Spitzer Documentation & Tools
Peakup PSF/PRF

This page describes the Point Source Functions (PSFs) and provides FITS files of the Point Response Functions (PRFs) for IRS Peak-Up Imaging. (Peak-up target acquisition images are obtained differently, using the Double Correlated Sampling mode.) A PRF is the convolution of an oversampled PSF with the pixel response function, and is required by the point source extraction module (APEX) within MOPEX to perform PSF fitting. An explanation of the difference between PRFs and PSFs is given in the document PRF v PSF (PDF, 41 KB).

PSFs

Blue

The PSF shown below is based on observations of the star HD 42525. The relevant data have AORKEYs 17080064 and 17082112, and were mosaicked using MOPEX.

PSF_for_web_blue
Blue Peak-up PSF, ~54 arcsec on a side.
PSF profile blue.  The FWHM for a source with a blue SED across the filter passband, such as a star, is 3.8 arcsec.
Blue Peak Up PSF Profile

Red

The PSF shown below is based on observations of the star HD 172728. The relevant data have AORKEYs 20552960 and 20678912, and were mosaicked using MOPEX.

psf_for_web_red
Red Peak-up PSF, ~54 arcsec on a side.
PSF profile red
Red Peak Up PSF Profile

PRFs

The SSC developed three different kinds of PRFs, with varying pixel scales and interpolation methods (see MOPEX User's Guide). Users should choose the PRF that best matches the data reduction technique used to create their mosaics.

1. standard pixel scale (1.8 arcsec) and default interpolation

2. resampled pixel scale (0.9 arcsec) and default interpolation

3. resampled pixel scale (0.9 arcsec) and drizzle interpolation