Origin of the asymmetry of the wind driven halo observed in high-contrast images

Cantalloube, F.; Por, E.H.; Dohlen, K.; Sauvage, J.-F.; Vigan, A.; Kasper, M.; Bharmal, N.; Henning, T.; Brandner, W.; Milli, J.; Correia, C.; Fusco, T.

doi:10.1051/0004-6361/201834311

Origin of the asymmetry of the wind driven halo observed in high-contrast images

Cantalloube, F.; Por, E.H.; Dohlen, K.; Sauvage, J.-F.; Vigan, A.; Kasper, M.; Bharmal, N.; Henning, T.; Brandner, W.; Milli, J.; Correia, C.; Fusco, T.

Authors

F. Cantalloube

E.H. Por

K. Dohlen

J.-F. Sauvage

A. Vigan

M. Kasper

Dr Nazim Bharmal n.a.bharmal@durham.ac.uk
Senior Adaptive Optics Scientist

T. Henning

W. Brandner

J. Milli

C. Correia

T. Fusco

Abstract

The latest generation of high-contrast instruments dedicated to exoplanets and circumstellar disk imaging are equipped with extreme adaptive optics and coronagraphs to reach contrasts of up to 10−4 at a few tenths of arcseconds in the near-infrared. The resulting image shows faint features, only revealed with this combination, such as the wind driven halo. The wind driven halo is due to the lag between the adaptive optics correction and the turbulence speed over the telescope pupil. However, we observe an asymmetry of this wind driven halo that was not expected when the instrument was designed. In this letter, we describe and demonstrate the physical origin of this asymmetry and support our explanation by simulating the asymmetry with an end-to-end approach. From this work, we find that the observed asymmetry is explained by the interference between the AO-lag error and scintillation effects, mainly originating from the fast jet stream layer located at about 12 km in altitude. Now identified and interpreted, this effect can be taken into account for further design of high-contrast imaging simulators, next generation or upgrade of high-contrast instruments, predictive control algorithms for adaptive optics, or image post-processing techniques.

Citation

Cantalloube, F., Por, E., Dohlen, K., Sauvage, J., Vigan, A., Kasper, M., …Fusco, T. (2018). Origin of the asymmetry of the wind driven halo observed in high-contrast images. Astronomy & Astrophysics, 620, Article L10. https://doi.org/10.1051/0004-6361/201834311

Journal Article Type	Article
Acceptance Date	Oct 27, 2018
Online Publication Date	Dec 10, 2018
Publication Date	Dec 10, 2018
Deposit Date	Jan 4, 2019
Publicly Available Date	Jan 4, 2019
Journal	Astronomy and astrophysics.
Print ISSN	0004-6361
Electronic ISSN	1432-0746
Publisher	EDP Sciences
Peer Reviewed	Peer Reviewed
Volume	620
Article Number	L10
DOI	https://doi.org/10.1051/0004-6361/201834311
Related Public URLs	https://arxiv.org/abs/1810.13171