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Absolute photometric calibration of IRAC: lessons learned using nine years of flight data

Carey, S. and Ingalls, J. and Hora, J. and Surace, J. and Glaccum, W. and Lowrance, P. and Krick, J. E. and Cole, D. and Laine, S. and Engelke, C. and Price, S. and Bohlin, R. and Gordon, K. (2012) Absolute photometric calibration of IRAC: lessons learned using nine years of flight data. In: Space telescopes and instrumentation 2012: optical, infrared, and millimeter wave. Proceedings of SPIE . No.8442. Society of Photo-Optical Instrumentation Engineers (SPIE) , Bellingham, WA, Art. No. 84421Z. ISBN 978-0-8194-9143-5.

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Significant improvements in our understanding of various photometric effects have occurred in the more than nine years of flight operations of the Infrared Array Camera aboard the Spitzer Space Telescope. With the accumulation of calibration data, photometric variations that are intrinsic to the instrument can now be mapped with high fidelity. Using all existing data on calibration stars, the array location-dependent photometric correction (the variation of flux with position on the array) and the correction for intra-pixel sensitivity variation (pixel-phase) have been modeled simultaneously. Examination of the warm mission data enabled the characterization of the underlying form of the pixelphase variation in cryogenic data. In addition to the accumulation of calibration data, significant improvements in the calibration of the truth spectra of the calibrators has taken place. Using the work of Engelke et al. (2006), the KIII calibrators have no offset as compared to the AV calibrators, providing a second pillar of the calibration scheme. The current cryogenic calibration is better than 3% in an absolute sense, with most of the uncertainty still in the knowledge of the true flux densities of the primary calibrators. We present the final state of the cryogenic IRAC calibration and a comparison of the IRAC calibration to an independent calibration methodology using the HST primary calibrators.

Item Type:Book Section
Related URLs:
URLURL TypeDescription
Carey, S.0000-0002-0221-6871
Ingalls, J.0000-0003-4714-1364
Hora, J.0000-0002-5599-4650
Surace, J.0000-0001-7291-0087
Lowrance, P.0000-0001-8014-0270
Laine, S.0000-0003-1250-8314
Additional Information:© 2012 SPIE. Published: 22 August 2012. The authors acknowledge the efforts of our colleagues in the IRAC instrument and instrument support teams in maintaining and characterizing the IRAC instrument as well as the operations teams at the Spitzer Science Center, JPL and Lockheed Martin. We are also grateful to our colleagues at NIST and StSci for their calibration efforts. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Support for this work was provided by NASA through an award issued by JPL/Caltech.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Subject Keywords:infrared detectors; space telescopes; Spitzer Space Telescope; IRAC; photometric calibration
Series Name:Proceedings of SPIE
Issue or Number:8442
Record Number:CaltechAUTHORS:20121219-080601801
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Official Citation:S. Carey ; J. Ingalls ; J. Hora ; J. Surace ; W. Glaccum ; P. Lowrance ; J. Krick ; D. Cole ; S. Laine ; C. Engelke ; S. Price ; R. Bohlin ; K. Gordon; Absolute photometric calibration of IRAC: lessons learned using nine years of flight data. Proc. SPIE 8442, Space Telescopes and Instrumentation 2012: Optical, Infrared, and Millimeter Wave, 84421Z (September 21, 2012); doi:10.1117/12.927183.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:36037
Deposited By: Tony Diaz
Deposited On:12 Feb 2013 23:06
Last Modified:09 Nov 2021 23:19

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