Code for computing extinction, optical polarization, and total and polarized emission from dust.

jsmDDpol computes dust extinction, optical polarization, total andpolarized emission for the three-component dust model described inSiebenmorgen R. 2023, A&A, 670, A115 Dust is heated either by the interstellar radiation field (ISRF;Mathis et al. 1983) or by a star/AGN in an optically thin environment. The relative masses of the dust components are derived from the inputabundances. Dust cross-sections (cm^2/g ISM dust) for absorption andscattering are computed in the subroutine sigtDark_AvEbvPol using grainefficiencies Q. The Q values depend on - optical constants of the material - axial ratio a/b (prolate grains) - porosity - magnetic field orientation Omega The corresponding Q files are provided via the Q-file library of dust cross-sections of spheroidal particles available at:https://doi.org/10.5281/zenodo.19185782 ----------------------------------------------------------------------Compilation---------------------------------------------------------------------- gfortran -ffixed-line-length-132 -O3 jsmDDpol.f sigtDark_AvEbvPol.f -o a.j ----------------------------------------------------------------------Dust model---------------------------------------------------------------------- 1) Nano-particles: vGr, PAH, vSi - Graphite (vGr) and PAH: 2175 AA bump, far-UV reddening, IR bands and continuum - Nano-silicates (vSi): far-UV and MIR contribution 2) Amorphous grains: aC and aSi - Radii: 6 nm to approximately 260 nm (MRN-type distribution) - Prolate shape - Optical constants: aSi: Demyk et al. (2023) aC : Zubko (1996) 3) Micron-sized aggregates (Dark Dust, DD) - Radii: 260 nm to approximately 3 micron - Dominate polarization in the NIR and submm - Abundance constrained via luminosity and trigonometric distance estimates of stars (Siebenmorgen et al. 2025, ApJ 979, L45) Alignment: - RAT alignment for a > arad_polmin - Smaller grains are randomly oriented - Si grains assumed perfectly aligned - aC grains: 50 percent paramagnetic, otherwise unaligned ----------------------------------------------------------------------Input (./Input/)---------------------------------------------------------------------- - jsmDDpol.inp Dust parameters for reddening fits (with or without nano-particles): * size distribution parameters * min/max radii of aC, aSi, DD * minimum alignment radius * abundances of aC, aSi, DD, vGr, vSi, PAH * PAH size (number of C atoms), cluster size, H/C ratio * radiation field (ISRF scaling or other option) * E(B-V) and maximum polarization (e.g. from Serkowski fit) - Wavelength grid file (e.g. w12_vv2_Ralf_283wave.dat) - d.Q* files Grain efficiencies for each component. Default example: a/b = 2, porosity = 10 percent, Omega = 60 deg For other configurations, copy appropriate files from the Q-file library of dust cross-sections of spheroidal particles available at: https://doi.org/10.5281/zenodo.19185782 ----------------------------------------------------------------------Output (./Output/)---------------------------------------------------------------------- - Kappa.out Absorption and scattering cross-sections converted to optical depth via column densities (see Eq. 11 in S26). - PolKappa.out Polarization cross-sections for aC, aSi, and DD. - tau4fit.out Extinction and reddening curves (normalized and absolute). Dust cross-sections are given in cm^2/g dust. Abundances may bespecified relative rather than absolute, since scaling all abundancesby a common factor leaves the reddening curve unchanged. ----------------------------------------------------------------------Example:---------------------------------------------------------------------- - see Figure: Example_RedPolEmis.png, Example_RedPolEmis.pdf - For reproduction of this pdf file run /a.j and use "idl istart" or use "python pl_RedPolEmis.py" ----------------------------------------------------------------------Contact:---------------------------------------------------------------------- For questions or issues, please contact:RalfSiebenmorgen@eso.org