IOT Overview: Integral Field Spectroscopy

Abstract

Integral Field Spectroscopy at the La Silla Paranal Observatory (LPO) is offered in three flavours:

1. VIMOS on UT3 is equipped with an integral field unit made of 6400 fibers operating in the 390–1000nm wavelength range. Two spatial scales per fiber are available: 0.67” and 0.33”; they correspond to fields of view from 13”×13” up to 54”×54” depending on the chosen spectral resolution (R=200–2500).

2. FLAMES-GIRAFFE on UT2 allows the observation of up to 15 targets simultaneously in the 370–940nm wavelength range: it uses 30 small fiber bundles, each covering 2”×3” on the sky and positioned in the 25’ diameter circular field of view. Alternatively, FLAMES-ARGUS uses a fiber bundle located in the centre of the FLAMES field of view, covering 6.6”×4.2” on the sky. In both cases the spectral resolution R=11,000–39,000.

3. SINFONI is a near-infrared (1.1–2.45 μm) integral field spectrograph fed by an adaptive optics module, currently installed at the Cassegrain focus of UT4. The spectrograph operates with four gratings in J, H, K and H+K (R=2000–4000) and three different scales (0.25”, 0.1” and 0.025”/pixel), corresponding to a field-of-view of 8”×8”, 3”×3”, or 0.8”×0.8” respectively. SINFONI can also be used in seeing limited mode (no AO) and, starting April 2007 is offered for use with an artificial laser guide star, which will increase the sky coverage dramatically.

In this paper we review the use and science applications of these instruments, their standard calibration and maintenance operations plans and the most important calibration issues affecting science.