IRIS Nugget
Welcome to the IRIS Science Nuggets: highlights of recent IRIS scientific results for the solar physics community.
{"id":"pod_polito_vanessa_2021-09-21T16:49:25.122Z","submitter":"","author":"Pradeep Kayshap","status":"published","creation-date":"2021-09-21T16:49:25.127Z","last-modified-date":"2021-10-13T18:51:47.273Z","credit":"Vellore Institute of Technology - VIT Bhopal University, Kothri Kalan, Astha, M.P., India","title":"Homologous surges as seen by IRIS","contentBlocks":[{"type":"text","text":"High-resolution%20IRIS%20spectral%20observations%20in%20the%20Mg%20II%20k%202796.35%20%26Aring%3B%20and%20h%202803.35%20%26Aring%3B%2C%20Si%20IV%201402.77%20%26Aring%3B%2C%20and%20O%20IV%201401.15%20%26Aring%3B%20lines%20%28De%20Pontieu%20et%20al.%202014%29%20were%20used%20to%20analyze%20six%20homologs%20surges%2C%20which%20occurred%20on%20July%207%2C%202014%20near%20the%20limb%20%28Figure%201%29.%20The%20peak%20of%20the%20last%20surge%20is%20displayed%20in%20panel%20A%20along%20with%20the%20intensity-time%20map%20%28panel%20B%29%20obtained%20in%20the%20IRIS%2FSJI%201330%20%26Aring%3B%20filter.%20Further%2C%20panels%20C1%20to%20C5%20show%20Si%20IV%20and%20O%20IV%20spectral%20profiles%20at%20five%20different%20locations%20within%20the%20surge%20plasma%2C%20which%20are%20indicated%20by%20different%20slits%20in%20panel%20A.%20Despite%20being%20optically%20thin%2C%20we%20find%20that%20both%20lines%20show%20double%20peaks%20at%20all%20locations%20%28except%20the%20middle%20position%20which%20is%20a%20single%20peak%20profile%29%2C%20and%20are%20fitted%20by%20a%20double%20Gaussian%20function%20%28except%20panel%20C3%29.%20Interestingly%2C%20one%20peak%20of%20the%20Si%20IV%20line%20remains%20around%20-100%20km%2Fs%20for%20all%20five%20profiles%20while%20the%20other%20peak%20shows%20the%20change%20from%20red-shifts%20%28panel%20C1%29%20to%20blue-shifts%20%28panel%20C5%29%20as%20we%20move%20across%20the%20surge.%20The%20rest%20positions%20of%20Si%20IV%20and%20O%20IV%20are%20displayed%20by%20vertical%20blue%20and%20red%20dashed%20lines%2C%20respectively.%20A%20similar%20behavior%20is%20also%20found%20for%20the%20O%20IV%20line%20which%20is%20displayed%20in%20the%20same%20panels%20%28solid%20red%20curve%29.%20We%20suggest%20that%20the%20stationary%20component%20is%20a%20result%20of%20translation%20motions%20as%20the%20surge%20plasma%20is%20ascending%20up%2C%20while%20the%20variable%20peak%20occurs%20because%20of%20the%20rotating%20motion%20of%20surge%20plasma.%20We%20found%20that%20all%20other%20surges%20also%20show%20a%20similar%20behavior%2C%20and%20we%20conclude%20that%20there%20is%20a%20prevalence%20of%20rotating%20motions%20in%20these%20homologous%20surges."},{"type":"image","file":"","url":"nuggetvideos/2021/09/21/pod_polito_vanessa_2021-09-21T16%3A49%3A25.122Z/Nugget_2.png","hash":"2feabc60d6a135f9a85058d40dfa4fee","mimeType":"image/png","caption":"Figure%201%3A%20The%20strongest%20surge%20out%20of%20the%20six%20homologous%20surges%20%28panel%20A%29%20with%20five%20locations%20highlighted%20%28see%20colored%20slits%29%20and%20an%20intensity-time%20map%20%28panel%20B%29%20using%20IRIS%2FSJI%201330%20%26Aring%3B%20observations.%20The%20panels%20C1%20to%20C5%20display%20the%20Si%20IV%20and%20O%20IV%20spectral%20profiles%20from%20the%20selected%20five%20locations%20along%20with%20their%20rest%20positions%2C%20i.e.%2C%20blue%20and%20red-dashed%20lines%20for%20Si%20IV%20and%20O%20IV%2C%20respectively.%20We%20have%20fitted%20both%20the%20profiles%20with%20double%20Gaussians%20%28solid%20blue%20and%20red%20lines%20Si%20IV%20and%20O%20IV%2C%20respectively%29.%20We%20find%20that%20one%20peak%20remains%20at%20constant%20velocity%20while%20the%20Doppler%20shift%20of%20the%20other%20peak%20ranges%20from%20red%20to%20blue%20shifts."