) and highly luminous (V = 17.5, M[SUB]V[/SUB] = -30.3) quasar Q 1208 + 1011. As derived from the ... [more ▼]

The paper reports the discovery of a new gravitational lens candidate: the high redshift (z = 3.803) and highly luminous (V = 17.5, M[SUB]V[/SUB] = -30.3) quasar Q 1208 + 1011. As derived from the analysis of direct CCD frames taken with the ESO/MPI 2.2 m telescope, this multiple quasar consists of two pointlike images, separated by 0.45 arcsec and characterized by a brightness ratio of 3.5, in red light. Existing spectroscopic data support the gravitational lens interpretation for this system but cannot exclude the hypothesis of a binary quasar. In the former case, the spectrum suggests that, if the metallic absorption line system reported by Steidel (1990) at a redshift z = 2.9157 is associated with the deflector, the mass of the lens should be of the order of M = 7.8 x 10 exp 11 solar masses. Evaluation of a recent HST PC frame obtained for Q 1208 + 1011 within the snapshot survey for gravitational lenses confirms the above results. [less ▲]

Detailed reference viewed: 43 (4 ULg)
Full Text
Peer Reviewed
See detailQ fever IN JApaN: an update REVIEW
Porter, Sarah ULg; Czaplicki, G.; Mainil, Jacques ULg et al

in Veterinary Microbiology (2011), 149

Detailed reference viewed: 20 (4 ULg)
Full Text
Peer Reviewed
See detailQ Fever: Current State of Knowledge and Perspectives of Research of a Neglected Zoonosis
Porter, Sarah ULg; Czaplicki, G.; Mainil, Jacques ULg et al

in International Journal of Microbiology (2011)

Detailed reference viewed: 73 (9 ULg)
Full Text
See detailQ0059-2735: A Hybrid Starburst/Broad Absorption Line QSO ? Clues from Spectropolarimetry
Hutsemekers, Damien ULg; Lamy, H.

in Mass Outflow in Active Galactic Nuclei: New Perspectives. ASPC 255 (2002)

Not Available

Detailed reference viewed: 10 (0 ULg)
Full Text
Peer Reviewed
See detailQCD description of charmonium plus light meson production in p̄-N annihilation
Pire, Bernard; Semenov-Tyan-Shanskiy, Kirill ULg; Szymanowski, Lech

in Physics Letters B (2013), 724

Detailed reference viewed: 13 (2 ULg)
Full Text
See detailQGIS, une alternative open source à ArcGIS?
Bonnet, Stéphanie ULg; Gheysen, Thibaut; Lejeune, Philippe ULg

Learning material (2010)

Séminaire d'introduction au logiciel Quantum GIS, dispensé dans le cadre du cours de télédétection appliquée (18 février 2010) à Gembloux Agro-Bio Tech.

Detailed reference viewed: 154 (37 ULg)
Full Text
Peer Reviewed
See detailQingheiite-(Fe2+), a new member of the wyllieite group
Hatert, Frédéric ULg; Baijot, Maxime ULg; Philippo, Simon

in Acta Mineralogica-Petrographica, Abstract series (2010), 6

Detailed reference viewed: 10 (3 ULg)
Full Text
Peer Reviewed
See detailQingheiite-(Fe2+), Na2Fe2+MgAl(PO4)3, a new phosphate mineral from the Sebastião Cristino pegmatite, Minas Gerais, Brazil
Hatert, Frédéric ULg; Baijot, Maxime ULg; Philippo, Simon et al

in European Journal of Mineralogy (2010), 22

Detailed reference viewed: 33 (3 ULg)
Full Text
See detailLa qinghéiite-(Fe2+), une nouvelle espèce minérale de la pegmatite de Sebastiano Cristino, Minas Gerais, Brésil
Baijot, Maxime ULg; Hatert, Frédéric ULg; Philippo, Simon et al

in Abstract book, 27ème Réunion annuelle des collaborateurs scientifiques du Musée d'histoire naturelle du Luxembourg (2010)

Detailed reference viewed: 16 (1 ULg)
Full Text
See detailQoS Enhancements and the new transport services
Danthine, André ULg; Bonaventure, Olivier; Baguette, Yves et al

in Onvural, R.; Nilsson, A. (Eds.) Local Area Network Interconnection (1993)

