Cookbook: Extracting photometry from FEPS Legacy MIPS Observations of the Pleiades Star HII 173

In this demo, we extract photometry for the target of small-field 24 um photometry observations. This demo continues from the mosaicking step.

Requirements:

• DATA DOWNLOAD: Follow the instructions in Download Data using Leopard: FEPS Pleiades Star HII_173 to retrieve the data, and then mosaic the data following the demo of the mosaicking step.
• ESTIMATED TIME: This should only take a few seconds to a few minutes on your computer.

You will need to run these scripts:

• apex_1frame.pl

You will need to use these namelists:

• apex_1frame_MIPS24.nl

Step-by-Step Guide:

1. Get set up.

   unix% cd r5315584/ch1/bcd/ unix% mv /where/you/downloaded/apex_1frame_MIPS24.nl ./cdf/ unix% nedit cdf/apex_1frame_MIPS24.nl

   Edit the namelist to reflect the absolute pathnames, including the PRF you want to start from. Normally, it's best to create your own custom PRF for your own observations, but in this case, there aren't all that many bright sources, so we can't construct our own from this single observation. So, we have to depend on the version that came with the MOPEX package, or the version that is available online.

2. Extract sources!

   unix% apex_1frame.pl -n apex_1frame_MIPS24.nl OR unix% mkdir pbcd24 unix% apex_1frame.pl -n apex_1frame_MIPS24.nl > pbcd24/apex.log &

   The star dead on in the center is the target of the observation, and it's bright enough that it will probably be caught by this step. (actual apex log file) The parameters in the namelist are set such that the extraction step is included, and the final file with extracted sources is mosaic24_extract.tbl.

3. Identify sources in list.

   You can find the source you want by loading the image into your favorite viewer and looking by ra and dec for the specific object. However, I find it easier to actually use Spot. The extracted table file is in IPAC table format, which Spot can read.

   unix% spot unix% nedit pbcd24/Combine/mosaic24_extract.tbl

   Start up Spot, and load in the mosaic (images menu/fits file option) -- no AORs needed. Be sure to load the file you just created -- r5315584/ch1/bcd/pbcd24/Combine/mosaic.fits Next, load in the source list. (overlays menu/catalog file option) Select r5315584/ch1/bcd/pbcd24/Output_1Frame/mosaic_extract.tbl. Upon loading, choose the little red and blue table icon to get a table listing. Click on the target of the observation in the center. Its symbol changes from a red cross to a yellow one, and it is highlighted in the list. It's number 208 in my version. (see figure)

   |srcid          |RA             |Dec            |flux           |delta_flux     |
   |i              |d              |d              |r              |r              |
    208             55.9519738      25.1900192      1.79e+03        2.48e+01        
   

   From the header, we know the flux is in units of uJy. Final flux is therefore 1.79e+03 uJy.

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