EPoS Contribution
EPoS Contribution
Photometric Calibration and Accuracy of the Herschel/PACS Photometer Camera

Markus Nielbock
Max-Planck-Institut für Astronomie, Heidelberg, Germany
The Herschel Space Observatory is comprised of three instruments, of which PACS is a combined photometer camera and photoconductor spectrograph. A wide range of objects like stars, asteroids and planets have been used to derive a photometric calibration of the imaging camera for its three bands with nominal reference wavelengths at 70 (blue), 100 (green) and 160 micron (red). Based on some 300 individual observations executed in the two PACS photometer AOT modes (chopped point source and scan map), we find a photometric accuracy of currently better than plus/minus 10% in the blue and green bands, and better than plus/minus 20% in the red band. Furthermore, there is no indication of NIR filter leaks. The photometric calibration appears to be linear between 1 mJy and 1000 Jy in all bands. Colour correction terms are insignificant for sources above 30 K.
In addition to the central results of the photometric calibration, I will focus on how the photometric accuracy can provide crucial feedback to the modelling of both the prime calibrators and celestial sources of general scientific interest. Since the PACS instrument covers the peak of the SED of star forming regions like protostellar cores or even individual YSOs, its photometric accuracy is a vital parameter in the significance of SED model fits.
Collaborators:
U. Klaas, MPIA, Germany
Z. Balog, MPIA, Germany
H. Linz, MPIA, Germany
T. Müller, MPE, Germany
D. Lutz, MPE, Germany
E. Vilenius, MPE, Germany
B. Altieri, ESAC, Spain
M. Sauvage, CEA/SAp, France
and all members of the PACS ICC
Suggested Session: Herschel