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drphilmarshall / OM10

Tools for working with the Oguri & Marshall (2010) mock catalog of strong gravitational lenses
MIT License
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columns.md - XIMG/YIMG? #58

Open jennykim1016 opened 7 years ago

jennykim1016 commented 7 years ago

Hi @drphilmarshall ,

I was wondering why both XIMG and YIMG are length four arrays. I thought this would be the X and Y position of the lensing galaxy, which would just be a float. If I would want to select the X position of the lens, could I just go with the first number? The third and the fourth number always seem to be zero.

Thanks!

drphilmarshall commented 7 years ago

XIMG and YIMG are the x and y sky positions, East and North of the lens galaxy center, of the quasar image positions. If NIM=2 then the last two values are zero, but if its a quad system then all four values should be non-zero. Note that the MAG and time delay arrays also have four components, for the image magnifications and time delays. You'll need to use these maginfications when predicting image fluxes in each band based on your painted sources.

On Tue, Feb 28, 2017 at 1:01 AM, Jenny Kim notifications@github.com wrote:

Hi @drphilmarshall https://github.com/drphilmarshall ,

I was wondering why both XIMG and YIMG are length four arrays. I thought this would be the X and Y position of the lensing galaxy, which would just be a float. If I would want to select the X position of the lens, could I just go with the first number? The third and the fourth number always seem to be zero.

Thanks!

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