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Speckle Interferometric Observations With the Gemini 8-m Telescopes: Signal-to-Noise Calculations and Observational Results

Howell, Steve B. and Furlan, Elise (2022) Speckle Interferometric Observations With the Gemini 8-m Telescopes: Signal-to-Noise Calculations and Observational Results. Frontiers in Astronomy and Space Sciences, 9 (5). Art. No. 871163. ISSN 2296-987X. doi:10.3389/fspas.2022.871163.

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Using 3 years of observations with the Zorro and ’Alopeke speckle interferometric instruments at Gemini South and North, respectively, we present an analysis of the sensitivity of the data taken in two narrow-band optical filters centered at 562 and 832 nm (widths of 54 and 40 nm, respectively). In this paper we focus on model calculations of the predicted signal-to-noise values achievable and the results of over 2500 actual observations. We find that S/N values of several 100 are easily achieved, but that the sky background during full moon is a very limiting factor in the observations, especially those performed in the short-wavelength (blue) optical spectral range and for targets fainter than R ∼14. A comparison of our Gemini speckle observations over six observing semesters reveals that red band-pass observations provide more robust results in general, likely due to better atmospheric performance at these wavelengths. Using the identical instruments on Gemini North and South, we find that similar results are obtained, yielding typical contrast limits of 5-9 magnitudes from the diffraction limit out to 1.2″ for a range of target brightness (optical magnitudes from ∼ 3 to <mml:math xmlns:mml="" id="m1">>16). Using our S/N model along with the observational results, an estimation of the contrast limits achievable for a given observation can be predicted based on the target brightness, sky illumination and seeing conditions, and the total integration time.

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Howell, Steve B.0000-0002-2532-2853
Furlan, Elise0000-0001-9800-6248
Additional Information:© 2022 Howell and Furlan. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Received: 07 February 2022; Accepted: 25 April 2022; Published: 01 June 2022. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. We wish to thank the many staff members at the Gemini Observatory who have helped us with this observational program over the years. In particular, Andrew Stephens, Ricardo Salinas, Alison Peck, John White, and Andy Adamson. We also wish to thank the dedicated members of our speckle team that made the entire program happen: Elliott Horch, Mark Everett, Nic Scott, David Ciardi, Rachel Matson, Crystal Gnilka, and Katie Lester. This paper made use of observational data obtained with the High-Resolution Imaging instruments ‘Alopeke and Zorro, mounted on the Gemini North and Gemini South telescopes respectively. The authors thank Andy Adamson for his comments on a draft manuscript. All of the data is public and available at the NASA Exoplanet Archive. ‘Alopeke and Zorro were funded by the NASA Exoplanet Exploration Program and built at the NASA Ames Research Center by SH, Nic Scott, Elliott P. Horch, and Emmett Quigley. The International Gemini Observatory, a program of NSF’s OIR Lab, is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation. on behalf of the Gemini partnership: the National Science Foundation (United States), National Research Council (Canada), Agencia Nacional de Investigación y Desarrollo (Chile), Ministerio de Ciencia, Tecnología e Innovación (Argentina), Ministério da Ciência, Tecnologia, Inovações e Comunicações (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea). Facilities: Gemini–‘Alopeke, Zorro. Data Availability Statement: The datasets presented in this study can be found in online repositories. The names of the repository/repositories and accession number(s) can be found in the article/Supplementary Material. Author Contributions: All authors listed have made a substantial, direct and intellectual contribution to the work, and approved it for publication. Funding: All funding was provided by NASA research grants. Conflict of Interest: The authors declare that the discussion and research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Ames Research CenterUNSPECIFIED
Gemini PartnershipUNSPECIFIED
Subject Keywords:instrumentation–telescopes, speckle imaging, Gemini telescope, techniques, high resolution imaging
Issue or Number:5
Record Number:CaltechAUTHORS:20220712-629846000
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Official Citation:Howell SB and Furlan E (2022) Speckle Interferometric Observations With the Gemini 8-m Telescopes: Signal-to-Noise Calculations and Observational Results. Front. Astron. Space Sci. 9:871163. doi: 10.3389/fspas.2022.871163
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:115517
Deposited By: George Porter
Deposited On:13 Jul 2022 18:55
Last Modified:13 Jul 2022 18:55

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