Liger for Next-Generation Keck Adaptive Optics

Wright, Shelley A.; Jones, Tucker; Larkin, James E.; Kupke, Renate; Kassis, Marc; Fitzgerald, Michael P.; Brown, Aaron M.; Cosens, Maren; Kress, Evan; Rundquist, Nils-Erik; Surya, Arun; Wang, Eric; Wiley, James

doi:10.1117/12.2563039

Cited by 4 publications

(5 citation statements)

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“…Finally, as mentioned above, spatially resolved kinematics for large samples of lenses will be transformative. What is needed is continued support for the construction and deployment of the facilities (Wright et al 2020) and the allocation of sufficient telescope time.…”

Section: Observational Challengesmentioning

confidence: 99%

Strong lensing time-delay cosmography in the 2020s

Treu

Suyu

Marshall

2022

Astron Astrophys Rev

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Multiply imaged time-variable sources can be used to measure absolute distances as a function of redshifts and thus determine cosmological parameters, chiefly the Hubble Constant H$$_0$$ 0 . In the two decades up to 2020, through a number of observational and conceptual breakthroughs, this so-called time-delay cosmography has reached a precision sufficient to be an important independent voice in the current “Hubble tension” debate between early- and late-universe determinations of H$$_0$$ 0 . The 2020s promise to deliver major advances in time-delay cosmography, owing to the large number of lenses to be discovered by new and upcoming surveys and the vastly improved capabilities for follow-up and analysis. In this review, after a brief summary of the foundations of the method and recent advances, we outline the opportunities for the decade and the challenges that will need to be overcome in order to meet the goal of the determination of H$$_0$$ 0 from time-delay cosmography with 1% precision and accuracy.

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Section: Observational Challengesmentioning

confidence: 99%

Strong lensing time-delay cosmography in the 2020s

Treu

Suyu

Marshall

2022

Astron Astrophys Rev

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“…7 It is optimized for low wavefront error and high throughput. 8 It provides a 20.5"x20.5" field of view with 10 mas spatial sampling. Thanks to Liger's sequential design, the imager is used in parallel with the IFS in all observing modes.…”

Section: Imager Optical Assemblymentioning

confidence: 99%

“…The spectrograph RIO houses three mechanisms that use simple re-imaging optics, two of which are placed directly above the imaging detector, to preserve the pristine image quality provided by KAPA. 8 It transfers the beam from the imager focal plane to either the lenslet or slicer subsystems. As well as choosing between the lenslet and slicer, the RIO also allows choosing between the 14 and 31 mas mode for the lenslet and the 75 and 150 mas mode for the slicer.…”

Section: Re-imaging Opticsmentioning

confidence: 99%

Liger at Keck Observatory: design of imager optical assembly and spectrograph re-imaging optics

Wiley

Brown

Kupke

et al. 2022

Ground-Based and Airborne Instrumentation for Astronomy IX

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Liger is an adaptive optics (AO) fed imager and integral field spectrograph (IFS) designed to take advantage of the Keck All-sky Precision Adaptive-optics (KAPA) upgrade for the W.M. Keck Observatory. We present the design and analysis of the imager optical assembly including the spectrograph Re-Imaging Optics (RIO) which transfers the beam path from the imager focal plane to the IFS slicer module and lenslet array. Each imager component and the first two RIO mechanisms are assembled and individually aligned on the same optical plate. Baffling suppresses background radiation and scattered light, and a pupil viewing camera allows the imager detector to focus on an image of the telescope pupil. The optical plate mounts on an adapter frame for alignment of the overall system. The imager and RIO will be characterized in a cryogenic test chamber before installation in the final science cryostat.

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“…A more complete overview of the Liger instrument is provided in Wright et al (this conference). 4 Here we present the design of the Liger filter wheel and pupil stop. The imaging camera serves as the reimaging optical system for the spectrographs, so these elements (as well as the rest of the imager optics) will Full assembly with transparent housing to show internal components.…”

Section: Introductionmentioning

confidence: 99%

Liger for next-generation Keck AO: filter wheel and pupil design

Cosens

Wright

Arriaga

et al. 2020

Ground-Based and Airborne Instrumentation for Astronomy VIII

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Liger is a next-generation near-infrared imager and integral field spectrograph (IFS) for the W.M. Keck Observatory designed to take advantage of the Keck All-Sky Precision Adaptive Optics (KAPA) upgrade. Liger will operate at spectral resolving powers between R∼4,000 -10,000 over a wavelength range of 0.8-2.4µm. Liger takes advantage of a sequential imager and spectrograph design that allows for simultaneous observations between the two channels using the same filter wheel and cold pupil stop. We present the design for the filter wheels and pupil mask and their location and tolerances in the optical design. The filter mechanism is a multi-wheel design drawing from the heritage of the current Keck/OSIRIS imager single wheel design. The Liger multi-wheel configuration is designed to allow future upgrades to the number and range of filters throughout the life of the instrument. The pupil mechanism is designed to be similarly upgradeable with the option to add multiple pupil mask options. A smaller wheel mechanism allows the user to select the desired pupil mask with open slots being designed in for future upgrade capabilities. An ideal pupil would match the shape of the image formed of the primary and would track its rotation. For different pupil shapes without tracking we model the additional exposure time needed to achieve the same signal to noise of an ideal pupil and determine that a set of fixed masks of different shapes provides a mechanically simpler system with little compromise in performance.

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Liger for Next-Generation Keck Adaptive Optics

Cited by 4 publications

References 0 publications

Strong lensing time-delay cosmography in the 2020s

Strong lensing time-delay cosmography in the 2020s

Liger at Keck Observatory: design of imager optical assembly and spectrograph re-imaging optics

Liger for next-generation Keck AO: filter wheel and pupil design

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