EPIC MOS Cameras Research Articles

XMM‐NewtonObservations of the Supernova Remnant IC 443. I. Soft X‐Ray Emission from Shocked Interstellar Medium

The shocked interstellar medium around IC 443 produces strong X-ray emission in the soft energy band (E 1.5 keV). We present an analysis of such emission as observed with the EPIC MOS cameras on board the XMM-Newton observatory, with the purpose to find clear signatures of the interactions with the interstellar medium (ISM) in the X-ray band, which may complement results obtained in other wavelengths. We found that the giant molecular cloud mapped in CO emission is located in the foreground and gives an evident signature in the absorption of X-rays. This cloud may have a torus shape, and the part of torus interacting with the IC 443 shock gives rise to 2MASS Ks emission in the southeast. The measured density of emitting X-ray-shocked plasma increases toward the northeastern limb, where the remnant is interacting with an atomic cloud. We found an excellent correlation between emission in the 0.3-0.5 keV band and bright optical/radio filament on large spatial scales. The partial shell structure seen in this band therefore traces the encounter with the atomic cloud.

XMM – Newton observations of the Seyfert 1 galaxy ESO 141-G55

We report on an observation of the Seyfert 1 galaxy ESO 141–G55 performed in October 2001 with the EPIC MOS cameras and Reflection Grating Spectrometers (RGS) on board the XMM – Newton observatory. We find the hard (3–10 keV) continuum slope, including reflection, to be somewhat flatter (Γ=1.72±0.06) than that of a typical broad-line Seyfert 1 galaxy. The spectrum shows a weak emission line at 6.45 ± 0.04 keV with a measured equivalent width of ≈ 40 eV. A broad spectral feature is observed around 7 keV that can be fitted by an absorption edge at 7.6 ± 0.1 keV. The extrapolation of the primary power law continuum to energies lower than 2 keV indicates the presence of a soft excess component contributing 45± 3% of the overall flux in the 0.3–2.0 keV energy range. This soft-excess cannot be explained solely by enhanced reflection from a highly ionized disk.

The X-ray spectrum of the North Polar Spur

An analysis is presented of the soft X-ray background spectrum measured by the EPIC MOS cameras on XMM-Newton in three observations targeted on the North Polar Spur (NPS). Three distinct Galactic plasma components are identified, a cool Local Hot Bubble (LHB) component, T(sub lo) approx. 0.1 keV, a cool Galactic Halo component at a similar temperature and a hotter component, T(sub hi) approx. 0.26 keV, associated with the NPS itself. Using the new data in combination with the Rosat All-Sky Survey count rates measured in the 0.1-0.4 keV band, we estimate the emission measure of the LHB material to be 0.0040-0.0052 cm(exp -6) pc, which implies an electron density of 0.008-0.011 cm(exp -3) and pressure of approx. 22000 cm(exp -3) K. The halo and NPS components lie behind at least 50% of the line-of-sight cold gas for which the total Galactic column density is in the range (2 - 8) x 10(exp 20) cm(exp -2). Modelling the X-ray emitting superbubble as a sphere at distance 210 pc, radius 140 pc and center l(sub II) = 352 deg, b(sub II) = 15 deg, the implied electron density in the NPS is approx. 0.03 cm(exp -3) with pressure approx. 150000 cm(exp -3) K. The observed spectral line complexes from OVII, OVIII, FeXVII, NeIX, NeX and MgXI provide constraints on the composition of the plasma. The hot component in the NPS is depleted in oxygen, neon and, to some extent, magnesium and iron. Assuming the effective line of sight across the halo emission is 1 kpc, the electron density in the halo is 0.007-0.011 cm(exp -3) and the pressure is approx. 16500 cm(exp -3) K, conditions very similar to those in the LHB.

XMM–Newtonobservations of the Seyfert 1 galaxy ESO 141–G55

We report on an observation of the Seyfert 1 galaxy ESO 141–G55 performed in October 2001 with the EPIC MOS cameras and Reflection Grating Spectrometers (RGS) on board the XMM – Newton observatory. We find the hard (3–10 keV) continuum slope, including reflection, to be somewhat flatter ($\Gamma = 1.72 \pm 0.06$) than that of a typical broad-line Seyfert 1 galaxy. The spectrum shows a weak emission line at 6.45 ± 0.04 keV with a measured equivalent width of ≈ 40 eV. A broad spectral feature is observed around 7 keV that can be fitted by an absorption edge at 7.6 ± 0.1 keV. The extrapolation of the primary power law continuum to energies lower than 2 keV indicates the presence of a soft excess component contributing to 45 ± 3% of the overall flux in the 0.3-2.0 keV energy range. This soft-excess cannot be explained solely by enhanced reflection from a highly ionized disk.