This database table contains the current target list of the X-ray Multi-Mirror Newton (XMM-Newton) mission including those in (i) the routine calibration plan, (ii) the Guaranteed Time Observation (GTO) program, (iii) the triggered target candidates or ToOs accepted for the First through the Twentieth-Third Announcements of Opportunity (AO-1 through AO-23) programs, (iv) the AO-1 through AO-23 Guest Observer (GO) program targets with priority A or B, (v) the AO-1 through AO-19 GO program targets with priority C which have been observed, (vi) the AO-20 through AO-23 GO program targets with priority C, and (vii) the targets granted by agreement of the ESA Director of Science and the National Space Agency of Japan, following the loss of the original Astro-E spacecraft. For complete and authoritative information on the XMM-Newton mission, policies, and data archive, refer to the web pages of the European Space Agency's (ESA's) XMM-Newton Science Operations Center at <a href="http://xmm.esac.esa.int/">http://xmm.esac.esa.int/</a> and of NASA's XMM-Newton Guest Observer Facility at <a href="http://heasarc.gsfc.nasa.gov/docs/xmm/xmmgof.html">http://heasarc.gsfc.nasa.gov/docs/xmm/xmmgof.html</a> Notice that all priority C targets from AOs 1 through 19 which were never observed by XMM-Newton (and hence have expired) have been removed from this table. To check which targets have either already been observed by XMM-Newton or are on the short-term schedule to be observed in the next few weeks, users should examine the <a href="/db-perl/W3Browse/w3table.pl?tablehead=name%3Dxmmmaster&Action=More+Options">XMMMASTER</a> table which is also contained in Browse. To find out which targets are currently scheduled to be observed in the next three months, the user should check the XMM-Newton Advanced Plan at <a href="http://xmm.esac.esa.int/external/xmm_sched/advance_plan.shtml">http://xmm.esac.esa.int/external/xmm_sched/advance_plan.shtml</a> While abstracts are available for most proposals, there are a number of targets for which the HEASARC lacks the corresponding abstracts: e.g., the abstracts for AO-2 Guest Observer targets which have non-US PIs are not available. This database table was last updated by the HEASARC in December 2023, when AO-23's accepted targets were added. <p> AO-22's accepted targets were added in November 2022. <p> AO-21's accepted targets were added and AO-19's unobserved priority C targets were removed in December 2021. <p> AO-20's accepted targets were added and AO-18's unobserved priority C targets were removed in December 2020. <p> AO-19's accepted targets were added and AO-17's unobserved priority C targets were removed in April 2020. <p> In June 2019, many duplicate entries were removed. <p> AO-18's accepted targets were added and AO-16's unobserved priority C targets were removed in November 2018. <p> AO-17's accepted targets were added and AO-15's unobserved priority C targets were removed in November 2017. <p> AO-16's accepted targets were added and AO-14's unobserved priority C targets were removed in December 2016. <p> AO-15's accepted targets were added and AO-13's unobserved priority C targets were removed in December 2015. <p> In August 2015, proposal titles were added. <p> AO-14's accepted targets were added and AO-12's unobserved priority C targets were removed in December 2014. <p> AO-13's accepted targets were added and AO-11's unobserved priority C targets were removed in December 2013. <p> AO-12's accepted targets were added and AO-10's unobserved priority C targets were removed in December 2012. <p> AO-11's accepted targets were added and AO-9's unobserved priority C targets were removed in December 2011. <p> AO-10's accepted targets were added and AO-8's unobserved priority C targets were removed in December 2010. <p> AO-9's accepted targets were added and AO-7's unobserved priority C targets were removed in January 2010. <p> AO-8's accepted targets were added and AO-6's unobserved priority C targets were removed in December 2008. <p> AO-7's accepted targets were added and AO-5's unobserved priority C targets were removed in January 2008. <p> AO-6's accepted targets were added in January 2007, and, in November 2006, an effort was made to remove most of the unobserved priority C targets from previous AOs. This is a service provided by NASA HEASARC .