{"id":42870,"date":"2016-02-12T08:58:54","date_gmt":"2016-02-12T18:58:54","guid":{"rendered":"http:\/\/www.hawaii.edu\/news\/?p=42870"},"modified":"2018-12-04T16:01:58","modified_gmt":"2018-12-05T02:01:58","slug":"pan-starrs-chases-source-of-ligo-gravity-wave-event","status":"publish","type":"post","link":"https:\/\/www.hawaii.edu\/news\/2016\/02\/12\/pan-starrs-chases-source-of-ligo-gravity-wave-event\/","title":{"rendered":"<abbr title=\"Panoramic Survey Telescope and Rapid Response System\">Pan-STARRS<\/abbr>chases source of <abbr title=\"Laser Interferometer Gravitational-Wave Observatory\">LIGO<\/abbr> gravity wave event"},"content":{"rendered":"<span class=\"span-reading-time rt-reading-time\" style=\"display: block;\"><span class=\"rt-label rt-prefix\">Reading time: <\/span> <span class=\"rt-time\"> 3<\/span> <span class=\"rt-label rt-postfix\">minutes<\/span><\/span><figure id=\"attachment_42884\" aria-describedby=\"caption-attachment-42884\" style=\"width: 630px\" class=\"wp-caption alignleft\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/www.hawaii.edu\/news\/wp-content\/uploads\/2016\/02\/pan-starrs-2.jpg\" alt=\"\" width=\"620\" height=\"358\" class=\"size-full wp-image-42884\" srcset=\"https:\/\/www.hawaii.edu\/news\/wp-content\/uploads\/2016\/02\/pan-starrs-2.jpg 620w, https:\/\/www.hawaii.edu\/news\/wp-content\/uploads\/2016\/02\/pan-starrs-2-260x150.jpg 260w\" sizes=\"auto, (max-width: 620px) 100vw, 620px\" \/><figcaption id=\"caption-attachment-42884\" class=\"wp-caption-text\"><abbr>Pan-STARRS<\/abbr>1 near the summit of Haleakal&#257;, Maui at dawn. (photo credit: Rob Ratkowski)<\/figcaption><\/figure>\n<p><em>The email came in the evening of September 15. A potentially significant event had happened at the <a href=\"https:\/\/www.ligo.caltech.edu\/\">Laser Interferometer Gravitational-Wave Observatory<\/a>, or <abbr>LIGO<\/abbr>, during their engineering run. A ripple in spacetime had occurred somewhere in the universe. But where? <abbr>LIGO<\/abbr> had not yet started their formal observing run, and with only two Gravity Wave detectors, one in Hanford, <abbr title=\"Washington\">WA<\/abbr>, and one in Livingston, <abbr title=\"Los Angeles\">LA<\/abbr>, they could not pinpoint where in the sky, amongst billions and billions of galaxies, the source of this disturbance had occurred.<\/em><\/p>\n<p><em>The <abbr>LIGO<\/abbr> team&#8217;s first analysis was preliminary, but it showed that two black holes, in tight orbits around each other, had finally spiraled together and merged into a single black hole<\/a>. The resulting turmoil launched a cascade of vibrations into the very fabric of spacetime that ultimately set the astonishingly sensitive pendulums at <abbr>LIGO<\/abbr> swinging together. <\/em><\/p>\n<ul>\n<li><strong>Related<\/strong>: <a href=\"https:\/\/www.ligo.caltech.edu\/news\/ligo20160211\">&ldquo;Gravitational waves detected 100 years after Einstein&#8217;s prediction,&rdquo;<\/a> <abbr>LIGO<\/abbr> news release, February 11, 2016  <\/li>\n<\/ul>\n<p><abbr>Pan-STARRS<\/abbr>, the University of <span aria-label=\"Hawaii\">Â鶹´«Ã½<\/span>&#8217;s <a href=\"http:\/\/pan-starrs.ifa.hawaii.edu\/public\/\">Panoramic Survey Telescope and Rapid Response System<\/a>, was prepared for this eventuality. Built by the University of <span aria-label=\"Hawaii\">Â鶹´«Ã½<\/span>&#8217;s <a href=\"http:\/\/www.ifa.hawaii.edu\/\">Institute for Astronomy<\/a>, the <abbr>Pan-STARRS<\/abbr>1 Telescope spent years mapping the sky to find all kinds of changing celestial objects, all the while building the most detailed map of the sky in five colors. This image of the sky, the <abbr title=\"prototype telescope for a large optical synoptic survey telescope system\">PS<\/abbr>1 Sky Survey, which will be released to the public this spring through the Space Telescope Science Institute&#8217;s <abbr title=\"Mikulski Archive for Space Telescopes\">MAST<\/abbr> Archive, is the ideal resource for trying to find the source of the Gravity Wave Event. If &ldquo;sparks&rdquo; fly when black holes merge then a new point of light will be seen in the sky. <abbr>Pan-STARRS<\/abbr>, with its powerful surveying capability, can rapidly map the region of the sky identified by <abbr>LIGO<\/abbr>, compare it to the previous map and find anything that has changed. <\/p>\n<h2>Gravity wave hunt begins<\/h2>\n<p>To do this, the powerful computers of <abbr>Pan-STARRS<\/abbr> must construct a new image of the sky, and then carefully subtract the pre-existing deep sky image. Whatever remains are the objects that have changed in the universe since the map was made, called &ldquo;transients.