The Hinode/XRT Full-Sun Image Corrections and the Improved Synoptic Composite Image Archive

Takeda, Akira; Yoshimura, Kazuyuki; Saar, Steven H.

doi:10.1007/s11207-015-0823-8

Cited by 14 publications

(14 citation statements)

References 10 publications

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“…The team believes the increase of visible straylight to have been caused by a pinhole puncture in the entrance aperture filters. The analysis showed that the light leak affects only some of the X-Ray filters: a minor effect was detected for the Al-mesh and Al-poly filters but it was very small (≤ 5 DN s −1 ), while it strongly affected the Ti-poly and C-poly filters (Takeda et al 2016). In order to exclude the possibility that Venus residual flux in Ti-poly could be due to the straylight, we used data collected with the Al-mesh filter to repeat the analysis.…”

Section: Light Leak Effect On Xrt Filtersmentioning

confidence: 98%

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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: Light Leak Effect On Xrt Filtersmentioning

confidence: 98%

“…In order to exclude the possibility that Venus residual flux in Ti-poly could be due to the straylight, we used data collected with the Al-mesh filter to repeat the analysis. Importantly, the light leak has a very small effect on the Al-mesh filter, to such a level that it can be neglected (Takeda et al 2016).…”

Section: Light Leak Effect On Xrt Filtersmentioning

confidence: 99%

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

Afshari

Peres

Jibben

et al. 2016

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“…This connects our study to those earlier ones that were mainly based on SXR data. We analyze the XRT SXR data of this event, which are available in the full-disk synoptic mode with a low cadence (twice per day, at about 06:00 UT and 18:00 UT; Takeda et al 2016) and a relatively high spatial resolution (∼2" per pixel).…”

Section: Observational Data and Event Overviewmentioning

confidence: 99%

Formation of Large-scale Coronal Loops Interconnecting Two Active Regions through Gradual Magnetic Reconnection and an Associated Heating Process

Chen

Zhu

et al. 2018

ApJ

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Coronal loops interconnecting two active regions, called as interconnecting loops (ILs), are prominent large-scale structures in the solar atmosphere. They carry a significant amount of magnetic flux, therefore are considered to be an important element of the solar dynamo process. Earlier observations show that eruptions of ILs are an important source of CMEs. It is generally believed that ILs are formed through magnetic reconnection in the high corona (>150-200"), and several scenarios have been proposed to explain their brightening in soft X-rays (SXRs). Yet, the detailed IL formation process has not been fully explored and the associated energy release in the corona still remains unresolved. Here we report the complete formation process of a set of ILs connecting two nearby active regions, with successive observations by STEREO-A on the far side of the Sun and SDO and Hinode on the Earth side. We conclude that ILs are formed by gradual reconnection high in the corona, in line with earlier postulations. In addition, we show evidence supporting that ILs become brightened in SXRs and EUVs through heating at or close to the reconnection site in the corona (i.e., through direct heating process of reconnection), a process that has been largely overlooked in earlier studies on ILs.According to the statistical study of Pevtsov (2000) with Yohkoh data, about one third of ARs exhibit TLs. Therefore, ILs or TLs are not rare phenomena. They have attracted much attention mainly due to their important roles in the solar dynamo process and origin of solar eruptions. ILs (or TLs) with a significant poloidal component of magnetic field are regarded as evidence of the conversion of toroidal to poloidal component of the solar magnetic field, a critical

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“…Spatially integrated hard X-ray spectra are currently also available from the Fermi Gamma ray Burst Monitor (GBM) [Meegan et al, 2009]. Spectroscopic imaging in soft X-rays is provided by the X-Ray Telescope (XRT) on Hinode [Golub et al, 2007;Takeda et al, 2016]. An X-ray spectroscopic imager using a Fourier transform imaging technique similar to that of RHESSI, the Spectrometer Telescope for Imaging X-rays (STIX), is currently under development for inclusion on Solar Orbiter [Benz et al, 2012].…”

Section: X-ray Spectroscopymentioning

confidence: 99%

Scientific considerations for future spectroscopic measurements from space of activity on the Sun

Holman

2016

JGR Space Physics

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High‐resolution UV and X‐ray spectroscopy are important to understanding the origin and evolution of magnetic energy release in the solar atmosphere, as well as the subsequent evolution of heated plasma and accelerated particles. Electromagnetic radiation is observed from plasma heated to temperatures ranging from about 10 kK to above 10 MK, from accelerated electrons emitting photons primarily at X‐ray energies, and from ions emitting in γ rays. These observations require space‐based instruments sensitive to emissions at wavelengths shorter than the near UV. This article reviews some recent observations with emphasis on solar eruptive events, the models that describe them, and the measurements they indicate are needed for substantial progress in the future. Specific examples are discussed demonstrating that imaging spectroscopy with a cadence of seconds or better is needed to follow, understand, and predict the evolution of solar activity. Critical to substantial progress is the combination of a judicious choice of UV, EUV, and soft X‐ray imaging spectroscopy sensitive to the evolution of this thermal plasma combined with hard X‐ray imaging spectroscopy sensitive to suprathermal electrons. The major challenge will be to conceive instruments that, within the bounds of possible technologies and funding, have the flexibility and field of view to obtain spectroscopic observations where and when events occur while providing an optimum balance of dynamic range, spectral resolution and range, and spatial resolution.

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The Hinode/XRT Full-Sun Image Corrections and the Improved Synoptic Composite Image Archive

Cited by 14 publications

References 10 publications

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

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

Formation of Large-scale Coronal Loops Interconnecting Two Active Regions through Gradual Magnetic Reconnection and an Associated Heating Process

Scientific considerations for future spectroscopic measurements from space of activity on the Sun

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