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Background-limited Imaging in the Near Infrared with Warm InGaAs Sensors: Applications for Time-domain Astronomy

Simcoe, Robert A. and Fűrész, Gábor and Sullivan, Peter W. and Hellickson, Tim and Malonis, Andrew and Kasliwal, Mansi and Shectman, Stephen A. and Kollmeier, Juna A. and Moore, Anna (2019) Background-limited Imaging in the Near Infrared with Warm InGaAs Sensors: Applications for Time-domain Astronomy. Astronomical Journal, 157 (2). Art. No. 46. ISSN 1538-3881. doi:10.3847/1538-3881/aae094.

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We describe test observations made with a customized 640 × 512 pixel indium gallium arsenide (InGaAs) prototype astronomical camera on the 2.5 m DuPont telescope. This is the first test of InGaAs as a cost-effective alternative to HgCdTe for research-grade astronomical observations. The camera exhibits a background of 113 e– s^(–1)/pixel (dark + thermal) at operating sensor temperature T = −40°C, maintained by a simple thermoelectric cooler. The optomechanical structure floats at ambient temperature with no cold stop, unlike most IR instruments which must be cooled to mitigate thermal backgrounds. Measurements of the night sky using a reimager scaled at 0.”4/pixel show that the sky flux in Y is comparable to the dark current. At J the sky exceeds dark current by a factor of four, dominating the noise budget. The read noise (~43 e−) falls below sky + dark noise for exposures of t > 7 s in Y and 3.5 s in J. We observed several representative science targets, including two supernovae, a z = 6.3 quasar, two local galaxies monitored for IR transients, and a galaxy cluster at z = 0.87. We observe a partial transit of the hot Jupiter HATS-34b, demonstrating the photometric stability to detect a 1.2% transit. A tiling of larger-format sensors would produce an IR survey instrument with significant cost savings relative to HgCdTe-based cameras, if one is willing to forego the K band. Such a camera would be sensitive for a week or more to isotropic emission from r-process kilonova ejecta similar to that observed in GW170817, over the full 190 Mpc horizon of Advanced LIGO.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Simcoe, Robert A.0000-0003-3769-9559
Kasliwal, Mansi0000-0002-5619-4938
Kollmeier, Juna A.0000-0001-9852-1610
Moore, Anna0000-0002-2894-6936
Additional Information:© 2019 The American Astronomical Society. Received 2018 May 19; revised 2018 August 22; accepted 2018 August 29; published 2019 January 11. We gratefully acknowledge support from the Kavli Research Investment Fund at MIT for early development of custom InGaAs detector cameras and their associated hardware and optics. We also thank the technical staff of Carnegie Observatories and Las Campanas for their logistical support of a complex shipment to Chile and successful installation and operation on the telescope, as well as the scientific staff and Director for arranging time and support for our observations on the DuPont telescope. Facility: Du Pont. - Software: fitsh (Pál 2012), SExtractor (Bertin & Arnouts 1996), Scamp (Bertin 2006), Swarp (Bertin 2010).
Group:Astronomy Department
Funding AgencyGrant Number
Massachusetts Institute of Technology (MIT)UNSPECIFIED
Subject Keywords:instrumentation: detectors
Issue or Number:2
Record Number:CaltechAUTHORS:20190111-103223089
Persistent URL:
Official Citation:Robert A. Simcoe et al 2019 AJ 157 46
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:92214
Deposited By: Tony Diaz
Deposited On:12 Jan 2019 05:51
Last Modified:16 Nov 2021 03:48

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