Disambiguation of cool and hot emission in IRIS/Slit-Jaw Imager and AIA channels

Disambiguation of cool and hot emission in IRIS/Slit-Jaw Imager and AIA channels | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Disambiguation of cool and hot emission in IRIS/Slit-Jaw Imager and AIA channels Patrick Antolin, Frédéric Auchère, Bart De Pontieu, Elie Soubrié This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7488300/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 7 You are reading this latest preprint version Abstract Accurate temperature diagnostics of the solar corona are necessary for detecting the heating and cooling processes, and better understanding the conversion of the magnetic energy into thermal energy. A major obstacle in this enterprise is the multi-temperature emission contained in Ultra Violet (UV) and Extreme UV (EUV) passbands such as those of the \textit{Atmospheric Imaging Assembly} (AIA) of the \textit{Solar Dynamics Observatory} (SDO) and the Slit-Jaw Imager (SJI) of the \textit{Interface Region Imaging Spectrograph} (IRIS). In this work we extend the Response Fitting (RFit) method to disambiguate between cool, warm and hot emission in the SDO/AIA and IRIS/SJI passbands. We improve previous results for AIA 304 \AA, and find very good cool/hot decomposition for AIA 94 \AA, allowing to improve previous empirical disambiguation methods for this passband. The hot temperature coverage of AIA allows RFit to be applied across instruments. This allows to diambiguate the hot flaring emission from \ion{Fe}{XXI} contained within the SJI 1330 \AA, and SJI 1400 \AA, passbands, supported by IRIS/SG results. We also find ways to constrain to some degree of accuracy the hot emission in AIA 211 \AA, and the very hot (flaring) emission in AIA 131 \AA, and AIA 193 \AA. We apply RFit to an AIA-IRIS co-observation that includes a flare, and calculate the average relative contribution for the cool-hot emission to find 10/90, 17/83, 68/32, 62/38, respectively, for AIA 304 \AA, AIA 94 \AA, SJI 1330 \AA, and SJI 1400 \AA. We obtain a more coherent picture of the hot temperature evolution in the $\log T =6.8-7.15$ temperature range and its spatial localisation during the flare. We further accurately detect and quantify the cool plasma from coronal rain, which is observed to increase ten-fold due to the flare-driven cooling. Corona Structures Heating Corona Heating in Flares Instrumental Effects Prominences Spectral Line Intensity and Diagnostics Spectrum Ultraviolet Transition Region Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 24 Oct, 2025 Reviews received at journal 24 Oct, 2025 Reviewers agreed at journal 27 Sep, 2025 Reviewers invited by journal 13 Sep, 2025 Editor assigned by journal 08 Sep, 2025 Submission checks completed at journal 07 Sep, 2025 First submitted to journal 29 Aug, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7488300","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":516357785,"identity":"512da107-2862-4f02-bec2-a3d0ffb58306","order_by":0,"name":"Patrick 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A major obstacle in this enterprise is the multi-temperature emission contained in Ultra Violet (UV) and Extreme UV (EUV) passbands such as those of the \\textit{Atmospheric Imaging Assembly} (AIA) of the \\textit{Solar Dynamics Observatory} (SDO) and the Slit-Jaw Imager (SJI) of the \\textit{Interface Region Imaging Spectrograph} (IRIS). In this work we extend the Response Fitting (RFit) method to disambiguate between cool, warm and hot emission in the SDO/AIA and IRIS/SJI passbands. We improve previous results for AIA~304~\\AA\\, and find very good cool/hot decomposition for AIA~94~\\AA\\, allowing to improve previous empirical disambiguation methods for this passband. The hot temperature coverage of AIA allows RFit to be applied across instruments. This allows to diambiguate the hot flaring emission from \\ion{Fe}{XXI} contained within the SJI~1330~\\AA\\, and SJI~1400~\\AA\\, passbands, supported by IRIS/SG results. We also find ways to constrain to some degree of accuracy the hot emission in AIA~211~\\AA, and the very hot (flaring) emission in AIA~131~\\AA\\, and AIA~193~\\AA. We apply RFit to an AIA-IRIS co-observation that includes a flare, and calculate the average relative contribution for the cool-hot emission to find 10/90, 17/83, 68/32, 62/38, respectively, for AIA~304~\\AA, AIA~94~\\AA, SJI~1330~\\AA\\, and SJI~1400~\\AA. We obtain a more coherent picture of the hot temperature evolution in the $\\log T =6.8-7.15$ temperature range and its spatial localisation during the flare. We further accurately detect and quantify the cool plasma from coronal rain, which is observed to increase ten-fold due to the flare-driven cooling.","manuscriptTitle":"Disambiguation of cool and hot emission in IRIS/Slit-Jaw Imager and AIA channels","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-22 00:55:22","doi":"10.21203/rs.3.rs-7488300/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-10-24T10:42:47+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-24T10:17:31+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"304475378910940586766325362647714115844","date":"2025-09-27T09:15:04+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-09-13T13:14:07+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-09-08T10:14:41+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-09-07T06:42:35+00:00","index":"","fulltext":""},{"type":"submitted","content":"Solar Physics","date":"2025-08-29T11:36:42+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"solar-physics","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"sola","sideBox":"Learn more about [Solar Physics](http://link.springer.com/journal/11207)","snPcode":"11207","submissionUrl":"https://submission.nature.com/new-submission/11207/3","title":"Solar Physics","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"daaad3c0-3278-4c5c-8df0-1a4e719a98d4","owner":[],"postedDate":"September 22nd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-04-04T22:38:42+00:00","versionOfRecord":[],"versionCreatedAt":"2025-09-22 00:55:22","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7488300","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7488300","identity":"rs-7488300","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}