GRAVITY Science Verification

GRAVITY,  is a 4-beam interferometric combiner at VLT-I operating in K-band. It is fully described on these pages.

Eighteen nights from 15 to 23 June 2016 and from 15 to 23 September 2016 were allocated to the GRAVITY Science Verification (SV) with the ATs. A call for proposals has been issued and the community is invited to submit proposals for the GRAVITY SV using this proposal template and associated LaTeX file.

Deadline for GRAVITY SV proposals is March 25 2016 18:00 (CET). Proposals need to be submitted to gravitysv@eso.org. This is the only submission channel.

GTO protected targets

The list of protected targets for the  GRAVITY Guaranteed Time Observations is available for P97 and P98. Note that both lists will apply when selecting SV targets. Observations of targets protected by the GRAVITY GTO will not be accepted for SV.

The observations will be conducted in Service Mode by a dedicated team of ESO astronomers and in close collaboration with the GRAVITY team. The GRAVITY SV team will be able to assist the successful PI¹s in the preparation and optimisation of the OBs on a best effort basis only. The collected data will be made available to the whole ESO user community.

WARNING: all (raw) data and calibrations are public immediately after the observations. There is no proprietary period nor earlier data release to the PIs. See the VLT Science Verification Policy and Procedures for more details.

Offered modes

2 modes are offered for the GRAVITY SV: single and double field. Note that the astrometric mode is NOT offered. For each mode, the HR (R=4000) and MR (R=500) spectral resolutions are available (NO LR). The GRAVITY User Manual can be found here.

Limiting correlated magnitudes

Limiting correlated magnitudes will be considered for two specific seeing regimes: <1 “ and <1.5”.  They are shown for the two GRAVITY modes below:

IMPORTANT NOTE: +3 is the dynamic range of the acquisition camera in terms of magnitude. It is not possible to observe 2 objects (one on the fringe tracker and one on the science camera) whose magnitudes differ by more than 3 magnitudes.   

The magnitude at which the Fringe Tracker saturates is K=-2. 

Observing Time

The conservative estimation of a CAL/SCI sequence is one hour. This duration should be taken as the basis in your proposal preparation. In order to offer a fare share of the science verification time we recommend the submission of programs that do not request more than 1 night (10 hours) of cumulated time (i.e. 10 CAL-SCI points). Any proposal requesting more should have a strong scientific justification.

AT configurations

The offered AT configurations for SV were updated (see table below). The exact scheduling will be optimised by the SV committee to maximise scientific return while maintaining a reasonable load on the reconfigurations requests. 

Science Verification Team

Jean-Philippe Berger
Willem-Jan de Wit
Frank Eisenhauer
Xavier Haubois
Antoine Mérand
Thibaut Paumard
Markus Schoeller
Markus Wittkowski
Julien Woillez
Burkhard Wolff

Schedule

March 1: Issue Call for Proposals
March 25: Deadline for proposal submission
April 15: Deadline for comments by proposal reviewers
May 4th: Proposers informed about the outcome
May 20: Deadline for Phase 2 Material for SV I
June 15-23: Science Verification I
July 20: Deadline for Phase 2 Material for SV II
Sept 15-23: Science Verification II --> rescheduled to Sept 10-18

Pipeline

The GRAVITY data reduction pipeline was released. Instructions for installing and running the pipeline can be found here:

http://www.eso.org/sci/software/pipelines/gravity/gravity-pipe-recipes.html

Note this version is preliminary and has not been fully verified. If you notice unexpected behaviour, please consult the "Bug Reports" section of the page.

Citation Policy

When publishing GRAVITY SV data, please use the following reference for the GRAVITY instrument:

GRAVITY Collaboration⋆: R. Abuter, M. Accardo, A. Amorim, N. Anugu, G. Ávila, N. Azouaoui, M. Benisty, J. P. Berger, N. Blind, H. Bonnet et al. (123 more), 2017, A&A, 602, A94

List of programmes selected for the GRAVITY SV

Clicking on the programme ID for each programme provides a link to the raw data in the ESO archive.

* "Too resolved" means that, given the instrument performances during the SV runs, the fringe detection/tracking was not feasible on these resolved objects.

General Information

An integral part of the commissioning of a new instrument at the VLT is the Science Verification phase. SV programmes include a set of typical scientific observations that should verify and demonstrate to the community the capabilities of the new instrument in the operational framework of the VLT Observatory. In accordance with its SV Policy and Procedures (http://www.eso.org/sci/activities/vltsv/svdoc.pdf) ESO encourages the community to submit also highly challenging or risky science observations that will push GRAVITY and the VLTI to its limits in order to better understand the performance parameter space and its envelope.  

Useful Links

• GRAVITY Instrument pages
• GRAVITY public page
• VLT Science Verification pages