Abstract
A high spectral resolution observation of the diffuse X-ray background in the 60-1000 eV energy range has been made using an array of 361 mm2 microcalorimeters flown on a sounding rocket. Detector energy resolution ranged from 5 to 12 eV FWHM, and a composite spectrum of ∼1 sr of the background centered at l = 90°, b = +60° was obtained with a net resolution of ∼9 eV. The target area includes bright 1/4 keV regions but avoids Loop I and the North Polar Spur. Lines of C VI, O VII, and O VIII are clearly detected with intensities of 5.4 ± 2.3, 4.8 ± 0.8, and 1.6 ± 0.4 photons cm-2 s-1 sr-1, respectively. The oxygen lines alone account for a majority of the diffuse background observed in the ROSAT R4 band that is not due to resolved extragalactic discrete sources. We also have a positive detection of the Fe-M line complex near 70 eV at an intensity consistent with previous upper limits that indicate substantial gas-phase depletion of iron. We include a detailed description of the instrument and its detectors.
Original language | English (US) |
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Pages (from-to) | 188-203 |
Number of pages | 16 |
Journal | Astrophysical Journal |
Volume | 576 |
Issue number | 1 I |
DOIs | |
State | Published - Sep 1 2002 |
Externally published | Yes |
Keywords
- Instrumentation: detectors
- Instrumentation: spectrographs
- Intergalactic medium
- Space vehicles: instruments
- X-rays: ISM
- X-rays: diffuse background
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science