P. Santin

UVES Observations of QSO 0000–2620: Oxygen and Zinc Abundances in the Damped Lyα Galaxy at zabs = 3.3901*

Observations of the QSO 0000-2620 with the Ultraviolet-Visual Echelle Spectrograph at the 8.2 m ESO Kueyen telescope are used for abundance analysis of the damped Lyα system at zabs = 3.3901. Several oxygen lines are identified in the Lyα forest, and a measure for the oxygen abundance is obtained at [O/H] = -1.85 ± 0.15 by means of the unsaturated O I λ925 and O I λ950 lines. This represents the most accurate O measurement in a damped Lyα galaxy so far. We have also detected Zn II λ2026 and Cr II λλ2056, 2062 redshifted at ≈8900 A and found abundances [Zn/H] = -2.07 ± 0.10 and [Cr/H] = -1.99 ± 0.09. Furthermore, previous measurements of Fe, Si, Ni, and N have been refined, yielding [Fe/H] = -2.04 ± 0.09, [Si/H] = -1.90 ± 0.08, [Ni/H] = -2.27 ± 0.09, and [N/H] = -2.68 ± 0.12. The abundance of the nonrefractory element zinc is the lowest among the damped Lyα systems, showing that the associated intervening galaxy is indeed in the early stages of its chemical evolution. The fact that the Zn abundance is identical to that of the refractory elements Fe and Cr suggests that dust grains have not formed yet. In this damped Lyα system the observed [O, S, Si/Zn, Fe, Cr] ratios, in whatever combination are taken, are close to solar (i.e., 0.1-0.2 dex) and do not show the [α-element/Fe] enhancement observed in Milky Way stars of comparable metallicity. The observed behavior supports a galaxy evolution model characterized by either episodic or low star formation rate rather than a Milky Way-type evolutionary model.

ESPRESSO: the Echelle spectrograph for rocky exoplanets and stable spectroscopic observations

ESPRESSO, the Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations, will combine the efficiency of modern echelle spectrograph design with extreme radial-velocity precision. It will be installed on ESOs VLT in order to achieve a gain of two magnitudes with respect to its predecessor HARPS, and the instrumental radialvelocity precision will be improved to reach cm/s level. Thanks to its characteristics and the ability of combining incoherently the light of 4 large telescopes, ESPRESSO will offer new possibilities in various fields of astronomy. The main scientific objectives will be the search and characterization of rocky exoplanets in the habitable zone of quiet, nearby G to M-dwarfs, and the analysis of the variability of fundamental physical constants. We will present the ambitious scientific objectives, the capabilities of ESPRESSO, and the technical solutions of this challenging project.

Installation and first results of FLAMES, the VLT multifibre facility

FLAMES is the VLT Fibre Facility, installed and being commissioned at the Nasmyth A of UT2 (Kueyen Telescope). FLAMES has been built and assembled at the VLT telescope in about 4 years through an international collaboration between 10 institutes in 6 countries and 3 continents. It had first light with the fibre link to the red arm of UVES on April 1, and with the GIRAFFE spectrograph on July 3. We have not yet enough data to compare the observed vs. expected astronomical performances, although these first data are encouraging in many respects. We aim at proceeding soon with the remaining tests

X-Shooter: A Medium-resolution, Wide-Band Spectrograph for the VLT

X-shooter is the first second-generation instrument for the ESO Very Large Telescope, and will be installed in 2008. It is intended to become the most powerful optical & near-infrared medium-resolution spectrograph in the world, with a unique spectral coverage from 300 to 2500 nm in one shot. The X-shooter consortium members are from Denmark, France, Italy, The Netherlands and ESO.

Adoption of new software and hardware solutions at the VLT: the ESPRESSO control architecture case

ESPRESSO is a fiber-fed cross-dispersed echelle spectrograph which can be operated with one or up to 4 UT (Unit Telescope) of ESOs Very Large Telescope (VLT). It will be located in the Combined-Coudé Laboratory (CCL) of the VLT and it will be the first permanent instrument using a 16-m equivalent telescope. The ESPRESSO control software and electronics are in charge of the control of all instrument subsystems: the four Coudé Trains (one for each UT), the front-end and the fiber-fed spectrograph itself contained within a vacuum vessel. The spectrograph is installed inside a series of thermal enclosures following an onion-shell principle with increasing temperature stability from outside to inside. The proposed electronics architecture will use the OPC Unified Architecture (OPC UA) as a standard layer to communicate with PLCs (Programmable Logical Controller), replacing the old Instrument Local Control Units (LCUs) for ESO instruments based on VME technology. The instrument control software will be based on the VLT Control Software package and will use the IC0 Field Bus extension for the control of the instrument hardware. In this paper we present the ESPRESSO software architectural design proposed at the Preliminary Design Review as well as the control electronics architecture.

