Principal: Chad Engelbracht
Deputy: Dean Hines, Dave Frayer, Almudena Alonso, Jeonghee Rho
Data Monkey(s): Eiichi Egami
Priority: Necessary
Downlink Priority: Normal
Analysis Time: 48h
Last Updated:
This is the 160µm flux calibration to be done at the beginning and end of every campaign after the instrument has been basically checked out and the telescope temperature has stabilized.
This is the standard campaign 160µm flux calibration. 1 flux standard will be observed using 2 cycles of the photometry AOR, using superresolution mode and 3-second DCEs. This observation requires about 11 minutes, much less than the 20 minutes allocated for this task. This task is intended to establish the DN to Jy conversion factor for the campaign. Other tasks perform a detailed characterization of the dependence of this factor on integration time (mips-251), background (mips-921), or flux (mips-350).
The current target is HD 131873. This star was chosen because it is near the CVZ (and thus has a large visibility window) and because it is about 0.6 Jy at 160µm, which makes it bright enough to measure at a high ratio of signal to noise but faint enough that it is only 1/3 well in a 3s exposure, and is thus very unlikely to saturate the detector.
This task will generate 78 DCEs. The 60 non-stimulator images will be combined to produce 12 observations of the star.
Array Data Desired:
160 µm
Data Reformatting Option:
Special Instructions:
The main goal of the analysis is to determine the flux conversion factor for this campaign. The data will be processed with both the SSC pipeline and the MIPS DAT (using default parameters); the derived flux conversion factors will be compared to check for problems in the data processing. To derive the flux conversion factor, photometry will be performed on the mosaicked image. This must done in a way that corrects for distortion. The errors will be derived using the error images that accompany the BCDs. The assumed flux of the star (from the tables on the MIPS IST web page) will be divided by the measured counts (corrected from the measured aperture to the total star counts using an aperture correction) to compute the flux conversion factor.
A mosaic of the stellar images will be generated. This image will be examined visually for any obvious problems, such as poor matching of background levels between DCEs, missing data, asteroids in the field, etc. The mosaic may need to be regenerated if inappropriate data were used in the initial mosaic generation.
If the standard anomaly response actions do result in usable data, calibration can still be achieved using the redundant set of observations at the beginning or end of the campaign.