Detailed reference viewed: 12 (1 ULg)
Full Text
See detailThe Qos Enhancements in OSI95
Danthine, André ULg; Bonaventure, Olivier; Leduc, Guy ULg

in The OSI95 Transport Service with Multimedia Support (1994)

The new communication environment has brought new requirements on the qualities of service for which the present "best effort" semantics is inadequate. The response to this evolution goes through the ... [more ▼]

The new communication environment has brought new requirements on the qualities of service for which the present "best effort" semantics is inadequate. The response to this evolution goes through the definition of a new model of QoS for the lower layers. In the Òbest effortÓ model, when a service provider accepts a transmission with a given QoS, it does not commit itself to any duty about the way it will take account of this QoS. The "guaranteed" QoS requires resources reservation mechanisms which are not always available. We present in this paper a new semantics for the QoS. It allows a service user to express more accurately its requirements, and although it does not include yet a concept of guarantee of the result, the fact is that it assures the users that the provider will monitor the selected parameters and return some defined feedback about the way it succeeds in meeting their requirements. New negotiation rules have also been specified, which are consistent with the new semantics. An example illustrates the practical use of the notions we have introduced which are at the origin of the OSI95 transport service. [less ▲]

Detailed reference viewed: 17 (2 ULg)
Full Text
See detailQoS specification of ODP binding objects
Février, Arnaud; Najm, Elie; Leduc, Guy ULg et al

in Telektronikk (1997), 93(1), 42-49

We present a QoS oriented notation suitable for the ODP framework. In particular, we focus on a computational view of objects: we consider systems described as configurations of interacting objects and we ... [more ▼]

We present a QoS oriented notation suitable for the ODP framework. In particular, we focus on a computational view of objects: we consider systems described as configurations of interacting objects and we deal with two types of communications: message passing and flows. In message passing, signals (from one object to another) are conveyed through the (implicit) underlying infrastructure. This form of interaction is suitable for client/server applications where no strong real time or ordering constraints are needed from the communication infrastructure. In contract, in a flow type of communication, signals are conveyed through third party (binding) objects that may be explicitly called for in order to ensure specific QoS requirements needed by specific applications. A building blocks approach for the formal specification of binding objects in the ODP computational model is presented. The formal notation that is used is based on LOTOS extended with two features - real time and gate passing. These features are among the extensions that are currently studied in the ISO standardisation Formal Description Techniques group. We apply our building blocks approach to the specification of a multicast, multimedia binding object. [less ▲]

Detailed reference viewed: 13 (3 ULg)
Full Text
Peer Reviewed
See detailQSO 2237+0305 VR light curves from Gravitational Lenses International Time Project optical monitoring
Alcalde, D.; Mediavilla, E.; Moreau, O. et al

in Astrophysical Journal (2002), 572(2, Part 1), 729-734

We present VR observations of QSO 2237+ 0305 conducted by the Gravitational Lensing International Time Project collaboration from 1999 October 1 to 2000 February 3. The observations were made with the 2 ... [more ▼]

We present VR observations of QSO 2237+ 0305 conducted by the Gravitational Lensing International Time Project collaboration from 1999 October 1 to 2000 February 3. The observations were made with the 2.56 m Nordic Optical Telescope at Roque de los Muchachos Observatory, La Palma ( Spain). The pointspread function ( PSF) fitting method and an adapted version of the ISIS subtraction method have been used to derive the VR light curves of the four components ( A D) of the quasar. The mean errors range in the intervals 0.01-0.04 mag ( PSF fitting) and 0.01-0.02 mag ( ISIS subtraction), with the faintest component ( D) having the largest uncertainties. We address the relatively good agreement between the A and D light curves derived using different filters, photometric techniques, and telescopes. The new VR light curves of component A extend the time coverage of a high-magnification microlensing peak, which was discovered by the OGLE team. [less ▲]

Detailed reference viewed: 39 (7 ULg)
Full Text
See detailQSO colors in the proposed GAIA photometric systems
Claeskens, Jean-François ULg; Royer, P.; Surdej, Jean ULg

in Proceedings of the GAIA Workshop (2001)

Detailed reference viewed: 14 (6 ULg)
Full Text
Peer Reviewed
See detailThe QSO HE0450-2958: Scantily dressed or heavily robed? A normal quasar as part of an unusual ULIRG
Jahnke, Knud; Elbaz, David; Pantin, Eric et al

in Astrophysical Journal (2009), 700(2), 1820-1830

(Abridged) The luminous z=0.286 quasar HE0450-2958 is interacting with a companion galaxy at 6.5 kpc distance and the whole system is a ULIRG. A so far undetected host galaxy triggered the hypothesis of a ... [more ▼]