Performances of X-shooter, the new wide-band intermediate resolution spectrograph at the VLT

X-shooter is the first second-generation instrument newly commissioned a the VLT. It is a high efficiency single target intermediate resolution spectrograph covering the range 300 - 2500 nm in a single shot. We summarize the main characteristics of the instrument and present its performances as measured during commissioning and the first months of science operations.

EVALSO: enabling virtual access to Latin American southern observatories

In the field of observational astrophysics, the remoteness of the facilities and the ever increasing data volumes and detectors poses new technological challenges. As an example, the VISTA and VST wide field telescopes, which are being constructed at the ESOs Cerro Paranal Observatory and will be ready in the next few years, have cameras which will produce after just one year of operation a volume of data that will exceed all the data collected by the VLT since the start of operations in 1999. This sets serious limitations if such large quantities of data must be transferred and accessed in a short time by the participating European Institutions. The EVALSO project, approved by the European Community, addresses these targets in two major ways. It will create a physical infrastructure to efficiently connect these facilities to Europe. This infrastructure will be complementary to the international infrastructure already created in the last years with the EC support (RedCLARA, ALICE, GEANT). Besides this, it will provide the astronomers with Virtual Presence (VP), i.e. the tools to perform and control an astronomical observation from the users site. The main role of INAF - Astronomical Observatory of Trieste (OAT) within the project will be the definition of the architecture, the development of VP system and the integration of a prototype to be used as a demonstrator. This paper will focus on the description of the Virtual Presence system.

New direction in the development of the observation software framework (BOSS)

The Observation Software (OS) of astronomical instruments, which lie directly beneath the instructions of astronomers, carrying out exposures and calibrations is the supervisor of the multi-process and multi-layer instrument software package. The main responsibility of the OS is the synchronization of the subsystems (detectors and groups of mechanical devices) and the telescope during exposures. At ESO a software framework Base Observation Software Stub (BOSS) takes care of the common functionalities of all OS of various instruments at the various sites VLT, VLTI, La Silla and Vista. This paper discusses the latest applications and how their new generic requirements contributes to the BOSS framework. The paper discusses the resolution of problems of event queues, interdependent functionalities, parallel commands and asynchronous messages in the OS using OO technologies.

Control software and electronics architecture design in the framework of the E-ELT instrumentation

During the last years the European Southern Observatory (ESO), in collaboration with other European astronomical institutes, has started several feasibility studies for the E-ELT (European-Extremely Large Telescope) instrumentation and post-focal adaptive optics. The goal is to create a flexible suite of instruments to deal with the wide variety of scientific questions astronomers would like to see solved in the coming decades. In this framework INAF-Astronomical Observatory of Trieste (INAF-AOTs) is currently responsible of carrying out the analysis and the preliminary study of the architecture of the electronics and control software of three instruments: CODEX (control software and electronics) and OPTIMOS-EVE/OPTIMOS-DIORAMAS (control software). To cope with the increased complexity and new requirements for stability, precision, real-time latency and communications among sub-systems imposed by these instruments, new solutions have been investigated by our group. In this paper we present the proposed software and electronics architecture based on a distributed common framework centered on the Component/Container model that uses OPC Unified Architecture as a standard layer to communicate with COTS components of three different vendors. We describe three working prototypes that have been set-up in our laboratory and discuss their performances, integration complexity and ease of deployment.

Instruments in Grid: the Instrument Element

This work is focused on the interoperability aspects between the Grid and the scientific instrumentation. The IE (Instrument Element) makes possible the monitoring and the remote control of any kind of scientific instrumentation, although the test-bed of this first implementation is constituted of telescopes and related astronomical instrumentation. The first implementation of the IE deals with monitoring aspects; astronomers can remotely interface the telescope and related instrumentation and check the telemetric and scientific data when they are acquired. Future releases of the IE will include extensions, so that remote control capabilities will be also covered.