Daily Image
15-04-2010
Today´s colloquium: Strong gravitational lensing in the radio domain (A. Berciano Alba, ASTRON)
| Submitter: | Alicia Berciano Alba |
| Description: | In this talk, I will present some of the results of my thesis, which I defended the 9th November 2009. The first part will be focused on the gravitational lens system B1600+434, in which a galaxy is producing two images of a distant quasar. This is one of the few gravitational lenses for which it has been possible to measure the time delay between images. In addition, it is the only radio lens that has shown extrinsic image flux changes (due to the galaxy lens and not to the quasar). To establish which physical mechanism is producing this extrinsic variability (microlensing by compact objects sitting in the galaxy halo or scattering/scintillation due to the ISM of our own galaxy), a multi-wavelength observational campaign was carried out with the VLA between 1999 and 2003 to monitor this system. I will show the new light-curves of the quasar images at 8.5 GHz produced with this data, present the new time delay derived from it, and discussed the presence of the previously reported extrinsic variability. The second part of the talk is dedicated to arc statistics, i.e. the study of the abundance of large tangential arcs in galaxy clusters. I will present the first detailed predictions on the abundance of gravitational arcs produced by sub-millimeter galaxies both at radio and sub-mm wavelengths. |
| Copyright: | Alicia Berciano Alba |
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