Seminars and Colloquia at ESO Santiago

The ESPRESSO spectrograph, mounted on the VLT, was designed to achieve a long-term radial velocity (RV) precision of 10 cm/s, enabling the detection of Earth-mass planets within the habitable zones (HZ) of their host stars.

I present results from the instrument’s Guaranteed Time Observations campaign on three low-activity G, K, and M stars. We characterize the precision achievable from the timescales of minutes and dominated by pulsations, to timescales of years as required for HZ planet detection. To achieve this, we employ different RV calculation methods and activity indicators, assessing the limiting factors of both instrumental precision and stellar RV stability. Using a comprehensive analysis, we reach a RV floor level of 40 cm/s over a timescale of several years.

Interestingly, the ESPRESSO data shows no evidence for several previously announced planetary signals; we discuss the population of planets that, while not directly observed, remain consistent with ESPRESSO data. 

Finally, I explore the stellar physical phenomena that can be studied to further improve RV precision and enhance our planet detection capabilities. This is key for the future precise RV campaigns as enabled by ESPRESSO and similar instruments.

fist - FITS Inspection Streamlined Tool

The most commonly used FITS display tools, such as RTD or DS9 are now more than 25 years old. They are extremely powerful but can at times lack flexibility, specially in what comes scripting and interfacing. I created ´fist´ as a simple browser-based FITS interface, programmed completely on python. The package already includes the most commonly used features and allows for including additional instruments or tools.

exoptima: an observability and radial precision interface for observing Exoplanets  

´exoptima´ is a web-based interface that computes observability for a given object, and evaluates this observability not only for a specific date but also over the whole year. It also estimates radial velocity precision for a given instrument/telescope using a simple scaling from the ESPRESSO ETC values. The tool can be a valuable aid at planning Exoplanet RV observations.

The James Clerk Maxwell Telescope (JCMT) has been monitoring eight nearby low-mass star-forming regions in the Gould Belt at submillimetre wavelengths for more than eight years to search for and quantify the time dependent brightness variability of the resident deeply embedded protostars. Secular variability is common among these protostars; greater than 25% of the sample show measurable long-term brightness changes and 10% show burst behaviour lasting months to years. We interpret this secular variability as reflecting changes in the mass accretion rate from the disk to the protostar, as predicted by theoretical models of (proto)stellar assembly. For a subset of our sample we have contemporaneous mid-IR light-curves which allow additional constraints on the conditions responsible for the brightness variations, confirming that the submillimetre variability is driven by changes in the dust temperature profile of the envelope. Furthermore, we have combined, for one source, single dish and interferometric sub-mm monitoring, which has allowed us to unambiguously recover a time lag in the variability at larger angular scales and use the results to confirm the envelope structure surrounding the embedded protostar.

tbd

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.

tbd

tbd

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