Pierre Magain

University of Liège

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

F. Courbin

École Polytechnique Fédérale de Lausanne

M. Gillon

University of Liège

Damien Hutsemékers

University of Liège

Emmanuël Jehin

University of Liège

D. Queloz

University of Geneva

G. Meylan

École Polytechnique Fédérale de Lausanne

C. Moutou

Centre National de la Recherche Scientifique

F. Bouchy

University of Geneva

M. Deleuil

Laboratoire d’Astrophysique de Marseille

Anne Thoul

University of Liège

Cooperative Institutions

Centre National de la Recherche Scientifique

185

University of Liège

139

Max Planck Society

118

Max Planck Institute for Astronomy

European Southern Observatory

Université Paris Cité

University of Maryland, College Park

Australian National University

Institute of Astronomy

Consejo Nacional de Investigaciones Científicas y Técnicas

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Empirical study of departures from the excitation equilibrium of FeI in metal-poor stars.

Astronomy and Astrophysics (1996)

Pierre Magain Gang Zhao

Source

Cite

Citations (0)

Pre- and post-perihelion spectrographic and photometric observations of Comet Wilson (1986 l)

The Messenger (1988)

C. Arpigny F. Dossin Jean Manfroid Pierre Magain R. Haefner

Source

Cite

Citations (2)

Analysis of luminosity distributions of strong lensing galaxies: subtraction of diffuse lensed signal

Astronomy and Astrophysics (2017)

Judith Biernaux Pierre Magain Clémentine Hauret

Strong gravitational lensing gives access to the total mass distribution of galaxies. It can unveil a great deal of information about the lenses dark matter content when combined with the study of the lenses light profile. However, gravitational lensing galaxies, by definition, appear surrounded by point-like and diffuse lensed signal that is irrelevant to the lens flux. Therefore, the observer is most often restricted to studying the innermost portions of the galaxy, where classical fitting methods show some instabilities. We aim at subtracting that lensed signal and at characterising some lenses light profile by computing their shape parameters. Our objective is to evaluate the total integrated flux in an aperture the size of the Einstein ring in order to obtain a robust estimate of the quantity of ordinary matter in each system. We are expanding the work we started in a previous paper that consisted in subtracting point-like lensed images and in independently measuring each shape parameter. We improve it by designing a subtraction of the diffuse lensed signal, based only on one simple hypothesis of symmetry. This extra step improves our study of the shape parameters and we refine it even more by upgrading our half-light radius measurement. We also calculate the impact of our specific image processing on the error bars. The diffuse lensed signal subtraction makes it possible to study a larger portion of relevant galactic flux, as the radius of the fitting region increases by on average 17\%. We retrieve new half-light radii values that are on average 11\% smaller than in our previous work, although the uncertainties overlap in most cases. This shows that not taking the diffuse lensed signal into account may lead to a significant overestimate of the half-light radius. We are also able to measure the flux within the Einstein radius and to compute secure error bars to all of our results.

Einstein radius

Strong gravitational lensing

Einstein ring

SIGNAL (programming language)

10.1051/0004-6361/201730907

Cite

Citations (3)

The missing opacity and the temperature calibration of solar-type stars.

Astronomy and Astrophysics (1987)

Pierre Magain

On etablit un nouvel etalonnage de la temperature d'indices de couleur pour des naines F et G

Opacity

Effective temperature

Source

Cite

Citations (3)

VizieR Online Data Catalog: GJ 1214 Trappist and Spitzer light curves (Gillon+, 2014)

VizieR Online Data Catalog (2014)

M. Gillon Drake Deming Nikku Madhusudhan S. Seager Andras Zsom

Source

Cite

Citations (0)

Q 1208 + 1011: the most distant multiply imaged quasar, or a binary?

