ESPRESSO@VLT -- On-sky performance and first results
Abstract
ESPRESSO is the new high-resolution spectrograph of ESO's Very-Large Telescope (VLT). It was designed for ultra-high radial-velocity 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 (UT) of the VLT at a spectral resolving power of 140,000 or 190,000 over the 378.2 to 788.7 nm wavelength range, or with all 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. We provide a general description of the ESPRESSO instrument, report on the actual on-sky performance, and present our Guaranteed-Time Observation (GTO) program with its first results. 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 1st, 2018, but improvements to the instrument and re-commissioning runs were conducted until July 2019. The measured overall optical throughput of ESPRESSO at 550 nm and a seeing of 0.65 arcsec exceeds the 10% mark under nominal astro-climatic conditions. We demonstrate a radial-velocity precision of better than 25 cm/s during one night and 50 cm/s over several months. These values being limited by photon noise and stellar jitter show that the performanceis compatible with an instrumental precision of 10 cm/s. No difference has been measured across the UTs neither in throughput nor RV precision. 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 characterisation and many other fields.
Keywords
Cite
@article{arxiv.2010.00316,
title = {ESPRESSO@VLT -- On-sky performance and first results},
author = {F. Pepe and S. Cristiani and R. Rebolo and N. C. Santos and H. Dekker and A. Cabral and P. Di Marcantonio and P. Figueira and G. Lo Curto and C. Lovis and M. Mayor and D. Mégevand and P. Molaro and M. Riva and M. R. Zapatero Osorio and M. Amate and A. Manescau and L. Pasquini and F. M. Zerbi and V. Adibekyan and M. Abreu and M. Affolter and Y. Alibert and M. Aliverti and R. Allart and C. Allende Prieto and D. Álvarez and D. Alves and G. Avila and V. Baldini and T. Bandy and S. C. C. Barros and W. Benz and A. Bianco and F. Borsa and V. Bourrier and F. Bouchy and C. Broeg and G. Calderone and R. Cirami and J. Coelho and P. Conconi and I. Coretti and C. Cumani and G. Cupani and V. D'Odorico and M. Damasso and S. Deiries and B. Delabre and O. D. S. Demangeon and X. Dumusque and D. Ehrenreich and J. P. Faria and A. Fragoso and L. Genolet and M. Genoni and R. Génova Santos and J. I. González Hernández and I. Hughes and O. Iwert and F. Kerber and J. Knudstrup and M. Landoni and B. Lavie and J. Lillo-Box and J. -L. Lizon and C. Maire and C. J . A. P. Martins and A. Mehner and G. Micela and A. Modigliani and M. A. Monteiro and M. J. P. F. G. Monteiro and M. Moschetti and M. T. Murphy and N. Nunes and L. Oggioni and A. Oliveira and M. Oshagh and E. Pallé and G. Pariani and E. Poretti and J. L. Rasilla and J. Rebordão and E. M. Redaelli and S. Santana Tschudi and P. Santin and P. Santos and D. Ségransan and T. M. Schmidt and A. Segovia and D. Sosnowska and A. Sozzetti and S. G. Sousa and P. Spanò and A. Suárez Mascareño and H. Tabernero and F. Tenegi and S. Udry and A. Zanutta},
journal= {arXiv preprint arXiv:2010.00316},
year = {2021}
}
Comments
26 pages, 28 figures