Editing Einstein@Home (section)

== Scientific objectives ==
The Einstein@Home project was originally created to perform all-sky searches for previously unknown continuous gravitational-wave (CW) sources using data from the [[Laser Interferometer Gravitational-Wave Observatory]] ([[LIGO]]) detector instruments in Washington and Louisiana, USA.<ref name="allsky">{{cite web | url = http://einsteinathome.org/about/allsky.html | title = Einstein@Home All Sky Search | publisher = [[American Physical Society]] | access-date = 2006-06-03 |archive-url = https://web.archive.org/web/20060504233801/http://www.einsteinathome.org/about/allsky.html <!-- Bot retrieved archive --> |archive-date = 2006-05-04}}</ref> The best understood potential CW sources are rapidly spinning [[neutron stars]] (including [[pulsars]]) which are expected to emit gravitational waves due to a deviation from [[Rotational symmetry]]. Besides validating Einstein's theory of General Relativity, direct detection of gravitational waves would also constitute an important new astronomical tool. As most neutron stars are electromagnetically invisible, gravitational-wave observations might also reveal completely new populations of neutron stars. A CW detection could potentially be extremely helpful in neutron-star astrophysics and would eventually provide unique insights into the nature of matter at high densities, because it provides a way of examining the bulk motion of the matter.<ref name="CWsearch">{{cite web | url = http://www.2physics.com/2010/07/deepest-all-sky-surveys-for-continuous.html | title = Deepest All-Sky Surveys for Continuous Gravitational Waves | author = Holger J. Pletsch | publisher = 2Physics.com | access-date = 2010-07-25 | archive-date = 2012-06-01 | archive-url = https://web.archive.org/web/20120601143424/http://www.2physics.com/2010/07/deepest-all-sky-surveys-for-continuous.html | url-status = live }}</ref>

Since March 2009, part of the Einstein@Home computing power has also been used to analyze data taken by the [[PALFA Survey|PALFA]] Consortium at the [[Arecibo Observatory]] in [[Puerto Rico]].<ref name="aei.mpg.de">{{cite news |title=New Einstein@Home Effort launched: Thousands of homecomputers to search Arecibo data for new radio pulsars |url=http://www.aei.mpg.de/123478/New_Einstein_Home_effort_launched |work=MPI for Gravitational Physics |publisher=MPI for Gravitational Physics |date=March 24, 2009 |access-date=2016-11-16 |archive-date=2016-11-16 |archive-url=https://web.archive.org/web/20161116230559/http://www.aei.mpg.de/123478/New_Einstein_Home_effort_launched |url-status=live }}</ref> This search effort is designed to find radio pulsars in tight binary systems.<ref name="ABP">{{cite web | url = https://einsteinathome.org/science/abp | title = The Einstein@Home Arecibo Radio Pulsar search | access-date = November 16, 2016 | archive-date = November 16, 2016 | archive-url = https://web.archive.org/web/20161116230137/https://einsteinathome.org/science/abp | url-status = live }}</ref> It is expected that there is one radio pulsar detectable from Earth in an orbital system with a period of less than one hour.<ref name=":6" /> A similar search has also been performed on two archival data sets from the Parkes Multi-beam Pulsar Survey.<ref>{{cite web| url = https://einsteinathome.org/content/what-are-we-doing-science-behind-brp5#comment-116702| title = Einstein@Home forum post about searches in Parkes Observatory data| access-date = November 16, 2016| archive-date = November 17, 2016| archive-url = https://web.archive.org/web/20161117023420/https://einsteinathome.org/content/what-are-we-doing-science-behind-brp5#comment-116702| url-status = live}}</ref> The Einstein@Home radio pulsar search employs mathematical methods developed for the search for gravitational waves.<ref name=":6">{{cite journal |last=Allen |first=Bruce | display-authors=etal |date=2013 |title= The Einstein@Home search for radio pulsars and PSR J2007+2722 discovery |arxiv = 1303.0028 |doi=10.1088/0004-637X/773/2/91 |bibcode=2013ApJ...773...91A |volume=773 |issue=2 |journal=The Astrophysical Journal |page=91|s2cid=119253579 }}</ref>

Since July 2011, Einstein@Home is also analyzing data from the Large Area Telescope (LAT), the primary instrument on [[Fermi Gamma-ray Space Telescope]] to search for pulsed gamma-ray emission from spinning neutron stars (gamma-ray pulsars).<ref>{{cite web| url = https://einsteinathome.org/content/launching-fermi-lat-gamma-ray-pulsar-search| title = Launching Fermi-LAT gamma ray pulsar search| access-date = November 16, 2016| archive-date = November 17, 2016| archive-url = https://web.archive.org/web/20161117001811/https://einsteinathome.org/content/launching-fermi-lat-gamma-ray-pulsar-search| url-status = live}}</ref> Some neutron stars are only detectable by their pulsed gamma-ray emission, which originates in a different area of the neutron star magnetosphere than the radio emission. Identifying the neutron star's rotation rate is computationally difficult, because for a typical gamma-ray pulsar only thousands of gamma-ray photons will be detected by the LAT over the course of billions of rotations.<ref>{{cite journal |last=Pletsch |first=Holger J. | display-authors=etal |year=2012 |title= Discovery of Nine Gamma-Ray Pulsars in Fermi-LAT Data Using a New Blind Search Method |arxiv = 1111.0523 |doi=10.1088/0004-637X/744/2/105 |bibcode=2012ApJ...744..105P |volume=744 |issue=2 |journal=The Astrophysical Journal |page=105|s2cid=51792907 }}</ref> The Einstein@Home analysis of the LAT data makes use of methods initially developed for the detection of continuous gravitational waves.