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Filtering by: Creator Mathioudakis, Mihalis Remove constraint Creator: Mathioudakis, Mihalis

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  • 1v53k1188?file=thumbnail
    Article
    Keenan, Francis P.
    We present high-cadence observations and simulations of the solar photosphere, obtained using the Rapid Oscillations in the Solar Atmosphere imaging system and the MuRAM magnetohydrodynamic (MHD) code, respectively. Each data set demonstrates a wealth . . .
  • Qf85nf30t?file=thumbnail
    Article
    Keenan, Francis P.
    In this paper we investigate the validity of the optically thin assumption in the transition region of the late-type star AU Mic. We use Far-Ultraviolet Spectroscopic Explorer (FUSE) observations of the C iii multiplet and Ovi resonance lines, hence y . . .
  • Sq87bx66f?file=thumbnail
    Article
    Mathioudakis, Mihalis
    Detection of 6Li has been shown for energetic solar events, one chromospherically active binary, and several dwarf halo stars. We had previously found a 6Li / 7Li � 0:03 0:01 for active K dwarf GJ 117 using VLT UVES observations. Here we present high . . .
  • F7623g474?file=thumbnail
    Article
    Keenan, Francis P.
    We present far-UV and UV spectroscopic observations of Proxima Centauri obtained as part of our continued investigation into the optically thin approximation assumed for the transition regions of late-type stars. Significant opacity is found in the C . . .
  • Pn89d942h?file=thumbnail
    Article
    Keenan, Francis P.
    Context. Radiative transfer calculations have predicted intensity enhancements for optically thick emission lines, as opposed to the normal intensity reductions, for astrophysical plasmas under certain conditions. In particular, the results are predic . . .
  • 4q77fv248?file=thumbnail
    Article
    Thorstensen, John R.
    We present x-ray, ultraviolet, and optical observations of the mysterious EUV/soft x-ray source EUVE J0356-336 (= MS0354.6-3650). Initial Einstein observations identified this source with a cluster of galaxies, but the relatively high source count rat . . .
  • N009w5304?file=thumbnail
    Article
    Mathioudakis, Mihalis
    We study the temporal evolution of the Na i D1 line profiles in the M3.9 flare SOL2014-06-11T21:03 UT, using observations at high spectral resolution obtained with the Interferometric Bidimensional Spectrometer instrument on the Dunn Solar Telescope c . . .
  • C534fr702?file=thumbnail
    Article
    Mathioudakis, Mihalis
    The Extreme Ultraviolet Explorer (EUVE) Right Angle Program (RAP) obtains photometric data in four bands centered at 100 (Lexan/B), 200 (Al/Ti/C), 400 (Ti/Sb/Al), and 550 (Sn/SiO) during pointed spectroscopic observations. RAP observations are up to 2 . . .
  • 8c97kt35x?file=thumbnail
    Article
    Mathioudakis, Mihalis
    We present the serendipitous detection of an extreme-ultraviolet flare on EUVE J0613-3.9B. The flare showed over a 200-fold increase above the quiescent emission in the DS/Lexan 60-200 A wavelength band. Optical spectroscopy revealed that the event wa . . .
  • 6h440w202?file=thumbnail
    Article
    Lee, Jeongwoo
    The He I D3 line has a unique response to a flare impact on the low solar atmosphere and can be a powerful diagnostic tool for energy transport processes. Using images obtained from the recently digitized films of the Big Bear Solar Observatory, we re . . .