Hinode X-Ray Telescope Detection of Hot Emission from Quiescent Active Regions: A Nanoflare Signature? |
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Joan Schmelz Submitted: 2009-02-13 14:52
The X-Ray Telescope (XRT) on the Japanese/USA/UK {it Hinode (Solar-B)} spacecraft has detected emission from a quiescent active region core that is consistent with nanoflare heating. The fluxes from 10 broadband X-ray filters and filter combinations were used to constructed Differential Emission Measure (DEM) curves. In addition to the expected active region peak at Log T = 6.3-6.5, we find a high-temperature component with significant emission measure at Log T > 7.0. This emission measure is weak compared to the main peak - the DEM is down by almost three orders of magnitude - which accounts of the fact that it has not been observed with earlier instruments. It is also consistent with spectra of quiescent active regions: no Fe XIX lines are observed in a CHIANTI synthetic spectrum generated using the XRT DEM distribution. The DEM result is successfully reproduced with a simple two-component nanoflare model.
Authors: Schmelz, J.T., Saar, S.H., DeLuca, E.E., Golub, L., Kashyap, V.L., Weber, M.A. Klimchuk, J.A.
Projects: Hinode/XRT
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Publication Status: Accepted for publication in ApJ Letters
Last Modified: 2009-02-14 10:40
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