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Published January 2023 | Version Published
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The Near Infrared Imager and Slitless Spectrograph for JWST. V. Kernel Phase Imaging and Data Analysis

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Abstract

Kernel phase imaging (KPI) enables the direct detection of substellar companions and circumstellar dust close to and below the classical (Rayleigh) diffraction limit. The high-Strehl full pupil images provided by the James Webb Space Telescope (JWST) are ideal for application of the KPI technique. We present a kernel phase analysis of JWST NIRISS full pupil images taken during the instrument commissioning and compare the performance to closely related NIRISS aperture masking interferometry (AMI) observations. For this purpose, we develop and make publicly available the custom Kpi3Pipeline data reduction pipeline enabling the extraction of kernel phase observables from JWST images. The extracted observables are saved into a new and versatile kernel phase FITS file data exchange format. Furthermore, we present our new and publicly available fouriever toolkit which can be used to search for companions and derive detection limits from KPI, AMI, and long-baseline interferometry observations while accounting for correlated uncertainties in the model fitting process. Among the four KPI targets that were observed during NIRISS instrument commissioning, we discover a low-contrast (∼1:5) close-in (∼1 λ/D) companion candidate around CPD-66 562 and a new high-contrast (∼1:170) detection separated by ∼1.5 λ/D from 2MASS J062802.01-663738.0. The 5σ companion detection limits around the other two targets reach ∼6.5 mag at ∼200 mas and ∼7 mag at ∼400 mas. Comparing these limits to those obtained from the NIRISS AMI commissioning observations, we find that KPI and AMI perform similar in the same amount of observing time. Due to its 5.6 times higher throughput if compared to AMI, KPI is beneficial for observing faint targets and superior to AMI at separations ≳325 mas. At very small separations (≲100 mas) and between ∼250 and 325 mas, AMI slightly outperforms KPI which suffers from increased photon noise from the core and the first Airy ring of the point-spread function.

Additional Information

© 2023. The Author(s). Published by IOP Publishing Ltd on behalf of the Astronomical Society of the Pacific (ASP). Original content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. These observations were made possible through the efforts of the many hundreds of people in the international commissioning team for JWST. This work is based on observations made with the NASA/ESA/CSA James Webb Space Telescope. The data were obtained from the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127 for JWST. These observations are associated with program #1093. Support for programs #1194, #1411, and #1412 was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127. This research has made use of the Spanish Virtual Observatory (https://svo.cab.inta-csic.es) project funded by MCIN/AEI/10.13039/501100011033/ through grant PID2020-112949GB-I00. F.M. acknowledges support from from the European Research Council (ERC) under the European Unions Horizon 2020 research and innovation program (grant agreement CoG-683029). A.C. acknowledges support by the Heising-Simons Foundation through grant 2020-1825. A.G. acknowledges support from the ANID-ALMA fund No. ASTRO20-0059. D.J. is supported by NRC Canada and by an NSERC Discovery Grant. J.S.B. acknowledges the full support from the CONACyT "Ciencia de Frontera" project CF-263975. M.R. would like to acknowledge funding from the Natural Sciences and Research Council of Canada (NSERC), as well as from the Fonds de Recherche du Québec—Nature et Technologies (FRQNT) and the Institut de Recherche sur les Exoplanètes (iREx). T.V. acknowledges support from the Fonds the Recherche du Québec—Nature et Technologies (FRQNT) and the Institut de Recherche sur les Exoplanètes (iREx). The manuscript was substantially improved following helpful comments from an anonymous referee.

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Additional details

Identifiers

Eprint ID
120272
Resolver ID
CaltechAUTHORS:20230321-821906400.67

Funding

NASA
NAS 5-03127
Ministerio de Ciencia e Innovación (MCIN)
MCIN/AEI/10.13039/501100011033/
Ministerio de Ciencia e Innovación (MCIN)
PID2020-112949GB-I00
European Research Council (ERC)
683029
Heising-Simons Foundation
2020-1825
Agencia Nacional de Investigación y Desarrollo (ANID)
ASTRO20-0059
Consejo Nacional de Ciencia y Tecnología (CONACYT)
CF-263975
Natural Sciences and Engineering Research Council of Canada (NSERC)
Fonds de recherche du Québec - Nature et technologies (FRQNT)
Institut de Recherche sur les Exoplanètes (iREx)

Dates

Created
2023-06-08
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Updated
2023-06-08
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Infrared Processing and Analysis Center (IPAC)