Doppler shift of the quiet region measured by meridional scans with the EUV imaging spectrometer on board Hinode

Journal Article · Fri Jan 01 00:00:00 EST 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/0004-637X/816/1/14· OSTI ID:22882328

Kitagawa, N.; Yokoyama, T. ^[1]

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1. The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 (Japan)

Spatially averaged (>50{sup ′′}) EUV spectral lines in the transition region of solar quiet regions are known to be redshifted. Because the mechanism underlying this phenomenon is unclear, we require additional physical information on the lower corona in order to limit the theoretical models. To acquire this information, we measured the Doppler shifts over a wide coronal temperature range (logT [K]=5.7–6.3) using the spectroscopic data taken by the Hinode EUV Imaging Spectrometer. By analyzing the data over the center-to-limb variations covering the meridian from the south to the north pole, we successfully measured the velocity to an accuracy of 3 km s{sup −1}. Below logT [K]=6.0, the Doppler shifts of the emission lines were almost zero with an error of 1–3 km s{sup −1}; above this temperature, they were blueshifted with a gradually increasing magnitude, reaching −6.3±2.1 km s{sup −1} at logT [K]=6.25.

• OSTI ID: 22882328
• Journal Information: Astrophysical Journal, Vol. 816, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Since 2009, the country of publication for this journal is the UK.; ISSN 0004-637X
• Country of Publication: United Kingdom
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
DOPPLER EFFECT
EMISSION
EXTREME ULTRAVIOLET RADIATION
RED SHIFT
SOLAR CORONA
SUN
VELOCITY