{"id":6215,"date":"2026-10-19T09:48:38","date_gmt":"2026-10-19T09:48:38","guid":{"rendered":"https:\/\/phd.hi.is\/doktorsvorn\/doktorsvorn-i-edlisfraedi-jan-david-burger\/"},"modified":"2026-10-19T09:48:38","modified_gmt":"2026-10-19T09:48:38","slug":"doktorsvorn-i-edlisfraedi-jan-david-burger","status":"publish","type":"phd_defence","link":"https:\/\/phd.hi.is\/en\/doktorsvorn\/doktorsvorn-i-edlisfraedi-jan-david-burger\/","title":{"rendered":"Doktorsv\u00f6rn \u00ed e\u00f0lisfr\u00e6\u00f0i &#8211; Jan David Burger"},"content":{"rendered":"<div class=\"field-items\">\n<div class=\"field-item even\" property=\"content:encoded\">\n<p><strong>Streymi:\u00a0 <a href=\"https:\/\/livestream.com\/hi\/doktorsvornjandavidburger\">https:\/\/livestream.com\/hi\/doktorsvornjandavidburger<\/a> <\/strong><\/p>\n<p><strong>Doktorsefni:\u00a0<\/strong>Jan David Burger<\/p>\n<p><strong>Heiti ritger\u00f0ar:<\/strong>\u00a0Brautarferlar stjarna \u00ed \u00feyngdarm\u00e6tti hulduefnis sem breytist me\u00f0 \u00f3vermnum e\u00f0a me\u00f0 sn\u00f6gglegum h\u00e6tti (Stellar orbits in adiabatically and impulsively evolving dark matter dominated potentials)<\/p>\n<p><strong>Andm\u00e6lendur:<\/strong> <br \/> Dr. Justin Read, pr\u00f3fessor vi\u00f0 University of Surrey, Bretlandi<br \/> Dr. Nicola Amorisco, lektor vi\u00f0 University of Durham, Bretlandi<\/p>\n<p><strong>Lei\u00f0beinandi:\u00a0<\/strong>Dr. Jes\u00fas Zavala Franco, d\u00f3sent vi\u00f0 Raunv\u00edsindadeild H\u00e1sk\u00f3la \u00cdslands<\/p>\n<p><strong>Einnig \u00ed doktorsnefnd:<\/strong> <br \/> Dr. Gunnlaugur Bj\u00f6rnsson, v\u00edsindama\u00f0ur vi\u00f0 Raunv\u00edsindastofnun H\u00e1sk\u00f3lans<br \/> Dr. Miguel \u00c1ngel Sanchez-Conde, Talento Fellow vi\u00f0 Universidad Aut\u00f3noma de Madrid, Sp\u00e1ni<\/p>\n<p><strong>Doktorsv\u00f6rn st\u00fdrir:\u00a0<\/strong>Dr. Einar \u00d6rn Sveinbj\u00f6rnsson, pr\u00f3fessor og deildarforseti Raunv\u00edsindadeildar H\u00e1sk\u00f3la \u00cdslands<\/p>\n<p><strong>\u00c1grip<\/strong><\/p>\n<p>\u00cd hinu samr\u00e6mda \u039bCDM l\u00edkani er um fimmtungur alls efnis s\u00fdnilegar \u00feungeindir og fj\u00f3rir fimmtu hlutar hulduefni. L\u00edkani\u00f0 gefur g\u00f3\u00f0a l\u00fdsingu \u00e1 \u00fev\u00ed hvernig st\u00f3rger\u00f0 alheimsins er til komin vegna l\u00edtilla \u00fe\u00e9ttleikasveiflna \u00ed \u00e1rdaga og hvernig yfir\u00fe\u00e9ttleiki hulduefnis \u00fer\u00f3ast yfir \u00ed \u00feyngdarbundna hj\u00fapa sem h\u00fdsa s\u00fdnilegar vetrarbrautir. Sterkasta \u00e1skorun l\u00edkansins kemur fram \u00e1 skala dvergvetrarbrauta en gangfr\u00e6\u00f0i \u00feeirra vir\u00f0ist stangast \u00e1 vi\u00f0 \u00fe\u00e9ttleikapr\u00f3f\u00edl hulduefnishj\u00fapanna sem