Open AccessColour change measurements of gravitational microlensing events by using the difference image analysis method
Author(s) -
Han Cheongho,
Park SeongHong
Publication year - 2001
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2001.03926.x
Subject(s) - gravitational microlensing , physics , gravitational lens , lens (geology) , stars , light curve , astrophysics , binary number , point source , event (particle physics) , image (mathematics) , optics , astronomy , artificial intelligence , computer science , galaxy , mathematics , arithmetic , redshift
Detecting colour changes of a gravitational microlensing event induced by the limb‐darkened extended source effect is important for obtaining useful information about both the lens and the source star. However, precise measurements of the colour changes are hampered by blending, which also causes colour changes of the event. In this paper, we show that although the colour change measured from the subtracted image by using the recently developed photometric method of the ‘difference image analysis’ (DIA) differs from the colour change measured by using the conventional method based on the extraction of the individual source stars’ point spread functions, the curve of the colour changes (colour curve) constructed by using the DIA method enables one to obtain the same information about the lens and source star, but with significantly reduced uncertainties due to the absence of blending. We investigate the patterns of the DIA colour curves for both single lens and binary lens events by constructing colour change maps.