The origin of the unfocused XMM-Newton background, its variability and lessons learned for ATHENA
arXiv:2202.05286 · doi:10.3847/1538-4357/ac5403
Abstract
We analyzed the unexposed to the sky outFOV region of the MOS2 detector on board XMM-Newton covering 15 years of data amounting to 255 Ms. We show convincing evidence that the origin of the unfocused background in XMM-Newton is due to energetic protons, electrons and hard X-ray photons. Galactic Cosmic Rays are the main contributors as shown by the tight correlation (2.6% of total scatter) with 1 GeV protons data of the SOHO EPHIN detector. Tight correlations are found with a proxy of the Chandra background rate, revealing the common source of background for detectors in similar orbits, and with the data of the EPIC Radiation Monitor (ERM), only when excluding Solar Energetic Particles events (SEPs). The entrance to the outer electron belts is associated to a sudden increase in the outFOV MOS2 rate and a spectral change. These facts support the fact that MeV electrons can generate an unfocused background signal. The correlation between MOS2 outFOV data and the SOHO EPHIN data reveals a term constant in time and isotropic similar to the one found in the study of the pn data. The most plausible origin of this component is hard unfocused X-ray photons of the Cosmic X-ray Background (CXB) Compton-scattering in the detector as supported by the strength of the signal in the two detectors with different thicknesses. Based on this physical understanding a particle radiation monitor on board ATHENA has been proposed and it is currently under study. It will be able to track different species with the necessary accuracy and precision to guarantee the challenging requirement of 2% reproducibility of the background.
arXiv comment14 pages, 15 figures, accepted for publication in ApJ
References in corpus (24)
- The European Photon Imaging Camera on XMM-Newton: The MOS Cameras
- Some Aspects of Measurement Error in Linear Regression of Astronomical Data
- The 2-8 keV cosmic X-ray background spectrum as observed with XMM-Newton
- A Catalog of Galaxy Clusters Observed by XMM-Newton
- X-ray background measurements with XMM-Newton EPIC
- The XMM-Newton serendipitous survey. VII. The third XMM-Newton serendipitous source catalogue
- Radial temperature profiles for a large sample of galaxy clusters observed with XMM-Newton
- The XMM-Newton EPIC Background: Production of Background Maps and Event Files
- Probing the Dark Matter and Gas Fraction in Relaxed Galaxy Groups with X-ray observations from Chandra and XMM
- The XMM-Newton EPIC Background and the production of Background Blank Sky Event Files
- Annual Cosmic Ray Spectra from 250 MeV up to 1.6 GeV from 1995 - 2014 Measured With the Electron Proton Helium Instrument onboard SOHO
- The EXTraS Project: Exploring the X-ray transient and variable sky
- A Systematic Analysis of the XMM-Newton Background: II. Properties of the in-Field-Of-View Excess Component
- Monte Carlo simulations of soft proton flares: testing the physics with XMM-Newton
- A systematic analysis of the XMM-Newton background: IV. Origin of the unfocused and focused components
- Characterisation of the Particle-Induced Background of XMM-Newton EPIC-pn: Short and Long Term Variability
- A Systematic Analysis of the XMM-Newton Background: I. Dataset and Extraction Procedures
- Prediction and understanding of soft proton contamination in XMM-Newton: a machine learning approach
- Analysis of the unconcentrated background of the EPIC-pn camera on board XMM-Newton
- A systematic analysis of the XMM-Newton background: III. Impact of the magnetospheric environment
- Fifteen years of the Advanced CCD Imaging Spectrometer
- Prediction of soft proton intensities in the near-Earth space using machine learning
- Data-Driven Modelling of the Van Allen Belts: The 5DRBM Model for Trapped Electrons
- The role of the background in past and future X-ray missions