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

By Marvin L. Cohen, S. Megeath, P. Hammersley, F. Martı́n-Luis, J. Stauffer. 2003

153 citations recorded by the source corpus.

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.

Subfields: Aerospace Engineering, Astronomy and Astrophysics, Computational Mechanics

View Paper: https://www.semanticscholar.org/paper/0492a1252ea2704f2a3dbc6beba8a388c35c6dd5

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Citations in the corpus

The Spitzer Survey of the Small Magellanic Cloud: S3MC Imaging and Photometry in the Mid- and Far-Infrared Wave Bands (2006, methodology): “The final catalog compiled has over 400,000 point sources and is available electronically at the project URL.12 To produce a uniform catalog, we expressed all fluxes in Jy, using the following photometric zero points for BVIJHK: 4060, 3723, 2459, 1594, 1024, and 666.8 Jy (Cohen et al. 2003a, 2003b).”
The Wavelength Dependence of Interstellar Extinction from 1.25 to 8.0 μm Using GLIMPSE Data (2004, background): “…flat-spectrum isophotal wavelengths for 2MASS are 1.235, 1.662, and 2.159 m, and the SSC-provided isophotal wavelengths for IRAC are 3.535, 4.502, 5.650, and 7.735 m. with modeled fluxes for five early A-type dwarf stars—these agreed to within 7% for all IRAC bands (Cohen et al. 2003; Kurucz 1993).”
The Mid-Infrared Properties of Starburst Galaxies from Spitzer-IRS Spectroscopy (2006, methodology): “We built our RSRF by extracting the spectra of calibration stars (Cohen et al. 2003) in the same way as we perform on our sources, then divided the template spectra of those standard stars by the spectra we extracted with the column extraction method.”
THE SPITZER–WISE SURVEY OF THE ECLIPTIC POLES (2011, methodology): “…the paucity of W3 and W4 calibrators in the EP-N, a set of bright K/M giant stars, with known IRAC and MIPS-24 photometry (Engelbracht et al. 2007; Cohen et al. 2003), that are located just outside of both polar CVZs were developed, including optical-infrared spectroscopy and spectral…”
Mid-Infrared Properties of Low-Metallicity Blue Compact Dwarf Galaxies from the Spitzer Infrared Spectrograph (2005, methodology): “Then the spectra were flux-calibrated by multiplication with the relative spectral response function (RSRF), which was created from the IRS standard stars Lac for SL and LL and Dra for SH and LH for which accurate templates were available (Cohen et al. 2003).”
The Infrared Camera (IRC) for AKARI–Design and Imaging Performance (2007, background): “…by observations of standard stars prepared on the basis of the same standard star networks as MSX and IRAC, which assures that the IRC calibration is tied with IRAC and other facilities whose calibration is based on the same networks (Cohen et al. 1999; Cohen et al. 2003; Ishihara et al. 2006b).”
High-Resolution Mid-Infrared Spectroscopy of Ultraluminous Infrared Galaxies (2007, methodology): “Wavelength and flux calibration were performed by dividing the extracted spectra by that of a standard star, Dra, and multiplying by its template (Cohen et al. 2003).”
A NEW CLASS OF LUMINOUS TRANSIENTS AND A FIRST CENSUS OF THEIR MASSIVE STELLAR PROGENITORS (2008, methodology): “In order to convert MIR and optical magnitudes to fluxes, we used zeropoints in Reach et al. (2005) and Cohen et al. (2003) for the EAGBs and LBV candidates, respectively.”
GROND—a 7-Channel Imager (2008, background): “The spectral types of both stars are also known (Drilling & Landolt 1979, Cohen et al. 2003).”
CRYSTALLINE SILICATES AND DUST PROCESSING IN THE PROTOPLANETARY DISKS OF THE TAURUS YOUNG CLUSTER (2007, methodology): “…spectra were made for two standard stars, α Lac (A1V) for SL and LL, and ξ Dra (K2III) for SH and LH. Relative spectral response functions (RSRFs) were made by dividing these spectra into the template spectra corresponding to the stars (Cohen et al. 2003; M. Cohen 2004, private communication).”
Hubble Space Telescope Absolute Spectrophotometry of Vega from the Far-Ultraviolet to the Infrared (2004, methodology): “…for the definition of the Landolt V bandpass: the Kitt Peak filter+detector (A. U. Landolt 1998, private communication), the CTIO filter+detector (Landolt 1992), and the latter as modified by Cohen et al. (2003a) to include an estimate of the atmospheric transparency above the CTIO observatory.”
Spitzer SAGE Survey of the Large Magellanic Cloud. II. Evolved Stars and Infrared Color-Magnitude Diagrams (2006, methodology): “A network of 238 absolute calibration stars has been developed near the area observed by SAGE (137 stars overlap the SAGE survey area) using the identical technique by which IRAC primary standards were established (Cohen et al. 2003).”
A Survey and Analysis of Spitzer Infrared Spectrograph Spectra of T Tauri Stars in Taurus (2006, methodology): “The spectra were extracted using a variable-width column extraction, which varies with the width of the point-spread function, and cal- ibrated with Lac (A1 V) and its template spectrum (Cohen et al. 2003).”
Effective temperature scale and bolometric corrections from 2MASS photometry (2006, methodology): “Both in the case of Cohen et al. (2003a) and in our case, the value of the offset in the H band differs significantly from the offsets in J and K.”
Calibration of Synthetic Photometry Using DA White Dwarfs (2005, methodology): “…BG04, we use the Landolt (1992a, 1992b) JohnsonKron-Cousins Cerro Tololo Inter-American Observatory filter response functions, as modified for atmospheric transmission by Cohen et al. (2003a), and directly compute the synthetic UBVRI magnitudes for both Vega and the four primary HST flux standards.”