XMM-Newton: 20 years and counting

One of the powerhouse X-ray telescopes of our time, XMM-Newton, has just recently turned 20 years old. MSSL has been heavily involved in this mission. Sam Grafton-Waters, a third year PhD student at the lab use uses data from XMM to study active galactic nuclei, tells us more about this enduring satellite, and looks to the future.

Launched on 10th December 1999 in French Guiana (South America), XMM-Newton celebrated its 20th anniversary at the end of 2019. The mission objectives were broad, to investigate the cosmic unknowns, from black holes to the origins of the universe. XMM-Newton is 10 meters in length with three X-ray telescopes and one optical monitor which enables the additional observations of both optical and UV wavelengths. For X-ray observations, XMM-Newton contains two high energy and imaging detectors (EPIC-MOS and EPIC-PN) and a reflection grating spectrometer (RGS) for high resolution spectra. Due to the Earth’s atmosphere blocking out X-rays, it is necessary to send telescopes into space in order to observe X-ray sources in the Universe.

High resolution X-ray spectrum of Jupiter taken with the reflection grating spectrometer (RGS) instrument (shown in blue). The RGS spectra show absorption (troughs) or emission (peaks) features at particular energies or wavelenghts that are signatures of a particular ion. Present in the spectrum of Jupiter are emission lines of Oxygen and Iron (labelled in red and green, respectively). We use these features to infer information about the object in question by fitting models to the data (solid red line), trying to trace as best as we can the lines we observe, to give us a greater understanding.  Image courtesy of Graziella Branduardi-Raymont (MSSL, UCL) and ESA. Credit: ESA/ XMM-Newton.

XMM-Newton, along with NASA’s Chandra satellite, paved the way for high resolution X-ray spectroscopy at the turn of the millennium, allowing X-ray sources to be analysed and observed in greater detail than ever before. For each observation, all four instruments work simultaneously, allowing for in depth multi-wavelength studies to be achieved from a variety of data, leading to a full analysis and strong understanding of these exciting phenomenon. XMM-Newton has observed and imaged over 500,000 X-ray sources including black holes, galaxies, stars and even planets in our own solar system.

False-colour X-ray image of NGC 4258. EPIC (red, green and blue for increasing energies, respectively) overlaid onto UV optical monitor OM image (grey). In order to obtain the full picture of an active galactic nuclei (AGN) or galaxy, we collect data from RGS, OM and EPIC instruments to decipher all the features and regions that make up these objects, allowing us to explain and understand what we see. Image courtesy of Rosemary Willatt, Pedro Rodriguez (ESAC) and ESA. Credit ESA/XMM-Newton.

Despite being 20 years old, XMM-Newton is still going strong. Diagnostics of the satellite’s fuel levels, instrument and hardware, and overall system vitals indicate that XMM-Newton could be operational until the early 2030s. This coincides with the launch of ESA’s new X-ray mission, Athena, set to explore the hot and energetic universe. We are excited for the next step, but for now XMM-Newton is doing brilliantly.

Featured Image: Artists impression of XXM-Newton in space. Here you can see the openings of the three X-ray telescopes that collect the X-rays as they travel 10m to the various detectors. Credit: ESA – D. Ducros