Open jennykim1016 opened 7 years ago
Scipy optimize curve fit fails regardless of the initial value. I will just use numpy.polyfit to generate the data.
Thus I need to
This is the final plot that I produced!
Nice work, Jenny! You did that super-fast :-) Let me just check real quick: are the sizes in the Sonnenfeld et al table in arcsec or in kpc? We expect a correlation in physical size (in kpc) but maybe not in apparent size (where the different redshifts cause the sizes to get mixed up). If the sizes are in arcsec, can you please convert to kpc (using lenspop angular diameter distances) and re-do your fit? Thanks!
Also - are you updating the OM10 notebook to include a section and a conclusion on lens galaxy sizes? You should! :-)
Hi @drphilmarshall ,
I used arcsecond -- I just fixed it to use kpc. From the virial theorem it seems reasonable to have a correlation between the size and the velocity dispersion, but it is not apparent in the non-logged graph, so I changed the graph to log-log graph and calculated the sizes from there.
It seems like, however, there are two columns in om10 - 'REFF' and 'REFF_T'. I have been updating REFF and would want to check that this is the right column. I also updated the columns.md
, specifying that the REFF
has a unit of kpc. However, if you think it is better to save REFF
in arcseconds for consistency, I can fix it!
And yes, I have been updating the notebooks :) It is in the size_compute
branch in this forked repository.
Final Plot)
I'm not sure what the _T
stands for, but it might be "theta". I think you
shoudl put the Reff in kpc in REFF
and the Reff in arcsec in REFF_T
-
this way we won't need to recalculate either one!
Good idea to fit log size vs log vdsip, and also to define a Gaussian
scatter in log size to draw from. I agree that there is not much of a
correlation - but then, we are only looking at the most massive galaxies.
One last thing - it's usual to use log_10
for these sorts of quantities,
and then qhen you quote the width of the Gaussian distribution you say "a
scatter of XX dex". Thanks!
I see! I fixed all the notebooks / codes to have log_10. I will finish updating the REFF_T
and request the review soon. Thanks!
This is the raw scatterplot of the data we have from Sonnenfeld's table. I expected to have data that looks like this (its a log-log graph):
I think I can still try to fit in the curves onto the plot...