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IRS: Peak-Up PSF and PRFs |
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Sample Point-Spread-Function Images for IRS Peak-Up ImagingFor additional information on peak-up image characteristics and data processing, see Chapter 6, pp. 44-53 in the IRS Data Handbook.These images were obtained with the IRS Peak-Up Imaging (PUI) AOT -- see Section 7.2.3.4 in the Spitzer Observer's Manual. (Peak-up target acqusition images are obtained differently, using the Double Correlated Sampling mode -- see Section 7.1.3.1.2 in the SOM). The data were mosaiced using MOPEX. All data from the associated AORs are publicly available in the Spitzer archive as AORs 17080064, 17082112 (Blue) and 20552960, 20678912 (Red).
Blue Peak-up PSF, about 54 arcsec on a side. The observed star is HD 42525. The FWHM for a source with a blue SED across the filter passband, such as a star, is 3.8 arcsec.
Red Peak-up PSF, about 54 arcsec on a side. The observed star is HD172728. The FWHM for a source with a blue SED across the filter passband, such as a star, is 5.3 arcsec. The PSFs are on 0.9" pixels which is half the intrinsic pixel scale. The PSFs are normalized to 1 inside the aperture used for flux calibration and have the sky background removed. Please see calibration details and aperture corrections at http://ssc.spitzer.caltech.edu/irs/pu_fluxcal.txt
Sample Point-Response-Function Images for IRS Peak-Up ImagingTo do PSF fitting, the point source extraction module (APEX) within MOPEX requires a Point Response Function (PRF). This is the convolution of an oversampled PSF with the pixel response function. An explanation of the difference with PSFs is given in the document PRF_vs_PDF. The updated PRFs are included as part of the MOPEX distribution within the cal directory, and are also provided to users who download the cal directory for PU data from Leopard. We include those files here:
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help@spitzer.caltech.edu http://ssc.spitzer.caltech.edu/irs/puipsf/
