ESPRESSO at VLT

Abstract

Context. ESPRESSO is the new high-resolution spectrograph of ESO's Very Large Telescope (VLT). It was designed for ultra-high radial-velocity (RV) precision and extreme spectral fidelity with the aim of performing exoplanet research and fundamental astrophysical experiments with unprecedented precision and accuracy. It is able to observe with any of the four Unit Telescopes (UTs) of the VLT at a spectral resolving power of 140 000 or 190 000 over the 378.2 to 788.7 nm wavelength range; it can also observe with all four UTs together, turning the VLT into a 16-m diameter equivalent telescope in terms of collecting area while still providing a resolving power of 70 000. Aims. We provide a general description of the ESPRESSO instrument, report on its on-sky performance, and present our Guaranteed Time Observation (GTO) program along with its first results. Methods. ESPRESSO was installed on the Paranal Observatory in fall 2017. Commissioning (on-sky testing) was conducted between December 2017 and September 2018. The instrument saw its official start of operations on October 1, 2018, but improvements to the instrument and recommissioning runs were conducted until July 2019. Results. The measured overall optical throughput of ESPRESSO at 550 nm and a seeing of 0.65 exceeds the 10% mark under nominal astroclimatic conditions. We demonstrate an RV precision of better than 25 cm s −1 during a single night and 50 cm s −1 over several months. These values being limited by photon noise and stellar jitter shows that the performance is compatible with an instrumental precision of 10 cm s −1. No difference has been measured across the UTs, neither in throughput nor RV precision. Conclusions. The combination of the large collecting telescope area with the efficiency and the exquisite spectral fidelity of ESPRESSO opens a new parameter space in RV measurements, the study of planetary atmospheres, fundamental constants, stellar characterization, and many other fields.

Power Law Duality in Classical and Quantum Mechanics

“…In summary, the inversion maps a hyperbolic orbit under attraction into a hyperbolic orbit under repulsion, whereas any rotation takes a hyperbolic orbit under attraction (repulsion) to a hyperbolic orbit under attraction (repulsion). According to Chandrasekhar's book [18], what Newton established for (−1, −1) and (2,2) are that the attractive inverse square force law is dual to the repulsive inverse square force law, and that the repulsive linear force law is dual to itself. Thus, we are led to a view that Newton's (−1, −1) is due to the inversion and their (2, 2) is due to a rotation.…”

“…The action in semiclassical theory is of the form, W = dq p, which is Hamilton's characteristic function and essentially the same as that in (2). The semiclassical action for the radial motion reads…”

“…Let ψ (1) (r) and ψ (2) (r) be two independent solutions of the radial Equation (166). Let us assume that ψ (1) (r) remains finite as r → ∞ while the second solution obeys ψ (2) (0) = 0.…”

“…Let ψ (1) (r) and ψ (2) (r) be two independent solutions of the radial Equation (166). Let us assume that ψ (1) (r) remains finite as r → ∞ while the second solution obeys ψ (2) (0) = 0. With these solutions, following the standard procedure [70], we can construct the Green function G(r, r ; E, L) as (1) , ψ (2) ]…”

“…One of the best Doppler spectrographs to discover low-mass exoplanets using the radial velocity method are HARPS (High Accuracy Radial Velocity Planet Searcher) installed on ESO's 3.6 m telescope at La Silla and ESPRESSO (Echelle Spectrograph for Rocky Exoplanet-and Stable Spectroscopic Observations) installed on ESO's VLT at Paranal Observatory in Chile. See, e.g., [1,2]. NASA's Kepler space telescope has discovered more than half of the currently known exoplanets using the so-called transit method.…”