Calibrating Data from the Hinode/X-Ray Telescope and Associated Uncertainties

Kobelski, Adam; Saar, Steven H.; Weber, Mark; McKenzie, D. E.; Reeves, Katharine K.

doi:10.1007/s11207-014-0487-9

Cited by 34 publications

(31 citation statements)

References 9 publications

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“…We have measured a significant X-Ray residual flux from Venus' dark side (i.e., from the Earth-facing side) during the transit that was significantly above the estimated noise level of 2 DN s −1 , as reported by Kobelski et al (2014). Let us discuss the systematic uncertainties of XRT flux.…”

Section: Resultsmentioning

confidence: 75%

“…Let us discuss the systematic uncertainties of XRT flux. According to Kobelski et al (2014) there are two kinds of systematic uncertainties for XRT. The first are those which have a reliable quantitative correction procedure such as: dark current, Fourier, vignetting, and JPEG compression noise sources; their correction procedures have been successfully embedded in xrt prep.pro (the calibration reformatter).…”

Section: Resultsmentioning

confidence: 99%

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x-Raying the Dark Side of Venus—scatter From Venus’ Magnetotail?

Afshari

Peres

Jibben

et al. 2016

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This work analyzes the X-ray, EUV and UV emission apparently coming from the Earth-facing (dark) side of Venus as observed with Hinode/XRT and SDO/AIA during a transit across the solar disk occurred in 2012. We have measured significant X-Ray, EUV and UV flux from Venus' dark side. As a check we have also analyzed a Mercury transit across the solar disk, observed with Hinode/XRT in 2006. We have used the latest version of the Hinode/XRT Point Spread Function (PSF) to deconvolve Venus and Mercury X-ray images, in order to remove possible instrumental scattering. Even after deconvolution, the flux from Venus' shadow remains significant while in the case of Mercury it becomes negligible. Since stray-light contamination affects the XRT Ti-poly filter data from the Venus transit in 2012, we performed the same analysis with XRT Al-mesh filter data, which is not affected by the light leak. Even the Al-mesh filter data show residual flux. We have also found significant EUV (304Å, 193Å, 335Å) and UV (1700Å) flux in Venus' shadow, as measured with SDO/AIA. The EUV emission from Venus' dark side is reduced when appropriate deconvolution methods are applied; the emission remains significant, however. The light curves of the average flux of the shadow in the X-ray, EUV, and UV bands appear different as Venus crosses the solar disk, but in any of them the flux is, at any time, approximately proportional to the average flux in a ring surrounding Venus, and therefore proportional to the average flux of the solar regions around Venus' obscuring disk line of sight. The proportionality factor depends on the band. This phenomenon has no clear origin; we suggest it may be due to scatter occurring in the very long magnetotail of Venus.

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Section: Resultsmentioning

confidence: 75%

Section: Resultsmentioning

confidence: 99%

x-Raying the Dark Side of Venus—scatter From Venus’ Magnetotail?

Afshari

Peres

Jibben

et al. 2016

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“…XRT level 0 data were converted to level 1 by using the Solarsoft routine xrt_prep. pro, which subtracts the dark current and removes the CCD bias and telescope vignetting (Kobelski et al 2014). …”

Section: Hinode/eis and Xrtmentioning

confidence: 99%

Simultaneous Iris and Hinode/Eis Observations and Modeling of the 2014 October 27 X2.0 CLASS Flare

Polito

Reep

Reeves

et al. 2016

ApJ

105

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We present a study of the X2-class flare which occurred on 2014 October 27 and was observed with the Interface Region Imaging Spectrograph (IRIS) and the EUV Imaging Spectrometer (EIS) on board the Hinode satellite. Thanks to the high cadence and spatial resolution of the IRIS and EIS instruments, we are able to compare simultaneous observations of the Fe XXI1354.08 Åand Fe XXIII263.77 Åhigh-temperature emission (10 MK) in the flare ribbon during the chromospheric evaporation phase. We find that IRIS observes completely blueshifted Fe XXIline profiles, up to 200 km s −1 during the rise phase of the flare, indicating that the site of the plasma upflows is resolved by IRIS. In contrast, the Fe XXIIIline is often asymmetric, which we interpret as being due to the lower spatial resolution of EIS. Temperature estimates from SDO/AIA and Hinode/XRT show that hot emission (log(T[K]) >7.2) is first concentrated at the footpoints before filling the loops. Density-sensitive lines from IRIS and EIS give estimates of electron number density of 10 12 cm −3 in the transition region lines and 10 10 cm −3 in the coronal lines during the impulsive phase. In order to compare the observational results against theoretical predictions, we have run a simulation of a flare loop undergoing heating using the HYDRAD 1D hydro code. We find that the simulated plasma parameters are close to the observed values that are obtained with IRIS, Hinode, and AIA. These results support an electron beam heating model rather than a purely thermal conduction model as the driving mechanism for this flare.

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“…After the deconvolution, we calibrate the images to Level 1.5 by a standard procedure aia prep.pro that co-aligns and adjusts the plate scales and roll angles between AIA channels. For the XRT observations, we calibrate the images using a procedure (xrt prep.pro) in SolarSoft (Kobelski et al 2014). Then, we deconvolve the calibrated images using a point spread function supplied by the XRT team (Afshari et al 2016).…”

Section: Observationsmentioning

confidence: 99%

Heating of an Erupting Prominence Associated with a Solar Coronal Mass Ejection on 2012 January 27

Lee

Raymond

Reeves

et al. 2017

ApJ

Self Cite

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We investigate the heating of an erupting prominence and loops associated with a coronal mass ejection and X-class flare. The prominence is seen in absorption in EUV at the beginning of its eruption. Later the prominence changes to emission, which indicates heating of the erupting plasma. We find the densities of the erupting prominence using the absorption properties of hydrogen and helium in different passbands. We estimate the temperatures and densities of the erupting prominence and loops seen as emission features using the differential emission measure method, which uses both EUV and X-ray observations from the Atmospheric Imaging Assembly on board Solar Dynamics Observatory and the X-ray Telescope on board Hinode. We consider synthetic spectra using both photospheric and coronal abundances in these calculations. We verify the methods for the estimation of temperatures and densities for the erupting plasmas. Then we estimate the thermal, kinetic, radiative loss, thermal conduction, and heating energies of the erupting prominence and loops. We find that the heating of the erupting prominence and loop occurs strongly at early times in the eruption. This event shows a writhing motion of the erupting prominence, which may indicate a hot flux rope heated by thermal energy release during magnetic reconnection.

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Calibrating Data from the Hinode/X-Ray Telescope and Associated Uncertainties

Cited by 34 publications

References 9 publications

x-Raying the Dark Side of Venus—scatter From Venus’ Magnetotail?

x-Raying the Dark Side of Venus—scatter From Venus’ Magnetotail?

Simultaneous Iris and Hinode/Eis Observations and Modeling of the 2014 October 27 X2.0 CLASS Flare

Heating of an Erupting Prominence Associated with a Solar Coronal Mass Ejection on 2012 January 27

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