Announcement of opportunity
for XRISM Guest Scientists (XGS)


4 April 2022

This Announcement of Opportunity (AO) solicits the participation of the scientific community of ESA Member States in the role of Guest Scientists for the XRISM mission. Through the appointment of the XRISM Guest Scientists (XGS), ESA aims at involving a scientific community as wide and diverse as possible in the exploitation of the data of the Performance Verification Phase (PVP) of the XRISM mission.

The Japan Aerospace Exploration Agency (JAXA) is developing the X-Ray Imaging and Spectroscopic Mission (XRISM) with contributions by NASA and ESA. With its unprecedented capabilities, XRISM will pioneer diverse fields in astrophysical research. The major scientific goal of the XRISM mission is to reveal the formation history of the large-scale structure in the Universe and galaxy clusters, the history of baryonic circulation, and mechanisms of energy transportation and circulation in the Universe. In addition, XRISM will open the new observational window of non-dispersive, high-resolution X-ray spectroscopy. The innovative XRISM payload includes a micro-calorimeter, an array of CCD detectors, and a large-area soft X-ray telescope.

The XRISM instrument and spacecraft performances and calibrations will be verified during the Performance Verification phase. A prioritized list of targets has been compiled for this phase by the XRISM Science Team and, for each target, a Target Team has been formed to lead the observation planning, data analysis, and publication of science results. The XRISM Guest Scientist (XGS) program provides an opportunity for scientists who are not in the XRISM Science Team to participate in the scientific activites related to the Performance Verification phase.

XGSs are expected to enhance the scientific return of the XRISM Performance Verification observations by bringing unique expertise that includes, but is not limited to: complementary data on the target from other X-ray observatories or other wavebands, substantial theoretical insight, or specialized data analysis techniques.

ESA will select five XGSs. Successful candidates will be appointed ad personam by the ESA Director of Science. Applications from groups or teams will be not considered.

Full details of this AO, including the appointment requirements and conditions, can be found in the Announcement of Opportunity for XRISM Guest Scientists document.


Letter of Intent and Proposal Submission forms

Proposals for participation as a XRISM Guest Scientist must be preceded by a mandatory Letter of Intent. Proposals not preceded by a Letter of Intent will not be considered. The Letters of Intent and proposals must be submitted using the online forms – see links to the forms below or in the left-hand menu.

Letter of Intent Submission Form
The deadline for receipt of your Letter of Intent was:
4 May 2022, 12:00 (noon) CEST


Proposal Submission Form
The deadline for receipt of your proposal is:
4 July 2022, 12:00 (noon) CEST


Schedule for this call and important dates

Activity Date
AO for XRISM Guest Scientists issued 4 April 2022
Mandatory Letter of Intent due 4 May 2022, 12:00 (noon) CEST
Deadline for receipt of proposals 4 July 2022, 12:00 (noon) CEST
Appointment of XRISM Guest Scientists 3rd Quarter 2022



Requests for further information should be addressed to:

Paul McNamara
​​​​Astronomy and Astrophysics Coordinator
2200 AG Noordwijk
The Netherlands


Last updated: 4 May 2022


To be informed about new Announcements or Calls from the ESA Science Directorate please subscribe to the dsciannounce mailing list.