NFIRAOS: TMT narrow field near-infrared facility adaptive optics

Herriot, Glen; Hickson, Paul; Ellerbroek, Brent L.; Andersen, David; Davidge, T. J.; Erickson, Darren; Powell, Ian; Clare, Richard; Gilles, Luc; Boyer, Corinne; Smith, Malcolm J.; Saddlemyer, Leslie; Véran, Jean-Pierre

doi:10.1117/12.672337

Cited by 26 publications

(25 citation statements)

References 15 publications

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“…These levels of wavefront error can be produced by much simpler systems than are required for the near-infrared 4,10,11 . A suitable mid-infrared adaptive optics system (MIRAO) is likely to be useful even with somewhat worse than average atmospheric conditions, because well-corrected images should still be possible at the longer wavelengths.…”

Section: Adaptive Optics Requirementsmentioning

confidence: 99%

Design of the TMT mid-infrared echelle: science drivers and design overview

et al. 2006

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We present a discussion of the science drivers and design approach for a high-resolution, mid-infrared spectrograph for the Thirty-Meter Telescope. The instrument will be integrated with an adaptive optics system optimized for the midinfrared; as a consequence it is not significantly larger or more complex than similar instruments designed for use on smaller telescopes. The high spatial and spectral resolution possible with such a design provides a unique scientific capability. The design provides spectral resolution of up to 120,000 for the 4.5-25 m region in a cross-dispersed format that provides continuous spectral coverage of up to 2% to 14 m. The basic concept is derived from the successful TEXES mid-infrared spectrograph. To facilitate operation, there are separate imaging channels for the near-infrared and the mid-infrared; both can be used for acquisition and the mid-infrared imaging mode can be used for science imaging and for guiding. Because the spectrograph is matched to the diffraction limit of a 30-m telescope, gains in sensitivity are roughly proportional to the square of the telescope diameter, opening up a volume within the Galaxy a thousand times greater than existing instruments.

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Section: Adaptive Optics Requirementsmentioning

confidence: 99%

Design of the TMT mid-infrared echelle: science drivers and design overview

et al. 2006

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“…NFIRAOS has a stringent total wavefront error constraint of 133 nm rms [8]. Given that the LGS aberrations for all three sodium profiles in Table 2 exceed this requirement, it is imperative to correct for these aberrations.…”

Section: Tmtmentioning

confidence: 99%

“…Given that the LGS aberrations for all three sodium profiles in Table 2 exceed this requirement, it is imperative to correct for these aberrations. For NFIRAOS, the proposed design includes measuring with the TT NGS WFS the focus variations arising from the height of the sodium layer changing [8].…”

Section: Tmtmentioning

confidence: 99%

“…A number of new LGS AO systems for existing and future telescopes are in the design stages, such as the TMT AO system, NFIRAOS, [8,9] and the Keck I LGS AO system [10]. Because the LGS aberrations measured with the Keck II system are so significant, it is important to understand and be able to model the LGS aberrations before building the next generation of LGS AO systems.…”

Section: Introductionmentioning

confidence: 99%

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Modeling low order aberrations in laser guide star adaptive optics systems

Clare¹,

Dam²,

Bouchez³

2007

Opt. Express

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When using a laser guide star (LGS) adaptive optics (AO) system, quasi-static aberrations are observed between the measured wavefronts from the LGS wavefront sensor (WFS) and the natural guide star (NGS) WFS. These LGS aberrations, which can be as much as 1200 nm RMS on the Keck II LGS AO system, arise due to the finite height and structure of the sodium layer. The LGS aberrations vary significantly between nights due to the difference in sodium structure. In this paper, we successfully model these LGS aberrations for the Keck II LGS AO system. We use this model to characterize the LGS aberrations as a function of pupil angle, elevation, sodium structure, uplink tip/tilt error, detector field of view, the number of detector pixels, and seeing. We also employ the model to estimate the LGS aberrations for the Palomar LGS AO system, the planned Keck I and the Thirty Meter Telescope (TMT) LGS AO systems. The LGS aberrations increase with increasing telescope diameter, but are reduced by central projection of the laser compared to side projection.

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“…As for the 8-m class Extreme AO instruments, the 30-m class Extreme AO instruments will also be able to measure cloud colors only down to a level ultimately limited by systematic trends in the photometry, due to the instrumental changes, atmospheric variations, etc. The most significant improvement of the 30-m Extreme AO over the 8-m Extreme AO instruments will be in their ability to do moderate-resolution (R ∼ 100 -1000) spectroscopy both in the near IR with an Integral Field Spectrograph (IFS) on ELT/EPICS, TMT/NFIRAOS and GMT/NIRExAO Imager (Vérinaud et al 2010;Herriot et al 2006;Johns 2008) and in the mid-IR using, for example, instruments like GMT/TIGER in the 8 to 20 µm wavelength coverage (Jaffe et al 2010). Further improvements will come in the form of polarimetric measurements and the extended time-domain probed with the faster cadence, allowing detection of smaller-scale variations.…”

Section: -M Class Telescopes With Next-generation Extreme Ao (30m+ mentioning

confidence: 99%

Mapping Directly Imaged Giant Exoplanets

Kostov

Apai

2012

ApJ

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With the increasing number of directly imaged giant exoplanets the current atmosphere models are often not capable of fully explaining the spectra and luminosity of the sources. A particularly challenging component of the atmosphere models is the formation and properties of condensate cloud layers, which fundamentally impact the energetics, opacity, and evolution of the planets.Here we present a suite of techniques that can be used to estimate the level of rotational modulations these planets may show. We propose that the timeresolved observations of such periodic photometric and spectroscopic variations of extrasolar planets due to their rotation can be used as a powerful tool to probe the heterogeneity of their optical surfaces. In this paper we develop simulations to explore the capabilities of current and next-generation ground-and space-based instruments for this technique. We address and discuss the following questions: a) what planet properties can be deduced from the light curve and/or spectra, and in particular can we determine rotation periods, spot-coverage, spot colors, spot spectra; b) what is the optimal configuration of instrument/wavelength/temporal sampling required for these measurements; and, c) can principal component analysis be used to invert the light curve and deduce the surface map of the planet.1 To whom correspondence should be addressed. Email: vkostov@pha.jhu.edu -2 -Our simulations describe the expected spectral differences between homogeneous (clear or cloudy) and patchy atmospheres, outline the significance of the dominant absorption features of H 2 O, CH 4 , and CO and provide a method to distinguish these two types of atmospheres. Assuming surfaces with and without clouds for most currently imaged planets the current models predict the largest variations in the J-band. Simulated photometry from current and future instruments is used to estimate the level of detectable photometric variations. We conclude that future instruments will be able to recover not only the rotation periods, cloud cover, cloud colors and spectra but even cloud evolution. We also show that a longitudinal map of the planet's atmosphere can be deduced from its disk-integrated light curves.

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NFIRAOS: TMT narrow field near-infrared facility adaptive optics

Cited by 26 publications

References 15 publications

Design of the TMT mid-infrared echelle: science drivers and design overview

Design of the TMT mid-infrared echelle: science drivers and design overview

Modeling low order aberrations in laser guide star adaptive optics systems

Mapping Directly Imaged Giant Exoplanets

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