&rdquo; In the large area provided by <abbr>LIGO<\/abbr>, there will be many more common variable objects like supernovae, stellar flares, highly variable stars, even variations in the active nuclei of galaxies, also fueled by black holes. The team had to eliminate the &ldquo;normal&rdquo; ones, and search for something truly new. But <abbr>Pan-STARRS<\/abbr> was prepared for this from its years of ground breaking work on every kind of astronomical transient.<\/p>\n<p>&ldquo;I&#8217;ve been interested in gravity waves since I was kid.&rdquo; says <abbr>Pan-STARRS<\/abbr> Director <a href=\"https:\/\/www.ifa.hawaii.edu\/users\/chambers\/\"><strong>Ken Chambers<\/strong><\/a>, an astronomer at the Institute for Astronomy at the University of <span aria-label=\"Hawaii\">Â鶹´«Ã½<\/span>. He jumped at the possibility to sign up with <abbr>LIGO<\/abbr> to get their email alerts. &ldquo;Most people thought the odds of them finding anything were too small to spend anytime on it, but I was thrilled at the chance.&rdquo; But when that email came in the night, he knew it would be hard. <\/p>\n<p>The region <abbr>LIGO<\/abbr> had identified as most likely to contain the source was rising with the sun at dawn, observable only for a few minutes before the sky became too bright. With its infrared filters, Pan<abbr>STARRS<\/abbr> could observe the brightening sky for longer, and over the course of a few weeks <abbr>PS<\/abbr>1 was able to map the most important sky regions. <abbr>PS<\/abbr>1 identified 56 astronomical explosions over 41 days after the <abbr>LIGO<\/abbr> event. But what were they?<\/p>\n<h2>No unusual behavior detected<\/h2>\n<p>Professor <a href=\"http:\/\/star.pst.qub.ac.uk\/~sjs\/\">Stephen Smartt<\/a>, director of the <a href=\"https:\/\/star.pst.qub.ac.uk\/\">Astrophysics Research Centre<\/a> at Queen&#8217;s University Belfast, leader of the spectroscopic effort to follow up the <abbr>Pan-STARRS<\/abbr> discoveries, explains: &ldquo;We didn&#8217;t find anything in our data that was likely related to the gravitational wave source. We discovered over 50 new sources that are normal supernovae&#8212;exploding stars that we find all the time. We didn&#8217;t see any hint of unusual behavior.&rdquo; <\/p>\n<p>There are two likely reasons. One is that the source was too far in the southern hemisphere, not visible from <span aria-label=\"Hawaii\">Â鶹´«Ã½<\/span>. The other is that the source may have been too faint to detect it in the time available. &ldquo;That is science&rdquo; says Chambers. &ldquo;Sometimes all you can report is what you don&#8217;t see, because that is important information too. <abbr>LIGO<\/abbr> has opened a brand new field of astronomy and confirmation from facilities like <abbr>Pan-STARRS<\/abbr> will be very important to understanding them.&rdquo;<\/p>\n<p>A scientific paper describing the details of the <abbr>Pan-STARRS<\/abbr> follow-up effort has been submitted to the <em>Monthly Notices of the Royal Astronomical Society<\/em>. The limits <abbr>Pan-STARRS<\/abbr> has set for a potential counterpart will be important for constraining theories of what should have been seen and demonstrate the infrastructure is in place to respond the next time <abbr>LIGO<\/abbr> finds a gravity wave. <abbr>LIGO<\/abbr> will have another observing campaign in the fall, when <abbr>PS<\/abbr>2, the second <abbr>Pan-STARRS<\/abbr> telescope, will be ready, doubling the survey power of the system. Meanwhile, <abbr>PS<\/abbr>1 continues to map the sky every night, seeking the unknown.<\/p>\n<p>&#8212;<a href=\"http:\/\/www.ifa.hawaii.edu\/info\/press-releases\/LIGO-panstarrs\/\"><em>An Institute for Astronomy news release<\/em><\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p><abbr title=\"University of Hawaii\">UH<\/abbr>&#8217;s Panoramic Survey Telescope and Rapid Response System maps the sky looking for <abbr title=\"Laser Interferometer Gravitational-Wave Observatory\">LIGO<\/abbr> gravity wave event.<\/p>\n","protected":false},"author":16,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[30],"tags":[34,35,36,9],"class_list":["post-42870","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-research","tag-astronomy","tag-institute-for-astronomy","tag-pan-starrs","tag-uh-manoa","entry","has-media"],"aioseo_notices":[],"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/posts\/42870","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/users\/16"}],"replies":[{"embeddable":true,"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/comments?post=42870"}],"version-history":[{"count":13,"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/posts\/42870\/revisions"}],"predecessor-version":[{"id":88329,"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/posts\/42870\/revisions\/88329"}],"wp:attachment":[{"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/media?parent=42870"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/categories?post=42870"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/tags?post=42870"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}