A catalogue of dual-field interferometric binary calibrators
Abstract
Dual-field interferometric observations with VLTI/GRAVITY sometimes require the use of a "binary calibrator", a binary star whose individual components remain unresolved by the interferometer, with a separation between 400 and 2000 mas for observations with the Units Telescopes (UTs), or 1200 to 3000 mas for the Auxiliary Telescopes (ATs). The separation vector also needs to be predictable to within 10 mas for proper pointing of the instrument. Up until now, no list of properly vetted calibrators was available for dual-field observations with VLTI/GRAVITY on the UTs. Our objective is to compile such a list, and make it available to the community. We identify a list of candidates from the Washington Double Star (WDS) catalogue, all with appropriate separations and brightness, scattered over the Southern sky. We observe them as part of a dedicated calibration programme, and determine whether these objects are true binaries (excluding higher multiplicities resolved interferometrically but unseen by imaging), and extract measurements of the separation vectors. We combine these new measurements with those available in the WDS to determine updated orbital parameters for all our vetted calibrators. We compile a list of 13 vetted binary calibrators for observations with VLTI/GRAVITY on the UTs, and provide orbital estimates and astrometric predictions for each of them. We show that our list guarantees that there are always at least two binary calibrators at airmass < 2 in the sky over the Paranal observatory, at any point in time. Any Principal Investigator wishing to use the dual-field mode of VLTI/GRAVITY with the UTs can now refer to this list to select an appropriate calibrator. We encourage the use of "whereistheplanet" to predict the astrometry of these calibrators, which seamlessly integrates with "p2Gravity" for VLTI/GRAVITY dual-field observing material preparation.
Cite
@article{arxiv.2402.05019,
title = {A catalogue of dual-field interferometric binary calibrators},
author = {M. Nowak and S. Lacour and R. Abuter and A. Amorim and R. Asensio-Torres and W. O. Balmer and M. Benisty and J. -P. Berger and H. Beust and S. Blunt and A. Boccaletti and M. Bonnefoy and H. Bonnet and M. S. Bordoni and G. Bourdarot and W. Brandner and F. Cantalloube and B. Charnay and G. Chauvin and A. Chavez and E. Choquet and V. Christiaens and Y. Clénet and V. Coudé du Foresto and A. Cridland and R. Davies and R. Dembet and J. Dexter and A. Drescher and G. Duvert and A. Eckart and F. Eisenhauer and N. M. Förster Schreiber and P. Garcia and R. Garcia Lopez and T. Gardner and E. Gendron and R. Genzel and S. Gillessen and J. H. Girard and S. Grant and X. Haubois and G. Heißel and T. Henning and S. Hinkley and S. Hippler and M. Houllé and Z. Hubert and L. Jocou and J. Kammerer and M. Keppler and P. Kervella and L. Kreidberg and N. T. Kurtovic and A. -M. Lagrange and V. Lapeyrère and J. -B. Le Bouquin and P. Léna and D. Lutz and A. -L. Maire and F. Mang and G. -D. Marleau and A. Mérand and J. D. Monnier and C. Mordasini and D. Mouillet and E. Nasedkin and T. Ott and G. P. P. L. Otten and C. Paladini and T. Paumard and K. Perraut and G. Perrin and O. Pfuh and N. Pourré and L. Pueyo and D. C. Ribeiro and E. Rickman and Z. Rustamkulov and J. Shangguan and T. Shimizu and D. Sing and J. Stadler and T. Stolker and O. Straub and C. Straubmeier and E. Sturm and M. Subroweit and L. J. Tacconi and E. F. van Dishoeck and A. Vigan and F. Vincent and S. D. von Fellenberg and J. J. Wang and F. Widmann and T. O. Winterhalder and J. Woillez and Ş. Yazıcı and A. Young and the GRAVITY Collaboration},
journal= {arXiv preprint arXiv:2402.05019},
year = {2024}
}
Comments
16 pages, 6 figures. Submitted to A&A