Suppression of Hydrogen Emission in a White-light Solar Flare

We present an analysis of an X-class flare that occurred on 11 June 2014 in active region NOAA 12087 using a newly developed high cadence Image<br/>Selector operated by Astronomical Institute in Ondrejov, Czech Republic. This instrument provides spectra in the 350 - 440 nm wavelength range, which<br/>covers the higher order Balmer lines as well as the Balmer jump at 364 nm. However, no detectable increase in these emissions were detected during<br/>the flare, and support observations from SDO/EVE MEGS-B also show that the Lyman line series and recombination continuum were also suppressed,<br/>particularly when compared to an M-class flare that occurred an hour earlier, and two other X-class flares on the preceding day. The X-class flare under<br/>investigation also showed strong white light emission in SDO/HMI data, as well as an extremely hard electron spectrum ( 3.6), and <br/>-ray emission,<br/>from RHESSI data. This unique combination of datasets allows us to conclude that the white light emission from this flare corresponds to a black body<br/>heated by high-energy electrons (and/or ions), as opposed to optical chromospheric emission from hydrogen.