XMM-Newton Publications From 2000 to 2024

Abstract

XMM-Newton is an ESA space x-ray observatory launched on 11 December 1999, and after 25 years, a study is presented demonstrating that the data of the mission are efficiently used by an engaged and productive community. The total number of refereed papers published between 2000 and 2024 is 8486. These papers have a total of 15,627 different authors, including 3292 unique first authors. The total available science time during this period amounts to 556 Ms (16,894 observations) 87% of which (84% of observations) have been used in at least one refereed publication, excluding primary catalogue papers. Accounting for multiple use, the observation time has been over-used by a factor of up to 15 in dedicated publications and even a factor of up to 30 when including a small fraction of papers classified as survey/catalogue. The speed with which observations are published for the first time peaks around 2 years and is thus longer than the proprietary period for Guest–Observer (GO) observations. A strong secondary peak at 3 years suggests that data not published by the proposing teams are picked up by the community, then also taking about 2 years to be published. The publication rate remains stable at $\sim 400$ refereed articles per year with a small increase in recent years, owed to an increased use of primary XMM-Newton catalogues. 95% of articles focus on specific data using observations while 99% of articles use less than 239 observations. Since 2010, the annual number of first-time authors has remained relatively constant, equalling the number of last-time authors. This implies that the number of scientists engaged in research utilising XMM-Newton data has remained constant at 4300, of whom 570 are lead (first) authors. A histogram of the activity period demonstrates that 51% of first authors publish for only 1 year, 24% of first authors are active for up to 6 years, and 25% were active for more than 6 years. We further identify a highly productive core community of approximately 120 scientists publishing an XMM-Newton article at least every 2 year as first authors. When all authors are considered, the figures are 40%, 25% and 35%, respectively. The considerable number of time-limited activities may reflect a high level of utilisation during the early stages of a research career, from Master's studies through the PhD and initial postdoctoral years. The trends assessed indicate a vital community with positive perspectives and a continued, active interest in XMM-Newton for the future.