Hinode, TRACE, SOHO, and ground-based observations of a quiescent prominence

Heinzel, P. et al. (2008) Hinode, TRACE, SOHO, and ground-based observations of a quiescent prominence. Astrophysical Journal, 686(2), pp. 1383-1396. (doi:10.1086/591018)

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Publisher's URL: http://dx.doi.org/10.1086/591018

Abstract

A quiescent prominence was observed by several instruments on 2007 April 25. The temporal evolution was recorded in Hα by the Hinode SOT, in X-rays by the Hinode XRT, and in the 195 Å channel by TRACE. Moreover, ground-based observatories (GBOs) provided calibrated Hα intensities. Simultaneous extreme-UV (EUV) data were also taken by the Hinode EIS and SOHO SUMER and CDS instruments. Here we have selected the SOT Hα image taken at 13:19 UT, which nicely shows the prominence fine structure. We compare this image with cotemporaneous ones taken by the XRT and TRACE and show the intensity variations along several cuts parallel to the solar limb. EIS spectra were obtained about half an hour later. Dark prominence structure clearly seen in the TRACE and EIS 195 Å images is due to the prominence absorption in H I, He I, and He II resonance continua plus the coronal emissivity blocking due to the prominence void (cavity). The void clearly visible in the XRT images is entirely due to X-ray emissivity blocking. We use TRACE, EIS, and XRT data to estimate the amount of absorption and blocking. The Hα integrated intensities independently provide us with an estimate of the Hα opacity, which is related to the opacity of resonance continua as follows from the non-LTE radiative-transfer modeling. However, spatial averaging of the Hα and EUV data have quite different natures, which must be taken into account when evaluating the true opacities. We demonstrate this important effect here for the first time. Finally, based on this multiwavelength analysis, we discuss the determination of the column densities and the ionization degree of hydrogen in the prominence.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Labrosse, Dr Nicolas
Authors: Heinzel, P., Schmieder, B., Farnik, F., Schwartz, P., Labrosse, N., Kotrc, P., Anzer, U., Molodij, G., Berlicki, A., DeLuca, E.E., Golub, L., Watanabe, T., and Berger, T.
Subjects:Q Science > QB Astronomy
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Astrophysical Journal
ISSN:0004-637X
ISSN (Online):1538-4357

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
465931Solar, stellar and cosmological plasmas: a synthesis of data, modelling and theory.Declan DiverScience & Technologies Facilities Council (STFC)ST/F002149/1Physics and Astronomy