Seminars and Colloquia at ESO/Santiago

For ESO and ESO-related Conferences and Workshops in Europe and Chile please check the main Conferences and Workshops page.


Broadcast of the ESO talks is available upon request.  If anyone is interested, kindly contact us via email
at least 60 min prior  to the beginning of the talk.


December 2014

16.12.14 (Tuesday)
15:30
"Explorations of theoretical uncertainty limits on Photometry & Astrometry through the Cramér-Rao minimum variance bound"
Rene A. MENDEZ (U. Chile & ESO Visiting Scientist)
Abstract
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"Explorations of theoretical uncertainty limits on Photometry & Astrometry through the Cramér-Rao minimum variance bound."

Rene A. MENDEZ (U. Chile & ESO Visiting Scientist)

Abstract

Optimal parameter estimation can, in general, be formulated using “decision-making” theory (Cover & Thomas 2006). This framework can also provide absolute lower bounds to the uncertainty of these estimators. For example, the "Cramer-Rao (CR) lower uncertainty bound" determines the minimum theoretical variance achievable by any unbiased estimator (Stuart, Ord, & Arnold 2004). We analyze the CR bound of a linear-detector in a 2-dimensional (2d) estimation scenario: Astrometric location and total flux of the source. Our CR estimates agree very well with the empirically determined maximum precisions achieved in photometry and astrometry: Astrometric accuracy vs. flux, ground (HST) & space-based optical astrometry, photometric precision at extremely high S/N. Thus, the CR can be used as a benchmark to guide in detector design, monitoring instrument performance, testing of pipelines, science planning and design of observational strategies. We plan to extend these studies to incorporate more subtle observational/detector features such as non-uniform pixel response functions, non-symmetric PSFs, rapidly fluctuating backgrounds, moving targets, radiation damage and CTE effects, among others. I will discuss some of the limitations of the classical CR formulation, and possible solutions to overcome them.

17.12.14 (Wednesday)
15:30
"From CASPEC to ESPRESSO and beyond: Cosmology of the Intergalactic Medium"
Stefano CRISTIANI (Trieste Observatory)
Abstract
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"From CASPEC to ESPRESSO and beyond: Cosmology of the Intergalactic Medium"

Stefano CRISTIANI (Trieste Observatory)

Abstract

Moving to ESO as a young fellow, about 30 years ago, opened to me the entirely new possibility of obtaining the high resolution spectra of relatively faint objects needed to study the Intergalactic Medium, in which is recorded the history of the Universe during and soon after the Dark Ages.
In the following three decades amazing progresses in collecting power, instruments and detectors were achieved at ESO. A new paradigm emerged from the study of the spatial distribution, motions, chemical enrichment, and ionization histories of gaseous structures from redshift seven and beyond until the present. A surprising number of important conclusions about Cosmology and Fundamental Physics have been obtained, in particular linking the information provided by absorption lines with the complementary information derived from the evolutionary properties of luminous galactic structures.


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