sp\u00e1\u00f0 er \u00ed fj\u00f6lagna hermireikningum. \u00de\u00f3 v\u00edsbendingarnar um \u00feetta misr\u00e6mi s\u00e9u umdeildar eru nokkrar m\u00f6gulegar sk\u00fdringar \u00e1 \u00fev\u00ed hvernig \u00e1 \u00feessu getur sta\u00f0i\u00f0. Oft byggjast \u00feessar sk\u00fdringar \u00e1 \u00feyngdarverkunarlausum hrifum sem breyta massadreifingu hulduefnishj\u00fapsins og \u00fear me\u00f0 einnig \u00feyngdarm\u00e6tti hans. \u00dea\u00f0 fer svo eftir e\u00f0li hrifanna hvort massadreifingin breytist \u00e1 t\u00edmaskala sem er styttri e\u00f0a lengri en d\u00e6miger\u00f0ur hreyfifr\u00e6\u00f0ilegur t\u00edmi stjarna \u00ed dvergvetrarbrautum. \u00cd \u00feessari ritger\u00f0 er s\u00fdnt a\u00f0 nota m\u00e1 stj\u00f6rnur sem hreyfifr\u00e6\u00f0ilega spora (tracer) til a\u00f0 greina \u00e1 milli annars vegar \u00f3verminna (h\u00e6gfara) breytinga \u00e1 m\u00e6ttinu og hins vegar sn\u00f6ggra breytinga \u00e1 \u00fev\u00ed. \u00cd \u00f3vermnum breytingum er verkun hreyfifr\u00e6\u00f0ilegu sporanna var\u00f0veitt. \u00de\u00e1 er s\u00fdnt a\u00f0 \u00ed k\u00falusamhverfu m\u00e6tti sem \u00fer\u00f3ast mi\u00f0lungi hratt er rad\u00edalverkunin b\u00e6\u00f0i truflin (perturbative) og sveiflukennd og a\u00f0 l\u00fdsa m\u00e1 \u00fer\u00f3un dreifingar rad\u00edalverkunarinnar me\u00f0 sveimj\u00f6fnu. T\u00edma\u00fer\u00f3un rad\u00edalverkunar sporanna ver\u00f0ur \u00f3truflin \u00feegar t\u00edma\u00fer\u00f3un m\u00e6ttisbreytinganna ver\u00f0ur hra\u00f0ari en sem nemur \u00fat\u00fe\u00e1ttarlotu (radial period) sporanna. Vi\u00f0 sn\u00f6gga breytingu \u00ed \u00feyngdarm\u00e6ttinu, \u00fear sem verkunin er ekki var\u00f0veitt, breytist orka sporanna um st\u00e6r\u00f0 sem er h\u00e1\u00f0 brautarfasa \u00feeirra. Me\u00f0 st\u00fdr\u00f0ri hermun fj\u00f6lagnakerfa s\u00fdni \u00e9g a\u00f0 aflei\u00f0ing hins s\u00ed\u00f0arnefnda er a\u00f0 \u00ed fasar\u00fami sporanna koma fram merki um hvelamyndun \u00ed brautum \u00feeirra. \u00deeim m\u00e1 l\u00fdsa allvel me\u00f0 fj\u00f6lskyldum stjarna af svipu\u00f0um aldri og m\u00e1lminnihaldi. Fasabl\u00f6ndun fj\u00f6lskyldna brauta stjarna \u00ed dvergvetrarbrautum me\u00f0 h\u00e6gt vaxandi sn\u00faningshra\u00f0arit er v\u00edsbending um sterka og sn\u00f6gga sprengistj\u00f6rnusv\u00f6run sem g\u00e6ti hafa breytt \u00fe\u00e9ttleikapr\u00f3f\u00edl hj\u00faps dvergvetrarbrautarinnar. Me\u00f0 hermun einangra\u00f0rar dvergvetrarbrautar er s\u00fdnt a\u00f0 hreyfifr\u00e6\u00f0i gass og stjarna er \u00f3l\u00edk eftir \u00fev\u00ed hvort kjarni hj\u00fapsins hefur \u00fer\u00f3ast \u00f3vermi\u00f0 e\u00f0a sn\u00f6gglega. Ef engin merki er a\u00f0 finna um fasabl\u00f6ndnun brautarfj\u00f6lskyldna er \u00fea\u00f0 sterk v\u00edsbending um a\u00f0 hj\u00fapurinn hafi \u00fer\u00f3ast \u00e1 \u00f3verminn h\u00e1tt, t.d. me\u00f0 eiginv\u00edxlverkun \u00e1 milli einda hulduefnisins.