Re: Exporting unabsorbed data points

    Fabien> But, what I would like to get now is the unabsorbed data fluxes with
    Fabien> their errors. And I have not been able to figure out how to export
    Fabien> those ... I guess I have missed something obvious.


    Michael> Unabsorbed data fluxes is not something we normally do in X-ray astronomy.
    Michael> (Yeah, I know, optical guys do it all the time...  Crazy!)

Given that it might be crazy, (you are "unfolding" the data, but for
low-fi work, or an overview figure, OK, be crazy...),

    Michael> Best I can suggest is get the model values with and without absorption,
    Michael> take the ratio, and multiply the data flux values (and their errors) by that ratio.
    Michael> Not perfect (it ignores the error in the N_h), but it should work.

... it might be easier to just eval the abs function instead of
ratioing models with and without:

   transmission = eval_fun2( "tbabs", w1, w2, your_nH22 );

which gives you the transmission function on the grid defined by w1,
w2; well, I don't know tbabs - if it has more parameters, they have to
be passed - read the eval_fun2 help.   For wabs with one parameter,
this, for example, works:

   (w1,w2) = linear_grid( 1.0, 100.0, 8192);
   transmission = eval_fun2( "wabs", w1, w2, 1.0 );
   plot( w1, transmission );


Doesn't flux_corr() provide the "corrected" data (with errors)?  This
is the isis built-in function, similar to Mike's plot_unfold, in part.
It creates an array which is the data divided by the integral of
arf*rmf (that is, the counts divided by counts per constant flux
model; the instrumental convolution is included).  You can then
get_data_flux(n), and then scale by the transmission.

If you have combined data, you might have to be careful to get the
right weighting (or get each one and do it yourself).


-- Dave

David Huenemoerder  617-253-4283 (o); -253-8084 (f); http://space.mit.edu/home/dph
MIT Kavli Institute for Astrophysics and Space Research
70 Vassar St., NE80-6065,
Cambridge, MA  02139
[Admin. Asst.: Elaine Tirrell, 617-253-7480, egt_at_email.domain.hidden
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