XMM-Newton Announcement of Opportunity (AO-25) Closed

The Twenty-fifth Announcement of Opportunity (AO-25) for XMM-Newton closed on 10 October 2025.

A total of 463 valid proposals were received for this cycle, which covers a one-year period with 10 Ms of observing time available. In contrast, 85.6 Ms of science time were requested, resulting in an over-subscription factor of 8.6.

This marks a significant increase in over-subscription compared to recent years. The rise is primarily due to reduced available observing time in AO-25, driven by operational constraints such as increased expected radiation levels and the ongoing evolution of the spacecraft’s orbit.

Proposal breakdown:

• Large Programmes: 45 proposals
• Fulfil Programmes: 13 proposals
• Anticipated Target of Opportunity observations: 81 proposals

Joint Programme submissions totalled 114 proposals:

Proposals were submitted by 375 different Principal Investigators from 42 countries. Including co-investigators, approximately 1,700 individual scientists participated in the response the Twenty-fifth Announcement of Opportunity.

Erik Kuulkers appointed as new XMM-Newton Project Scientist

As of 8 September 2025, Erik Kuulkers is leading XMM-Newton as Project Scientist, taking this role over from Norbert Schartel. Since 2013, Erik has been Project or Study Scientist for various missions, including Einstein Probe, Theseus, NewAthena, and, for over 10 years, INTEGRAL. Erik's main research interests are in the realm of transient and explosive X-ray phenomena in the universe. Erik is looking forward to continue writing the success story that is X-ray astronomy with XMM-Newton, allowing scientific discoveries spanning many decades, back from Apollo 15 to the 2030s and beyond.

Further details on our XMM-Newton SOC web portal.

XMM-Newton Announcement of Opportunity (AO-25)

Letter of Invitation by the ESA Director of Science

Dear Colleague,

I am pleased to invite you to respond to the 25th “Announcement of Opportunity" to submit proposals for observations to be performed with the XMM-Newton observatory.

This Announcement solicits proposals to be carried out between May 2026 and April 2027. Proposers from institutes located worldwide are welcome to participate. All proposals will be subject to peer review by the XMM-Newton Observing Time Allocation Committee.

The detailed schedule of milestones of the announcement, the required software tools and the documentation are available from:

     https://www.cosmos.esa.int/web/xmm-newton/ao25

I would appreciate it if you would distribute this invitation to interested colleagues.

I wish you every success in using the XMM-Newton observatory.

Yours sincerely,
Professor Carole Mundell
Director of Science

Key milestones for this announcement

Timeline for Phase II proposal submission

After the cycle of proposal submission and selection, the observation details for successful proposals must be entered into the observatory system. This is done during "Phase II" proposal submission.

Find below for your information the anticipated timeline for that eventual Phase II:

Further details on the XMM-Newton SOC web portal.