22 November 2012, 15:00 CET
Chair: Bruno Altieri (HSC)
C31, ESAC

Present: Bruno Altieri, David Atlee, Jacopo Fritz, Jean Matagne, Paola Andreani, Bruno MerĂ­n, Alvaro Ribas, marcio
Total: 8, 5 external

Presentations and demos at ftp://ftp.sciops.esa.int/pub/baltieri/PACS/webinarNov2012/

PACS photometry webinar presentation




PACS photometry webinar video tutorial




Questions and Answers


Demos run with HIPE 10.
Q-Jacopo Fritz: Is the high pass filter technical note just posted on the PACS twiki page the same that as been submitted to astro-ph yesterday?
A: yes, exactly the same.

Q-Jacopo Fritz: Can you also process sub-area maps with mad map?
A: currently not, because of the nature of the mad map processing philosophy.

Q-Jacopo Fritz: At this point should we already use HIPE 10?
A: no, the new version will be publicly available in December and only the deconvolution plugin only works in HIPE 10 but the rest should run in HIPE 9 equally well.

Q-AlvaroRibas: the PSF in the scanamorphos maps is not very stable, so which method would be better to use to extract the point sources? The suss extractor needs the beam area for 60 arcsec/sec parallel mode maps, which is not easy. For the aperture photometry I do also not know which aperture corrections to use because when combining both scan and cross-scan maps they look like a cross.
A: We have not really characterized the EEF for fast scan maps.

Q-Alvaro Ribas: Sussectractor fluxes are 0.6 x the aperture photometry fluxes. The FWHM would be 10 arc sec, while using standard PSFs, the numbers are not consistent within the quoted errors.
A: I would rely better on aperture photometry which guarantees that you would get all the flux. In general the largest value tends to be the most correct.
A: Send me one of those maps to study it with the photometer experts. It is a difficult issue.

BA: potential future improvements:
- The focal plane and field distortion in PACS could have changed with time and re-calibrating it would then improve the PSF, which then would translate to more accurate photometry.
- The knowledge on the actual pointing accuracy is being improved in parallel, which will translate to better resolution in the 70 and 100 micron fluxes.

Webinar contents


  1. Basic principles of PACS photometer data reduction
  2. Latest mapping possibilities inside and outside HIPE
  3. Convolving PACS and SPIRE maps
  4. Point source extraction in HIPE, fluxes, errors and upper limits
  5. Questions and Answers

Webinar Material (demo scripts and presentation)


ftp://ftp.sciops.esa.int/pub/baltieri/PACS/webinarNov2012/