$SSW/packages/chianti/idl/make_chianti_spec.pro

PROJECT : CHIANTI

CHIANTI is an Atomic Database Package for Spectroscopic Diagnostics of
Astrophysical Plasmas. It is a collaborative project involving the Naval
Research Laboratory (USA), the University of Florence (Italy), the
University of Cambridge and the Rutherford Appleton Laboratory (UK).

NAME : MAKE_CHIANTI_SPEC

PURPOSE :
To create a CHIANTI synthetic spectrum

CALLING SEQUENCE:

IDL> make_chianti_spec, TRANSITIONS, LAMBDA, SPECTRUM,$
[BIN_SIZE= , ,INSTR_FWHM= , PIXEL=PIXEL, BINSIZE = BINSIZE, $
WRANGE= , ALL=ALL, continuum=continuum, $
ABUND_NAME= , MIN_ABUND=, photons=photons, effarea=effarea

CALLED BY:
GOES_TF, GOES_TF_COEFF
HW_SYNSPEC__DEFINE defines the class HW_SYNSPEC Objects of this [1]
HW_SYNSPEC__DEFINE defines the class HW_SYNSPEC Objects of this [2]
SYNTHETIC, ch_ss, make_goes_chianti_response [1]
make_goes_chianti_response [2], make_goes_chianti_response [3]
make_goes_chianti_response [4]
PROCEDURE :

From information contained in the structure TRANSITIONS, constructs
a synthetic spectrum

By default, routine assumes thermal widths for lines.

PROGRAMMING NOTES

The line profile is constructed using the IDL gaussint routine.
For a wavelength pixel centred at l and with width dl, gaussint
is used to integrate the Gaussian up to l-dl/2 and up to l+dl/2.
The difference between the two is the intensity in this pixel.

INPUTS :

TRANSITIONS, the structure created by ch_synthetic.pro.

OPT. INPUTS :

LAMBDA Array of wavelengths (X-values). If not defined as input, it is
calculated on the basis of BIN_SIZE, and returned as an output.
If defined as input, the routine checks that there are at least
10 points in the wavelength range defined by WRANGE. If there
are, the corresponding subset of LAMBDA is returned, otherwise
the routine exits with an error.

BIN_SIZE Bin size in Angstroms of the spectrum to be created. A linear
spectrum is assumed. In case an effective area file is used, the
wavelenghts in the file (that might not be linear) are used to
create the spectrum, and this bin size looses any meaning.

WRANGE Allows a subset of the wavelength range to be turned into
a spectrum. When using syn_plot, this speeds up the routine
a lot if you've elected to zoom in on a region.

INSTR_FWHM Instrumental FWHM (Angstroms).
In case an effective area file is used, The line intensities
contributing to each bin are summed, and subsequently convolved
with a gaussian of full-width-half-maximum FWHM if FWHM is not
set = 0 . Please make sure that the FWHM value (if not set to
zero) is larger than the bin size.

ABUND_NAME A CHIANTI abundance file name can be set.
It allows the abundance file given in transitions.abund_name
(if present) to be over-ridden. Note that it also used for
the continuum calculation.

MIN_ABUND: If set, calculates line intensities only from those elements
which have an abundance greater than min_abund.
Can speed up the calculations. For example, from Allen
(1973):

abundance (H) = 1.
abundance (He) = 0.085
abundance (C) = 3.3e-4
abundance (O) = 6.6e-4
abundance (Si) = 3.3e-5
abundance (Fe) = 3.9e-5

FILE_EFFAREA
The Effective Area File (TWO COLUMNS - wavelengths in
Angstroms and cm^2 values) If defined, then the spectrum is
multiplied with these values. Any input LAMBDA value is
over-written by the wavelenghts in the file (that might not
be linear) and are used to create the spectrum.
Note that this option only works well if a sufficient number
of bins is given. The line intensities contributing to each
bin are summed, and subsequently convolved with a gaussian
of full-width-half-maximum FWHM, if FWHM is not set = 0.
Please note that the convolution might not work if a small
number of bins is defined.

OUTPUTS :

LAMBDA Array of wavelengths (X-values).
If not defined as input, it is
calculated on the basis of BIN_SIZE, and returned as an output.
If defined as input, the routine checks that there are at least
10 points in the wavelength range defined by WRANGE. If there
are, the corresponding subset of LAMBDA is returned, otherwise
the routine exits with an error.

SPECTRUM A structure containing all the information:

LAMBDA The array of X-values
SPECTRUM The array of Y-values
UNITS The units of LAMBDA, SPECTRUM
INSTR_FWHM The Instrumental FWHM
BIN_SIZE Width of the Bins (fixed) in angstroms
ABUND_NAME The CHIANTI abundance file name
ABUND The abundance values
MIN_ABUND The minimum abundance value used
ABUND_REF The references
CONTINUUM The values of the continuum (if calculated)

FILE_EFFAREA The Effective Area File used (optional)
EFFAREA The array of effective area values
(optional - same size of LAMBDA)

.LINES An array of structures, for all the lines used
to calculate the SPECTRUM.
The tags are the same as those created by
CH_SYNTHETIC, plus
.PEAK The peak intensity of the line in the spectrum
(approx. value)

OPT. OUTPUTS:

BINSIZE If BIN_SIZE is not specified, then the spectrum
bin-sizes are computed automatically, and the size of the
bin returned in BINSIZE.

