340 likes | 457 Views
Studying the microlens mass function from statistical analysis of the caustic concentration. Teresa Mediavilla Gradolph Octavio Ariza Sánchez Evencio Mediavilla Gradolph. Introduction
E N D
Studying the microlens mass function from statistical analysis of the caustic concentration Teresa Mediavilla Gradolph Octavio Ariza Sánchez Evencio Mediavilla Gradolph
Introduction Statistical analysis of the caustic concentration based on caustic crossing counts. Application to QSO 2237+0305 Conclusions Index
Gravitational mirage Without gravity With gravity
First discovered gravitational lens (QSO 0957+561)
One Source several->imagesMagnification X Y T. LIOUVILLE
Simulation and statistical analysis • Comparison between observed and simulated microlensed effect allows to study: • Source • Size at different wavelengths. • Quasar luminosity profile • Lens galaxy • Mass distribution • Microlenses • Abundance • Mass • Lens system • Transversal velocity • Determination of these parameters can be only statistically done.
Statistical study problems • Experimental errors and intrinsical variability can affect data and results
Simplify the problem reducing microlensing to a series of discrete events, the caustics crossings. If the source size is small enough : They appear well separated They are of high magnification They are difficult to mistake with other variability features Objectives
Statistical analysis of the caustic concentration based on caustic crossing counts. Application to QSO 2237+0305
Magnification Maps 1 solar mass microlenses A Y B C D Microlenses distributed in a range of masses A Y B C D
Caustics 1 solar mass microlenses A Y B D C Microlenses distributed in a range of masses A Y B C D
Results (I) D IMAGE We can distinguish between A and B hypothesis
Results (II) Can we solve the size / transversal velocity degeneracy?
Results (II) D imagemicrolensesdistributedin a range of masses Number of caustics (X axis) > 6 Window > 1.2 Einstein radii Number of caustics (X axis) < 3 Window < 1.2 Einstein radii Number of caustics (Y axis) > 9 Window > 1.2 Einstein radii Number of caustics (Y axis) < 3 Window < 1.2 Einstein radii
Bayesian Analysis D image 400 pixels X axis 400 píxels Y axis In a 76% of cases we can distinguish between both hypothesis with more than 80% of likelihood In a 77% of cases we can distinguish between both hypothesis with more than 70% of likelihood
Conclusions • Caustic crossing statistics is affected by the microlenses mass function and by the shear. • For QSO 2237+0305D the detection of a small number of events will allow to distinguish between the unimodal and distributed in a range mass distributions • We could determinate the size of the observing window