On the Origin of the Flare Emission in IRIS' SJI 2832 Filter: Balmer Continuum or Spectral Lines?

被引：17

作者：

Kleint, Lucia ^{[1
]}

Heinzel, Petr ^{[2
]}

Krucker, Sam ^{[1
,3
]}

机构：

[1] Univ Appl Sci & Arts Northwestern Switzerland, Bahnhofstr 6, CH-5210 Windisch, Switzerland

[2] Acad Sci Czech Republ, Astron Inst, Fricova 298, Ondrejov 25165, Czech Republic

[3] Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA

来源：

ASTROPHYSICAL JOURNAL | 2017年 / 837卷 / 02期

关键词：

Sun: chromosphere; Sun: flares; IMAGING-SPECTROGRAPH IRIS; SOLAR-FLARES; WHITE-LIGHT; RHESSI;

D O I：

10.3847/1538-4357/aa62fe

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

Continuum ("white-light," WL) emission dominates the energetics of flares. Filter-based observations, such as the IRIS SJI 2832 filter, show WL-like brightenings during flares, but it is unclear whether the emission arises from real continuum emission or enhanced spectral lines, possibly turning into emission. The difficulty in filter-based observations, contrary to spectral observations, is to determine which processes contribute to the observed brightening during flares. Here we determine the contribution of the Balmer continuum and the spectral line emission to IRIS' SJI 2832 emission by analyzing the appropriate passband in simultaneous IRIS NUV spectra. We find that spectral line emission can contribute up to 100% to the observed slitjaw images (SJI) emission, that the relative contributions usually temporally vary, and that the highest SJI enhancements that are observed are most likely because of the Balmer continuum. We conclude that care should be taken when calling SJI 2832 a continuum filter during flares, because the influence of the lines on the emission can be significant.

引用

页数：7