Categories: Eventi & Manifestazioni
Si informa che 8 febbraio alle ore 11:00, presso la Sala Conferenze dell'Osservatorio, il Dott. Davide Magurno, dell'Università di Roma Tor Vergata, terrà un seminario dal titolo: "Optical/NIR high resolution spectroscopy of field and cluster RR Lyrae"
ABSTRACT: RR Lyrae stars are the cross-road of a paramount theoretical (stellar pulsation and evolution) and observational (OGLE, CATALINA, ASAS) efforts. They are excellent distance indicators and robust tracers of stellar populations older than 10 Gyr. They are ubiquitous (late and early type galaxies) and can provide solid constraints in the systematics affecting both population and II standard candles. However, the number of RR Lyrae for which are available accurate estimates of iron, alpha and neutron capture elements is of the order of five dozen. To fill this gap we undertake an observing campaign aimed at collecting optical (M2FS at Magellan, UVES at VLT) and near-infrared (zYJ, WINERED at NTT and at Magellan), high resolution, high signal to noise spectra. We present a brief overview of the approach (equivalent widths) we adopt to estimate the abundances. In particular, we focus our attention on the different methods adopted in the literature for telluric subtraction (telluric standards vs sky models). We present preliminary results concerning cluster RR Lyrae in the globular NGC3201. I am also planning to show some preliminary results concerning simultaneous OPTICAL/NIR spectroscopy of field RR Lyrae.