Dear Colleague, 20-August-2019 NASA is pleased to call to the attention of members of the U.S. scientific community the release by the European Space Agency (ESA) of the Announcement of Opportunity (AO), "XMM-Newton Call for Observing Proposals", soliciting Guest Observing proposals for the 19th cycle (AO-19) observing program for ESA's X-ray Multi-Mirror Mission (XMM-Newton). The subject Announcement solicits proposals for observations to be performed during a 12-month period commencing in May 2020. Due to the nature of the NASA-ESA bilateral agreement, only proposals from scientists affiliated with U.S. institutions are solicited by this Letter; others are advised to contact ESA directly. U.S. scientists may propose either as Principal Investigators or as Co-Investigators on proposals with either U.S. or non-U.S. (foreign PI proposals) PIs. The AO may be accessed directly from ESA at the following address: https://www.cosmos.esa.int/web/xmm-newton/ao19 The XMM-Newton Guest Observer Facility (GOF) at the Goddard Space Flight Center (GSFC) is the support center for XMM-Newton activities in the U.S. Information of interest to U.S. observers, as well as general project information, can be found at the following address: https://heasarc.gsfc.nasa.gov/docs/xmm/xmmgof.html A detailed description of the mission, including instrument capabilities and additional information pertaining to the proposal preparation and submission procedures, is also available via links from the XMM-Newton home page at that address. (General questions concerning XMM-Newton and participation by U.S. investigators should be addressed to xmmhelp@bigbang.gsfc.nasa.gov.) ESA will be responsible for conducting a peer review of all submitted proposals, including those from U.S. investigators, and determining the associated time allocation. Current plans call for ESA to notify proposers and NASA of the results of the peer review in mid-December 2019. Based on the outcome of the 2019 Senior Review of Operating Missions, NASA currently expects to allocate approximately $2.5 M for a Guest Observer (GO) program to support the analysis, interpretation and publication of data obtained by U.S. proposers who are granted Open Time observing on XMM-Newton under AO-19. This level is comparable to the amount available for the support of US GOs for AO-17 and AO-18. In light of existing budgetary constraints, it is anticipated that only US PIs with Category "A" or "B" proposals will be invited to apply for support from the US XMM-Newton GO program for AO-19. Pending the results of the ESA selection of observing proposals submitted to AO-19, NASA will issue an update to this DCL to inform US proposers of any changes to the above. For additional technical or programmatic information regarding U.S. participation in the XMM-Newton mission, please contact: Technical Information: Dr. Kim Weaver Goddard Space Flight Center Code 662 Greenbelt, MD 20771 Tel: (301) 286-4256 Kimberly.A.Weaver@nasa.gov Programmatic Information: Dr. Stefan Immler Astrophysics Division 300 E Street SW Washington, DC 20546 Tel: 202-358-0615 Stefan.M.Immler@nasa.gov Sincerely, Dr. Stefan Immler U.S. XMM-Newton Program Scientist A service of the XMM-Newton GOF, NASA/GSFC