ABOUT LAMBDA

COBE

COBE DIRBE Zodiacal Light Prediction Software

This is software written in IDL for calculating the zodiacal light predicted from the DIRBE team interplanetary dust model (Kelsall et al. 1998, ApJ, 508, 44). This model was obtained by fitting the time variation of DIRBE all-sky observations over 10 months with a parameterized model of the dust cloud. Thus it is constrained over solar elongation angles ranging from 64 to 124 degrees.

The Kelsall_zodi_model.tar.gz file - recommended download procedure for '.fits' or '.tar.gz' files: right click on the file name and save - contains

The top level routine is the function get_zmod.pro:

@zmodel_init
;---------------------------------------------------------------------
; Function GET_ZMOD
;
; Function to compute the Kelsall et al. 1998 (ApJ,508,44) ZODI model 
; intensity for a given set of LOS, Wavelength, and Time.
;
; Written By: 	BA Franz
; Date:		23 January 1995
;
; Usage:
;     zodi = GET_ZMOD(lambda,day,lon,lat)
;
; Inputs:
;     lambda - nominal DIRBE wavelength(s) in microns (any combination
;               of 1.25, 2.2, 3.5, 4.9, 12, 25, 60, 100, 140, 240) 
;     day    - 1990 day number(s), where 1.0 = 1 Jan 1990
;     lon    - ecliptic longitude(s)
;     lat    - ecliptic latitude(s)
;
;     note: lambda, day, lon, lat can be any mixture of scalars or arrays,
;           but all arrays must be of same length.
;
; Outputs:
;
;     zodi - scalar or array of zodi model intensity in MJy sr-1
;            For comparison with DIRBE data, this is 'quoted' intensity
;            at the nominal wavelength(s) for an assumed source
;            spectrum nu*F_nu = constant
;
; Optional Keyword Inputs:
;
;     zpar=zpar - array of zodi model params.  If not specified, the
;                 default will be restored from zpars.xdr
;     no_colcorr=no_colcorr - if set, the result will be actual
;                  intensity at the specified wavelength(s) instead of
;                  quoted intensity for a spectrum nu*F_nu = constant
;              
;---------------------------------------------------------------------
function get_zmod,lambda,day,lon,lat,zpar=zpar,no_colcorr=no_colcorr

if (n_elements(zpar) eq 0) then begin
    aend    = 0
    astart  = 0
    chisqr  = 0
    covar   = 0
    sigma_a = 0
    freevars= 0
    wiring  = 0
    restore,'zpars.xdr'
    zpar = aend
endif
;showpars,zpar

data = mk_zdata(lambda,day,lon,lat)

zkernel,data,zpar,z,no_colcorr=no_colcorr

return,z
end

A service of the HEASARC and of the Astrophysics Science Division at NASA/GSFC
Goddard Space Flight Center, National Aeronautics and Space Administration
HEASARC Director: Dr. Alan P. Smale
LAMBDA Director: Dr. Eric R. Switzer
NASA Official: Dr. Eric R. Switzer
Web Curator: Mr. Michael R. Greason