Re: Aped Modelling Question

On Mon, Nov 18, 2002 at 13:40 -0500, Nat Butler wrote:
> This might be an APED issue rather than an ISIS issue, but here goes.
>
> I'm trying to use APED models for a CIE plasma at z~1.  For some reason the
> model spectrum cuts off at around 5 keV, perhaps because the calculation
> only goes to ~10keV in the source frame.
>
> I've been setting up the model using default_plasma_state, create_aped_fun,
> and the APED database: /nfs/cxc/a1/share/atomdb/aped-1.2.0.
>
> Is there some way to ensure that the calculation, particularly of the
> continuum, goes to higher energies?  It appears that the atom database
> contains lines only down to 1.198 A.  Can this be extended?
>
> -Nat

Hi Nat,

I think its mostly an APED issue.  Looking at the continuum file
  apec_v1.2.0_coco.fits.gz
I believe all the energy grids cut off at 10 keV.

When computing redshifted models on a particular observer frame
grid, isis first shifts the specified grid into the emitter
frame, computes the model there and then shifts back into the
observer frame.  That ensures that the full emitter frame
spectrum is included -- in this case, the 10 keV cutoff comes
from the database itself.

Future releases of APED may extend the wavelength coverage,
but I don't know when those data may be available in APED.

In principle, users should be able to extend the database by
providing files in the APED format.  As long as the file format
is the same, isis could use such user-provided emissivity
database files to compute and fit multicomponent spectral
models. Although computing new spectral models would be
nontrivial (to say the least), it should be possible in
principle.

-John

--
John C. Houck                       MIT Center for Space Research
NE80-6005: 617-253-3849                   77 Massachusetts Avenue
42:21:55.105N, 71:05:28.122W             Cambridge, MA 02139-4307
----
You received this message because you are
subscribed to the isis-users list.
To unsubscribe, send a message to
isis-users-request_at_email.domain.hiddenwith the first line of the message as:
unsubscribe