A systematic analysis of the XMM-Newton background: IV

Gastaldello, F.; Ghizzardi, S.; Marelli, M.; Salvetti, D.; Molendi, S.; Luca, A. De; Moretti, A.; Rossetti, M.; Tiengo, A.

doi:10.1007/s10686-017-9549-y

Cited by 24 publications

(22 citation statements)

References 27 publications

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“…The temporal changes in the fractional A, B, and C frame rates are shown in Figure 2. The clear modulation with solar cycle observed in the fraction of Case A, B, and C frames is consistent with the previously observed modulations in the count rates in unexposed corners of MOS2 detector, EPIC Radiation Monitor on board of XMM-Newton (Gastaldello et al 2017), and Chandra high energy (12-15 keV) count rate for the ACIS-S3 CCD as a function of year. 2 GCR flux is modulated in anti-correlation with solar activity due to the solar wind (Neher & Anderson 1962).…”

Section: Long Term Variabilitysupporting

confidence: 90%

“…The results summarized here from the XMM-Newton EPIC-pn FWC observations can be used to reduce the particle background level of the future silicon-based X-ray detectors. For instance, the earlier EPIC MOS results were used to optimize FWC rotation strategy to sample particle background component during Athena WFI observations of faint objects (Gastaldello et al 2017;von Kienlin et al 2018).…”

Section: Spatial Correlation Between Particle and Valid Eventsmentioning

confidence: 99%

“…The XMM-Newton observatory, carrying two types of silicon-based X-ray detectors on board, the European Photon Imaging Camera (EPIC) MOS (Turner et al 2001) and the EPIC pn (Strüder et al 2001), provides an excellent opportunity to explore the instrumental background of silicon-based X-ray detectors. The unexposed corners of the XMM-Newton EPIC MOS detector that are masked off and the MOS data obtained when the filter wheel is in the closed position (FWC data) serve as estimators of the particle background for each observation that are used in the X-ray analysis of faint extended sources (De Luca & Molendi 2004;Gastaldello et al 2017). The particle background of XMM-Newton EPIC-pn is difficult to predict and eliminate due to the fact that the unexposed region on the detector is small, i.e., statistics on the background level is limited.…”

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confidence: 99%

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Characterization of the Particle-induced Background of XMM-Newton EPIC-pn: Short- and Long-term Variability

Bulbul

Kraft

Nulsen

et al. 2020

ApJ

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The particle-induced instrumental background of X-ray observatories is dominated by the highly energetic Galactic Cosmic Ray (GCR) primary protons, electrons, and He ions depositing some of their energy as they pass through the detector. The interactions of these primary particles with the detector housing produce secondary particles that mimic X-ray events from celestial sources and constitute the particle-induced background. We investigate the short and long-term properties of the unfocused particle background of the XMM-Newton EPIC-pn camera taken in the small window mode (SWM), with the filter wheel closed. We then compare the results with the SWM observations of astrophysical sources taken through the thick and thin filters. The long term variability of particle-induced background shows strong modulation with the solar cycle, indicating that this background is mostly dominated by GCRs. We find that valid events within a 30 pixel radius of the particle events are highly correlated with these GCR particle primaries. The spectral properties and branching ratios of valid events show some variation, depending on their origin, i.e., particle-induced or astrophysical sources. These results can be used to characterize and reduce the non-X-ray background in XMM-Newton and future silicon-based X-ray detectors.

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Section: Long Term Variabilitysupporting

confidence: 90%

Section: Spatial Correlation Between Particle and Valid Eventsmentioning

confidence: 99%

mentioning

confidence: 99%

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Characterization of the Particle-induced Background of XMM-Newton EPIC-pn: Short- and Long-term Variability

Bulbul

Kraft

Nulsen

et al. 2020

ApJ

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“…We allow these to vary between observations but not between instruments, then scale the flux appropriately to the source regions. We also scaled the best-fit values for the residual proton flares to account for vignetting and the source region areas (Gastaldello et al 2017;Fioretti et al 2016).…”

