We present accurate time delays for the quadruply imaged quasar HE 0435-1223 .
The delays were measured from 575 independent photometric points obtained in the R-band between January 2004 and March 2010 .
With seven years of data , we clearly show that quasar image A is affected by strong microlensing variations and that the time delays are best expressed relative to quasar image B .
We measured \Delta t _ { \mathrm { BC } } = 7.8 \pm 0.8 days , \Delta t _ { \mathrm { BD } } = -6.5 \pm 0.7 days and \Delta t _ { \mathrm { CD } } = -14.3 \pm 0.8 days .
We spacially deconvolved HST NICMOS2 F160W images to derive accurate astrometry of the quasar images and to infer the light profile of the lensing galaxy .
We combined these images with a stellar population fitting of a deep VLT spectrum of the lensing galaxy to estimate the baryonic fraction , f _ { b } , in the Einstein radius .
We measured f _ { b } = 0.65 ^ { +0.13 } _ { -0.10 } if the lensing galaxy has a Salpeter IMF and f _ { b } = 0.45 ^ { +0.04 } _ { -0.07 } if it has a Kroupa IMF .
The spectrum also allowed us to estimate the velocity dispersion of the lensing galaxy , \sigma _ { ap } = 222 \pm 34 km s ^ { -1 } .
We used f _ { b } and \sigma _ { ap } to constrain an analytical model of the lensing galaxy composed of an Hernquist plus generalized NFW profile .
We solved the Jeans equations numerically for the model and explored the parameter space under the additional requirement that the model must predict the correct astrometry for the quasar images .
Given the current error bars on f _ { b } and \sigma _ { ap } , we did not constrain H _ { 0 } yet with high accuracy , i.e. , we found a broad range of models with \chi ^ { 2 } < 1 .
However , narrowing this range is possible , provided a better velocity dispersion measurement becomes available .
In addition , increasing the depth of the current HST imaging data of HE 0435-1223 will allow us to combine our constraints with lens reconstruction techniques that make use of the full Einstein ring that is visible in this object .