},{"type":"text","text":"We%20have%20estimated%20the%20Mg%20II%20k%2Fh%20ratio%20%28Rkh%29%2C%20Doppler%20velocity%2C%20and%20width%20maps%20for%20the%20complete%20observations%20%28covering%20all%20six%20surges%29%20which%20are%20shown%20in%20panels%20A%2C%20B%2C%20and%20C%20of%20Figure%202.%20The%20blue%20shifts%20dominate%20in%20the%20first%20half%20of%20all%20surges%2C%20and%20the%20Rkh%20is%20less%20than%202.0%2C%20suggesting%20that%20the%20Mg%20II%20resonance%20lines%20may%20be%20formed%20under%20optically%20thick%20conditions%20during%20the%20upflow%20phase%20of%20these%20surges.%20The%20second%20half%20of%20the%20surge%20is%20dominated%20by%20redshifts%2C%20and%20interestingly%2C%20the%20Rkh%20is%20greater%20than%202.0%2C%20i.e.%2C%20now%2C%20the%20line%20may%20be%20formed%20under%20optically%20thin%20conditions.%20The%20values%20of%20Rkh%20increase%20with%20the%20Doppler%20velocity%20pattern%20%28i.e.%2C%20from%20blueshift%20to%20redshifts%29%20and%20width%20pattern%20of%20each%20surge%20%28i.e.%2C%20widths%20of%20the%20lines%20decrease%20over%20the%20lifetime%20of%20each%20surge%29."},{"type":"image","file":"","url":"nuggetvideos/2021/09/21/pod_polito_vanessa_2021-09-21T16%3A49%3A25.122Z/Figure_Two.png","hash":"610c254b84b09deb854244edd7cdbc20","mimeType":"image/png","caption":"Figure%202%3A%20Mg%20II%20k%20to%20h%20ratio%20%28Rkh%3B%20panel%20a%29%2C%20Doppler%20velocity%20%28panel%20b%29%2C%20and%20width%20maps%20%28panel%20c%29%20of%20the%20Mg%20II%20k%202796.35%20%26Aring%3B%20line%20are%20displayed%20here.%20In%20the%20upflow%20phases%20of%20all%20surges%2C%20the%20Rkh%20is%20less%20than%20two%20%28i.e.%2C%20suggestive%20of%20optically%20thick%20conditions%29%20while%20Rkh%20becomes%20more%20than%202%20%28i.e.%2C%20the%20line%20may%20be%20formed%20under%20optically%20thin%20conditions%29%20during%20the%20downflow%20phases%20of%20all%20surges.%20The%20Gaussian%20width%20is%20high%20in%20the%20initial%20phases%20and%20decreases%20as%20time%20progress%20for%20each%20surge%2C%20i.e.%2C%20the%20Rkh%20increases%20as%20the%20line%20width%20decreases.%20On%20the%20right%20side%2C%20we%20show%20he%20Mg%20II%20k%20and%20h%20line%20profiles%2C%20which%20are%20single%20peaked%20profiles%20being%20formed%20in%20the%20optically%20thick%20atmosphere."},{"type":"text","text":"The%20height-time%20%28HT%29%20diagrams%20from%20IRIS%2FSJI%201330%20%26Aring%3B%2C%20SDO%2FAIA%20304%20%26Aring%3B%2C%20171%20%26Aring%3B%2C%20and%2094%20%26Aring%3B%20%28see%20right%20column%20of%20Figure%203%29%20are%20produced%20using%20the%20displayed%20slits%20%28see%3B%20left-column%20of%20figure%203%29.%20All%20surges%20are%20highlighted%20in%20the%20SJI-1330%20%26Aring%3B%20and%20AIA-304%20%26Aring%3B%20HT%20diagrams.%20We%20have%20drawn%20several%20slits%20highlighting%20the%20up%20flow%20and%20downfall%20phases%20of%20each%20surge%20to%20estimate%20various%20properties%20of%20the%20surges%2C%20namely%2C%20upflow%20and%20downflow%20velocities%2C%20lifetime%2C%20acceleration%2C%20and%20deceleration.%20It%20is%20found%20the%20homologous%20surges%20exhibit%20a%20large%20range%20of%20these%20parameters.%20We%20did%20not%20find%20signatures%20of%20the%20surges%20in%20the%20high-temperature%20channels%20of%20AIA%2C%20namely%2C%20171%20%26Aring%3B%20and%20304%20%26Aring%3B."},{"type":"image","file":"","url":"nuggetvideos/2021/09/21/pod_polito_vanessa_2021-09-21T16%3A49%3A25.122Z/Figure_Three.png","hash":"fdfa54fb3be55c09f41e8a2e5156b0c0","mimeType":"image/png","caption":"Figure%203%3A%20IRIS%2FSJI%201330%20%26Aring%3B%20%28panel%20a%29%2C%20AIA%20304%20%26Aring%3B%20%28panel%20b%29%2C%20171%20%26Aring%3B%20%28panel%20c%29%2C%20and%2094%20%26Aring%3B%20%28panel%20d%29%20images%20of%20the%20surges%20with%20overlaid%20the%20position%20of%20the%20slits%20we%20used%20to%20obtain%20the%20HT%20diagrams%20%28left%20panels%29.