Ricardo Herbonnet's home page

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Information

Email			:herbonnet@strw.leidenuniv.nl


Current position	: PhD Student at the University of Leiden
			: Member of the weak lensing group under dr. Hoekstra and prof. dr. Kuijken
			: Member of the KiDS data analysis team
			: Member of the Euclid Consortium

Research interest	: Cosmology and Dark matter
			: Weak gravitational lensing
			: Shape measurement methods

Education		: Stedelijk Gymnasium Breda 2000-2006
			: Universiteit Leiden BSc Physics 2006-2009
			: Universiteit Leiden BSc Astronomy 2006-2009
			: Universiteit Leiden MSc Astronomy 2009-2012


Written works		: Minor thesis	A Comparison of Shear-finding Methods (not published)
			  Supervisor	prof dr. Kuijken
			: Major thesis	Finding and Characterizing Protoclusters with SPIRE (not published)
			  Supervisor	prof dr. Rottgering

Current work

My work is primarily focused on improving and applying shape measurement methods for the Kilo 
Degree Survey. The main goal is to predict the degrading effects of noise on shear finding
methods; the galaxy image appears rounder and the centroid is misplaced. For moment based 
methods I am modeling the noise in a quantative way and will then correct for the bias it 
introduces on simulated images. This will hopefully lead to improved results on the cosmo-
logical parameters for KiDS and in the long run for Euclid.

A second project looks at the effect of galaxy morphology on shape measurement methods. Subtle 
changes in the appearance of a galaxy can have an effect on the shear estimate in a 
non-straightforward way. These changes may also affect the noise bias calibration. By doing
simulated tests I aim to find out if morphology should be taken into account for shape 
measurement methods.

For KiDS I am also involved in creating simulated galaxy images, which will be used as a test
before the actual data releases. I do this using GalSim, the software package that will be 
used to create the GREAT3 weak lensing challenge. Since this package is still under 
construction, I might contribute here as well.