dustem_mathis_field.pro
1.24 KB
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FUNCTION DUSTEM_MATHIS_FIELD, x, unit=unit
; computes the Mathis interstellar radiation field SED (ISRF)
; in W/m2 (4*!pi*nu*I_nu)
; from Mathis et al. 1983, A&A 128, 212
; X (I): X-grid for the ISRF
; UNIT (I): unit of the ISRF. Choices are
; 'W': wave in um [Default]
; 'F': frequency in cm-1
; 'E': energy in eV
if n_elements( UNIT ) EQ 0 then unit = 'W' $
else unit = strupcase( strcompress( unit,/rem) )
ly_limit = 9.11267101235d-2
x = double( x )
;
; visible part
;
wdil = 4.d0 * [ 4.d-13, 1.d-13, 1.d-14] ; Mathis definition
; 4*!pi*Wdil*B_nu
field = !pi * x * DUSTEM_BLACKBODY( x, [ 3.d3, 4.d3, 7.5d3 ], wdil=wdil, unit=unit )
;
; UV part
;
; first convert to (lambda / 1e3 AA)
CASE unit of
'W': x3 = 1.d1 * x
'F': x3 = 1.d5 / x
'E': x3 = 12.4 / x
ENDCASE
il = where( x3 LE 2.46, cl )
if cl GT 0 then field(il) = 0.D0
il = where( x3 GE 1d1*ly_limit AND x3 LT 1.11, cl )
if cl GT 0 then field(il) = 1.4817d-6 * x3(il)^(4.4172)
il = where( x3 GE 1.11 AND x3 LT 1.34, cl )
if cl GT 0 then field(il) = 2.0456d-6 * x3(il)
il = where( x3 GE 1.34 AND x3 LT 2.46, cl )
if cl GT 0 then field(il) = 3.3105d-6 * x3(il)^(-0.6678)
RETURN, field
END ;FUNCTION DUSTEM_MATHIS_FIELD