%20We%20also%20draw%20different%20slits%20in%20the%20HT%20diagrams%20of%20each%20surge%20%28see%3B%20panels%20e%20and%20f%29%20to%20estimate%20various%20kinematical%20properties.%20The%20surges%20are%20rarely%20visible%20in%20the%20AIA%20171%26Aring%3B%20and%20AIA%2094%20%26Aring%3B%20channels."},{"type":"text","text":"Finally%2C%20we%20have%20performed%20a%20differential%20emission%20measure%20%28DEM%29%20analysis%20for%20all%20surges%20using%20the%20software%20developed%20by%20Cheung%20et%20al.%20%282015%29.%20We%20show%20here%20the%20DEM%20distribution%20from%20the%20base%20%28black%20histogram%29%20and%20spire%20%28blue%20histogram%29%20of%20all%20six%20surges%20%28Figure%204%29.%20The%20footpoints%20of%20the%20surges%20show%20cool%20%28log%20T%2FK%20%7E%206.37%29%20and%20hot%20components%20%28log%20T%2FK%20%7E%206.91%29%2C%20while%20the%20spires%20of%20surges%20only%20show%20cool%20components.%20Hence%2C%20the%20presence%20of%20hot%20components%20only%20at%20the%20base%20of%20surges%20suggests%20heating%20in%20that%20location."},{"type":"image","file":"","url":"nuggetvideos/2021/09/21/pod_polito_vanessa_2021-09-21T16%3A49%3A25.122Z/Nugget_7.png","hash":"f0f80c00799c5f2629d7e124ccc46a6","mimeType":"image/png","caption":"Figure%204%3A%20DEM%20distributions%20at%20the%20base%20%28black%20histogram%29%20and%20spire%20%28blue%20histogram%29%20of%20all%20surges.%20We%20see%20two%20peaks%20at%20the%20base%20of%20surge%20%28i.e.%2C%20one%20peak%20in%20cool%20temperature%20regime%20while%20another%20peak%20in%20hot%20temperature%20regime%29%2C%20which%20are%20fitted%20by%20two%20Gaussian%20%28solid%20black%20curve%29%20lines.%20The%20DEM%20distribution%20of%20the%20spire%20region%20from%20each%20surge%20shows%20only%20a%20cool%20temperature%20peak%2C%20which%20is%20fitted%20by%20a%20single%20Gaussian%20%28solid%20blue%20curve%29."},{"type":"text","text":"It%20is%20the%20first%20time%20that%20surge%20emission%20is%20analyzed%20in%20the%20Mg%20II%20h%20and%20k%2C%20and%20O%20IV%20spectral%20lines.%20Earlier%2C%20only%20one%20work%20%28i.e.%2C%20N%26oacute%3Bbrega-Siverio%20et%20al.%202017%29%20has%20reported%20surge%20emission%20in%20Si%20IV.%20We%20find%20that%20the%20rotating%20motion%20is%20present%20in%20all%20surges%20along%20with%20heating%20signatures%20near%20the%20base%20of%20the%20surges.%20The%20presence%20of%20a%20heated%20base%20with%20rotating%20motion%20may%20suggest%20the%20occurrence%20of%20magnetic%20reconnection%20near%20the%20bases%20of%20surges%20as%20suggested%20by%20Fang%20et%20al.%20%282014%29%20and%20Kayshap%20et%20al.%20%282018%29.%20We%20suggest%20that%20this%20magnetic%20reconnection%20is%20responsible%20for%20the%20formation%20of%20these%20surges.%20In%20general%2C%20the%20Rkh%20is%20high%20in%20the%20homologous%20surges%20as%20compared%20to%20other%20features%20%28e.g.%2C%20flare%20emission%20%5BKerr%20et%20al.%202015%5D%20and%20filament%20eruption%20%5BHarra%20et%20al.%202014%5D%29.%20Please%20see%20Kayshap%20et%20al.%20%282021%29%20for%20the%20full%20details%20of%20this%20works."}],"references":["Cheung M. C. M., Boerner P., Schrijver C. J., Testa P., Chen F., Peter H., Malanushenko A., ApJ, 807, 143 (2015)","De Pontieu, B., Title, A. M., Lemen, J. R., et al. Solar Physics, 289, 2733 (2014)","Harra L. K., Matthews S. A., Long D. M., Doschek G. A., De Pontieu B., ApJ, 792, 93 (2014)","Kerr G. S., Simões P. J. A., Qiu J., Fletcher L., A&A, 582, A50 (2015)","Leenaarts J., Pereira T. M. D., Carlsson M., Uitenbroek H., De Pontieu B., ApJ, 772, 90 (2013)","Nóbrega-Siverio D., Martínez-Sykora J., Moreno-Insertis F., Rouppe van der Voort L., ApJ, 850, 153 (2017)","Fang, Fang, Fan, Yuhong, McIntosh, Scott W, ApJL, 789, 19 (2014)","Kayshap, P., Murawski, K., Srivastava, A.K., Dwivedi, A.K., A&A, 616, 99 (2018)","Kayshap, P., Singh Payal, Rajdeep, Tripathi, Sharad C., Padhy, Harihara, MNRAS, 505, 5311 (2021)",""],"pubDate":"2021-10-13T18:52:08.957Z"}