[seminar] Astronomy Seminar on Wednesday, Sep 12, 3 pm

[Lana Ceraj]

Dear all, 

I’d like to invite you to the talk Dinko Milaković is going to give on Wednesday, Sep 12, 3 pm (sharp) in the Seminar room (F201) of the Physics Department.
Dinko is the PhD student currently working at the European Southern Observatory.

Title: Measuring the fine structure constant from Laser Frequency Comb calibrate quasar spectra

Abstract:
Variation of the fine structure constant, if detected, would require new physics in the form of additional quantum fields or additional dimensions. The only hint of its variation so far comes from measurements in high-resolution quasar spectra. These results, however, are dominated by systematic errors, the main source of which is the wavelength calibration of spectrographs. The Laser Frequency Comb (LFC) is a novel wavelength calibration source that will be instrumental in this respect, as it offers calibration accuracy three orders of magnitude better than currently available.

I will present our project to obtain the first LFC-calibrated quasar spectrum and measure fine structure constant free of wavelength calibration systematic effects. I will discuss our analysis of the LFC system currently in use on ESO/HARPS and its comparison with an independent LFC used simultaneously on the same spectrograph. This analysis will allow us to obtain the first quasar spectrum with wavelength accuracy 10^-9. Finally, I will talk about the role of LFC systems in measuring the expansion history of the Universe with the Extremely Large Telescope in the future.

See you all on Wednesday,
Lana Ceraj
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