next up previous contents
Next: XRT Data Simulator Up: Simulation Tools Previous: Simulating Swift Data Using   Contents


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.

An example is comparing what Swift will see from a GRB similar to one that was observed by BeppoSAX. Take a GRB with a peak count rate in the SAX/MECS detector of 65 counts/s, that is in its early phase, and was measured to be well-described by a power law with a photon index 1.2. What would Swift observe?

To perform this comparison using WEBPIMMS do the following.

  1. Choose SAX/MECS Count Rate 2 MECS 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. If the count rate you have is over a smaller range of energy change the default energy range in the next box.

  3. Input 65 in the Source: Flux/Count Rate box. WEBPIMMS will automatically chose the units of counts/s 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 1e19 cm$^2$ for nH, and a redshift of 0.65.

  5. Choose a source model. For this example select a power law with a photon index of 1.2.

  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: Model #3: Model #4:

P_l/keV: 1.2 P_l/kev: P_l/keV #3:

Galactic nH: 1e19 cm-2
Intrinsic nH: 0.0 //cm-2

Redshift: 0.65
From: sax mecs
Output Flux energy range: keV;
Count Rate: 65 cps
Internal model normalization = 1.174E+00
Redshifted with z= 0.6500 and a Galactic Hh= 1.000E+19



Useful mission related information may be found at:
http://swiftsc.gsfc.nasa.gov/
http://heasarc.gsfc.nasa.gov/docs/sax/inst_papers.html



                               SWIFT XRT 


PIMMS predicts 1.429E+02 cps with SWIFT XRT PC
(Grade 0-12 on-axis count rate for an infinite extraction region)
or 1.117E+03 cps in Grade 0


                               SWIFT XRT 


PIMMS predicts 1.521E+02 cps with SWIFT XRT WT
(Grade 0-12 on-axis count rate for an infinite extraction region) 
or 1.401E+02 cps in Grade 0 


                               SWIFT XRT 


PIMMS predicts 1.632E+02 cps with SWIFT XRT PD
(Grade 0-12 on-axis count rate for an infinite extraction region) 
or 1.591E+02 cps in Grade 0 


                               SWIFT BAT 

PIMMS predicts 9.052E-02 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 0.204 s 

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


    Channel / Energy     Source     BGD    Detection


   3-7 /  14-24 keV         0.020  0.0766      1.127 s


   8-19/  24-48.9 keV       0.033  0.0835      0.510 s


  20-41/48.9-98.8 keV       0.030  0.0646      0.496 s


  42-78/98.8-194.9 keV  7.828E-03  0.0373      3.662 s


Note PIMMS is primarily an X-ray tool, and extrapolation to the UV
regime introduces additional uncertainties. In particular, PIMMS
assumes E(B-V) = N_H / 4.8E+21 and an average Milky Way extinction law.


                               SWIFT UVOT


PIMMS predicts 1.305E+01 cps with SWIFT UVOT UVW1


                               SWIFT UVOT


PIMMS predicts 8.418E+00 cps with SWIFT UVOT UVM2


                               SWIFT UVOT


PIMMS predicts 1.982E+01 cps with SWIFT UVOT U


                               SWIFT UVOT


PIMMS predicts 1.481E+01 cps with SWIFT UVOT B


                               SWIFT UVOT


PIMMS predicts 5.610E+00 cps with SWIFT UVOT V


                               SWIFT UVOT

Note: Grisms still use pre-flight effective area files
PIMMS predicts 9.199E+01 cps with SWIFT UVOT UGRISM


                               SWIFT UVOT


Note: Grisms still use pre-flight effective area files
PIMMS predicts 8.686E+01 cps with SWIFT UVOT VGRISM


                               SWIFT UVOT


PIMMS predicts 9.497E+01 cps with SWIFT UVOT WHITE


next up previous contents
Next: XRT Data Simulator Up: Simulation Tools Previous: Simulating Swift Data Using   Contents
Eleonora Troja 2013-09-03