Seminars and Colloquia at ESO Santiago

I will present the status and summarise the science case of the QUVIK mission. QUVIK will be an ultraviolet (UV) space observatory on a 200 kg small satellite with a moderately fast repointing capability and a near-real-time alert communication system. It is a Czech-led mission realised through ESA as a 3rd-party project, with significant international participation. The mission will provide imaging in the NUV ( 260-360 nm) and FUV ( 150-200 nm) bands, with the latter provided by the Italian community (ASI and INAF). The mission will fill an important wavelength gap in our observing capabilities at the beginning of the next decade, providing key follow-up capabilities for transients detected by gravitational wave observatories and future wide-field multi-wavelength surveys. The mission will target sources of interest identified by
the upcoming ULTRASAT satellite in complementary near- and far-UV bands. Between observations of transient sources, the satellite will observe other targets of interest to the scientific community, such as stars, stellar systems, and galactic nuclei. The mission will also provide open time to the worldwide astronomical community and a public archive.

Planets form in discs around young intermediate-mass stars (Herbig stars) within the first 10 Myr. These protoplanetary discs have been studied extensively, and can be classified into 2 groups, depending on their geometry: flared with a gap (group I) or flat/self-shadowed and continuous (group II) . Within group I, we can still distinguish between objects with a warm inner dust disc and those without. In this talk, I will present a study of the properties of Herbig stars, concentrating on the influence of the presence of a warm inner disc. In particular, I will discuss the stellar metallicity. In a second part, I will present recent findings about the evolution of the accretion rate in intermediate-mass stars, that appears to increase with age. 

Intensity interferometry connects optical telescopes electronically by software.  The error budget is shifted from optical phase stability to the time domain, where a noise of, say, 1 ns corresponds to 30 cm light-travel distance, making the method insensitive to atmospheric seeing or telescopic imperfections, and thus enabling long baselines.  Also Cherenkov telescopes can be used, as currently done at VERITAS, H.E.S.S. and MAGIC + CTAO North on La Palma (especially during bright-Moon time, when gamma-ray observations are constrained).  The numerous forthcoming telescopes of CTAO in the Paranal/Armazones area should enable interferometry across a few square km, where any pair or triplet of telescopes can be electronically connected, reaching optical resolutions comparable to the EHT in radio.  Detector developments and telescopes with tighter specifications hold the promise to reach fainter targets, eventually realizing a fully electronic optical array for two-dimensional imaging with baselines of 10 km or more.

tbd

tbd

tbd

tbd

tbd

tbd

TBD

tbd

TBD