Please use this identifier to cite or link to this item: http://hdl.handle.net/2248/5766
Title: J-state interference signatures in the second solar spectrum. Modeling the Cr I triplet at 5204-5208
Authors: Smitha, H. N
Nagendra, K. N
Stenflo, J. O
Bianda, M
Sampoorna, M
Ramelli, R
Anusha, L. S
Keywords: Line: profiles;Line:polarization;Line:scattering;Methods: numerical;Methods: radiative transfer;Sun: atmosphere
Issue Date: May-2012
Publisher: EDP Sciences
Citation: Astronomy & Astrophysics, Vol. 541, A24
Abstract: The scattering polarization in the solar spectrum is traditionally modeled with each spectral line treated separately, but this is generally inadequate for multiplets where J-state interference plays a significant role. Through simultaneous observations of all the 3 lines of a Cr I triplet, combined with realistic radiative transfer modeling of the data, we show that it is necessary to include J-state interference consistently when modeling lines with partially interacting fine structure components. Polarized line formation theory that includes J-state interference effects together with partial frequency redistribution for a two-term atom is used to model the observations. Collisional frequency redistribution is also accounted for. We show that the resonance polarization in the Cr I triplet is strongly affected by the partial frequency redistribution effects in the line core and near wing peaks. The Cr I triplet is quite sensitive to the temperature structure of the photospheric layers. Our complete frequency redistribution calculations in semi-empirical models of the solar atmosphere cannot reproduce the observed near wing polarization or the cross-over of the Stokes Q/I line polarization about the continuum polarization level that is due to the J-state interference. When however partial frequency redistribution is included, a good fit to these features can be achieved. Further, to obtain a good fit to the far wings, a small temperature enhancement of the FALF model in the photospheric layers is necessary.
URI: http://hdl.handle.net/2248/5766
???metadata.dc.rights???: © ESO
???metadata.dc.relation.uri???: http://dx.doi.org/10.1051/0004-6361/201118466
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