(Abridged) The luminous z=0.286 quasar HE0450-2958 is interacting with a companion galaxy at 6.5 kpc distance and the whole system is a ULIRG. A so far undetected host galaxy triggered the hypothesis of a mostly "naked" black hole (BH) ejected from the companion by three-body interaction. We present new HST/NICMOS 1.6micron imaging data at 0.1" resolution and VLT/VISIR 11.3micron images at 0.35" resolution that for the first time resolve the system in the near- and mid-infrared. We combine these with existing optical HST and CO maps. (i) At 1.6micron we find an extension N-E of the quasar nucleus that is likely a part of the host galaxy, though not its main body. If true, this places HE0450-2958 directly onto the M_BH-M_bulge-relation for nearby galaxies. (ii) HE0450-2958 is consistent with lying at the high-luminosity end of Narrow-Line Seyfert 1 Galaxies, and more exotic explanations like a "naked quasar" are unlikely. (iii) All 11.3micron radiation in the system is emitted by the quasar nucleus, which is radiating at super-Eddington rate, L/L_Edd=6.2+3.8-1.8, or 12 M_sun/yr. (iv) The companion galaxy is covered in optically thick dust and is not a collisional ring galaxy. It emits in the far infrared at ULIRG strength, powered by Arp220-like star formation (strong starburst-like). An M82-like SED is ruled out. (v) With its black hole accretion rate HE0450-2958 produces not enough new stars to maintain its position on the M_BH-M_bulge-relation, and star formation and black hole accretion are spatially disjoint; the bulge has to grow by redistribution of preexisting stars. (vi) Systems similar to HE0450-2958 with spatially disjoint ULIRG-strength star formation and quasar activity are rare. At z<0.43 we only find <4% (3/77) candidates for a similar configuration. [less ▲]

Detailed reference viewed: 28 (7 ULg)
Full Text
Peer Reviewed
See detailQSO mass constraints from gravitational lensing studies of quasar pairs. The cases of Q1548+114 A & B and Q1148+0055 A & B
Claeskens, Jean-François ULg; Lee, D.-W.; Remy, M. et al

in Astronomy and Astrophysics (2000), 356

New constraints on the mass of quasars are derived from gravitational lensing studies of the QSO pairs Q1548+114 A & B and Q1148+0055 A & B, for which new ground-based and Hubble Space Telescope (HST ... [more ▼]

New constraints on the mass of quasars are derived from gravitational lensing studies of the QSO pairs Q1548+114 A & B and Q1148+0055 A & B, for which new ground-based and Hubble Space Telescope (HST) direct imagery have been obtained. In the case of Q1548+114 A & B, QSO A has been resolved into its host galaxy and a close companion. The non-detection with HST of a secondary lensed image of the background QSO in the close vicinity of the foreground one and the modeling of the host of QSO A, of the companion and of field galaxies with Singular Isothermal Spheres (SIS) yield a robust upper limit on the central compact mass of 4.5 10[SUP]11[/SUP] M[SUB]sun[/SUB]. On the other hand, the combined mass of Q1148+0055 B plus host must be smaller than 6.5 10[SUP]11[/SUP] M[SUB]sun[/SUB] since no secondary lensed image has been detected with HST. Photometry and relative astrometry of all the detected objects are reported. Based on data collected with the Hubble Space Telescope and at the European Southern Observatory, La Silla, Chile [less ▲]

Detailed reference viewed: 28 (1 ULg)
See detailQSO Type1/Type2 dichotomy (Borguet+, 2008)
Borguet, Benoît ULg; Hutsemekers, Damien ULg; Letawe, Géraldine ULg et al

Textual, factual or bibliographical database (2007)

This table contains the measurements/compilation of host galaxy/ extended emission position angle in the visible and near-IR domain, polarimetric data, and radio axis orientation for the 135 quasars of ... [more ▼]

This table contains the measurements/compilation of host galaxy/ extended emission position angle in the visible and near-IR domain, polarimetric data, and radio axis orientation for the 135 quasars of our sample. The angles are given in degrees east of north. The table gives the spectral and the radio-loud/radio-quiet classification of each object according to the references. (2 data files). [less ▲]

Detailed reference viewed: 26 (2 ULg)