11.1.1 ``New'' Kurucz Models

First, there is a routine called KURGET1 that will extract one model:

KURGET1,WK,FK,tk,gk,zk,vk,bv,ub,nlc,nhe,bc, $
/interpolate,/solar,/vega 

WK	Wavelengths for the Kurucz model. If you entered a wavelength array, the Kurucz model chosen will be resampled to match it.
FK	Fluxes for Kurucz model.
tk	Effective temperature for desired Kurucz model. Note that the model temperatures go from 3500 K through 50000 K in steps of 250 K. If you enter a temperature that does not match an available model, the closest one will be returned to you. If tk is undefined, you will be prompted for it.
gk	Log of surface gravity for desired Kurucz model. Note that the model log g values go from 0. to 5. in steps of 0. 5. If you enter a value for which there is no available model, the closest one will be selected and gk reset. If gk is undefined, you will be prompted for it.
zk	Log of abundance (abundance is in solar units) for desired Kuruzc model. Note that model log z values go from -3.5 to 1.0 in steps of 0.1. If you enter a value that does not match an available model, the closest one will be returned to you. If zk is undefined you will be prompted for it.
vk	V magnitude for model selected (with respect to the surface of the ``model star''). This is an output parameter only.
bv	B-V color for model selected (output only).
ub	U-B color for model selected (output only).
nlc	Number of Lyman continuum photons for model selected (output only).
nhe	Number of helium ionizing photons for model selected (output only).
bc	Bolometric correction for model selected (output only).
interpolate	If this keyword is set, and the model specified using the TK, GK, and ZK parameters is not available, the nearest models in the database will be linearly interpolated to match the given TK, GK, and ZK. The output parameters listed above will be interpolated appropriately. Interpolation will be done with respect to TK first, GK second, and ZK third, as necessary. Note that you may abbreviate the keyword (e.g., /i).
solar	Retrieves the solar model (teff=5777, logg=4.4377).
vega	Retrieves the Vega model (teff=9550, logg=3.95).

You may extract more than one model at a time if you wish:

KURGET,WK,FK,tk,gk,zk,vk,bv,ub,nlc,nhe,bc,srch=srch 

The parameters for KURGET are identical to those for KURGET1, except:

1.

FK will be two dimensional if the criteria defined by tk, gk, and zk specify more than one model. In this case all other parameters will be vectors rather than scalars.

2.

There is no INTERPOLATE keyword, and no option for interpolating between models. If you try to select any model not available, the nearest one will be returned.

3.

The SRCH keyword may be used to set search criteria rather than TK, GK, and ZK. This is used to enter a search string as expected by the lower level database routines. Use DOC_LIBRARY to see some examples in the prolog of KURGET. See a staff member for more information. If this keyword is used, TK, GK, and ZK will be strictly output parameters.

If the fluxes are two dimensional, the first dimension will match the wavelength vector. If you did not enter a vector of wavelengths to begin with, you'll get the wavelengths from the Kurucz database, which have 1221 elements. The second dimension will correspond to the values of TK, GK, and ZK you entered. If you entered multiple values of more than one of those parameters (TK, GK, ZK), you will have a model for each possible combination. It is important that you enter TK, GK, and ZK as variables so that they will end up being the same dimension as the second dimension of FK, or it will be difficult to keep track of which model is which.

To plot multidimensional fluxes:

plot,wk,fk(*,3),title=strtrim(tk(3),2)+' K'

This plots the fourth model extracted, labeling the plot with the corresponding effective temperature. Don't forget that IDL subscripts start with 0; therefore the first model would have been fk(*,0).

Multidimensional models may be interpolated with a program called KLINEAR:

KLINEAR,TK,T,FK,F,vk,v,bk,b 

TK	Input Kurucz temperatures from KURGET or KURUCZ91.
T	Temperatures to which the fluxes should be interpolated.
FK	Two dimensional Kurucz fluxes.
F	Output two dimensional fluxes interpolated with respect to temperature to match T.
vk	V magnitudes from KURGET or KURUCZ91.
v	V magnitudes interpolated to match T.
bk	B-V colors from KURGET or KURUCZ91.
b	B-V colors interpolated to match T.

If you wish to interpolate with respect to log g or log z or whatever, replace TK and T with appropriate parameters. Also, VK, V, BK, and B may be replaced by other parameters. TK, VK, and BK must be the same size as the second dimension of FK. V, B, and the second dimension of F will have the same size as T. KLINEAR was written for two dimensional Kurucz models but it doesn't really care what sort of data you give it as long as TK, VK, BK, and the second dimension of FK have the same number of elements.

There is also a menu routine called KURUCZ91 that is reminiscent of SEARCH:

KURUCZ91,RESET,wave,flux,teff,logg,logz,v,bv,ub,nlyc,nhe,bol,/winterp 

RESET	As in SEARCH, this can either be a scalar dummy variable, or you can save the search parameters in it for later use.
wave	Wavelengths for Kurucz model(s) selected.
flux	Fluxes for Kurucz model(s) selected. Note: this may be a two dimensional array if more than one model was selected.
teff	Effective temperature(s) corresponding to model(s) selected.
logg	Log of surface gravity(ies) for model(s) selected.
logz	Log of abundance(s) (which are in solar units) for model(s) selected.
v	V magnitude(s) for model(s) selected.
bv	B-V color(s) for model(s) selected.
ub	U-B color(s) for model(s) selected.
nlyc	Number of Lyman continuum photons for model(s) selected.
nhe	Number of helium ionizing photons for model(s) selected.
bol	Bolometric correction(s) for model(s) selected.
winter	If set, and you enter a wave vector, the Kurucz model(s) selected will be interpolated to match the input wavelength scale.

As with KURGET, it is possible to end up with a two dimensional flux array, in which case the other parameters would be vectors. None of the parameters of KURUCZ91 (except keyword winterp, and possibly RESET and wave) are input parameters. KURUCZ91 can plot the models you select and can be used to browse through a number of models without passing the vectors back to you.

If you wish, you may use the lower-level database routines to access the Kurucz database. See a staff member for more information.

Once you have the wavelengths and fluxes for the models of interest, you may scale them to your data:

KSCALE,W,F,FK,VK,tk,rms,weight=weight, $
comment=comment,/go,/noplots 

W	Wavelengths for data.
F	Fluxes for data.
FK	Kurucz model fluxes, which must have been resampled to match W. The fitted models will be returned, overwriting the originals. One or two dimensional fluxes are allowed.
VK	Kurucz model V magnitude(s). Must be the same size as the second dimension of FK (scalar if FK is one dimensional).
tk	Kurucz model temperature(s). Must be the same size as VK.
rms	RMS values for the fit for each model.
go	If set, the program will not wait for the user to hit return before proceeding to the next plot.
weight	Weights for each data point (F) used in the fitting procedure.
comment	String(s) to appear on each plot. Either a single string or a string vector the same size as VK.
noplots	If set, no plotting will be done.

It may be a good idea to bin or trim your data and model before using this program; the ``negative fluxes'' one sees with IUE data may cause arithmetic errors and result in unattractive plots.