Section: Spectral Background Modelmentioning

confidence: 99%

The Hot, Accreted Halo of NGC 891

Hodges-Kluck

Bregman

2018

ApJ

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Galaxies are surrounded by halos of hot gas whose mass and origin remain unknown. One of the most challenging properties to measure is the metallicity, which constrains both of these. We present a measurement of the metallicity around NGC 891, a nearby, edge-on, Milky Way analog. We find that the hot gas is dominated by low metallicity gas near the virial temperature at kT = 0.20 ± 0.01 keV and Z/Z ⊙ = 0.14 ± 0.03(stat) +0.08 −0.02 (sys), and that this gas co-exists with hotter (kT = 0.71 ± 0.04 keV) gas that is concentrated near the star-forming regions in the disk. Model choices lead to differences of ∆Z/Z ⊙ ∼ 0.05, and higher S/N observations would be limited by systematic error and plasma emission model or abundance ratio choices. The low metallicity gas is consistent with the inner part of an extended halo accreted from the intergalactic medium, which has been modulated by star formation. However, there is much more cold gas than hot gas around NGC 891, which is difficult to explain in either the accretion or supernova-driven outflow scenarios. We also find a diffuse nonthermal excess centered on the galactic center and extending to 5 kpc above the disk with a 0.3-10 keV L X = 3.1 × 10 39 erg s −1 . This emission is inconsistent with inverse Compton scattering or single-population synchrotron emission, and its origin remains unclear.

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“…There have been many efforts to study and model the particle-induced background for individ-⋆ The tool mkacispback is available at https://github.com/ hiromasasuzuki/mkacispback. ual detectors onboard satellites (e.g., Tawa et al 2008 for Suzaku (XIS); Kuntz & Snowden 2008;Salvetti et al 2017;Gastaldello et al 2017;Marelli et al 2021 for XMM-Newton (EPIC); Wik et al 2014 for NuSTAR). These works provided sufficient information on how one should model the background in an arbitrary observation.…”

Section: Introductionmentioning

confidence: 99%

Spatial and temporal variations of the Chandra ACIS particle-induced background and development of a spectral-model generation tool

Suzuki

Plucinsky

Gaetz

et al. 2021

A&A

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Context. In X-ray observations, estimating the particle-induced background is important, especially for faint and/or diffuse sources. Although software exists to generate total (sky and detector) background data suitable for a given Chandra ACIS observation, no public software exists to model the particle-induced background separately. Aims. We aimed to understand the spatial and temporal variations of the particle-induced background of Chandra ACIS obtained in the two data modes, VFAINT and FAINT. Methods. Observations performed with ACIS in the stowed position shielded from the sky and the Chandra Deep Field South data sets were used. The spectra were modeled with a combination of the instrumental lines of Al, Si, Ni, and Au and continuum components. The spatial variations of the spectral shapes were modeled by dividing each CCD into 32 regions in the CHIPY direction. The temporal variations of the spectral shapes were modeled using all the individual ACIS-stowed observations. Results. Similar spatial variations of the spectral shapes were found in VFAINT and FAINT data, which are mainly due to the inappropriate correction of charge transfer inefficiency for events that convert in the frame-store regions. The temporal variation of the spectral hardness ratio is ∼ 10% maximum, which seems to be largely due to solar activity. We modeled this variation by modifying the spectral hardnesses according to the total count rate. Incorporating these properties, we developed a tool, mkacispback, to generate the particle-induced background spectral model corresponding to an arbitrary celestial observation. As an example application, we used the background spectrum produced by the mkacispback tool in an analysis of the unresolved cosmic X-ray background in the CDF-S observations. We found intensities of 3.10 (2.98-3.21) × 10 −12 erg s −1 cm −2 deg −2 in the 2-8 keV band and 8.35 (8.00-8.70) × 10 −12 erg s −1 cm −2 deg −2 in the 1-2 keV band, which are consistent with or lower than previous estimates. Conclusions. We modeled the spatial and temporal variations of the particle-induced background spectra of the Chandra ACIS-I and the S1, S2, and S3 CCDs, and developed a tool to generate a spectral model for an arbitrary celestial observation.

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A systematic analysis of the XMM-Newton background: IV

Cited by 24 publications

References 27 publications

Characterization of the Particle-induced Background of XMM-Newton EPIC-pn: Short- and Long-term Variability

Characterization of the Particle-induced Background of XMM-Newton EPIC-pn: Short- and Long-term Variability

The Hot, Accreted Halo of NGC 891

Spatial and temporal variations of the Chandra ACIS particle-induced background and development of a spectral-model generation tool

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