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Spectral Irradiance Calibration in the Infrared. XIII. Supertemplates and On-Orbit Calibrators for the SIRTF Infrared Array Camera

Cohen, Martin and Megeath, S. T. and Hammersley, Peter L. and Martín-Luis, Fabiola and Stauffer, John (2003) Spectral Irradiance Calibration in the Infrared. XIII. Supertemplates and On-Orbit Calibrators for the SIRTF Infrared Array Camera. Astronomical Journal, 125 (5). pp. 2645-2663. ISSN 0004-6256. doi:10.1086/374362.

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We describe the technique that will be used to develop a set of on-orbit calibrators for the Infrared Array Camera (IRAC) and demonstrate the validity of the method for stars with spectral types either K0–M0 III or A0–A5 V. For application to SIRTF, the approach is intended to operate with all available optical, near-infrared (NIR), and mid-infrared (MIR) photometry and to yield complete absolute spectra from UV to MIR. One set of stars is picked from Landolt's extensive network of optical (UBVRI) calibrators, the other from the Carter-Meadows set of faint IR standards. Traceability to the "Cohen-Walker-Witteborn" framework of absolute photometry and stellar spectra is assured. The method is based on the use of either "supertemplates," which represent the intrinsic shapes of the spectra of K0–M0 III stars from far-UV (1150 Å) to MIR (35 μm) wavelengths, or Kurucz synthetic spectra for A0–A5 V stars. Each supertemplate or Kurucz model is reddened according to the individual star's extinction and is normalized using available characterized optical photometry. This paper tests our capability to predict NIR (JHK) magnitudes using supertemplates or models constrained by Hipparcos/Tycho or precision ground-based optical data. We provide absolutely calibrated 0.275–35.00 μm spectra of 33 Landolt and Carter-Meadows optical standard stars to demonstrate the viability of this technique, and to offer a set of IR calibrators 100–1000 times fainter than those we have previously published. As an indication of what we can expect for actual IRAC calibration stars, we have calculated the absolute uncertainties associated with predicting the IRAC magnitudes for the faintest cool giant and hot dwarf in this new set of calibration stars.

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Megeath, S. T.0000-0001-7629-3573
Stauffer, John0000-0003-3595-7382
Additional Information:© 2003. The American Astronomical Society. Received 2002 November 19; accepted 2003 January 24. M. C.'s work on IRAC's calibrators is supported by contract SV9-69008 between the University of California, Berkeley and the Smithsonian Astrophysical Observatory. We are grateful to Arlo Landolt for supplying electronically readable tables of his network of stars, and of his filters and phototube response curves, and to Andrew Pickles for his extremely helpful and detailed review. We thank David Shupe for extracting the most accurate coordinates from SIMBAD for the Landolt stars for our first observing runs at Mount Hopkins, and Mike Calkins and Perry Berlind for their invaluable efforts to secure FAST spectra. We thank Fred Witteborn, Jesse Bregman, and Diane Wooden for the use of the unpublished HIFOGS KAO spectra of β UMi from one of our collaborative flight series in 1995. This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Smithsonian Astrophysical ObservatorySV9-69008
Subject Keywords:infrared radiation ; methods: analytical; stars: late-type; techniques: spectroscopic
Issue or Number:5
Record Number:CaltechAUTHORS:20170408-140503585
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Official Citation:Martin Cohen et al 2003 AJ 125 2645
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:75915
Deposited By: 1Science Import
Deposited On:19 Apr 2017 19:22
Last Modified:15 Nov 2021 16:56

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