BSMOOTH2 can be used either in a command-line format (which makes inclusion in batch files easy), or will prompt the user for the necessary information. In the prompt mode, BSMOOTH2 gives the following prompts:
Enter name of input file >
Enter name of output file >
Enter output resolution in Angstroms >
Enter spacing in Angstroms of the spectrum in the output file >
All other information, such as the spacing in the original file is kept in a header in the binary file.
Use the following format for the command-line mode:
bsmooth2 infile outfile resolution spacing
BFLXSM2 is a very similar program which may be used on the binary output of SPECTRUM (for absolute flux, or non-normalized specific intensity) and has identical prompts. Please note: the spacing in the output file must be an integer multiple of the spacing in the input file!!! For instance, if you compute the spectrum with a spacing of 0.02A, an appropriate output spacing might be 0.1A, but not 0.05A! This goes for BSMOOTH2, BFLXSM2 and SMOOTH2 (which works on ascii files). If this rule is not obeyed, bizarre results can be expected!
A program, quite similar to BSMOOTH2, called CUSTOMSM, will smooth the binary output of SPECTRUM using a mixed (i.e. pseudo-Voigt) profile instead of a Gaussian profile. This is quite useful when it is necessary to duplicate the more complicated line-spread profile of a real spectrograph. It is available upon special request.
The following are programs which are related to SPECTRUM, and may be of some use to the user. These programs, except for XMK16 and XMKF are included in the UNIX distribution of SPECTRUM. However, XMK16 and XMKF (warning - still an experimental program!) are available on the same ftp site as the UNIX/Linux version of SPECTRUM. Check under the xmk directory under the directory for SPECTRUM.
b) BLACKWEL: BLACKWEL computes "Blackwell diagrams" (cf. Blackwell
and
Shallis 1979) for a given set of spectral lines with measured
equivalent
widths. Blackwell diagrams are used to determine the elemental
abundances
and microturbulent velocity for a star, given an appropriate atmosphere
model. That is to say, Blackwell diagrams give the same information as
the classical curve of growth method, but without the debilitating
effects
of the many invalid assumptions. The set of spectral lines used
to
construct the Blackwell diagram should be placed in a file in which
each
line has the following format (very similar format to the lines in
luke.lst):
wavelength code E(lower)
E(higher)
log(gf) df TT
EqW
source
Here the wavelength, code, E(lower) and E(higher) - both in inverse
cm, log(gf), the damping factor, df and the transition type, TT, are in
exactly the same format as in luke.lst. The equivalent width,
EqW,
measured in a stellar spectrum (such as the solar flux atlas), is
expressed
in milliangstroms. It is required to place a "source", a short
string
of 5 or fewer characters at the end of each line. An example file
feI.eqw is given in the distribution. It can be used in
conjunction with the model 67244k2p00.mod to test BLACKWEL.
The output from BLACKWEL has the format:
wavelength code vt Atot AH
where vt is the microturbulent velocity, Atot is the abundance of
the
element represented by code on the abundance scale used by SPECTRUM,
whereas
AH is the abundance scale based on Hydrogen. See section
II for more details. How does one use this
output?
BLACKWEL calculates the abundance (Atot, AH)
of the element in question which yields the equivalent width for the
given line for a range of microturbulent velocities (which you input
into
BLACKWEL). If
you plot the abundance versus the microturbulent velocity the
result is a sloping line going from high abundances for low
microturbulent
velocity to low
abundances for high microturbulent velocities. Different spectral
lines will give differently sloping lines; the intersection (or the
region
of least confusion)
will give the optimal microturbulent velocity for the star and the
abundance of the element in question. For best results, use
isolated
lines with well-determined log(gf)'s with strengths ranging from weak
to
medium. Strong lines will not give satisfactory results.
In releases of SPECTRUM with version numbers 2.65 and later, a
Tcl/Tk graphical interface for BLACKWEL is now available. See the
section on Graphical User Interfaces for more
details and for some tips on how to use and interpret the results from
BLACKWEL.
c) GFADJUST: GFADJUST is the program which was used (see section II.a) to "adjust" some of the gf values in the line file, luke.lst, by inverting the Solar atlas. GFADJUST is not limited to inverting the Solar atlas, but can be used with any other star which can be represented by an LTE stellar atmosphere model.
To compute the log(gf) for a given line, measure the equivalent width of the line in the spectrum of a star with well-determined physical parameters (the sun!) and an appropriate Kurucz model. Make a line list file with exactly the format used by BLACKWEL; GFADJUST will calculate log(gf) values for all of the lines in the file.
d) LINES: will run in exactly the same way as SPECTRUM, but instead
of outputting a synthetic spectrum, will print out a file containing
the
equivalent width and the central depth of the lines in the spectral
range
being computed. This can be very useful for identifying specific
lines in the synthetic spectrum.
e) VSINI: will rotationally broaden the binary output of SPECTRUM
and
output the rotationally broadened spectrum to a binary file of the same
format. This binary file can then be further smoothed by BSMOOTH2
or BFLXSM2. The program AVSINI will handle ascii output from
SPECTRUM.
For VSINI, supply the projected rotational velocity for the spectrum
(vsini)
and an appropriate value of the limb-darkening parameter. You can
read more about the limb-darkening parameter in David Gray's stellar
atmosphere
book, but a value of 0.6 will suffice for most cases. For AVSINI,
you will also have to supply the spacing in the input ascii spectrum
and
the spacing in the output file. It is a good idea to use the same
value for both. Both VSINI and AVSINI can be run on the command
line;
the order of the input parameters is the same as in the prompts.
f) MACTURB: can be used to introduce macroturbulent broadening into
the spectrum. This program uses the radial-tangential formulation
of David Gray. MACTURB works only on ascii spectra. It
should be used before smoothing the spectrum with SMOOTH2.
f) XMK16/18/19: XMK16/18/19 are X-windows based spectral
analysis programs. They are the descendent of the DOS programs MK
and MK32, both written originally for performing MK spectral
classification
on digital spectra. XMK16 has a number of other capabilities, however,
including a rectification capability, and the ability to measure
equivalent
widths. Equivalent widths are measured by direct trapezoidal
integration
of the line profile. A sister program (XMKF, available by special
request) can measure equivalent widths by performing a nonlinear
least squares fit of a number of mixed (i.e. pseudo Voigt) profiles to
a blended line profile (see section IIa above for details).