7 papers
High accuracy proper motions in crowded fields
C. Alard
The image subtraction method is a powerful tool to analyze the light variations in crowded fields. This method is able to achieve a nearly optimal differential photometry, even in…
Structure of the Sagittarius dwarf galaxy at low Galactic latitudes
Patrick Cseresnjes, Christophe Alard, Jean Guibert
We report the detection of 1500 RR Lyrae of Bailey type ab located in the Sagittarius dwarf galaxy (Sgr). These variables have been detected on two ESO Schmidt fields centre…
Interstellar extinction towards the inner Galactic Bulge
M. Schultheis, S. Ganesh, G. Simon +7
DENIS observations in the J (1.2 micron) and K_S (2.15 micron) bands together with isochrones calculated for the RGB and AGB phase are used to draw an extinction map of the inner G…
Image subtraction with non-constant kernel solutions
C. Alard
It is demonstrated that non-constant kernel solution, that can fit the spatial variations of the kernel can be obtained with minimum computing time. The CPU cost required with this…
Analysis of the OGLE microlensing candidates using the image subtraction method
C. Alard
The light curves of the OGLE microlensing candidates have been reconstructed using the image subtraction method. A large improvement of the photometric accuracy has been found in c…
Lensing of unresolved stars towards the Galactic Bulge
C. Alard
Previous calculations of the rates and optical depths due to microlensing only considered resolved stars. However, if a faint unresolved star lens is close enough to a resolved sta…