KEYWORDS :

PIXEL The spectrum is given in /pixel units rather /ang
(DISABLED)

ALL Add lines that originally had negative wavelengths

PHOTONS If set=1, the output intensities will be in photons instead of
ergs.

CONTINUUM
If set, then the continuum is added to the
spectrum.

VERBOSE If set, then print out information while the routine is
running.

KEV If set, then the output spectrum is in units
erg cm^-2 s^-1 keV^-1.

CALLS : ***
ADD_TAG [1], ADD_TAG [2], AVERAGE, BIGPICKFILE, CH_GET_FILE, CONCAT_DIR [1]
CONCAT_DIR [2], CONCAT_DIR [3], DELVARX [1], DELVARX [2], DELVARX [3], DELVARX [4]
FILE_EXIST [2], GAUSS_PUT, GET_ATOMIC_WEIGHT, READ_ABUND, READ_ASCII, READ_IONEQ
REM_TAG [1], REM_TAG [2], REVERSE, SPLINE, TAG_EXIST [1], TAG_EXIST [2], TWO_PHOTON
VALID_NUM [1], VALID_NUM [2], VALID_NUM [3], ch_check_str, concat_dir [4]
delvarx [5], dir_exist [1], dir_exist [2], file_exist [1], file_exist [3]
freebound, freefree, hastogram, mid2bound, rebinw
RESTRICTIONS: The input structure has to be of the type created by ch_synthetic.
The LAMBDA, EFFAREA values must be ordered in wavelength and the
LAMBDA values must be in Angstroms.

SIDE EFFECTS: None known yet.

EXAMPLES :

make_chianti_spec, output_struct, LAMBDA, SPECTRUM,$
bin_size=0.01, instr=0.1

CATEGORY :
spectral synthesis.

PREV. HIST. :

WRITTEN :
Peter Young , CfA, pyoung@cfa.harvard.edu 1-Sept-2000

MODIFICATION HISTORY:

Version 1, PRY 1-Sept-2000

Version 2, Giulio Del Zanna (GDZ) 10-Oct-2000

put ALL keyword, removed the FWHM obsolete and
confusing call. Reorganised various minor things.

Version 3, PRY 19-Oct-2000
Corrected the way continuum is treated for an isothermal
spectrum.

V. 4, 2-Nov-2001 GDZ. Now MIN_ABUND is effective not only in the
continuum calculation but also in the line spectrum.
Modified for the use of logt_isothermal

V.5, GDZ, added EFFAREA keyword: an ascii file with lambdas and
effective areas can be read
in. The line intensities are
calculated in a different way.
Also, changed the output.

V.6, GDZ, 28-Apr-02 redefined completely the OUTPUT structure.
Major revision (added two_photon verbose).

V.7, GDZ, 3-May-2002
fixed a bug, when negative angpix values occur.

V.8, GDZ, 22 May 2002, changed some tags of the output, and
added min_abund in the continuum call.

V.9, GDZ, 30-May-02 replaced fix() with round()

V. 10, 15-July-2002 , GDZ
changed the location of Effective area files.

V.11 14-Aug-02, GDZ
speeded up the routine, by changing the way the PEAK tag is
added to the structure. The drawback is that only the
'standard v.4 tags' are allowed, and future additions will
have to be dealt properly.

v.12 2-Dec-2002, GDZ.
Fixed a bug: Removed the plotting of the window with the effective areas.

v.13 26-Apr-2005, Enrico Landi (EL)
Fixed a minor bug: if the lines were more than 32768 (2^15), the main
loop crashed.

v.14 22-Jul-2005 GDZ
-fixed a bug. When the routine was run once without
defining the lambdas, and then with the lambdas
defined (the units were switched to photons)
-fixed a bug. When the effective areas were used,
all lines were used to create the spectrum.
-added hard-wired switch to photons when using
effective area files.

-added the keV option

-now can output a spectrum only with the continuum
(i.e. even if no emission lines are present).

v.15, 2-Aug-2005, GDZ
Added a check on the input structure. If it was
calculated with ch_synthetic and the keyword
/no_sum_int, it cannot be used here.

v.16, 31-Aug-2005, GDZ
Fixed a typo (keyowrd_set).

v.17, 10-Mar-2006, Peter Young
The /keV keyword is now passed to the continuum routines,
rather than make_chianti_spec performing the conversion
itself.

v.18, 4-May-2006, Peter Young
Changed LAMBDA to be a double array in order to correct a
problem with line profiles for very small bin sizes.
Problem pointed out by Matthew West (Imperial).

VERSION : 18, 4-May-2006, Peter Young

STILL TO DO:

-speed up the routine with the use of arrays.
-add the option to select only a list of ions, also in the
continuum procedures.
-Allow the use of user-defined line profiles.
-Enable PIXEL keyword