Gordon, Karl D. and Engelbracht, Charles W. and Fadda, Dario and Stansberry, John and Wachter, Stefanie and Frayer, Dave T. and Rieke, George and Noriega-Crespo, Alberto and Latter, William B. and Young, Erick and Neugebauer, Gerry and Balog, Zoltan and Beeman, Jeffrey W. and Dole, Hervé and Egami, Eiichi and Haller, Eugene E. and Hines, Dean and Kelly, Doug and Marleau, Francine and Misselt, Karl and Morrison, Jane and Pérez‐González, Pablo and Rho, Jeonghee and Wheaton, Wm. A. (2007) Absolute Calibration and Characterization of the Multiband Imaging Photometer for Spitzer. II. 70 μm Imaging. Publications of the Astronomical Society of the Pacific, 119 (859). pp. 1019-1037. ISSN 0004-6280 http://resolver.caltech.edu/CaltechAUTHORS:20100420-110506497
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The absolute calibration and characterization of the Multiband Imaging Photometer for Spitzer (MIPS) 70 μm coarse‐and fine‐scale imaging modes are presented based on over 2.5 yr of observations. Accurate photometry (especially for faint sources) requires two simple processing steps beyond the standard data reduction to remove long‐term detector transients. Point‐spread function (PSF) fitting photometry is found to give more accurate flux densities than aperture photometry. Based on the PSF fitting photometry, the calibration factor shows no strong trend with flux density, background, spectral type, exposure time, or time since anneals. The coarse‐scale calibration sample includes observations of stars with flux densities from 22 mJy to 17 Jy, on backgrounds from 4 to 26 MJy sr^(−1), and with spectral types from B to M. The coarse‐scale calibration is 702 ± 35 MJy sr^(−1) MIPS70^(−1) (5% uncertainty) and is based on measurements of 66 stars. The instrumental units of the MIPS 70 μm coarse‐ and fine‐scale imaging modes are called MIPS70 and MIPS70F, respectively. The photometric repeatability is calculated to be 4.5% from two stars measured during every MIPS campaign and includes variations on all timescales probed. The preliminary fine‐scale calibration factor is 2894 ± 294 MJy sr^(−1) MIPS70F^(−1) (10% uncertainty) based on 10 stars. The uncertainties in the coarse‐ and fine‐scale calibration factors are dominated by the 4.5% photometric repeatability and the small sample size, respectively. The 5 σ, 500 s sensitivity of the coarse‐scale observations is 6–8 mJy. This work shows that the MIPS 70 μm array produces accurate, well‐calibrated photometry and validates the MIPS 70 μm operating strategy, especially the use of frequent stimulator flashes to track the changing responsivities of the Ge:Ga detectors.
|Additional Information:||© 2007 Astronomical Society of the Pacific. Received 2006 November 15; accepted 2007 April 16; published 2007 October 2. We thank the anonymous referee for comments that improved the paper. 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 NASA contract 1407. Support for this work was provided by NASA through contract 1255094 issued by JPL/Caltech.|
|Official Citation:||Absolute Calibration and Characterization of the Multiband Imaging Photometer for Spitzer. II. 70 μm Imaging Karl D. Gordon, Charles W. Engelbracht, Dario Fadda, John Stansberry, Stefanie Wachter, Dave T. Frayer, George Rieke, Alberto Noriega‐Crespo, William B. Latter, Erick Young, Gerry Neugebauer, Zoltan Balog, Jeffrey W. Beeman, Hervé Dole, Eiichi Egami, Eugene E. Haller, Dean Hines, Doug Kelly, Francine Marleau, Karl Misselt, Jane Morrison, Pablo Pérez‐González, Jeonghee Rho, and Wm. A. Wheaton Publications of the Astronomical Society of the Pacific 2007 119:859, 1019-1037|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Jason Perez|
|Deposited On:||20 Apr 2010 20:56|
|Last Modified:||26 Dec 2012 11:59|
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