<\/p>\n<p><strong>Um doktorsefni\u00f0<\/strong><br \/> Jan Burger f\u00e6ddist \u00ed Saarbr\u00fccken \u00ed \u00de\u00fdskalandi hinn 7. febr\u00faar 1992. Hann lauk B.Sc. gr\u00e1\u00f0u \u00ed e\u00f0lisfr\u00e6\u00f0i fr\u00e1 RWTH Aachen \u00e1ri\u00f0 2014 og M.Sc. gr\u00e1\u00f0u \u00ed e\u00f0lisfr\u00e6\u00f0i fr\u00e1 sama sk\u00f3la \u00e1ri\u00f0 2016. Fyrra \u00e1rinu \u00ed meistaran\u00e1mi var\u00f0i hann vi\u00f0 Universidad Aut\u00f3noma de Madrid \u00e1 ERASMUS+ styrk. \u00c1ri\u00f0 2017 flutti Jan til \u00cdslands og h\u00f3f doktorsn\u00e1m \u00ed stjarne\u00f0lisfr\u00e6\u00f0i vi\u00f0 H\u00e1sk\u00f3la \u00cdslands undir handlei\u00f0slu Jes\u00fas Zavala Franco.<\/p>\n<\/div><\/div>","protected":false},"featured_media":4980,"template":"","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"_phd_date_start":"2021-08-20T10:00:00+00:00","_phd_date_end":"2021-08-20T12:00:00+00:00","_phd_location":"A\u00f0albygging H\u00e1t\u00ed\u00f0arsalur","_phd_admission":"A\u00f0gangur \u00f3keypis","_phd_thesis_title":"Brautarferlar stjarna \u00ed \u00feyngdarm\u00e6tti hulduefnis sem breytist me\u00f0 \u00f3vermnum e\u00f0a me\u00f0 sn\u00f6gglegum h\u00e6tti (Stellar orbits in adiabatically and impulsively evolving dark matter dominated potentials)","_phd_source_url":"https:\/\/gamli.hi.is\/vidburdir\/doktorsvorn_i_edlisfraedi_jan_david_burger","_phd_source_node_id":"378391","_phd_source_type":"vidburdir","_phd_member_id":739,"footnotes":""},"phd_school":[101,93],"phd_discipline":[105],"class_list":["post-6215","phd_defence","type-phd_defence","status-publish","has-post-thumbnail","hentry","phd_school-raunvisindadeild","phd_school-verkfraedi-og-natturuvisindasvid","phd_discipline-phd-i-edlisfraedi"],"_links":{"self":[{"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/phd_defence\/6215","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/phd_defence"}],"about":[{"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/types\/phd_defence"}],"version-history":[{"count":0,"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/phd_defence\/6215\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/media\/4980"}],"wp:attachment":[{"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/media?parent=6215"}],"wp:term":[{"taxonomy":"phd_school","embeddable":true,"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/phd_school?post=6215"},{"taxonomy":"phd_discipline","embeddable":true,"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/phd_discipline?post=6215"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}