Astronomy and Astrophysics (1992)

Pierre Magain B. Pirenne C. Vanderreist Jean Surdej Damien Hutsemékers

Source

Cite

Citations (0)

WASP-50 b: a hot Jupiter transiting a moderately active solar-type star

Astronomy and Astrophysics (2011)

M. Gillon A. P. Doyle M. Lendl P. F. L. Maxted A. H. M. J. Triaud

We report the discovery by the WASP transit survey of a giant planet in a close orbit (0.0295+-0.0009 AU) around a moderately bright (V=11.6, K=10) G9 dwarf (0.89+-0.08 M_sun, 0.84+-0.03 R_sun) in the Southern constellation Eridanus. Thanks to high-precision follow-up photometry and spectroscopy obtained by the telescopes TRAPPIST and Euler, the mass and size of this planet, WASP-50b, are well constrained to 1.47+-0.09 M_jup and 1.15+-0.05 R_jup, respectively. The transit ephemeris is 2455558.6120 (+-0.0002) + N x 1.955096 (+-0.000005) HJD_UTC. The size of the planet is consistent with basic models of irradiated giant planets. The chromospheric activity (log R'_HK = -4.67) and rotational period (P_rot = 16.3+-0.5 days) of the host star suggest an age of 0.8+-0.4 Gy that is discrepant with a stellar-evolution estimate based on the measured stellar parameters (rho_star = 1.48+-0.10 rho_sun, Teff = 5400+-100 K, [Fe/H]= -0.12+-0.08) which favours an age of 7+-3.5 Gy. This discrepancy could be explained by the tidal and magnetic influence of the planet on the star, in good agreement with the observations that stars hosting hot Jupiters tend to show faster rotation and magnetic activity (Pont 2009; Hartman 2010). We measure a stellar inclination of 84 (-31,+6) deg, disfavouring a high stellar obliquity. Thanks to its large irradiation and the relatively small size of its host star, WASP-50b is a good target for occultation spectrophotometry, making it able to constrain the relationship between hot Jupiters' atmospheric thermal profiles and the chromospheric activity of their host stars proposed by Knutson et al. (2010).

Hot Jupiter

Ephemeris

Stellar rotation

Rotation period

Giant planet

10.1051/0004-6361/201117198

Cite

Citations (43)

Resolution of the [O I]+NH 2 blend in comets.

Liege International Astrophysical Colloquia (1987)

C. Arpigny Pierre Magain Jean Manfroid F. Dossin R. Haefner

Source

Cite

Citations (0)

The secondary eclipse of CoRoT-1b

Astronomy and Astrophysics (2009)

R. Alonso A. Alapini S. Aigrain M. Auvergne A. Baglin

The transiting planet CoRoT-1b is thought to belong to the pM-class of planets, in which the thermal emission dominates in the optical wavelengths. We present a detection of its secondary eclipse in the CoRoT white channel data, whose response function goes from ~400 to ~1000 nm. We used two different filtering approaches, and several methods to evaluate the significance of a detection of the secondary eclipse. We detect a secondary eclipse centered within 20 min at the expected times for a circular orbit, with a depth of %. The center of the eclipse is translated in a 1-σ upper limit to the planet's eccentricity of . Under the assumption of a zero Bond Albedo and blackbody emission from the planet, it corresponds to a K. We provide the equilibrium temperatures of the planet as a function of the amount of reflected light. If the planet is in thermal equilibrium with the incident flux from the star, our results imply an inefficient transport mechanism of the flux from the day to the night sides.

Eclipse

Black-body radiation

Eccentricity (behavior)

Tidal heating

Hot Jupiter

10.1051/0004-6361/200912102

Cite

Citations (89)

High accuracy transit photometry of the planet OGLE-TR-113b with a new deconvolution-based method

Astronomy and Astrophysics (2006)

M. Gillon F. Pont C. Moutou F. Bouchy F. Courbin

A high accuracy photometry algorithm is needed to take full advantage of the potential of the transit method for the characterization of exoplanets, especially in deep crowded fields. It has to reduce to the lowest possible level the negative influence of systematic effects on the photometric accuracy. It should also be able to cope with a high level of crowding and with large scale variations of the spatial resolution from one image to another. A recent deconvolution-based photometry algorithm fulfills all these requirements, and it also increases the resolution of astronomical images, which is an important advantage for the detection of blends and the discrimination of false positives in transit photometry. We made some changes to this algorithm in order to optimize it for transit photometry and used it to reduce NTT/SUSI2 observations of two transits of OGLE-TR-113b. This reduction has led to two very high precision transit light curves with a low level of systematic residuals, used together with former photometric and spectroscopic measurements to derive new stellar and planetary parameters in excellent agreement with previous ones, but significantly more precise.

10.1051/0004-6361:20065844

Cite

Citations (110)