Spectral Simulation Tool for AstroSat
     ======================================

astrosat.sl is ISIS/Slang code that can be used 
to simulate multi-wavelength spectra using all the 
co-aligned Astrosat instruments (UVIT, SXT, LAXPC, CZTI). 
The tool can also be used to predict count rate for any
given instrument including various UVIT filters. 
At present, the tool cannot be used to simulate UVIT 
grating spectra.

The tool runs under ISIS Version 1.6.2-35.  ISIS was 
developed at MIT for the analysis and interpretation 
of high resolution spectra. For details and installation 
of ISIS, please visit http://space.mit.edu/ASC/ISIS/.  
If you are new to ISIS, please read the ISIS vs. XSPEC article 
by Mike Nowak (http://space.mit.edu/home/mnowak/isis_vs_xspec/).

astrosat.sl uses plotting function from the ISIS Start-up 
scripts written by Mike Nowak. Please download these scripts from 
http://space.mit.edu/home/mnowak/isis_vs_xspec/download.html.


astrosat.sl uses X-ray responses provided by the 
instrument teams. The rmf/arf files for UVIT were generated 
using the filter effective areas provided by the UVIT team.  

Download response files for UVIT and X-ray instruments 
provided with this tool and edit path for  response files as e.g.,

static variable resp_path = "/soft/astrosat/responses/astrosat_xray_uvit_resp_12may2017/";


This path includes the directories CZTI, LAXPC, SXT and UVIT which 
contain the rmf/arf files.


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Usage :
 ISIS> .load astrosat.sl
 This will make available a number of function beginning 
 with astrosat_ e.g.
 
 isis> astrosat_ (TAB)
 astrosat_czti_simulate_spec   astrosat_get_count_rate
 astrosat_laxpc1_simulate_spec astrosat_laxpc2_simulate_spec
 astrosat_laxpc3_simulate_spec astrosat_multi_rebin_spec
 astrosat_sim                  astrosat_sxt_simulate_spec
 astrosat_uvit_fuv_baf2_sim    astrosat_uvit_fuv_caf21_sim
 astrosat_uvit_fuv_caf22_sim   astrosat_uvit_fuv_saph_sim
 astrosat_uvit_fuv_sil_sim     astrosat_uvit_fuv_sim
 astrosat_uvit_nuv_b13_sim     astrosat_uvit_nuv_b15_sim
 astrosat_uvit_nuv_b4_sim      astrosat_uvit_nuv_n2_sim
 astrosat_uvit_nuv_sil_sim     astrosat_uvit_nuv_sim
 astrosat_uvit_sim             astrosat_uvit_vis_bk7_sim
 astrosat_uvit_vis_nd1_sim     astrosat_uvit_vis_sim
 astrosat_uvit_vis_vis1_sim    astrosat_uvit_vis_vis2_sim
 astrosat_uvit_vis_vis3_sim    astrosat_xray_simulate_spec

 Just type one of the commands above followed by semicolon, it will output its usage e.g.,

 isis> astrosat_sim ;
Usage: astrosat_sim(Double_Type exposure);

where

 exposure=exposure time in seconds

isis>

 To simulate spectra for all the instruments

 First define a spectral model such as a simple absorbed powerlaw.

 ISIS> fit_fun("tbabs*powerlaw");

 Then issue the command.

 ISIS> astrosat_sim(Double Type exposure_time_in_sec);

 To plot all the spectra,

 ISIS> plot_data(get_data_indices);

 To simulate spectra for X-ray instruments only
 ISIS> astrosat_xray_simulate_spec(Double Type exposure_time_in_sec);

 To simulate single instrument spectrum e.g., SXT
 ISIS> astrosat_sxt_simulate_spec (Double Type exposure_time_in_sec);

 To simulate uvit count rates for all filters
 ISIS> astrosat_uvit_sim (Double Type exposure_time_in_sec);

 To simulate count rates in all FUV filter
 ISIS> astrosat_uvit_fuv_sim(Double Type exposure_time_in_sec);

 To simulate count rates in a single FUV filter
 ISIS> astrosat_uvit_fuv_baf2_sim (Double Type exposure_time_in_sec);
 
 To calculate count rates for a single instrument or UVIT filter, use
 astrosat_get_count_rate(data_index);

 ======================================================