WebPIMMS

WEBPIMMS is a Web tool based on PIMMS (the Portable Interactive Multi-Mission Simulator) created by Koji Mukai. WEBPIMMS implements a subset of the functionalities of the command line PIMMS. It allows easy access and use without the need to install the software, but WEBPIMMS does not have all the functionality of the command line version.

As an example, let’s consider an X-ray source with flux 10$^{-13}$erg cm$^{-2}$ s$^{-1}$ (0.5-2.0 keV) and a power-law spectral shape of photon index 2.1. To estimate what Swift will observe using WEBPIMMS do the following.

1. Choose Flux for Convert From using the pull-down menu.

2. Choose SWIFT for Into from the pull-down menu. You may use the default values for the energy range of the input detector. For this example the flux is measured over a smaller range of energy, and you need to change the default energy range in the next box to “0.5-2.0``.

3. Input 1E-13 in the Source: Flux/Count Rate box. WEBPIMMS will automatically chose the units of flux due to your choice of input above.

4. Choose a value of the Galactic hydrogen column density, nH, and a redshift. For this example choose 1e20 cm$^2$ for nH, and a redshift of 0.25.

5. Choose a source model. For this example select a power law with a photon index of 2.1.

6. Click the Estimate Count Rate button to perform the calculation.

The WEBPIMMS output screen (see below) summarizes the input parameters and displays estimated count rates for the XRT, BAT and UVOT. More information about the response matrices used can be found on the SSC Web site.

                          Output from PIMMS 


Input Parameters:

Model #1: Power Law
Model #2: n/a
Model #3: n/a
Model #4: n/a

P_I/keV #1: 2.1
P_I/keV #2: 
P_I/keV #3: 
Galactic nH: 1E20 cm-2 
Intrinsic nH: 0.0 / / cm-2


Redshift: 0.25
From: flux 1E-13 ergs/cm2/s 0.5-2.0 
Input Flux energy range: 0.5-2.0 keV
Internal model normalization = 7.429E-05
Redshifted with z= 0.2500 and a Galactic Nh= 1.000E+20


Useful mission related information may be found at:
http://swift.gsfc.nasa.gov/
 

                             SWIFT XRT


PIMMS predicts 8.157E-03 cps with SWIFT XRT PC
(Grade 0-12 on-axis count rate for an infinite extraction region) 
or 6.885E-03 cps in Grade 0 

                             SWIFT XRT

PIMMS predicts 8.647E-03 cps with SWIFT XRT WT
(Greade 0-2 on-axis count rate for an infinite extraction region) 
or 8.285E-03 cps in Grade 0 

                             SWIFT XRT

PIMMS predicts 8.959E-03 cps with SWIFT XRT PD
(Grade 0-5 on-axis count rate for an infinite extraction region) 
or 8.858E-03 cps in Grade 0-2 

                             SWIFT BAT

PIMMS predicts 2.468E-07 cps with SWIFT BAT SINGLE
(Channel 3-78 count rate per fully illuminated detector) 
With 0.2620 background cps, it can be detected at S/N=5.0 in 2.344E+10 s 

Results in the 4 standard Swift/BAT survey bands are: 



    Channel / Energy     Source     BGD    Detection


   3-7 /  14-24 keV     1.010E-07  0.0766  4.090E+10 s


   8-19/  24-48.9 keV   9.411E-08  0.0835  5.138E+10 s


  20-41/48.9-98.8 keV   4.481E-08  0.0646  1.754E+11 s


  42-78/98.8-194.9 keV  6.860E-09  0.0373  4.316E+12 s


Note PIMMS is primarily an X-ray tool, and extrapolation to the UV regime introduces additional uncertainties. In particular, PIMMS assumes
EB-V = NH / 4.8 x 1021 and an average Milkyway extinction law.

                             SWIFT UVOT

PIMMS predicts 1.031E-01 cps with SWIFT UVOT UVW1

 
                            SWIFT UVOT

PIMMS predicts 5.628E-02 cps with SWIFT UVOT UVM2


                             SWIFT UVOT

PIMMS predicts 2.092E-01 cps with SWIFT UVOT U


 
                            SWIFT UVOT

PIMMS predicts 1.949E-01 cps with SWIFT UVOT B

 
                            SWIFT UVOT

PIMMS predicts 9.149E-02 cps with SWIFT UVOT V

 
                             SWIFT UVOT

Note:Grisms still use pre-flight effective area files

PIMMS predicts 8.110E-01 cps with SWIFT UVOT UGRISM


                             SWIFT UVOT

Note:Grisms still use pre-flight effective area files

PIMMS predicts 1.045E+00 cps with SWIFT UVOT VGRISM

 
                             SWIFT UVOT

PIMMS predicts 9.217E-01 cps with SWIFT UVOT WHITE