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Previous: Sample Sessions


Using Multi-component Models

The ability to add up to 8 component models together, including Gaussian lines, have been added to PIMMS starting v3.0. Since this is a new feature, and the command syntax can become complex, this new section contains 3 examples. These, and the 4 example from the previous section, are avialable as *.xco files, in the new sample subdirectory of PIMMS.



Example 1. Estimating ASCA SIS count rates

*** PIMMS version 3.0 ***
    2000 April 28 release
    (this version does not simulate images)
    Reading mission directory, please wait
* Current model is BREMSSTRAHLUNG, kT=  10.0000 keV; NH =  1.000E+21
   <--- Use 'MODEL' command to change
* By default, input rate is taken to be
 Flux (    2.000-   10.000 keV) in ergs/cm/cm/s
   <--- Use 'FROM' command to change the default
* Simulation product will be
 Count rate in ASCA SIS
   <--- Use 'INSTRUMENT' command to switch to another instrument
PIMMS > mo rs logt 6.6 3e19 rs logt 7.2 3e19 0.5 1.0
PIMMS > output rs2t 0.1 4.0 0.002
PIMMS > inst rosat pspc open
PIMMS > from flux ergs 0.1-2.0 u
PIMMS > go 3e-11
* For Raymond Smith model with kT= 0.3431 keV (logT= 6.60); NH =  3.000E+19
    + Raymond Smith model with kT= 1.3657 keV (logT= 7.20); NH =  3.000E+19
             (  0.5000 times component 1 at     1.0000 keV)
   and an unabsorbed flux (    0.100-    2.000keV) of  3.000E-11 ergs/cm/cm/s
  (Model normalization =  6.958E-03)
* PIMMS predicts  3.639E+00 cps with ROSAT PSPC OPEN

This first example illustrates the use of two-temperature Raymond-Smith model. The absorption columns (to be specified explicitly for each component) are the same in this example. The second component has a flux at 1 keV which is 50% of the first component. Note, however, this is a tricky proposition for the line-rich Raymond-Smith models, and the composite model may differ significantly depending on whether the low (default) or the high (extra) resolution version is used. It is best to check this via the output command, which allows the users to check the actual model spectrum.

Example 2. Partial covering absorber

*** PIMMS version 3.0 ***
    2000 April 28 release
    (this version does not simulate images)
    Reading mission directory, please wait
* Current model is BREMSSTRAHLUNG, kT=  10.0000 keV; NH =  1.000E+21
   <--- Use 'MODEL' command to change
* By default, input rate is taken to be
 Flux (    2.000-   10.000 keV) in ergs/cm/cm/s
   <--- Use 'FROM' command to change the default
* Simulation product will be
 Count rate in ASCA SIS
   <--- Use 'INSTRUMENT' command to switch to another instrument
PIMMS > mo brems 15 3e23 brems 15 1e20 0.1 10 ga 6.5 0.1 250
PIMMS > output partial 0.1 10.0 0.005
PIMMS > inst xmm pn thin
PIMMS > go 0.5 asca sis
* For thermal Bremsstrahlung model with kT= 15.0000 keV; NH =  3.000E+23
    + thermal Bremsstrahlung model with kT= 15.0000 keV; NH =  1.000E+20
             (  0.1000 times component 1 at    10.0000 keV)
    + Gaussian model with E=  6.5000 keV; sigma= 0.1000 keV; NH =  3.000E+23
                          (Eq.W=250.0000 eV)
  and  5.000E-01 cps in ASCA SIS
  (Model normalization =  1.122E-02)
* PIMMS predicts  8.409E+00 cps with XMM PN THIN
  before dead time correction

% Pile-up and dead-time corrected count rates in 4 energy bands
  using various window options are:

 Window    Pileup  Dead                Corrected Good Count Rates
   Option   frac.   Time    0.1-0.4   0.4-1.0   1.0-2.5  2.5-10.0     Total

 Full      1.092%   7.0%     0.8676    1.4627    1.4825    3.4925      7.7348
 FullExtd  5.090%   2.0%     0.8773    1.4790    1.4991    3.5315      7.8212
 Large     0.633%   9.0%     0.8529    1.4379    1.4574    3.4332      7.6036
 Small     0.021%  29.0%     0.6696    1.1288    1.1441    2.6952      5.9690
 Timing   -------   1.5%     0.9291    1.5663    1.5876    3.7399      8.2826
 Burst    -------  99.8%   1.89E-03  3.18E-03  3.22E-03  7.59E-03      0.0168

% Any pile-up predictions over 10% are highly uncertain
This example shows how to set up a spectrum suffering from partial covering absorption. In addition, a Gaussian is added which has a different syntax: the three parameters are the line energy (keV), the physical width (keV), and the equivalent width (eV). Absorbing column is assumed to be the same as the first component (it can be specified explicitly, as the third parameter before the equivalent width).

Example 3. A redshifte example

*** PIMMS version 3.0 ***
    2000 April 28 release
    (this version does not simulate images)
    Reading mission directory, please wait
* Current model is BREMSSTRAHLUNG, kT=  10.0000 keV; NH =  1.000E+21
   <--- Use 'MODEL' command to change
* By default, input rate is taken to be
 Flux (    2.000-   10.000 keV) in ergs/cm/cm/s
   <--- Use 'FROM' command to change the default
* Simulation product will be
 Count rate in ASCA SIS
   <--- Use 'INSTRUMENT' command to switch to another instrument
PIMMS > mo pl 1.7 3e23 ga 6.4 0.2 150 rs 1.2 0.0 1.0 2.5 z 0.01 8e19
WARNING - this version of PIMMS has a grid of  59 Raymond-Smith plasma models
      from log T of  5.60; kT =  0.034
        to log T of  8.50; kT = 27.250
          choosing the nearest one, hope that's okay
         New temperature is  1.217 keV (log T is  7.15)
PIMMS > output agn_sb 0.1 10.0 0.01
PIMMS > inst chandra acis-s
PIMMS > go 1e-11
Warning:: integration to energies > model table
* For power law model with photon index = 1.7000; NH =  3.000E+23
    + Gaussian model with E=  6.4000 keV; sigma= 0.2000 keV; NH =  3.000E+23
                          (Eq.W=150.0000 eV)
    + Raymond Smith model with kT=  1.2172 keV (logT=7.2); NH =  0.000E+00
             (  1.0000 times component 1 at     2.5000 keV)
 ...redshifted with z=  0.0100 and a Galactic Nh= 8.000E+19
   and a flux (  2.000- 10.000keV) of  1.000E-11 ergs/cm/cm/s
  (Model normalization =  7.429E-03)
* PIMMS predicts  1.642E-01 cps with CHANDRA ACIS-S-BI
% Pileup estimate for ACIS:
  Pile-up is tolerable (10.0 %) at a frame-time of  1.612 s
In this example, the entire composite model is to be redshifted with z=0.01. Absorption specified with each component is taken to be intrinsic (i.e., also redshifted). Additionally, a Galactic (unredshifted) absorption is specified. For "unabsorbed" flux, both intrinsic and Galactic absorption will temporarily be set to 0.



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