Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
A First Comparison of Millimeter Continuum and MgII Ultraviolet Line Emission from the Solar Chromosphere
Show others and affiliations
Number of Authors: 7
2017 (English)In: Astrophysical Journal Letters, ISSN 2041-8205, E-ISSN 2041-8213, Vol. 845, no 2, L19Article in journal (Refereed) Published
Abstract [en]

We present joint observations of the Sun by the Atacama Large Millimeter/submillimeter Array (ALMA) and the Interface Region Imaging Spectrograph (IRIS). Both millimeter/submillimeter-lambda continuum emission and ultraviolet (UV) line emission originate from the solar chromosphere and both have the potential to serve as powerful and complementary diagnostics of physical conditions in this enigmatic region of the solar atmosphere. The observations were made of a solar active region on 2015 December 18 as part of the ALMA science verification effort. A map of the Sun's continuum emission was obtained by ALMA at a wavelength of 1.25 mm (239 GHz). A contemporaneous map was obtained by IRIS in the Mg II h doublet line at 2803.5 angstrom. While a clear correlation between the 1.25 mm brightness temperature T-B and the Mg II h line radiation temperature T-rad is observed, the slope is <1, perhaps as a result of the fact that these diagnostics are sensitive to different parts of the chromosphere and that the Mg II h line source function includes a scattering component. There is a significant difference (35%) between the mean TB (1.25 mm) and mean T-rad (Mg II). Partitioning the maps into sunspot, quiet areas, and plage regions we find the relation between the IRIS Mg II h line Trad and the ALMA TB region-dependent. We suggest this may be the result of regional dependences of the formation heights of the IRIS and ALMA diagnostics and/or the increased degree of coupling between the UV source function and the local gas temperature in the hotter, denser gas in plage regions.

Place, publisher, year, edition, pages
2017. Vol. 845, no 2, L19
Keyword [en]
Sun: chromosphere, Sun: radio radiation, Sun: UV radiation
National Category
Physical Sciences
Identifiers
URN: urn:nbn:se:su:diva-147076DOI: 10.3847/2041-8213/aa844cISI: 000407971200007OAI: oai:DiVA.org:su-147076DiVA: diva2:1142134
Available from: 2017-09-18 Created: 2017-09-18 Last updated: 2017-09-18Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Leenaarts, Jorrit
By organisation
Department of Astronomy
In the same journal
Astrophysical Journal Letters
Physical Sciences

Search outside of DiVA

GoogleGoogle Scholar

Altmetric score

Total: 5 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf